GroupDIY

Project Specific Discussions => Filters/Equalizers => Topic started by: dagoose on May 31, 2008, 04:30:38 AM

Title: sontec 1 RU build thread
Post by: dagoose on May 31, 2008, 04:30:38 AM
I get quite a lot of PM's about this project because I started this thread but i'm NOT the 'designer' of this great EQ, Igor is. He also took care of the great boards and other stuff so for questions regarding this EQ, please ask in this topic and please don't PM me about it.

Some info collected together (feel free to add more)

UPDATED DOCS BY IGOR:

http://ij-audio.com/downloads/SONTEC_RED.rar
http://ij-audio.com/downloads/SONT_MS_UPGR.rar

Some pics of the build version with tat's case:

http://i251.photobucket.com/albums/gg291/diy33609/P1020019.jpg
http://i251.photobucket.com/albums/gg291/diy33609/P1020023.jpg
http://i251.photobucket.com/albums/gg291/diy33609/P1020025.jpg
http://i251.photobucket.com/albums/gg291/diy33609/P1020026.jpg
http://i251.photobucket.com/albums/gg291/diy33609/P1020027.jpg
http://i251.photobucket.com/albums/gg291/diy33609/P1020029.jpg
http://i251.photobucket.com/albums/gg291/diy33609/P1020031.jpg

hardware bypass, balanced THAT I/O, MS, power supply - at one PCB!
http://www.groupdiy.com/index.php?topic=48527.0

<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>
Title: sontec 1 RU build thread
Post by: Igor on May 31, 2008, 09:23:36 AM
UPDATE: HERE YOU CAN FIND ALL DOCS:

http://twin-x.com/groupdiy/thumbnails.php?album=399

Quote
I probably go for DOA's in the IO board, what parts should i leave out?
There are some resistors that are on the side of the DOA square.


In case of DOA, solder these parts from bottom. Forssels have very short pins for example.
Other issue with PCB, that I used to solder DOA's direct to board, and
holes are smaller than  Harwyn pins from Farnell you probably going to use..
Possible to put them on opamp then solder over the pads, this way you can have opamps in socket.

Quote
I'm about to order caps and some other stuff, are there any particular type/brand caps that have proven to be the best sounding ones in the sontec?
Will WIMA's be a good choice for the poly's?
Yes, Wima's are just fine.


Quote
There came 2 PSU's boards with the kit, is it OK to use one PSU board for both channels?
Sure. If you building two separate units, use 2 power supply's.
Normally, one power supply going for one stereo set of PCB's unless
you mentioned two PS, IIRC there were 3 people who needed separate
power supplys...
Title: sontec 1 RU build thread
Post by: Grooveteer on June 01, 2008, 04:11:24 PM
Here's a question:  BOM says: 1 150P C5/2.5 NOT NECESSARY WITH OPA604,  

I'm using OPA604's, do I just leave out the 150P cap or should I solder a bridge?

Thanks!

Cheers,

G.
Title: sontec 1 RU build thread
Post by: crisotop on June 03, 2008, 08:46:28 AM
probably post my questions better here instead of the order thread:

Quote
Busy sourcing parts here. Does anyone else have a problem getting the mica caps? Esp. 5 & 12 pF. Or are you just using poly's? (ceramics for the 5 & 12 pf)


I thought of getting 10pf + 2.2pf and use them in parallel (2.2 + 2.2 for the 5pf). couldn't find them either...

anyone lucky finding the 4pole 3.81mm molex in europe? What about RS# 173-3082, 245-4538, 173-3284  they are labelled as molex KK 3,96 - close enough in my opinion?

For the heatsink try farnell #1219493, a lot cheaper since igors recommendation is shipped from the us.

cheers!
christoph
Title: sontec 1 RU build thread
Post by: bearblock on June 03, 2008, 05:08:10 PM
I can't find the 3.81mm Molex connector either, but I think that screw-terminal blocks will work ok here - e.g. farnell #1727036.

re. the silver mica caps - rapid and farnell both have 4.7pF which is closer to 5 and cheaper than two 2.2pF in parallel. I was going to use 10pF in place of the 12pF; it looks like part of a lowpass filter so I figured it was better to go smaller than larger? Unfortunately none of these caps have the correct 2.5mm lead pitch but looking at the board, I think I can make them fit...
Title: sontec 1 RU build thread
Post by: keefaz on June 03, 2008, 05:33:40 PM
You don't have to use Mica caps for the 5pf ones, try NPO/COG types
I am building the 8 sontecs in a rack version, and I used NPO/COG for those little values, at least try both and listen if there is sound difference, I bet no

[edit]
Schematic reference:
http://i251.photobucket.com/albums/gg291/diy33609/schem_upd.gif
With 2604 opamps, Igor suggested to leave CF1.2, CF2.2, CF3.2 eg connect nothing here. Those caps are here to avoid opamp oscillation but not needed with 2604 opamps. I did not use them on mine and it works fine
On the contrary, CF5.1 is mandatory, as there will be oscillation without it
(on my version it's labeled CF4.1, but you have one more band with your eq so you may be able to leave the CF4.1 cap on your version as well)
Title: sontec 1 RU build thread
Post by: dagoose on June 04, 2008, 11:10:38 AM
I picked up the 3.81mm molex connectors today at stuut en bruin, a local electronics store, they had 'm in stock.

Just wondering about the purusha case and IO board, it looks like the XLR's are not going to fit on the board and then mounted to the rearpanel.
The holes in the panel are wider then where the connectors are supposted to be mounted on the board.
I don't have my connectors in yet (backorder at RS) so i'm not sure but looks like it..

I used 10p instead of 12 pf myself, i don't think that would be a problem indeed.
Title: sontec 1 RU build thread
Post by: crisotop on June 04, 2008, 11:31:03 AM
Quote
Just wondering about the purusha case and IO board, it looks like the XLR's are not going to fit on the board and then mounted to the rearpanel.
The holes in the panel are wider then where the connectors are supposted to be mounted on the board.


On Igors version it seems fine? Will check that as soon as I got home. I'll go for the 3,96 Molex at RS, will see if they fit, a little bit of (big) pin bending should do the trick...
Title: sontec 1 RU build thread
Post by: Grooveteer on June 04, 2008, 01:42:11 PM
Looks like PCB mounting the XLR's will not work with my case either. (also a Tat case).  No big deal, though.

Crisotop:  I used RS# 220-4850 and 220-4670, they're ugly (and expensive) but at least they are 3,81mm
Title: sontec 1 RU build thread
Post by: dagoose on June 04, 2008, 01:47:11 PM
Quote from: "Grooveteer"
Looks like PCB mounting the XLR's will not work with my case either. (also a Tat case).  No big deal, though.


OK, so it wasn't me :)
No big deal either, i'll just go with straigth solid copperwire (1.5mm) to connect the boards so they can 'hang' on the wire.
Title: sontec 1 RU build thread
Post by: crisotop on June 05, 2008, 03:25:25 AM
Quote
Crisotop: I used RS# 220-4850 and 220-4670, they're ugly (and expensive) but at least they are 3,81mm


Do they actually fit on the I/O Board? The spacing seems very narrow? But thanks for the link!

Quote
No big deal either, i'll just go with straigth solid copperwire (1.5mm) to connect the boards so they can 'hang' on the wire.


What about using one PCB mount Neutrik and one off-board? Would look neater, I think space is also an issue when soldering copperwire.

Btw, I just got a reply from Banzaieffects.com (German Shop), they'll stock 5pf Silver Micas in Week 26...

christoph
Title: sontec 1 RU build thread
Post by: Igor on June 05, 2008, 05:06:39 AM
Hi, can you explain me what's the deal with Neutrics?
I have 2 of these eq's assembled and fully working,
everything fits 100%...Just see pictures!
Title: sontec 1 RU build thread
Post by: crisotop on June 08, 2008, 03:17:00 PM
I finally found time to check my case + i/o board - they seem to fit perfectly, i haven't bought the connectors yet, but the mounting distance seems about right.

cheers
christoph
Title: sontec 1 RU build thread
Post by: Ghengis on June 08, 2008, 05:05:18 PM
Hi All,

I have tested mine, and while the specified XLRs (from the BOM) fit the I/O board, they don't fit the cutout length between the 2 XLR holes on Tat's case.  There is probably 5-10mm difference (I haven't measured it) Also, the cutouts for the XLR holes are to be too big.  The diameter of the plastic XLR sockets (that fit the I/O board) is slightly smaller to the standard metal neutriks (21? as opposed to 24?) Consequently the plastic neutriks "screw" terminals don't line up.  Even if you try to put just one XLR in, you cannot screw it at both mounting points.  They do mount the standard metal case XLRs perfectly.

My theory here (I'll wait for Tat's reply) is that somehow these are the "generic" 2 RU panels for other 2 RU projects, possibly forgetting about the special cutout diameters and the different length.

I'll post pics if it helps anyone.
Thanks
Ghengis
Title: sontec 1 RU build thread
Post by: crisotop on June 08, 2008, 05:45:25 PM
I've got about 5 different tat cases flying around, and each back panel is slightly different, I would assume that he sent out some "wrong" back panels. My mounting holes are too small for "regular" neutriks, and the spacing looks good as well.

good night,
christoph
Title: sontec 1 RU build thread
Post by: Grooveteer on June 09, 2008, 12:20:20 AM
Ghengis and I must have the same back panels; if I mount the XLR's on the PCB they won't fit the case.

I just used some regular panel mount XLR's
Title: sontec 1 RU build thread
Post by: crisotop on June 10, 2008, 09:10:09 AM
Regarding Molex 3.96 4pin connectors:

Header: Farnell 1462936
Connector: Farnell 1462876
Crimp Pins: Farnell 1462639

Thanks to rhgg2 and his 33609 bom...

hth, christoph
Title: sontec 1 RU build thread
Post by: Igor on June 17, 2008, 03:12:02 PM
Quote
Here's a question: BOM says: 1 150P C5/2.5 NOT NECESSARY WITH OPA604,

I'm using OPA604's, do I just leave out the 150P cap or should I solder a bridge?

Thanks!

Cheers,

G.


No need for bridge. Just leave them out.
Title: sontec 1 RU build thread
Post by: Grooveteer on June 24, 2008, 01:26:25 PM
Thanks!  :thumb:
Title: sontec 1 RU build thread
Post by: khstudio on August 11, 2008, 05:55:16 PM
Thanks for the Parts list... unit looks GREAT!!!  :thumb:  :green:
Title: sontec 1 RU build thread
Post by: pH on August 11, 2008, 09:06:31 PM
Does anyone have a good source for OPA604? Mouser and Digikey are both out of stock with very long lead times.


Cheers,
Paul
Title: sontec 1 RU build thread
Post by: dagoose on August 12, 2008, 01:47:18 AM
Quote from: "pH"
Does anyone have a good source for OPA604? Mouser and Digikey are both out of stock with very long lead times.


Cheers,
Paul


musikding.de or banzaimusicalparts.de have 'm
Title: sontec 1 RU build thread
Post by: khstudio on August 12, 2008, 03:08:02 PM
Can someone help me understand EUROPEAN to AMERICAN Resistor numbers???

I found this:
Quote
R-EU_0204/7 MEANS R EUROPEAN SYMBOL 0.25WATT 7.5MM PITCH


OK... but what does R-EU_0207/12 mean :?:
...and so on, like Watts, etc...

I tried searching & found nothing.

Thanks  :green:
Title: sontec 1 RU build thread
Post by: Igor on August 12, 2008, 06:23:53 PM
Hi, I bought opa604's last time from digikey, but for now seems they
 doesn't have them. Farnell is another option.
Regarding resistors, R-EU_0207/12 means 1/4w, 12 mm pitch.
I.e. common 1/4w resistor.
I used to draw pcbs in Eagle, really good prog ,but bom-wise, it is bad ;)
Title: sontec 1 RU build thread
Post by: khstudio on August 12, 2008, 08:42:45 PM
Thanks Igor :thumb:

Do you think it would be OK to use 1/8 watt resistors for:

11k5 & 17k4

I couldn't source the 1/4 or even 1/2 from Mouser. So far they have everything I need except these.
Title: sontec 1 RU build thread
Post by: Igor on August 13, 2008, 04:10:43 PM
Hi, iirc, these are for high-shelve...1/8w is ok.
Title: sontec 1 RU build thread
Post by: TornadoTed on August 18, 2008, 03:35:19 AM
I've decided to go with the Forrsell opamps instead of the OPA604.

Which ones should I use for IC6 and IC8?
Title: sontec 1 RU build thread
Post by: SALSA on August 18, 2008, 12:56:59 PM
Quote from: "TornadoTed"
I've decided to go with the Forrsell opamps instead of the OPA604.

Which ones should I use for IC6 and IC8?


Cheapest solution if you want to go Forssell : DLR-1 for IC8 and JFET-992 for IC6

Cheers,

Mike
Title: sontec 1 RU build thread
Post by: bearblock on August 18, 2008, 04:21:30 PM
my stereo sontec is coming along nicely - i have couple of questions though:

1) for those of us that aren't using the board-mounted neutriks, how should the i/o connectors be linked up? i.e. where are the 'hot' and 'cold' signals for input and output found on the i/o board? i could guess, but i don't want to accidentally flip the phase.

2) has anyone found a neat way of using the same knobs on the Q pots and the frequency & cut/boost pots? i have just spent a fairly frustrating couple of hours messing about with nylon pcb spacers, coils of wire, aluminium foil etc. with no real success.

cheers!
Title: sontec 1 RU build thread
Post by: khstudio on August 19, 2008, 06:29:39 AM
What type of KNOBs are these & were can I find them :?:
... anywhere in the US?

I really like the look (or something similar)

(http://i251.photobucket.com/albums/gg291/diy33609/fr_small.jpg)
Title: sontec 1 RU build thread
Post by: TomWaterman on August 19, 2008, 07:17:21 AM
Elma knobs from Farnell/Newark and I expect Mouser...

They come in all shaft sizes for this project so you don't need to use spacers,

and were the original knobs on both the ITI Sontec and the GML gear...

Igor also uses the pointed ring underneath the knob which gives it a very nice look.

-Tom
Title: sontec 1 RU build thread
Post by: khstudio on August 19, 2008, 07:22:27 AM
Thanks Tom :thumb:
Title: sontec 1 RU build thread
Post by: bearblock on August 23, 2008, 05:32:56 PM
done! tried them out on some drums today and i liked what i heard.

also here are my stereo 1176 and litter of 8 baby animals. check out the sweet panel graphics :razz:
(http://www.dildano.com/Image011.jpg)
Title: sontec 1 RU build thread
Post by: Igor on August 23, 2008, 06:08:27 PM
Woa!!!
Cool graphics. Pure Zen style!
;)
Inside pictures please!
;)

BTW, which opamps you used?
Title: sontec 1 RU build thread
Post by: Gold on August 23, 2008, 11:44:51 PM
Quote from: "khstudio"
What type of KNOBs are these & were can I find them :?:
... anywhere in the US?


I ordered some of these last week. http://www.okwenclosures.com/products/okw/comb-knobs.htm
They look nice in the pictures and they sell in quantities of 10pcs.
Title: sontec 1 RU build thread
Post by: bearblock on August 24, 2008, 11:29:36 AM
thanks Igor! both channels are loaded with OPA604s at the moment. I'd like to try some JLM99Vs at some point but thought i'd play it safe for now. i'll try and arrange a pic of the insides soon... i have a whole pile of mixes i want to use 'em on first though  :thumb:
Title: sontec 1 RU build thread
Post by: khstudio on August 24, 2008, 07:07:20 PM
OPA604s

Speaking of OPA604s... does anyone have 4 of these they'd sell me :?:

I'm in the US so anyone here would be better. I also wanted to get things rolling with them first, then upgrade to:

INPUT:
DLR-1 Differential Line Receiver

OUTPUT:
JFET-993 Discrete Opamp
 - OR -
JLM 990 Discrete Opamp

The FF's were recommended by Igor & the JLM was recommended by DRPAT  :!:
Title: sontec 1 RU build thread
Post by: crisotop on August 26, 2008, 08:49:08 AM
I might have missed this info, but do we need to solder the 7k5 resisotrs on the bottom side of the eq boards?

I received  16x5k7 resistors from igors resistor kit which wuild suit the needed amount, but not the value? EDIT: Ah upsidedown printing, might that be the problem? but according to the schematic 7k5s are needed?

Thanks
Christoph
Title: sontec 1 RU build thread
Post by: bearblock on August 27, 2008, 04:34:50 PM
hi Cristoph, yes those resistors have to go on the bottom, before you do the pots. as I understand it, they set the 'end points' of the cut/boost pots so smaller resistors = more range
Title: sontec 1 RU build thread
Post by: Grand Master Audio on August 28, 2008, 02:01:31 PM
hi all,

is there any advantage in using two regulated PSUs for a stereo unit? one for left, one for right?

i think i read about it some where that it improved some thing not quite sure what now...

best

Pete
Title: sontec 1 RU build thread
Post by: Gold on August 28, 2008, 03:58:10 PM
I got the OKW knobs today. They seem like they are of high quality and comparable to Elma.

I wish the pointer on the pointer ring was a little longer. They also don't offer a collet knob in gray with a line for a 1/4" shaft but you can get a cap with a line in gray. Close enough.
Title: sontec 1 RU build thread
Post by: therecordingart on August 28, 2008, 04:37:30 PM
Has anyone tried building this with rotary switches?
Title: sontec 1 RU build thread
Post by: khstudio on August 28, 2008, 11:23:25 PM
Quote from: "Gold"
I got the OKW knobs today. They seem like they are of high quality and comparable to Elma.

I wish the pointer on the pointer ring was a little longer. They also don't offer a collet knob in gray with a line for a 1/4" shaft but you can get a cap with a line in gray. Close enough.


I'm about to order from them too... looks like good stuff. :green:

What were the shaft sizes you got?
I ask because you mentioned 1/4 in & I thought the larger ones were 6mm.

Thanks,
Kevin
Title: sontec 1 RU build thread
Post by: Gold on August 28, 2008, 11:29:57 PM
The knobs I ordered aren't for this project. I haven't started on this yet. I ordered for 1/4" shafts. Most knob diameters come in 4mm, 6mm, 1/8" and 1/4". Some sizes have more limited options. 6mm always has all the options.

I haven't received my pots yet anyway.
Title: sontec 1 RU build thread
Post by: TornadoTed on August 29, 2008, 02:58:45 AM
Quote from: "SALSA"
Quote from: "TornadoTed"
I've decided to go with the Forrsell opamps instead of the OPA604.

Which ones should I use for IC6 and IC8?


Cheapest solution if you want to go Forssell : DLR-1 for IC8 and JFET-992 for IC6

Cheers,

Mike


Which parts, if any do I need to leave out if I use the Forssell DLR-1 and JFET-992?

Anyone know where I can get the 12pf Silver Micas. I have tried Mouser, DigiKey, Banzai, RS and Farnell?
Title: sontec 1 RU build thread
Post by: Grand Master Audio on August 29, 2008, 03:26:45 AM
Toronto Ted,

don't need to leave any parts our for the line receiver and 993.

you can get the 12pf silver mica on ebay....

best

Pete
Title: sontec 1 RU build thread
Post by: crisotop on August 29, 2008, 04:21:56 AM
Igor seiad 10p is perfectly fine for those, at least i use them....

cheers
christoph
Title: sontec 1 RU build thread
Post by: TornadoTed on August 29, 2008, 06:15:00 AM
I just found the 12pf on eBay, many thanks.

I double checked my list and I have everything now except the 4.7uf Poly

What are you guys using there?

Also it says use 4k7 resistors for more boost/cut on the bottom side of the board.

I have a Purusha case with 12dB of cut/boost. Do I need to use those resistors to roughly match the value on the case?

Many apologies if i am asking stupid questions, this is my first solo build and I only have a very basic knowledge of electronics!
Title: sontec 1 RU build thread
Post by: crisotop on August 29, 2008, 06:43:48 AM
I bought this (http://www.banzaieffects.com/WIMA-MKS4-4-7uF-250V-LS27-5-pr-23601.html) massive Wima from Banzai...

I'm not sure about the resistor values either, would be handy to know which value comes closest to +/-12dB...

hth, christoph
Title: sontec 1 RU build thread
Post by: bearblock on August 29, 2008, 07:40:17 AM
re. the 4.7uf poly - a similar Wima can be found at Farnell, order code 1006056. that's what I used.
Title: sontec 1 RU build thread
Post by: khstudio on August 29, 2008, 09:32:08 AM
Quote from: "crisotop"


I'm not sure about the resistor values either, would be handy to know which value comes closest to +/-12dB...

hth, christoph


uh oh... I'm using the 12dB scale & just loaded the 7.5's :?:

I'd like to know too before I mount the Pots.
Title: sontec 1 RU build thread
Post by: Igor on August 29, 2008, 09:40:24 AM
Hi, 4k7 will give exactly +/-12db.
Title: sontec 1 RU build thread
Post by: khstudio on August 29, 2008, 09:57:57 AM
Quote from: "Igor"
Hi, 4k7 will give exactly +/-12db.


Thanks Igor. :thumb:

Can I ask which way you prefer it?
I see that you also used Tat's case with the 12dB scale... did you set yours up with the 4.7's?

I may have some de-soldering to do today. :sad:
Title: sontec 1 RU build thread
Post by: king-rb on August 29, 2008, 02:19:25 PM
yehaaa...

i finished the sonntec!!! and it sound extreme cool! today i will check the eq on a mastering session.
...but i think i have to de solder the 7k5 and put 4k7 in for 12 db boost/cut..
Title: sontec 1 RU build thread
Post by: Igor on August 30, 2008, 01:27:11 PM
Hi, yes, I using 4k7 or 5k6 (which at stock at the moment).
If boost/cut less then 11.5 db with (4.7...5.6)k, just check
if filter's caps - 4u7, 3n3, 0.47u, 330p, 0.15u, 100p have 5%
tolerance with cap' meter.
Title: sontec 1 RU build thread
Post by: nielsk on August 30, 2008, 10:33:52 PM
Has anyone had luck getting the pots? I inquired with Alphastat, they email me every 4 months or so in German, suffice it to say I have not been able to place an order yet
Title: sontec 1 RU build thread
Post by: khstudio on August 31, 2008, 10:22:25 AM
Quote from: "nielsk"
Has anyone had luck getting the pots? I inquired with Alphastat, they email me every 4 months or so in German, suffice it to say I have not been able to place an order yet


I had a feeling they would be hard to get (when I placed the order for the PCB's) which is the reason I paid the extra for the KIT. :wink:

It was a lot of money for us USA folks but worth it for less headache.

Check with Igor about a POT & Switch KIT. he may still have some.
Title: sontec 1 RU build thread
Post by: TornadoTed on September 02, 2008, 05:34:42 AM
What happens at the spot on the PCB marked FB with a resistor outline with 0 in it?

A jumper?

Since I posted this I got the pots through the post from Igor. There are,

1x 270 - XS8776 - 0826 with 5 pins
3x 270 - XS8787 - 0827 with 3 pins

I'm confused as to why I have different 5k pots rather than 4 the same.

Does the 1x 270 - XS8776 - 0826 have to go in a certain position?
Title: sontec 1 RU build thread
Post by: khstudio on September 02, 2008, 08:31:33 AM
I received my Pots too.  :green:

But I can't answer your question.


Thanks Igor!!! :thumb:
 :guinness:  :sam:  :guinness:  :sam:  :guinness:
Title: sontec 1 RU build thread
Post by: crisotop on September 02, 2008, 08:38:34 AM
If I remember it right the five-pin version is the 'Q' Pot for the low frequency band - will be back home in a couple of hours and can double check.

hth, christoph
Title: sontec 1 RU build thread
Post by: crisotop on September 02, 2008, 08:39:14 AM
If I remember it right the five-pin version is the 'Q' Pot for the low frequency band - will be back home in a couple of hours and can double check.

hth, christoph
Title: sontec 1 RU build thread
Post by: Igor on September 02, 2008, 05:43:24 PM
Hi, pot with 5 pins is for low band, it has a switch
which changes beetween shelve/bell at ccw pos.
Title: sontec 1 RU build thread
Post by: pH on September 02, 2008, 07:08:00 PM
Igor, could you explain the extra cap (unspecified value-optional?) for CLF2'?

Thanks,
Paul
Title: sontec 1 RU build thread
Post by: crisotop on September 03, 2008, 03:02:02 AM
CLF2' is a second placement option for CLF2, if you are using really oversized caps for example. So either place the 4u7 in the slot for CLF2 OR CLF2'

htht, christoph
Title: sontec 1 RU build thread
Post by: bearblock on September 03, 2008, 04:55:49 AM
Ted, I used a ferrite bead for the 0 ohm resistor marked FB. Not sure if this was what Igor intended but it all seems to work. I expect a jumper would be fine too.
Title: sontec 1 RU build thread
Post by: khstudio on September 03, 2008, 08:16:07 AM
Quote from: "bearblock"
Ted, I used a ferrite bead for the 0 ohm resistor marked FB. Not sure if this was what Igor intended but it all seems to work. I expect a jumper would be fine too.


Interesting... I wondered what "FB" meant because I didn't see a Ferrite Bead in the parts list.

Igor, could you comment on this one.
Title: sontec 1 RU build thread
Post by: crisotop on September 03, 2008, 09:42:32 AM
Oh gosh, I made a terrible mistake, I just broke a dual 100k pot when I tried to shorten the shaft a bit :? - Igor do you still have some pots available, or is anyone else going to order pots in the near future?

Thanks!
Christoph
Title: sontec 1 RU build thread
Post by: Igor on September 03, 2008, 12:03:05 PM
Yap. I have some 100k dual pots and some 5k's, no 50k lin left.
Title: sontec 1 RU build thread
Post by: dagoose on September 13, 2008, 08:25:38 AM
Just to let you know, i finished my sontec! (will post pics later)
It worked at first power on (ok... i had 1 red and 1 orange led for bypass, damn bright leds) and it sounds great and is dead silent.

Tip:
When you have the purusha case don't solder the switches to the board yet!
wait untill the board is mounted to the panel and then solder the switch, otherwise the switch will be to low on the board and won't reach the hole in the panel and you have to desolder it. (i had to and it's not real easy to do)
Best thing to do is first mount the top board and then the lower board otherwise sodering the switch can be a bit hard because of the space between the top and bottom board..

For the rest...

Big respect for Igor for this project!!  :sam:  :sam:  :sam:  :sam:  :thumb:
Title: sontec 1 RU build thread
Post by: Purusha on September 13, 2008, 08:54:56 AM
Quote
ip:
When you have the purusha case don't solder the switches to the board yet!
wait untill the board is mounted to the panel and then solder the switch, otherwise the switch will be to low on the board and won't reach the hole in the panel and you have to desolder it. (i had to and it's not real easy to do)


UPS, I just soldered all my toggles on the boards  :shock:
Title: sontec 1 RU build thread
Post by: dagoose on September 13, 2008, 06:23:26 PM
Quote from: "Purusha"
Quote
ip:
When you have the purusha case don't solder the switches to the board yet!
wait untill the board is mounted to the panel and then solder the switch, otherwise the switch will be to low on the board and won't reach the hole in the panel and you have to desolder it. (i had to and it's not real easy to do)


UPS, I just soldered all my toggles on the boards  :shock:


it will fit but it's just a bit harder because you have to desolder the 'groundpins' near the screws.
So... best is to put it on board, fit the board to the panel and then solder it.
Title: sontec 1 RU build thread
Post by: Purusha on September 14, 2008, 03:03:08 AM
Actually they can be soldered in before mounting them but the legs should not come through on the bottom side, than they will be 100% in the right hight.

I guess I will need to buy a special desoldering wire to solve this problem...  :grin:
Title: sontec 1 RU build thread
Post by: dagoose on September 14, 2008, 05:03:06 AM
Quote from: "Purusha"
Actually they can be soldered in before mounting them but the legs should not come through on the bottom side, than they will be 100% in the right hight.

I guess I will need to buy a special desoldering wire to solve this problem...  :grin:


True.. but it's hard to 'guess' how high to solder 'm on board but it can be done.
I think it's best to leave the montage/ground pins unsoldered since you have some room then for ABB (Adjust By Bending) technique.  :cool:
I used quite a simple desoldering pump and a little screwdriver to lift the switch bit by bit.
The second switch i soldered after the board was mounted.
Title: sontec 1 RU build thread
Post by: pH on September 14, 2008, 12:06:27 PM
Wired up my first channel and got smoke from the 22R resistors, it seems the PSU markings on the filter board have + and - reversed. Once I traced through the schematic and hooked it up correctly all is fine.

Great EQ! Amazing level of precision.

Now does anyone have a faceplate layout so I can take it off the cardboard?
Title: sontec 1 RU build thread
Post by: TornadoTed on September 23, 2008, 04:17:22 PM
I'm about to order the Elma knobs from Farnell.

The shafts on Igor's pots are 1/8" 3.15mm

Farnell have 3mm & 4mm knobs. I'd imagine the 4mm would be too slack and the 3mm would just about fit.

Correct or am I way off?   :oops:
Title: sontec 1 RU build thread
Post by: Igor on September 23, 2008, 05:16:38 PM
Farnell should have 3.15mm version, IIRC it is just labelled
in inch, not mm...
Title: sontec 1 RU build thread
Post by: khstudio on September 23, 2008, 05:39:23 PM
Damn... I just checked & I ordered 3mm :mad:

They do NOT fit!!!

Great... over $100 for knobs & I get the wrong ones.
Time for careful drilling... wish me luck.

I thought for sure they'd fit.
Why the hell are there 3mm & 3.15 mm anyways?
Is the 3.15mm = to 1/4 in maybe?
Title: sontec 1 RU build thread
Post by: kazper on September 23, 2008, 07:58:50 PM
3.15mm =1/8"

6mm is not 1/4
6.35mm = 1/4"

the 1/4" collets will clamp down on 6mm no problem, but it's rather tuff to get 6mm collets onto a 1/4" shaft. It's mostly brand specific.

I also tried drilling out some and lets just say, I bought the knobs again and will use them for something else someday.

Mouser sells some nice ReAnn knobs in 1/8" and the price is good on large quanitys.
Title: sontec 1 RU build thread
Post by: Igor on September 23, 2008, 10:20:04 PM
Quote
Damn... I just checked & I ordered 3mm  

They do NOT fit!!!

Great... over $100 for knobs & I get the wrong ones.
Time for careful drilling... wish me luck.


Ahemmm.... I had same prob with 6.3mm Grayhill switches
and Elma 6mm knobs, used friend's Proxxon lathe, solved ;) ...
Anyway, if you don't have small lathe, try to fit collet into drill chunk,
but leave 2/3 outside of chunk - not to press the collet much,
otherwise hole will be too big.
With some care, should work.
Good luck  :sam:  :guinness:
Title: sontec 1 RU build thread
Post by: crisotop on September 26, 2008, 02:53:45 PM
One channel is up and running! Now I just have to wait for Igor's replacement pot I broke and Another ad706 which is backordered...

regards,
christoph
Title: sontec 1 RU build thread
Post by: TornadoTed on October 05, 2008, 09:26:21 PM
I fired mine up today with my friend who is an infinitly more knowledgable tech than I am.

It worked pretty well but we had a litle oscillation on the high shelf only at -9 dB cut though so he installed a small cap (can't remember what value) on the feedback resistor and it went away.

We also found that as the Q and Freq pots don't go through the case they weren't grounded as well as they could be. Rocking them slightly caused hum to come and go. We soldered wire between all the pots and then to ground and it disappeared. It doesn't look very neat but it worked a treat.

Anyway apart from just over an hours troubleshooting all is good and I have a fully functioning EQ.

Thank you to all who have made this possible and anyone who has helped me along the way.  :thumb:

Incidently I went for OPA604 in the end as pennies are a little tight at the moment. I will upgrade to Forssells once I've built the 8 channel S800 EQ and save a bit of money.
Title: sontec 1 RU build thread
Post by: khstudio on October 27, 2008, 03:55:48 AM
I PM'd Igor this question but if anyone else can help, please do.

Quote
Hi Igor,

I'm currently finishing my Sontec EQ & mounting the front PCB's to the face plate.

Did you used washers or spacers on the "GAIN" shafts ??? (that bolt onto the front panel)

I'm asking because there are little "Nubs.. or Tabs" on the flat part of the Pots which stops them from being mounted "Flush" to the face plate. Should they be filed off???

I looked at your pics & it looks like you used washers or spacers... are they needed?

Thanks,
Kevin
Title: sontec 1 RU build thread
Post by: AW_music on October 27, 2008, 07:24:33 AM
Hi all,
just finished mine.

http://www.groupdiy.com/index.php?topic=30060

Easy project and KILLER Eq !!

 :thumb:
Title: sontec 1 RU build thread
Post by: khstudio on October 27, 2008, 06:09:44 PM
Quote from: "Igor"
Quote
Damn... I just checked & I ordered 3mm  

They do NOT fit!!!

Great... over $100 for knobs & I get the wrong ones.
Time for careful drilling... wish me luck.


Ahemmm.... I had same prob with 6.3mm Grayhill switches
and Elma 6mm knobs, used friend's Proxxon lathe, solved ;) ...
Anyway, if you don't have small lathe, try to fit collet into drill chunk,
but leave 2/3 outside of chunk - not to press the collet much,
otherwise hole will be too big.
With some care, should work.
Good luck  :sam:  :guinness:


The Collette in the chuck worked GREAT!!!

Thanks for the tip.  :thumb:
Title: sontec 1 RU build thread
Post by: Igor on October 27, 2008, 11:01:09 PM
Enjoy :)
Title: sontec 1 RU build thread
Post by: Igor on October 27, 2008, 11:08:58 PM
By the way.
Received small package with Alpha pots....
The rest is coming at end of november-december.
People, who asked about pots, can share some for kits.
http://www.groupdiy.com/index.php?topic=29771
Title: sontec 1 RU build thread
Post by: crisotop on October 31, 2008, 10:10:26 AM
Finally finished mine too (thanks for the pot Igor!) - I have slightly different curve on the 6dB setting on the high shelves - look at the measurement:

(http://www.garage27.com/files/music/studio/DIY/sontec/sontecF.jpg)

I haven't matched the caps, but all other bands are perfectly fine - any suggestions?

Thanks!
Christoph
Title: sontec 1 RU build thread
Post by: Igor on October 31, 2008, 05:01:16 PM
Actually one curve looks 100% right
(resonant 12db/oct filter as it supposed to be) but second looks like
one cap or 100k pot's half missing...check caps, pot, switches,
resistors-all in this arrea.
Title: sontec 1 RU build thread
Post by: crisotop on October 31, 2008, 08:02:41 PM
Both curves are measured on the 6dB setting?!

Green or yellow, which one is right? the 12dB shelve is much steeper, and has a deeper cut right before the slope starts to boost.

thanks!
christoph
Title: sontec 1 RU build thread
Post by: khstudio on November 02, 2008, 01:02:05 AM
Quote from: "crisotop"
Both curves are measured on the 6dB setting?!

Green or yellow, which one is right? the 12dB shelve is much steeper, and has a deeper cut right before the slope starts to boost.

thanks!
christoph


If it's not the 6 - 12 switch... what are your sweeps from?

 - Movement of GAIN or FREQ?
Title: sontec 1 RU build thread
Post by: crisotop on November 02, 2008, 05:48:15 AM
doesn't matter how gain and/or frequ is adjusted, always the same slope (one channel is rising softly, one has a small cut before the boost starts)

cheers
christoph
Title: sontec 1 RU build thread
Post by: khstudio on November 02, 2008, 06:14:37 AM
Quote from: "crisotop"
doesn't matter how gain and/or frequ is adjusted, always the same slope (one channel is rising softly, one has a small cut before the boost starts)

cheers
christoph


Ohhhhhhhhh... it's Left & Right channels.

You never mentioned that.  :razz:
Title: sontec 1 RU build thread
Post by: crisotop on November 02, 2008, 07:20:44 AM
haha - sorry my bad  :oops:

I hope my problem makes more sense now :grin:

cheers
christoph
Title: sontec 1 RU build thread
Post by: Igor on November 02, 2008, 02:14:13 PM
So, you solved the prob? ;)
:twisted:
 :shock:
 :roll:
 :grin:
 :wink:
Title: sontec 1 RU build thread
Post by: crisotop on November 02, 2008, 02:35:08 PM
nope, not yet - which curve looks right for the 6 dB setting? then I'll start digging around ;)

Thanks Igor + Matt!
Christoph
Title: sontec 1 RU build thread
Post by: khstudio on November 02, 2008, 03:06:43 PM
Quote from: "crisotop"
nope, not yet - which curve looks right for the 6 dB setting? then I'll start digging around ;)

Thanks Igor + Matt!
Christoph


I think he said the "Smooth" one... without the dip. :idea:
Title: sontec 1 RU build thread
Post by: khstudio on November 03, 2008, 12:04:05 PM
Igor,

I just got my JLM 99v op-amps (for the outputs), Hybrids (inputs) & remanding parts in today & was hoping to finish this EQ up tonight but I have a problem...

The DOA Sockets I have won't fit in the holes on the PCB. :mad:

What size are the holes on your PCB :?:

I have 2 different types here:

1.87mm (got these from JLM)
1.65mm (these are pretty standard for all my other builds so I got 100 & thought they'd fit your PCB too & don't)

I thought about drilling out the holes but they're "Thru" holes... makes me nervous.
Title: sontec 1 RU build thread
Post by: Igor on November 05, 2008, 11:15:49 PM
Ahem....yes, there was an error with drill size tolerances.
Updated on new pcb's.
One thing is possible to do there, is just put pins on DOA's then
solder them to PCB from upside. IIRC someone did so...search....
Or, solder DOA's directly to PCB
(personally...don't like these pins on DOA).
Title: sontec 1 RU build thread
Post by: Igor on November 05, 2008, 11:16:14 PM
edit: d-leted (double post)
Title: sontec 1 RU build thread
Post by: khstudio on November 06, 2008, 03:59:12 AM
Quote from: "Igor"
Ahem....yes, there was an error with drill size tolerances.
Updated on new pcb's.
One thing is possible to do there, is just put pins on DOA's then
solder them to PCB from upside. IIRC someone did so...search....
Or, solder DOA's directly to PCB
(personally...don't like these pins on DOA).


Strange I never saw this mentioned or posted.

But, it's a good thing I'm handy... I just put the sockets in the chuck of my drill press, then used a small metal (smooth) file to taper them down and it worked.
Not the easiest thing to do & also time consuming.

I should have it done by the weekend. :green:
Title: sontec 1 RU build thread
Post by: Igor on November 06, 2008, 12:20:48 PM
Good luck!
Title: sontec 1 RU build thread
Post by: Holger on November 06, 2008, 04:17:14 PM
After weeks of starring at my non-working I/O PCB i finally figured out that I stuffed 2604 istead of 604... :oops:

Now my first one works wonderful.  :guinness: to Igor for this project.
Title: sontec 1 RU build thread
Post by: khstudio on November 06, 2008, 04:39:03 PM
Speaking of 604's... They're about impossible to find in the US at this point.  :mad:

Mouser & Digikey both are sold out with ridiculous wait times that arent even guaranteed.

So... for now, I'm just going to use a JLM HYBRID on the inputs (with the servo disengaged - because there's a servo already on Igor's PCB)
& the JLM 99v's for outs.

I too wanted to just get 604's for the inputs... oh well.  :sad:

Hey... do any of you guy have 2 spare 604's you can sell & send me :?:
I'm in the US.

Thanks,
Kevin
Title: sontec 1 RU build thread
Post by: Holger on November 06, 2008, 04:54:16 PM
PM sent...
Title: sontec 1 RU build thread
Post by: crisotop on November 08, 2008, 06:46:12 AM
Found my problem - had a bad solder joint on the 6/12dB slope switch - now both channels match perfectly, many thanks for the effort igor and the rest of the forum for your help!

happy eqing
Christoph
Title: sontec 1 RU build thread
Post by: jamesfei on November 08, 2008, 03:23:11 PM
Hello Igor (and other Sontec builders): Are the equations for calculating the filter boost/cut gain and frequencies available somewhere? I would like to build the EQ with 24 step switches for frequency select and boost/cut. Perhaps 6 or 12 step switches for slope. Many thanks.

Best,

James
Title: sontec 1 RU build thread
Post by: Igor on November 09, 2008, 09:20:49 AM
IMHO, faster way is to use decade resistors box..
:)
Title: sontec 1 RU build thread
Post by: khstudio on November 09, 2008, 10:06:37 AM
Igor,

I don't really know much about the Sontec (or ITT) EQ's except my friend has a Sontec MEP250a & told me all about it & how much he loves it...
which is one of the reasons I got your kit.

OK, he sent me a schematic for his MEP 250 (A)
I was checking over the filters & noticed none of the values match the ones in your clone.
Now, I know there are different revisions of this EQ BUT which Version is yours the closest to or derived from :?:

It's NOT a big deal & I'm not complaining... just trying to learn a little bit about what I have hear.

The other reason is I may want to make some changes to the circuit... actually the LOW SHELF. I may want to put it back to stock.

You mentioned changing it to a smother roll-off & I may prefer the SHARPER slope of the original.

Thanks IGOR,  :thumb:
Kevin

BTW... I would have had it done yesterday but the case i bought has defective side panels & missing parts. :sad:
I'm going to steal some parts from another case until they replace them so I can finish it TODAY... Hopefully.  :green:
Title: sontec 1 RU build thread
Post by: dagoose on November 09, 2008, 11:00:51 AM
Quote from: "jamesfei"
Hello Igor (and other Sontec builders): Are the equations for calculating the filter boost/cut gain and frequencies available somewhere? I would like to build the EQ with 24 step switches for frequency select and boost/cut. Perhaps 6 or 12 step switches for slope. Many thanks.

Best,

James


would be nice indeed... i'm also thinking of 'modding' my sontec with stepped swithes since it's just more accurate for mastering, which i use it for.
Title: Re: sontec 1 RU build thread
Post by: Holger on November 23, 2008, 04:59:17 AM
Here's my finished EQ. Thanks to Igor and Tat for this project, it sounds wonderful. I will build a second unit.

(http://audiofor.tv/diy/ProjectFotoFolder/DIY%20November/sontec-front.jpg)
(http://audiofor.tv/diy/ProjectFotoFolder/DIY%20November/sontec-open.jpg)
Title: Re: sontec 1 RU build thread
Post by: Purusha on November 23, 2008, 07:15:14 AM
Wow, these photos look really good  :P

Good job!  8)

BTW, where did you get those knobs?

Title: Re: sontec 1 RU build thread
Post by: Holger on November 23, 2008, 07:23:47 AM
Tat, the knobs are from Sifam, I purchased them from Sibalco.de
The article # is 3001768 for the 15mm and 3000195 for then 10mm knobs. Thanks for liking the photos  ;D
Title: Re: sontec 1 RU build thread
Post by: Purusha on November 23, 2008, 07:35:44 AM
Thanks. Do they take Paypal?
Title: Re: sontec 1 RU build thread
Post by: Holger on November 23, 2008, 07:38:06 AM
Tat, I assume not. Look at their website. IBAN is surely possible.
Title: Re: sontec 1 RU build thread
Post by: Purusha on November 23, 2008, 07:43:45 AM
Thanks!
Title: Re: sontec 1 RU build thread
Post by: Igor on November 24, 2008, 01:21:07 PM
Holger!!!!

Looks SWEET!!!

Very liked these knobs!!!
Title: Re: sontec 1 RU build thread
Post by: khstudio on December 02, 2008, 04:33:14 AM
OK... I FINISHED MY SONTEC!!!  ;D

It absolutely kicks ass & I LOVE it!!!!!!  :o

BUT... It's also kicking the ass of my mixing consoles insert returns.
WHY... because there's 3+ VOLTS OF DC coming out of the unit!!!!!!!!!!!!
My faders are scratchy. This NEVER, EVER happened before...

So, I put my meter on the output of the Sontec & there it was... 3+ VDC!

WHY?

What would cause this?

I have the servo installed!

I'm using JLM 99v's for the output.

PLEASE HELP... OR guide me on WHAT to check for to fix this.

(Note - I did have the output wiring messed up at first... I thought that pins 1, 2 & 3 on the XLR's would match the pins 1, 2 & 3 on the MOLEX connector  ::) "Standard stuff" NO???  Well...Not on this unit. I was having strange issues on the first fire-up, then finally looked at the schematic & sure enough... they were wrong, so I fixed it.)

I had Pins 2 (HOT) & 1 (GND) swapped!!!

Could that wiring mistake somehow "Damage" the Servo??????
Title: Re: sontec 1 RU build thread
Post by: khstudio on December 02, 2008, 05:00:56 PM
NEW INFO:::
I just tried installing NEW 2604's & it didn't help.

Also, ALL this testing & DC was found when I use the unit Un-Ballanced!
(grounding pins 1 & 3 on my patch bay - using 1/4 in, tip, ring plug)

I haven't tested for DC in Balanced I/O yet... but that shouldn't make a difference.

I also don't have the 150p (c59) installed!!!

Should I?     I thought it was for stability but I could be wrong.

My original plan was to use 604's first... which is why I didn't install c59.
I guess I should put them in???

Thanks
Title: Re: sontec 1 RU build thread
Post by: khstudio on December 02, 2008, 08:56:00 PM
OK...
I tried using the JLM Hybrid op-amp in BOTH the input & output positions &
... either the Hybrid doesn't have as much DC offset spitting out of it or the circuit (as designed) doesn't
work on removing the DC from the JLM 99v???

This doesn't make sense.  >:(
Title: Re: sontec 1 RU build thread
Post by: khstudio on December 03, 2008, 03:56:55 AM
EMAIL ABOUT SERVO & JLM 99v's

To Joe:
Quote
Hi Joe,

I'm using your 99v for the output of my SONTEC EQ.
The PCB has a Servo but it doesn't seem to be working right.
Could you PLEASE check out the schematic (posted below or attached) to see
if there's any problems or changes that should be made to work properly???

I'm getting over 3 Volts of DC, with the Servo hooked up!!!

I've tried a few things, like changing out the 2604's but nothing is
helping.

Thank You,
Kevin

FROM Joe:

Quote
HI Kevin
   With a 10k and 100R you would need to have the servo output go to
about -100v to remove the DC offset the way the circuit is. This is fine for
normal opamps with only small mV offsets but will not work on the 99v.
Remove R11 100R and it should work fine with the 99v. You could fit a 2u2
Bipolar cap or larger in thr R11 position instead to give a smoother DC
Servo with less noise from the servo opamp. 

Let me know how you go

Thanks
 
Joe Malone
 
JLM AUDIO
Title: Re: sontec 1 RU build thread
Post by: Igor on December 03, 2008, 07:50:20 AM
Hi Kevin, please check your e-mail.
JLM opamps are no good for Sontec.
They can be good for other things,
but not here. Or, Sontec will need some mods.
If you want discrete, use Forsselltech DLR and 993.

Quote
OK, he sent me a schematic for his MEP 250 (A)
I was checking over the filters & noticed none of the values match the ones in your clone.
Now, I know there are different revisions of this EQ BUT which Version is yours the closest to or derived from :?:

Please see on schematic :)
Title: Re: sontec 1 RU build thread
Post by: khstudio on December 03, 2008, 05:08:53 PM
Igor,
I've been talking about using the JLM 99v's for Month's... why not warn me earlier???

I really like the sound of the 99v's on the output & really can't afford to spend over $150 MORE for the 993's right now.

So... HOW can I or SHOULD I mod it to work???

It CAN"T be that much trouble... that's why I asked you. I can't believe your only advise is:
Quote
Put opa604's or Forssell's 993.

Best Regards, Igor.

Come on man.  :(

Also,
I don't understand your response about what "Version" or model this came from?
You said:
Quote
Please see on schematic Smiley

I don't get it.
Title: Re: sontec 1 RU build thread
Post by: delaymix on December 03, 2008, 06:22:18 PM
Igor,

Can you explain the differences in practice between DLR and a 990?
Thanks.
Title: Re: sontec 1 RU build thread
Post by: khstudio on December 03, 2008, 07:15:17 PM
I found these topics:
    
Sontec x 8 Build Thread:
http://www.groupdiy.com/index.php?topic=28215.msg340724#msg340724 (http://www.groupdiy.com/index.php?topic=28215.msg340724#msg340724)

I this thread, the guy mentioned using 99v's & Igor never mentions it being a problem... nor did the poster, or did he mention any DC on the output... maybe he didn't measure it???

Sontec Website:
http://www.groupdiy.com/index.php?topic=19895.msg234792#msg234792 (http://www.groupdiy.com/index.php?topic=19895.msg234792#msg234792)

This thread mentions using the 99v -

I know DrPat used 99v's for his "Real" Sontec's output & liked them a lot... but he was using & slightly modified Servo circuit.
He was the one that told me how KILLER they sounded on the output of this circuit & recommended me to get them, so I did.

I'm good friends with Pat but he's been busy mixing in LA for a few weeks & I can't reach him.

Also, Igor's AMP Section (& Servo setup) is a little different than the original which is the reason I'm asking HIM what to do.

Joe from JLM has emailed me a few times with regards to the 99v's & this circuits DC Servo  but I'm still left confused.  :-[

Here was the last email with Joe:

Quote
HI Kevin

Thank you soooo much man!
[Joe]  :-)

I will be posting this info on the "Sontec Help" thread to help others
too!!!!
[Joe] ok

OK,
I'm not questioning your 1st email... I'm just not sure if we're just
"patching" a wrong design???
[Joe] No the design is fine for small mV offset opamps. Just that the 99v
has a couple of volts offset.

#1 - do you even recommend a DC Servo with your 99v - because the offset
is so high?
[Joe] No the DC servo is fine. I am just not a big fan of DC servo unless it
has a very low time constant so it doesn't interfere with the low end.

       (Or should I just use a Cap on the output???)

[Joe] If you want to use no DC servo you would be best to use an output cap
from the opamp output as well as a second output cap from the opamp output
to feed the EQ bands.
 
#2 - are the recommendations you gave me optimal... or would YOU set it
up differently?
[Joe] For the 99v I would normally use a 100uF Bipolar in place of R11 just
because we have them in stock and that is about all that is needed.

       ( I don't mind making ANY changes that need be!!!)
#3 - Is there a DC Servo circuit posted on your web site that you'd
recommend for the 99v?
  Remember - THIS Sontec circuit is using the "Inverted input" for
signal & Non-inverted for Servo...
  does THAT make a difference in how the Servo is set up???

[Joe] Yes I prefer 12dB per octave DC servo instead of the 6dB per octave
version.

BTW... this EQ is amazing... I love it & can't believe how musical it is.
I'm sure your great op-amps are adding to the "sound".
[Joe]  :-)

Kevin
Title: Re: sontec 1 RU build thread
Post by: khstudio on December 12, 2008, 07:06:32 AM
Igor,
Sorry to be a PITA but I need you help.  ;D

I've been using the JLM Hybrids for both in & output amps for now & they sound OK...
But I'm not completely sold on them.

Before I go spending over $200 for the Forssell amps, I want to try removing the DC Servo circuits & use CAPs on the outputs of the Op-Amps instead... for BOTH the input & output. (I must admit, I don't care for DC Servo's 90% of the time... they seem to do funny stuff to the "Sound".)

Could you PLEASE list ALL the components that should be removed?  :-[

Also, could you recommend a Cap size & Voltage?

NOTE:
This will allow me to do 2 things... Here the circuit "without the Servo" & be able to test the 99v's.

Thanks man!

Kevin
Title: Re: sontec 1 RU build thread
Post by: Grand Master Audio on December 12, 2008, 11:52:34 AM
Hi Guys,

FWIW i have just finished mine, but i could not afford the 993 and DLR op-amps, i stuck with OPA604, i have to say it still sounds bloody fantastic and specs up very very well, very low noise floor, IMD and THD are just stupidly low,

I might one day swap them out, id be interested to see the difference, whether i could hear the difference i suppose is the more important question.

any way here it is..

http://www.sinestarproject.com/sontec.jpg (http://www.sinestarproject.com/sontec.jpg)

http://www.sinestarproject.com/sontecin.jpg (http://www.sinestarproject.com/sontecin.jpg)

Big thanks to Igor,

Cheers

Pete
Title: Re: sontec 1 RU build thread
Post by: Igor on December 12, 2008, 08:46:38 PM
Hi Kevin, you don't need to ask same question here and by mail.
Anyway, I'll answer twice :)
(in case someone stucked with same prob)

I never had any experience witj JLM op-amps in this circuit.
Just take into account, to make your EQ working with
JLM's I have first to buy them, then put inside EQ, then
fix all the issues , then tell you what to do.
And have no neither time nor other reasons to do it :)

As I can understand, JLM is not actually opamp,
it is kinda BA340 etc circuit where feedback comes to emitter of input transistor,
it means offset and different input impedance of + and - inputs.
Can't say it is bad, I using same thing on my single ended cascode FET-bipolar
topology amp. circuit in my pre-amp Albatross. For coloration in micpre,
SE is ideal. For circuit where you need ideal op-amp with some nice color....nope.

Take Forssell's if you want to make this EQ COOL
and say "here's the THE EQ with discrete opamps".

(me is a big fan of Forssell newer fast (993) opamps,
I think they UNBEATABLE by any other amplifier in this Sontec).
They are ideal opamps with very nice color.

I'd first finnished your EQ with 604's or 5534's then
after checking everything and being sure it works 100%
was going for discrete to listen and compere the differencies.
Get it working, then, play with op-amps.
Title: Re: sontec 1 RU build thread
Post by: Igor on December 12, 2008, 09:06:39 PM
@Pete:
Enjoy!
Nice case :)
Title: Re: sontec 1 RU build thread
Post by: khstudio on December 12, 2008, 11:58:03 PM
Igor,
Thanks for your response.
Bear with me bro... I DO love this EQ & think you did a great job & I appreciate your help!!! ;D

OK,
I wasn't asking YOU to "Buy & Try" the JLM's... I asked how I "Should disable the DC Servo correctly" so I could try it & hear it for myself!"

Also, it's not about me being able to say "Hey, check out my Discrete Op-Amp EQ"... it's about sounding good. (& the way I would like it to sound)... Not to mention more $$$ I have to put out for the Forssell's.

I DID try to find 604's but they were ALL sold out in the US. >:(

Also, I did call Fred about getting his amps.  ;) But I'd still like to hear the circuit "without" the Servo (& add a Cap)

I know you designed this EQ BUT this is DIY & I don't see anything wrong with "Trying" it... I just need your help with HOW to best disable the Servo... that's all.

One more thing... I mentioned DrPat using the JLM 99v in the output of his REAL Sontec MEP250A & he loves it.
NOTE: Pat runs a very Professional studio & has worked with many top artists... so I respect his opinion. He knows good gear & what he's listening to.
I DID have the 99v's in my outputs & REALLY, REALLY liked the way they sounded!
...BUT the only way I could use it was to plug it into other (Capacitor input) Gear.


The Sontec is the unofficial king of mastering EQ's. There are others, but boards are available for the Sontec. You're not gonna find the real opamps, but you can still build the essence of one with substitute opamps. I used JLM99V opamps in my real Sontec when my original opamps blew up.
 I had to change a couple of original components to make them work correctly, but it wasn't a big deal at all.


(http://i74.photobucket.com/albums/i276/velvettone/PDC_0039.jpg)

The mod sounds great! It's punchier, the low end is way nicer (and I liked the stock Sontec low end), and the high end is a tad bit more open. It definitely changed the sound, but it still has THAT Sontec character. In other words, I still reach for it for the same reasons that I would normally reach for a stock Sontec, plus it seems to work on other sources that the old personality, didn't seem to excel at, like kick drum.

I recommend this mod to all Sontec owners, weather their amps are dead or not.






Title: Re: sontec 1 RU build thread
Post by: Igor on December 13, 2008, 01:35:46 AM
Hi Kevin, I think it will be better to ask Joe about how to use JLM-99 in this EQ.
I don't want to give you solution pulled from the air and plain math.
Have to try it on my workbench first, test etc. Simply have no time for this.
I promissed to give support on this EQ, but not mods.
Title: Re: sontec 1 RU build thread
Post by: Grand Master Audio on December 13, 2008, 05:48:07 PM
guys!! guys!! guys!!

I just have to say, i have been playing with mine a lot, cant keep my hands off it, seriously i have not felt this close to a EQ ever, i'm more of a compression kind a guy...well a legs man too...but.. ::)

so maybe forget the JLM or forsell for now, just use it with OPA604 etc, which lets face it is not in any way bad, but personally i think it has a lot to do with the design rather than the components..which are of course important but you know what i'm saying..

pete



Title: Re: sontec 1 RU build thread
Post by: Igor on December 14, 2008, 12:39:30 PM
Farnell and Newark both have OPA604's.

http://il.farnell.com/texas-instruments/opa604apg4/op-amp-low-distortion-fet-604/dp/1178434
http://www.newark.com/texas-instruments/opa604ap/operational-amplifier-op-amp-ic/dp/88K1967
Title: Re: sontec 1 RU build thread
Post by: khstudio on December 14, 2008, 01:25:47 PM
Farnell and Newark both have OPA604's.

http://il.farnell.com/texas-instruments/opa604apg4/op-amp-low-distortion-fet-604/dp/1178434
http://www.newark.com/texas-instruments/opa604ap/operational-amplifier-op-amp-ic/dp/88K1967

Hey cool!!!  ;D

They must have JUST got more in... it's funny because they said the wait time was going to be MUCH longer. ::)

BTW, I tried using a cap on the output with the 99v & it STILL had DC on the other side of the cap. :o
I've never seen anything like it before... there must be something going on in the circuit I can't see or don't understand, so I put it back to stock.

NOTICE:
The FORSSELL DLR-1's are No longer being offered or made!!!!!!!!!!!!!!

I talked to Fred yesterday.
Title: Re: sontec 1 RU build thread
Post by: Tubefreak on December 15, 2008, 02:09:02 PM
Hi, 4k7 will give exactly +/-12db.

Hi, do you know which resistors I need if I only want 5dB of boost/cut as max scale?

THANX
Maarten
Title: Re: sontec 1 RU build thread
Post by: Holger on December 30, 2008, 07:58:44 AM
I've tested my second unit last weekend and wondered about the strange pot noises when adjusting freqs and levels. I also noticed a loud noise while switching the EQ on and off. I took it back home and measured a 20V DC on pin 2 of my output. Wow. Today I found -21V DC  at pin 1 (output) of the MF 3 band OPA 2604 in one channel.
Can someone point me to the place where this huge amount of DC is introduced? I exchanged some 2604, it's always the same problem, no matter if the EQ is switched on or off.
The board itself looks good, I didn't see any bad solder point (Edited: note to self: need better glasses)... My other three channels are working perfect.
Clueless: Holger

Fixed: forgot to solder pin 5 of the mid freq 3 OPA 2604. Oh, oh, what a bug... ::)
Title: Re: sontec 1 RU build thread
Post by: chinchaigo on January 22, 2009, 09:03:26 PM
Igor, I was going to put in a pair of DLR-1 and JFET-993 but I just found out that DLR-1 is not in production anymore; so, do you have any other recommendation for the opamps?  :)
Title: Re: sontec 1 RU build thread
Post by: Igor on January 22, 2009, 10:36:23 PM
Bad news :)
I very liked Fred's opamps.
For input, JE-990 or 992 (slower Forssel's opamp) will work fine.
OPA604 is very clean and fast cheap. I luv them as well.
You need something very fast for summing...
IMHO OPA604 is best chip for this.
I haven't tried JE-990 etc, because they are not fast enough.
Try to pm me for my design discrete opamps, they can be next sub to Forssel's IMHO.
Title: Re: sontec 1 RU build thread
Post by: Grand Master Audio on February 07, 2009, 06:13:16 AM

Hi Igor,

On the next Sontec build i would like to add a switches to enable or defeat each band,

Is it as simple as inserting a switch between R18 through to R21?

best

Pete
Title: Re: sontec 1 RU build thread
Post by: Igor on February 07, 2009, 08:14:56 AM
Exactly. Like S1 refering to schem.
Title: Re: sontec 1 RU build thread
Post by: rrs on February 19, 2009, 12:07:32 AM
Hi
Considdering this for my next project. 2 channels.
And anyone guide me on the cost of this in US dollars and what Opamp options there are?

Thanks.
Title: Re: sontec 1 RU build thread
Post by: Igor on February 19, 2009, 11:09:38 AM
Hi, for stereo Sontec, it comes up in range $450-800 depending on parts, case, shipping costs.
$800 is a bit over-estimated btw.

Opamp options.
The best IMHO are OPA604/2604. Clean, fast, no harsh at any frequency. Fine on +/-24V.
With power supply +/-18V, it is possible to use OP275, NE5532 in filters,
and NE5534, etc. in input/summing board.
To add really nice character, use fast Forssel's opamps in summing circuit.
Title: Re: sontec 1 RU build thread
Post by: mcfarlane_audio on March 03, 2009, 02:25:17 PM
has anyone built one of these sontecs with switches instead of pots? like on the pcbs fabio was selling? is this essentially the same circuit?

thanks !!
Title: Re: sontec 1 RU build thread
Post by: Igor on March 03, 2009, 05:57:43 PM
Hi, I built some of these Sontecs with stepped control.
Here's mastering studio where these EQ's are most prefereable favorite:
http://www.bardostudios.co.il/mastering/eng/
(just "refresh" to watch flash from start)
IMHO this PCB layout has better finnish and easy diy-able, what I can't say
from first glance at Fabio's pcb's...bit rough design...but maybe it is wrong mind.
The circuit is not essentially same.
After listening ITI, MEP230, and 8200, making some clones and comparing etc.,
I got to mind 8200 filter's are more flexible,
but by sound, op-amps are not as fast as Forssewl's or opa604's....
I did not liked high shelve, tried some circuits on breadboard again,
some of my friends listened to this, finally, shelve came from
Neumann/crossfaded with my design 2nd order 12db/oct resonant hi-shelve.
This EQ was designed more by ears...but with use of good measurement 'quippment...
btw, 16 of same design eq's are working on my design mixing console; at design stage, they
were preferred to many other's commercial products and test proto's.
Title: Re: sontec 1 RU build thread
Post by: mcfarlane_audio on April 01, 2009, 03:23:32 PM
Hello igor, im wondering if the "shape" on prushas case is just arbitrarily labeled, or is it actually .4 to 4......... i dont think this can be bandwith or db/oct, and Q would be the opposite.....so is it just an arbitrarily labeled?

Thanks so much, also im wiring mine up with switches everywhere, and am wondering how i should wire up the switch on the low shape control ? ill most likely need a 2 deck switch and just have that last position connect the 2 solder points on the rear of the pot/pcb board connector (on either side of the word "log" on the pcb? yes?

let me know if i dont make any sense

thanks so much! pics coming soon
Title: Re: sontec 1 RU build thread
Post by: Igor on April 01, 2009, 10:41:23 PM
Quote
so is it just an arbitrarily labeled?


I think yes. Take a look on front of 8200 :)

Quote
wiring mine up with switches everywhere, and am wondering how i should wire up the switch on the low shape control ?
ill most likely need a 2 deck switch and just have that last position connect the 2 solder points on the rear of the pot/pcb
board connector

Yes, it is quite simple: pos.1 is ccw, pos.11 is cw of switch.

First waffer, solder 10x499R resistors (1-res-2-res-3-res......res-11)
Second waffer, connect 2 thru 11, solder'em to one point of switch, wipper to second point of switch.

Roboporn always wellcome.
Title: Re: sontec 1 RU build thread
Post by: mcfarlane_audio on April 07, 2009, 05:33:25 PM
hello, im working on my sontec right now, and aqm about to start building the switches, for the reverse log pot (switches) im just double checking before i start soldering tons of switches that im correct in my method

so in ccw - i will start with my highest value, with the last position being the lowest value followed by a jumper on step 24

basically i have used silent arts' log switch excel calculator and reversed the values

here is what i think is correct

for 100k dual rev log (freq for sontec)

ccw

1 - 10k5
2 - 9k53
3 - 8k66
4 - 7k87
5 - 7k15
6 - 6k49
7 - 5k76
8 - 5k23
9 - 4k75
10-4k23
11-3k92
12-3k48
13-3k16
14-2k87
15-2k61
16-2k37
17-2k15
18-1k91
19-1k74
20-1k58
21-1k43
22-1k30
23-1k18
24-jumper

cw
 and the second deck will be exactly the same

correct?? thaks so much!

 the other ones are easy, its the total value of "pot" / total # of positions-1 correct??

then igor has already explained the "q" switch part

thanks in advance for your help, ill post some pics soon

Title: Re: sontec 1 RU build thread
Post by: dagoose on April 08, 2009, 02:47:45 AM
hello, im working on my sontec right now, and aqm about to start building the switches, for the reverse log pot (switches) im just double checking before i start soldering tons of switches that im correct in my method

so in ccw - i will start with my highest value, with the last position being the lowest value followed by a jumper on step 24

basically i have used silent arts' log switch excel calculator and reversed the values

here is what i think is correct

for 100k dual rev log (freq for sontec)

ccw

1 - 10k5
2 - 9k53
3 - 8k66
4 - 7k87
5 - 7k15
6 - 6k49
7 - 5k76
8 - 5k23
9 - 4k75
10-4k23
11-3k92
12-3k48
13-3k16
14-2k87
15-2k61
16-2k37
17-2k15
18-1k91
19-1k74
20-1k58
21-1k43
22-1k30
23-1k18
24-jumper

cw
 and the second deck will be exactly the same

correct?? thaks so much!

 the other ones are easy, its the total value of "pot" / total # of positions-1 correct??

then igor has already explained the "q" switch part

thanks in advance for your help, ill post some pics soon



Cool! That is one of the things i'd still like to do with my sontec, stepped switches! :)
Post those pics man and let us know how the switches work out and stuff like that.  ;)
Title: Re: sontec 1 RU build thread
Post by: mcfarlane_audio on April 08, 2009, 03:41:43 AM
thanks ill let you know, im going to start wiring as soon as someone tells me im not an idiot, im 98% sure this is right but im not 100% and dont want to have to desolder 780 resistors!

im going to start a new thread one i get into full bore on the project so keep an eye out, do these calculations seem correct to you??

ill post all the calculations and resistors and parts once i have that thread goin

my big thanks is to igor for his support so far and for making this project possible for us!!

Title: Re: sontec 1 RU build thread
Post by: Harpo on April 08, 2009, 11:18:20 AM
maybe a matter of taste, but the center frequency distance between steps at the cw end seems a little large. Have a look at my Sontec calculator (http://www.hausverwaltung-heger.de/al_leck_trick/SontecCalc_Igor.xls) to get the idea. (I added your resistor values, starting at cell T53 just for comparisons sake)

good luck
Title: Re: sontec 1 RU build thread
Post by: mcfarlane_audio on April 08, 2009, 01:42:28 PM
all hail harpo!

thank you thank you thank you, this is most exciting, and some amazing math, thank you thank you thank you, i cant say that enough, you are competely correct, it seemed as though the steps got silly at that end , so this is just great, ill post results soon!!!



THANK YOU! and damn this new forum for no beer emoticons, trust me you deserve a flat!
Title: Re: sontec 1 RU build thread
Post by: raffaelebonetti on April 12, 2009, 01:10:42 PM
Hi, for stereo Sontec, it comes up in range $450-800 depending on parts, case, shipping costs.
$800 is a bit over-estimated btw.

Opamp options.
The best IMHO are OPA604/2604. Clean, fast, no harsh at any frequency. Fine on +/-24V.
With power supply +/-18V, it is possible to use OP275, NE5532 in filters,
and NE5534, etc. in input/summing board.
To add really nice character, use fast Forssel's opamps in summing circuit.

Hello Igor!
What about AD706 vs OPA2604?

Cheers!
Raffaele
Title: Re: sontec 1 RU build thread
Post by: SJakobsen on April 15, 2009, 12:43:42 PM
Hi,
in the BOM there is 4-55k resistors, where to buy them?
55k isn't a standard value, is it okay to use 54k9?

Best Regards

Soeren
Title: Re: sontec 1 RU build thread
Post by: Harpo on April 15, 2009, 04:25:45 PM
55k isn't a standard value, is it okay to use 54k9?
Difference between these is 0.18%. ;) Don't care.
Title: Re: sontec 1 RU build thread
Post by: mcfarlane_audio on April 15, 2009, 07:18:42 PM
OK im making excellent progress, well i have switch #1 wired, i guess thats progress, 27 to go!!

but im taking breaks to finish the pcb, i have 2 questions

im a little confused about the rx resistors in the power supply, im using 2604's and 604's so i want 24 volts but what is Ux? in the equation

also ther is talk but i see pics of people using AND NOT using cf1.2, cf2.2,cf3.2 and leaving cf4.2 and 5.2?? should i wore these or not??

thanks for your help, roboporn soon
Title: Re: sontec 1 RU build thread
Post by: Harpo on April 15, 2009, 08:46:57 PM
im a little confused about the rx resistors in the power supply, im using 2604's and 604's so i want 24 volts but what is Ux? in the equation
Ux=24V in your case.
With current setting resistor 200R and 3K6 for Rx you get 1.25V*(1+3600/200) = 23.75V. Have a look at the LM317/337 datasheet for a 2nd safetybelt.
These 5pF caps for lead compensation look a little pointless. (only checking the HF band, LPF -3dB @ 1/(2*PI()*11000*5*10^-12)=2.9MHz. A 47pF might fit better if the amp oscillates without. YMMV)
Title: Re: sontec 1 RU build thread
Post by: mcfarlane_audio on April 15, 2009, 10:59:49 PM
wow thanks again, looking at it now it all makes sense i thought the BOM was saying rx value minus 3k6 and rx value plus 3k6.


aaaaanyways its all good




back to soldering!
Title: Re: sontec 1 RU build thread
Post by: mcfarlane_audio on April 16, 2009, 10:28:24 PM
every pic i see of the guts seems to tell me that everyone is using the same toroid i was thinking a 48vct at about 40va would do, what are you guys using? is that a case/shield i see around the toroid?

Thanks for all the help guys, i really appreciate it

Title: Re: sontec 1 RU build thread
Post by: raffaelebonetti on April 17, 2009, 04:06:38 PM
Hello Everyone,

I am very confused on what transformer to buy for this project. I will be powering one dual channel unit. Can someone refer to an ideal transformer from Newark or any other company!

Thanks and Cheers!
Raffaele
Title: Re: sontec 1 RU build thread
Post by: penguin on April 22, 2009, 10:05:43 PM
Hi, new to here, so hello to everyone.
i need little help on bom

i was wondering using TANTALLUM caps as suggested on bom, for

33U CPOL-EUE5-6  25-50V HIGH QUALITY TANTALLUM caps.
there are only 8 of them on stereo so, it wont kill me :)

there are so many to choose fom, and many different fitings. any idea which ones to use,,

and i am ok on using below opamps...?


INPUT opamp: IC8
DLR-1 Differential Line Receiver (no longer available)  so i will use
JE-990 or 992

OUTPUT opamp:IC6
JFET-993 Discrete Opamp.


which type of resistors are the best to get better performance ?



thank you




Title: Re: sontec 1 RU build thread
Post by: Igor on April 22, 2009, 11:05:49 PM
Quote
33U CPOL-EUE5-6  25-50V HIGH QUALITY TANTALLUM caps.
there are only 8 of them on stereo so, it wont kill me


33uF, 2.5-6mm pitch, radial leaded, 25-35V will be fine.
Depends on supplier which is better for you (shipping, price, availability, etc.)
Audio quality Panasonic, Philips, etc electrolyt's will be fine as well.

Quote
INPUT opamp: IC8
DLR-1 Differential Line Receiver (no longer available)
 so i will use
JE-990 or 992
Quote
OUTPUT opamp:IC6
JFET-993 Discrete Opamp.


Good combination IMHO: opa604 for input line receiver and 993 for summing,
opa2604 for dc servo.

Quote
which type of resistors are the best to get better performance ?

Hm....from point of view of audiofoollery, Roederstein, Dale Velvet,  0.1 % or something like this.
Practically, metal film resistors, 1%, 1/4W will work fine :)

Title: Re: sontec 1 RU build thread
Post by: penguin on April 23, 2009, 11:04:12 AM
farnell #1636659
(http://i236.photobucket.com/albums/ff117/drpenguen/1636652-40.jpg)
some values are available for this project...

they are very expensive around 20$ each 
and they are oversized... but possible to fit them to the PCB.
are they any good for this EQ, or they meant to be used on some high voltage etc stuff

they look mean :o


this is for poly cap list

AUDIO CAPACITOR, 1UF, 630V
Application:Audio
Capacitance:1µF
Tolerance, Capacitance:± 10%
Series:FE-XAL
Voltage, Rating:630V
Capacitor Dielectric Type:Polyester
Case Style:Axial
Termination Type:Axial Leaded
Diameter, Body:35mm
Length / Height, External:54mm




i have founded 0.1% resistors, they are tiny... with no legs... but still possible to make them fit on PCB.
Title: Re: sontec 1 RU build thread
Post by: Igor on April 23, 2009, 01:45:19 PM
OMG!!! No, just order normal parts from Franell/Mouser/Digikey, leave this stuff!!!!
Do you have a bit of feel of humor btw?
Title: Re: sontec 1 RU build thread
Post by: penguin on April 23, 2009, 03:54:23 PM
 ;D


Title: Re: sontec 1 RU build thread
Post by: raffaelebonetti on April 27, 2009, 03:36:05 PM
Hello Everyone,

I am very confused on what transformer to buy for this project. I will be powering one dual channel unit. Can someone refer to an ideal transformer from Newark or any other company!

Thanks and Cheers!
Raffaele

Anyone? Please help!
Title: Re: sontec 1 RU build thread
Post by: MikoKensington on April 27, 2009, 04:08:15 PM
What PSU are you using?  What's your location? 
Title: Re: sontec 1 RU build thread
Post by: kambo on April 28, 2009, 08:51:11 AM
18-0-18 for 24V operation,
am i right ?


Title: Re: sontec 1 RU build thread
Post by: Igor on April 28, 2009, 09:22:36 AM
Use 15-30w toroidal trafo, 2x (~24v)
Title: Re: sontec 1 RU build thread
Post by: mikeyB on April 28, 2009, 09:26:17 AM
What type of KNOBs are these & were can I find them :?:
... anywhere in the US?

I really like the look (or something similar)

(http://i251.photobucket.com/albums/gg291/diy33609/fr_small.jpg)

Ive looked in Farnell and others but can't find the small (shape/Q) knobs in grey
Is the pic of Igor's build? - if so can you tell me where you got your supply of knobs.
Thanks in advance :)
Title: Re: sontec 1 RU build thread
Post by: Igor on April 28, 2009, 10:19:14 AM
Hi Mikey, I got my knobs from Elma Israeli distributer. They available from Farnell as well.
IIRC there are Cat Nr's at this thread elsewhere.
Title: Re: sontec 1 RU build thread
Post by: kambo on April 28, 2009, 10:33:34 AM
Farnell codes for Elma knobs:
1209827
1209793
1209799
1209801
1209803
1209807
1209805
1209808
1209809
1209810
1209811
1209749
1209758
1209775
1209825
Title: Re: sontec 1 RU build thread
Post by: raffaelebonetti on April 30, 2009, 11:58:12 AM
What PSU are you using?  What's your location? 

I am using 24v. PCB board supplied by Igor!
Title: Re: sontec 1 RU build thread
Post by: raffaelebonetti on April 30, 2009, 12:18:43 PM
Use 15-30w toroidal trafo, 2x (~24v)

Thanks for the information Igor! I appreciate it.

Now, I am right with this choices, which would work the best?

http://www.newark.com/multicomp/mcfe050-25/transformer-50va-2-x-25v/dp/38K4554?_requestid=32364
http://www.newark.com/multicomp/mcfe015-25/transformer-15va-2-x-25v/dp/38K4544?_requestid=32734

Or this  other type:

http://www.newark.com/multicomp/mcta120-25/_/dp/38K4907?_requestid=33242

Thanks for you help!
Cheers!
Title: Re: sontec 1 RU build thread
Post by: kambo on May 10, 2009, 02:22:37 PM
i have founded this :

direct replacement discrete op-amp for opa2604

http://www.bursonaudio.com/burson_opamp.htm
(scroll down a little)

anyone used  this on Sontec EQ, or any other project. any opinions


Title: Re: sontec 1 RU build thread
Post by: dagoose on May 10, 2009, 03:54:24 PM
i have founded this :

direct replacement discrete op-amp for opa2604

http://www.bursonaudio.com/burson_opamp.htm
(scroll down a little)

anyone used  this on Sontec EQ, or any other project. any opinions



Nice one!

I'd also like to know how they sound and work.

Also noticed this google add :)

(http://www.dagoosemusic.nl/temp/burson.jpg)
Title: Re: sontec 1 RU build thread
Post by: Igor on May 13, 2009, 08:47:56 PM
Rafael, I hope you use +/- 24V I supplied with kit, right?
:)
This one seems fine:
http://www.newark.com/multicomp/mcfe050-25/transformer-50va-2-x-25v/dp/38K4554?_requestid=32364

Never tried Burston op-amps, but IMHO opa2604 are really good price- and quality- wise in Sontec.
Title: Re: sontec 1 RU build thread
Post by: raffaelebonetti on May 15, 2009, 03:47:22 PM
Rafael, I hope you use +/- 24V I supplied with kit, right?
:)
This one seems fine:
http://www.newark.com/multicomp/mcfe050-25/transformer-50va-2-x-25v/dp/38K4554?_requestid=32364

Never tried Burston op-amps, but IMHO opa2604 are really good price- and quality- wise in Sontec.

Yes I am! Thanks for your help Igor!
Cheers!
Title: Re: sontec 1 RU build thread
Post by: Siegfried Meier on May 25, 2009, 09:32:05 PM
hey guys,

I just cracked open the knobs that I got from Igor with the PCB's after many months.  I'm a little confused with the 5k Lin pots and the 100k Rlog pots.  2 of the 5k pots (of 10 in the package) have 5 legs, 3 in front, 2 in back.  The PCB accepts 5 legs, so where do I put the 2 I have?

The 100k pots have 6 legs, with a ground leg (?) in the back, but the PCB doesn't accept this ground leg, so do I just clip that off?

Also, should there have been nuts for the pots included?  I did not get any, so just curious...

Have read through this thread, but can't seem to find that info.

Thanks!
Sig
Title: Re: sontec 1 RU build thread
Post by: guitarmaker on May 25, 2009, 10:59:13 PM
The pictures I have of completed units have the 5 legged pot in the Lo Q position on the far left.

Steve
Title: Re: sontec 1 RU build thread
Post by: crisotop on May 26, 2009, 02:51:24 AM
It's all been discussed folks - the five legged pot has a switch built-in, if turned fully counter-clockwise, so you can have a shelving or peaking low band.

hth, christoph
Title: Re: sontec 1 RU build thread
Post by: Siegfried Meier on May 26, 2009, 08:23:55 AM
Ahh cool.  Well, I've read this entire thread, and I'll be honest I have not seen this before.  So the pads on the other 5k pots can just remain empty then?

What about the 100k pots and the extra leg?  And are nuts necessary for the pots?

Thanks a bunch,
Sig
Title: Re: sontec 1 RU build thread
Post by: crisotop on May 26, 2009, 08:29:29 AM
As far as I recall, this is "just" earth - i bent it away on my build. Nuts should have come with the pots, you need at least the gain pot nuts for mounting the pcb on the frontpanel.
Title: Re: sontec 1 RU build thread
Post by: Siegfried Meier on May 26, 2009, 01:03:28 PM
Cool thanks for the help.  I didn't get any nuts, but since I do only need those, I can just find them anywhere.

Thanks again,
Sig
Title: Re: sontec 1 RU build thread
Post by: Siegfried Meier on May 26, 2009, 01:17:37 PM
Farnell codes for Elma knobs:
1209827
1209793
1209799
1209801
1209803
1209807
1209805
1209808
1209809
1209810
1209811
1209749
1209758
1209775
1209825


These aren't correct.  The caps don't have lines, the knobs are black and no pointers.  Does anyone have the correct part numbers from Farnell to get the exact knobs that Igor used?

Thanks!
Sig
Title: Re: sontec 1 RU build thread
Post by: Grand Master Audio on May 26, 2009, 01:56:59 PM
As far as I know those exact types are not available through Farnell any more, in fact not any where that I looked.

good luck, i think you will have to use slightly different knobs.

For my most recent Sontec i used some knobs from Banazi that were very similar and sprayed the caps a different colour, masked the thin white marker line and you would never know the difference..

Pete

Title: Re: sontec 1 RU build thread
Post by: SIXTYNINER on June 12, 2009, 12:14:57 PM

BOM (with PSU at the bottom of the document)

http://www.dagoosemusic.nl/diy/sontec/bom_sontec.doc (http://www.dagoosemusic.nl/diy/sontec/bom_sontec.doc)

HELLO
and compliment for unit
please check bom list at above link
the digikey pots code must be inverted also quantity about must be checked
alphastat don't have parts codes indicated on the bom list
if you can complete bom list with some more code ,it can be help more then some guy
thanks in advance
6T9R
Title: Re: sontec 1 RU build thread
Post by: rrs on June 15, 2009, 10:38:47 AM
hi just wondering wether the 33uf electrolytic caps can be substituted for 47uf.
I can get good quality caps at that value.



Is there any wiring diagrams for the power PCB/ Toroid. It's looks a little confusing to me.
Title: Re: sontec 1 RU build thread
Post by: 1234 on June 15, 2009, 03:24:11 PM
Hello to everybody here!

This my first diy project here but it seems I can't find the schematics and part list for it... :-[
This information is probably here in this link at the beggining of the "Igor's high quality projects-pcb's, kit's, support threads" - http://www.groupdiy.com/index.php?topic=26599, but this link gives me only error messages. And of course I tried "search" function first, but did not find anything.

Could somebody help me find this information?

Excuse me if I'm asking such stupid questions for something which may be obvious, but...I still can't find this ???
Title: Re: sontec 1 RU build thread
Post by: kambo on June 23, 2009, 06:06:25 PM
just finished my sontec... whole thing took just over 6 hours... super fast built  ;D
easiest and the fastest DIY ever.
its all good... time to make some measurements...
thank you Igor,

kam

Title: Re: sontec 1 RU build thread
Post by: Igor on July 17, 2009, 03:40:17 PM
Enjoy :)
I have to update whole Sontec build thread-it is disappeared from forum...
Title: Re: sontec 1 RU build thread
Post by: mikeyB on July 22, 2009, 08:27:30 PM
Just finished 1st of 2 builds (2nd ready for case). Used the psu pcb from Igor with the heatsinks that fit the pcb footprint. Using a 2x25V toroid.
With both channels switched in but not passing audio, and with lid on the heatsink temp gets to around 60 centigrade. Although it's quite hot to touch, is this a safe operating temp? - or should I be thinking of putting the regs onto the chassis?
BTW -noise floor figures match the Sontec spec(-94dB out and -88db in) :)
Seems to be a bit of DC noise on some pots, but it appears to be diminishing more the unit is soaked in. Any comments welcome :)
Title: Re: sontec 1 RU build thread
Post by: Igor on July 22, 2009, 09:40:46 PM
Which op-amps and heatsinks are used? What are the PS voltages?
It makes some sense, if you minded DC noise on pots, something is wrong,
because there's DC servo.
Title: Re: sontec 1 RU build thread
Post by: mikeyB on July 23, 2009, 08:25:17 AM
Which op-amps and heatsinks are used? What are the PS voltages?
It makes some sense, if you minded DC noise on pots, something is wrong,
because there's DC servo.
Using heatsink from Farnell part no 4621311 - it fits your psu silkscreen/footprint and has a rating of 6.2 deg Centigrade per Watt.
twin 25V toroid used. PSU set as BOM for +/- 24 V - actual is +23.8 and -23.7 Volts. Using 6 2604's and 2 604's per channel.
I will take some pics asap so you can see the build. Each channel initially tested with 5534/5532 and bench 15V supply before chipping up with the good stuff!
Title: Re: sontec 1 RU build thread
Post by: Igor on July 25, 2009, 06:29:26 PM
OPA604's has excellent DC characteristics...dunno where  "bit of DC noise on some pots" comes from.
Heatsink should fit fine. Let the unit heat up few minutes, then check if DC noise still there.
Title: Re: sontec 1 RU build thread
Post by: 1234 on July 27, 2009, 10:53:54 AM
Hm, some questions... There is a resistor R23 - 10R on amp board, it is missing in BOM. I assume that the schematics and PCB are higher priority so i should solder it there?
And this: will be there a problem if my amp board is with OPA604 but i have allready soldered this 150pF capacitor (it was mentioned in the BOM that it is not nesery to solder it when you have OPA604 on this board)?
Title: Re: sontec 1 RU build thread
Post by: slowbass on August 03, 2009, 01:16:54 PM
Hello,
I can't find the 5K lin pots with center taps (waiting for alphastat answer)... Where could I find them ?
Would it be a problem if I'd used standard pots (without the center tap/center detent option) for the moment ?
Thanks !

+ same questions than 1234
Title: Re: sontec 1 RU build thread
Post by: mikeyB on August 05, 2009, 09:27:22 AM
Never too happy when a heatsink is too hot to touch - ended up with one reg on back panel and one on base plate - cool as a cucumber now!!
Lot of time spent getting it to look nice - pot nuts filed smaller to fit under the knob skirts. "Always keep your nuts covered!!" Q pots "bushed" up to same knob type.
First unit for me mate - pobaudio.com mastering. All resistors matched to 0.25%. Caps paired for stereo matching. Silver mica's used where specified except for 3n3. 604/2604's throughout.
This sounds SOOOOO GOOOOOOOOD  !!!!!!!!
A few pics to enjoy
http://i73.photobucket.com/albums/i215/mikerbaker/elevated.jpg
http://i73.photobucket.com/albums/i215/mikerbaker/front-2.jpg
http://i73.photobucket.com/albums/i215/mikerbaker/guts.jpg

- guts before regs moved to chassis. Notice the foil tape around mains wire to front panel switch. When eq top was set to CCW and boost to max - mains hum was up to -70dB floor. With tape on no (measurable)induced hum. Noise meets Sontec specs of -95dB bypass and -88dB in cct. This is at extreme settings - all bands fully boosted all frequencies at end stops and all q's set to sharp peak!! Backing these off even slightly gets the floor down to -92dB.

IGOR - a massive BIG-UP to you for this project and Tat for the cases - off to finish the 2nd unit!!
Title: Re: sontec 1 RU build thread
Post by: slowbass on August 06, 2009, 10:30:44 AM
I have another question... about capacitors this time : the amp pcb indicates 1x "1m" poly cap (labelled "CIN") and 2x "100m" elec. caps (labelled "C51" and "C2"). Are these millifarads or microfarads ? The schematics also use "1m and 100m". But studying the BOM, the values seem to be microF....
Title: Re: sontec 1 RU build thread
Post by: SIXTYNINER on August 06, 2009, 12:21:34 PM
Hello,
I can't find the 5K lin pots with center taps (waiting for alphastat answer)... Where could I find them ?
Would it be a problem if I'd used standard pots (without the center tap/center detent option) for the moment ?
Thanks !
+ same questions than 1234

HI  just checked here?
http://www.smallbearelec.com/Updates.htm

try to send they an email
because (as post in updates page) they are temporary in stand by,
for "US Customs" check.

kind regards
6t9r
Title: Re: sontec 1 RU build thread
Post by: slowbass on August 06, 2009, 02:57:49 PM
Thanks, I will follow this site !
Title: Re: sontec 1 RU build thread
Post by: Igor on August 09, 2009, 02:25:51 PM
@ mikeyB: I like this. Hope this EQ will help to make more good music.
@ slowbass: these are 50k lin centertap centerdetent pots from Alphastat, not 5k.
Please see BOM, for cat. Nr's.
Title: Re: sontec 1 RU build thread
Post by: mikeyB on August 11, 2009, 02:09:45 AM
@ mikeyB: I like this. Hope this EQ will help to make more good music.
@ slowbass: these are 50k lin centertap centerdetent pots from Alphastat, not 5k.
Please see BOM, for cat. Nr's.

Nearly finished 2nd unit(mine) - me mate at pobaudio.com mastering can't praise it enough - "incredibly versatile, powerful top end" You really have to get silly with the q to make it scratch - ps how about some vactrol elements in place of the pots for a mutron filter flavour? - hehe
Title: Re: sontec 1 RU build thread
Post by: Igor on August 15, 2009, 08:50:56 PM
I have voltage-controlled second order THAT2180-based VCF for this purpose :)
Title: Re: sontec 1 RU build thread
Post by: rrs on August 22, 2009, 12:15:39 AM
Woo -Hoo my Sontec fired up perfectly first go.

thanks Igor.   ;D
Title: Re: sontec 1 RU build thread
Post by: Igor on August 22, 2009, 11:31:53 PM
Happy about this. Have a fun!
Title: Re: sontec 1 RU build thread
Post by: kambo on September 01, 2009, 03:23:38 PM
are we using shorting or none_shorting switches for gain, frequency and Q



Title: Re: sontec 1 RU build thread
Post by: Igor on September 06, 2009, 01:34:09 PM
For mastering variant you mean? Shorting Elma's :)
Title: Re: sontec 1 RU build thread
Post by: kambo on September 08, 2009, 11:02:18 AM
thanks Igor,
mastering variant :)

Title: Re: sontec 1 RU build thread
Post by: Kingston on September 30, 2009, 05:31:40 AM
I have quite a few questions about the output stage and the weird grounding scheme.

1. Why is output XLR connector chassis combined to pin1 with a 10R resistor? seems a bit pointless.
2. Why is chassis ground combined to GND2 in the I/O section with the 0,1+22R filter?

I removed the 0,1+22R filter, used a jumper instead of the 10R resistor, and connected to chassis in PSU only, and on XLR's separately (pin1 never touches GND2). About 10dB less hum.

Same as I do in all my gear.

But most importantly, I don't quite understand the output section.

3. Why is GND2 connected to pin2 using a 68r resistor? What does this achieve? Isn't the output still basically unbalanced?

Might someone shed a bit light on the output topology?
Title: Re: sontec 1 RU build thread
Post by: Kingston on October 01, 2009, 08:11:02 AM
I just want to relay some information. It has been said in the thread before but maybe it needs to be said again, and maybe it needs to be updated in the schematic.

The 12pF compensation caps in the feedback loops of both the input and output section are, shall we say, optimistic, and maybe even a bit pointless. If we one wants to more freely swap opamps and especially different types of discrete opamps, there is a real danger of oscillation.

Use a 47-100pF. Still very wide bandwidth, but far less danger of oscillation.
Title: Re: sontec 1 RU build thread
Post by: RightOnMusic on October 03, 2009, 08:53:04 AM
where can i find the BOM for this?  the link on the OP is dead.  i'm considering buying a pcb set, but i'm certainly not going to if i cant get a darn parts list...  any help???
Title: Re: sontec 1 RU build thread
Post by: slowbass on October 03, 2009, 09:27:56 AM
I asked Igor and he sent me this bom (bom_sontec.doc) I've just changed the quantity of the pots from digikey : 1 x 5K lin potsw and 3 x 5k lin pot instead of the contrary. There maybe a resistor missing for the amp pcb. I hope it's ok to copy it here.

BOM  for 1 channel!

CONNECTORS

2 MOLEX 3 PIN (NOT USED WITH NEUTRIK CONNECTORS)
2 MOLEX 5 PIN
3 MOLEX 4 PIN 3.81 PITCH
1 OUT CON-NEUTRIK_AG_NC3.
1 IN CON-NEUTRIK_AG_NC3

FARNELL CODES FOR NEUTRIK'S:

Order Code: 724518
Manufacturer Part No: NC3FAH1

Order Code: 724543
Manufacturer Part No: NC3MAH


POTENTIOMETERS

1 5K LIN POTSW  (instead of 3)
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=CT2204-ND

3 5K LIN POT (instead of 1)
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=CT2226-ND

5 50k CTPOT
2207 RD1601-20F4-30R
ALPHASTAT 63250-01610/B50K 50K LIN CENTERTAPCENTERDETENT

5 100K RLOG DUAL_ALPHA_2
4196 RD1602-20B4-30R
ALPHASTAT 63256-02600/C100K 100K REV-LOG

WWW.ALPHASTAT.DE

SWITCH

2 SWITCH TOGGLE 2PDT RA PCB

FARNELL Order Code: 9473319



OP-AMP

1 ad706 OR OPA2604(24V PS) 'CAN BE OTHER LOW OFFSET DUAL OPAMP
2 OPA604 OR JE990 ETC 'CAN BE OTHER LOW DIST FAST HIGH CURRENT OPAMP (Forssell 993?)
5 OPA2604 OR OP275 ETC 'CAN BE OTHER LOW DIST FAST DUAL OPAMP


RESISTORS

5 22R R-EU_0207/10
2 68R R-EU_0204/7
2 100R R-EU_0204/7
2 100R R-EU_0207/15
4 392R R-EU_0204/7
8 1k6 R-EU_0204/7
2 3k R-EU_0204/7
1 4k7 R-EU_0204/7
1 8K2 R-EU_0204/7
1 10k R-EU_0204/7
1 10k REU_0207/12
1 11k R-EU_0204/7
4 11k5 R-EU_0204/7
1 17k4 R-EU_0204/7
10 20k R-EU_0204/7
4 20k R-EU_0207/12
4 30k9 R-EU_0204/7
4 36k5 R-EU_0204/7
4 55k R-EU_0204/7
10 1m R-EU_0204/7
1 2m R-EU_0204/7
1 3m9 R-EU_0204/7
1 510k R-EU_0204/7

8 7k5 R-EU_0204/7
'USE 4K7 FOR MORE BOOST/CUT; INSTALL ON BOTTOM SIDE OF FILTERS PCB


CAPACITORS-ELECTROLYTHIC
2 100U CPOL-EUE5-10.5
2 100U CPOL-EUE5-13
CAN BE 100-470 UF 35-50V, POWER SUPPLY BYPASS CAPS

4 33U CPOL-EUE5-6
USE 33U 25-50V HIGH QUALITY TANTALLUM OR AUDIO GRADE ELECTRILYTHICS


CAPACITORS-CERAMIC

17 0.1U 5MM PITCH CERAMIC POWER SUPPLY BYPASS
' VALUE CAN BE 0.047-0.33 UF 50V


CAPACITORS-POLY ETC.

1 0.15U C-10-15/6
2 0.47U C-10-15/6
8 1U C-10-15/6
1 2U2 C-10-15/6
1 1U C-10-15/6
2 2u2 C-10-15/6

1 4u7 C-10-15/6 (PITCH UP TO 35MM, POSSIBLE TO USE 2 CAPS IN PARALLEL)
1 ** C-10-15/6


CAPACITORS-SILVER MICA OR POLY

1 3n3 C-7-10/5
2 2n70 C-7-10/5
1 100P C7.5/3
1 150P C5/2.5 NOT NECESSARY WITH OPA604
2 330P C7.5/3


CAPACITORS-SILVER MICA OR COG
5 5p C2.5/2
2 12p C7.5/3


MISC
1 LED3MM

C2.5/2 MEANS PITCH 2.5MM, 2MM WIDTH
C-10-15/6 MEANS PITCH 10 OR 15MM, 6MM WIDTH
CPOL-EUE5-10.5 MEANS POLAR LYTHIC CAP EUROPEAN SYMBOL 5MM PITCH 10.5MM DIAMETER
R-EU_0204/7 MEANS R EUROPEAN SYMBOL 0.25WATT 7.5MM PITCH

Power supply BOM:

DIODES
4 1N4004 D20, D21, D22, D23
4 1N5400 D16, D17, D18, D19

RESISTORS 1/4W
1 10k R24
2 200R 2% R4, R5
1 rx+ 3k6 2% for 24v R1
1 rx- 3k6 2% for 24v R7

(200R/1.25V)=(Rx/(Ux-1.25V))
Rx in Ohms

IC'S
1 317 LM317 IC1
1 337 LM337 IC3

4 CERAMIC CAPS 0.1UX50V PITCH 2.5MM C9, C10, C11, C12

ELECTROLYTHIC CAPS 50V
4 100u CPOL-EUE3.5-8 PITCH 3.5MM
2 3300u CPOL-EUE7.5-18 PITCH 7.5 OR 10MM

2 HEATSINK FARNELL 1313891 , 1315516 , ETC


!!!!CHECK ALL RESISTORS BEFORE INSTALLING TO PCB.
BE PATIENT AND CAREFULL.
UNIT DONE WITHOUT MISTAKES
WORKING FROM FIRST FIREUP,
ONE WRONG BASTARD LIKE
33K INSTEAD OF 33R
OR REVERSED 'LYTHIC POWER SUPPLY BYPASS CAP
CAN ADD SOME HOURS OF HEADACHE.

Title: Re: sontec 1 RU build thread
Post by: Igor on October 06, 2009, 08:39:30 AM
Quote
I removed the 0,1+22R filter, used a jumper instead of the 10R resistor, and connected to chassis in
PSU only, and on XLR's separately (pin1 never touches GND2). About 10dB less hum.

Hi Kingston! Very ineresting about 10 db hum. I just did same experiment with Sontec which I had on my table.
Same -89 db unweighted noise level when EQ in, filters at 0.
No hum, hiss only.

Anyway. All these are OPTIONS. In many real life situations you will get less ground noise when pin 1 IS connected to
ground thru small resistor, 1...10 Ohm. Etc etc. Regarding the feedback capacitors, 12pF is quite enough with MOST opamps.
47-100 pf will make this EQ sounding bit phase-shifty on highs.

Regarding the 68R resistor, imagine the situation when eq out goes into electronically balanced line receiver. CMRR.
Take handbook for sound engineers, etc, this is so-called "ground compensated" unbalanced out.
I prefer high voltage opamp, ground compensated out to electronically balanced.
Anyway, you can throw here THAT1646.

BTW. If you don't like the way pcb's design done, make your own. Etc etc :)
Title: Re: sontec 1 RU build thread
Post by: Kingston on October 06, 2009, 09:27:21 AM
I had -95 unweighted noise level with EQ in with the RF filters and 10ohm resistor. -104 now that they're gone and pin1 never touches GND2 (only case). Quite impressive for unbalanced equipment. Decent PCB layout I'd say.

About the pin1 to ground through 10ohm resistor... That seems to be somewhat against most pin1 related guidelines I've seen. But this doesn't really matter because you made it optional anyway.

47-100 pf will make this EQ sounding bit phase-shifty on highs.

How can you hear that?!

LPF -3dB @ 1/(2*PI()*11000*47*10^-12)=300kHz

Great to know we have a dolphin doing the listening tests.  :o

 :D

BTW. If you don't like the way pcb's design done, make your own. Etc etc.

I'll admit it, this certainly crossed my mind when I realised how the pot placement had been implemented...

Only one third of them are physically attachable to the front panel, and this is the only support holding the PCB in place.

It will break. The tiny Q-pots will break first.

What's most strange about this is that the PCB is dual layer and the alphastat/digikey pots are recommended to be used here. It would have been trivial to move all the pots to the "front row" in your PCB design software so that they can be all attached to the front panel...

Just mild criticism for better future projects.
Title: Re: sontec 1 RU build thread
Post by: Igor on October 06, 2009, 09:15:50 PM
I like _constructive_ kind of criticism.
Regarding the cap, I said what I said. It came from testing not one circuit in several mastering studios.
You can call me audiofoolish as well as some of my customers. I will aggree. It will noty give any satisfaction to both sides :)

I can measure on my Sontec with: 20-20k filter, 0dbV in, 0dbV out _only_ 96db S/N  with EQ IN, all gains at 0.
Tell me where came -104 from. I feel something new here.

Regarding the pots etc. I used skirted Elma knobs for gains and knobs with pointers for the rest.
If the pots will be placed on front pannel with nuts, it will look really weird.

Let's do an experiment and try to brake freq and Q pots.

Next. I'd like to see your Sontec PCB and front design. Can promiss only _constructive_ criticism.
Title: Re: sontec 1 RU build thread
Post by: Sarcastic Sound on October 07, 2009, 03:53:20 AM
if you feel like you need to have ALL of the pots on the pcb attached to the front panel get out your lathe and make some hollow shaft extensions that are threaded internally on the pot end, and externally threaded on the face plate end. precision mill them to reach the faceplate and be nutted on with the rest of the pots.  this will give you the mechanical strength that you seem to need.

personally I feel them not necessary at all. if the front panel is made to a high tolerance the shaft should just fit threw the hole with 1.5mm clearance around the diameter of the shaft and the knob should be 2mm off the face plate (just enough space to not touch the faceplate when in rotation). this high tolerance does not allow enough stress to be put on the pot to even have a chance to break. if you push the pot the knob will hit the face plate and stop. if you move the knob horizontal or vertical (or anywhere in between) the face plate will hole will stop movement.

I thank Igor for contributing to the DIY community and feel it not necessary to scrutinize him on design choices. Especially when he is SOOOOO helpful in giving support to builders. Like said before, if you don't like the design then design your own!

Now go have a smoke and drink of choice.

Cheers Igor and THANKS!!!  ;D
Title: Re: sontec 1 RU build thread
Post by: Kingston on October 07, 2009, 04:10:34 AM
Guys what the heck!  >:(

Since when has it not been ok to discuss design choices? I thought that's what prodigy pro is all about.

I had no idea this was such a touchy subject for some. This is DIY, and it's all about modifications and making things work better.

Igor, if you don't want people to comment on your design, don't publish anything. Did you really think you had made some kind of perfect PCB with absolutely no errors? Come on, we know better not to argue about something like that.

Like said before, if you don't like the design then design your own!

Seriously now. That's just a plain stupid thing to say. In fact, it's logical fallacy in our context of discussion. http://en.wikipedia.org/wiki/Straw_man

This forum is all about discussing design - at best anyway. We're not all painting by the numbers here. How else are you going to learn design, other than discussing, testing and building?

Ps. I don't have a lathe nor access to one. I would have simply liked to used the existing threads of the pots. Much easier than having to make a highly specialised custom part because of a bad choice in PCB design.

I can measure on my Sontec with: 20-20k filter, 0dbV in, 0dbV out _only_ 96db S/N  with EQ IN, all gains at 0.
Tell me where came -104 from. I feel something new here.

Nothing new here that you wouldn't already know.

1. Well shielded PSU transformer.
2. Schottky diodes.
3. Big high quality PSU caps and lots of them.
4. great opamps.

These are Pier Pablo's (ppa here at the forum) FET opamps. They have exceptional specs by any standards.
Title: Re: sontec 1 RU build thread
Post by: Igor on October 07, 2009, 03:09:53 PM
Quote
Since when has it not been ok to discuss design choices?

Any prob here except the name of thread:
Quote
Topic: sontec 1 RU build thread

and it is good to have clean thread with high concentration of usefull information.

Quote
Did you really think you had made some kind of perfect PCB with absolutely no errors?
Never pretended to be errorless.
But...you know, if someone come and pissing off something you put a lot of time....etc etc.


Quote
Ps. I don't have a lathe nor access to one. I would have simply liked to used the existing threads
of the pots. Much easier than having to make a highly specialised custom part because of a bad choice in PCB design.

If I need to make my own good choice, I do my own pcb's :)

Quote
Nothing new here that you wouldn't already know.

1. Well shielded PSU transformer.
2. Schottky diodes.
3. Big high quality PSU caps and lots of them.
4. great opamps.

There can be microne difference (like -95 or -94.5 db) difference between mumetal shielded toroidal trafo or not shielded but quiet toroidal trafo
(2x25V 30VA from Farnell for xample) because there no high gain high impedance path. Etc etc.

Same about difference between say MBR360 and 1n5400.

Fully aggree about PS caps quality. Again, no need huge (10000u) values, low ESR is what really matter, and tones of bypass ceramics.

Yap. Forssell's are my discrete favorites. OPA(2)604 are my chip favorites.

If you want to promo opamps, please not here. Again, concentrated useful info for building this EQ.

If you so good in numbers, please calculate the noise of ideal opamp in inverting connection, feedback resistor 20k, input resistor 3.3k.
This is the noise of summing amp without filters and input bal. line receiver.
Add noise of input balanced line receiver. Than add noise from filter's opamps. Add some dB for "noise figure".
Etc. My friend simulated this EQ about 3 years ago and helped me with calculation of resistors for stepped EQ.
IIRC we got approx. -93db in theory. Sorry, I am very bad in mathematics.

BTW. It can be nice to have simulation graphs of freqresp and phase shift for opamp in connection mentioned above with Cfb 47-100pF.
Than, simulate hi freq filter and cut 3db. I'd really like to see the simulation plots :)

This is constructive part.

OOPS. Missed one little thing.

Quote
Quite impressive for unbalanced equipment.

Ahem...a....Why unbalanced????



Title: Re: sontec 1 RU build thread
Post by: Igor on October 08, 2009, 02:16:53 AM
Bump. No answer. Anyway, have a good day.
Title: Re: sontec 1 RU build thread
Post by: Kingston on October 08, 2009, 04:12:32 AM
Why are you so hostile? I suspect we have a classic case of language boundary here. You somehow think I'm making fun of your design.

Or maybe you really can't take mild criticism? Oddness.

Anyway, what do you need an answer for? You don't really want me to discuss anything at all and seem to be mad at me for some reason. I think it's best if I just leave the thread so you can police it as you see fit.

But this is what really ticks me off:

If you want to promo opamps, please not here. Again, concentrated useful info for building this EQ.

You are happy to relay your own experiences and that you love Forsells and whatever, but then when someone else has anything to say, alternative solutions etc, it's somehow not "concentrated useful info".

Someone already asked me in private about using alternative opamps. Probably because he was afraid you would be angered if he asked here. I think it's a testament of the "concentrated useful info" of this thread.

I have seen it more than once in the past, but when a developer throws a hissy fit in front of his customers or acts like a princess, it's instantly bad for business.

Here, you can have "your" thread back. Anywhere else seems better at prodigy pro.

Mike
Title: Re: sontec 1 RU build thread
Post by: Igor on October 08, 2009, 05:20:40 AM
Regarding hissy fits, you were first.

Cool. I can aggree with everything. But where -104dB came from? :)

Can you please specify measurement setup?

Regarding the language boundary's, I understood fine everything you wrote.
I droped some lines about noise and frequency responce, seems my english was wrong,
or you prefer take electonics discussion aside and move into psychology?
BTW. Mild critisism imho like "dude, why can't we take the pots to front?" etc.


Title: Re: sontec 1 RU build thread
Post by: MikoKensington on December 09, 2009, 04:05:15 PM
I've finally decided to get to work on my Sontec.  Before I pull the trigger on any orders I had questions about some of the BOM items.

Red flags are in red.  My questions/comments are in green.

BTW, does anyone have a USA BOM going for this project?  I'd like to compare parts and prices with what other folks have found.

Thanks!

I asked Igor and he sent me this bom (bom_sontec.doc) I've just changed the quantity of the pots from digikey : 1 x 5K lin potsw and 3 x 5k lin pot instead of the contrary. There maybe a resistor missing for the amp pcb. I hope it's ok to copy it here.

BOM  for 1 channel!

CONNECTORS

2 MOLEX 3 PIN (NOT USED WITH NEUTRIK CONNECTORS)
2 MOLEX 5 PIN
3 MOLEX 4 PIN 3.81 PITCH
1 OUT CON-NEUTRIK_AG_NC3.
1 IN CON-NEUTRIK_AG_NC3

^ Anyone have a part number on the Molex parts?

POTENTIOMETERS

1 5K LIN POTSW  (instead of 3)
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=CT2204-ND

3 5K LIN POT (instead of 1)
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=CT2226-ND

Links seem to be backwards.

CAPACITORS-ELECTROLYTHIC
2 100U CPOL-EUE5-10.5
2 100U CPOL-EUE5-13
CAN BE 100-470 UF 35-50V, POWER SUPPLY BYPASS CAPS

^Should these be Bi-Polar or will non-polar electrolytics work?

4 33U CPOL-EUE5-6
USE 33U 25-50V HIGH QUALITY TANTALLUM OR AUDIO GRADE ELECTRILYTHICS


CAPACITORS-CERAMIC

17 0.1U 5MM PITCH CERAMIC POWER SUPPLY BYPASS
' VALUE CAN BE 0.047-0.33 UF 50V


CAPACITORS-POLY ETC.

1 0.15U C-10-15/6
2 0.47U C-10-15/6
8 1U C-10-15/6
1 2U2 C-10-15/6
1 1U C-10-15/6
2 2u2 C-10-15/6

1 4u7 C-10-15/6 (PITCH UP TO 35MM, POSSIBLE TO USE 2 CAPS IN PARALLEL)
1 ** C-10-15/6   What the hell is this??


Title: Re: sontec 1 RU build thread
Post by: kambo on December 09, 2009, 05:49:31 PM
I've finally decided to get to work on my Sontec.  Before I pull the trigger on any orders I had questions about some of the BOM items.

Red flags are in red.  My questions/comments are in green.

BTW, does anyone have a USA BOM going for this project?  I'd like to compare parts and prices with what other folks have found.

Thanks!


pot with switch; you only need one per ch (lo-pass filter section)

power supply bypass caps etc caps are all polarized caps... get conformation from Igor,  if non-polar would work there...
(isnt bi-polar and non-polar same thing btw ?)

 
C10-15/6 means Cap; pitch 10-15mm / no idea on after slash
330P C7.5/3 means pitch 7.5mm
150P C5/2.5 means pitch 5mm
Title: Re: sontec 1 RU build thread
Post by: MikoKensington on December 09, 2009, 06:10:36 PM
pot with switch; you only need one per ch (lo-pass filter section)

Yes, I know.  But the links in the BOM are backwards on the "Edited" version.  So if you order from that you'll end up with the wrong quantities.  I was making a note for future builders.

power supply bypass caps etc caps are all polarized caps... get conformation from Igor,  if non-polar would work there...
(isnt bi-polar and non-polar same thing btw ?)

I meant polar or non-polar.   

C10-15/6 means Cap; pitch 10-15mm / no idea on after slash
330P C7.5/3 means pitch 7.5mm
150P C5/2.5 means pitch 5mm

I get all that, too.  The section I have in red, has no value.  I'm just trying to find out where and what that is. 
Title: Re: sontec 1 RU build thread
Post by: kambo on December 09, 2009, 06:27:21 PM
sorry, my mistake,  "My questions/comments are in green"... i couldnt distinguish your comments from your questions... all sounded like question to me :)
anyway,
1 ** C-10-15/6 What the hell is this??
a parallel cap,
so the value would be calculated by you, to be able to get 4u7
Title: Re: sontec 1 RU build thread
Post by: MikoKensington on December 09, 2009, 06:57:27 PM
Ah ha!  I thought that could be the case, but the note on the BOM was before that mystery cap.  Thus confusing me terribly.  :D 

Thanks Kambo!
Title: Re: sontec 1 RU build thread
Post by: involver on January 07, 2010, 10:35:18 AM
Hi all,

I have just finished my GSSL and am thinking of doing this as my next project. I will be using a Tat Purusha case. Just wanted to ask if there was anything that is very hard to source or any other gotchas in the project?

The only BOM I've been able to locate is this one: http://www.groupdiy.com/index.php?topic=27972.msg437569#msg437569 and I can't seem to find a store for the correct pots here in europe? Also, Igor has recommended 2604 and 604's as the opamaps with Forssell JFET-993's on the summing. Anyone built one with this setup?

Thanks
Title: Re: sontec 1 RU build thread
Post by: MrShhh on January 25, 2010, 07:00:03 AM
Sorry for the dumb question, what size fuse are people using for this project? I don't see it on the schematic or BOM I have. Thanks  :)
Title: Re: sontec 1 RU build thread
Post by: Igor on February 01, 2010, 06:31:50 PM
www.alphastat.de and digikey for pots;
I used 800 mA SB fuse for local 230v with 25VA toroid.
Title: Re: sontec 1 RU build thread
Post by: marige on February 03, 2010, 09:18:53 AM
Where does one get the nice "Tat Purusha" case?

//Martin
Title: Re: sontec 1 RU build thread
Post by: MrShhh on February 03, 2010, 02:35:08 PM
Where does one get the nice "Tat Purusha" case?

//Martin

http://www.diy-racked.com/diy-talk/viewtopic.php?f=7&t=18&sid=098fe289d0d9856c4a3c8b80945d4b43 (http://www.diy-racked.com/diy-talk/viewtopic.php?f=7&t=18&sid=098fe289d0d9856c4a3c8b80945d4b43)

PS Thanks Igor for the fuse size  :)
Title: Re: sontec 1 RU build thread
Post by: RedNoise on February 04, 2010, 07:33:00 AM
Quote
Rotational Angle
Total Rotation
Without Switch: 300° ± 5°
With Switch: 315° ± 5°
Effective Rotation
Without Switch: 300° (approximate)
With Switch: 290° (approximate)

This quote is pulled from the CTS 270 pots datasheet.
Could someone explain what's the difference between "total rotation" and "effective rotation" ???
For home front pannel designs , what degree did you use for tho pots ?


Thanks.
Title: Re: sontec 1 RU build thread
Post by: Igor on February 07, 2010, 06:07:10 AM
Please pm me your mail address to send .cdr file with design of front pannel.
Title: Re: sontec 1 RU build thread
Post by: haima on February 07, 2010, 10:25:40 AM
hey guys - i'm finally starting work on my sontec... have a set of the older run boards (v1.6 - the green ones).

does anyone know if there are any errors on the silk screen component values? or can i just stuff as per what's shown on the boards?

also, anyone had good/bad experiences with any types of capacitors in the sontec? i'm thinking i'll put in a wima order from TAW - polypropylene when they will fit, otherwise metallized polyester...

thanks mateys!
Title: Re: sontec 1 RU build thread
Post by: dagoose on February 08, 2010, 07:36:30 AM
Hi, 4k7 will give exactly +/-12db.
Just wondering, what resistance will give +/-6db?
I hardly use it for moe then maybe 3db boost/cut and so 12db is a bit much for me and so i want to set it to 6db +/-.
Title: Re: sontec 1 RU build thread
Post by: dagoose on February 10, 2010, 02:36:03 AM
Hi, 4k7 will give exactly +/-12db.
Just wondering, what resistance will give +/-6db?
I hardly use it for moe then maybe 3db boost/cut and so 12db is a bit much for me and so i want to set it to 6db +/-.

anyone? igor?
Title: Re: sontec 1 RU build thread
Post by: Igor on February 11, 2010, 04:51:49 PM
Change summing resistors (10 and 20k) to twice higher. It will give 6db range.
You can do a on-off-on swich for every band to get 12-0-6 on it.
Title: Re: sontec 1 RU build thread
Post by: haima on February 11, 2010, 07:46:32 PM
thanks igor! too easy...  :)

btw: do you know of any errors on the v1.6 silkscreen values? or is everything ok? i'm stuffing mine right now...
Title: Re: sontec 1 RU build thread
Post by: dagoose on February 12, 2010, 06:28:45 AM
Change summing resistors (10 and 20k) to twice higher. It will give 6db range.
You can do a on-off-on swich for every band to get 12-0-6 on it.
OK, never thought of making it switchable.. nice idea!
So basically 20k on the summing buss will give 6db range and 10k (7k5 on the schematic) will give 12db range?
I mean, the resistors are on the cut and boost buss in series with potmeter.
Title: Re: sontec 1 RU build thread
Post by: kambo on February 12, 2010, 06:51:35 AM
i think Igor means the summing resistors, far right on schematic, (separated  small schematic),
thats where i placed my switches for 0-12db...
Title: Re: sontec 1 RU build thread
Post by: dagoose on February 12, 2010, 09:09:30 AM
OK, so if i understand it correct, the 20k resistors should be 40k for 6db and the 10k (for hi band that is) should be 20k for 6db range.
(http://www.dagoosemusic.nl/temp/sontecsum.jpg)
Title: Re: sontec 1 RU build thread
Post by: kambo on February 12, 2010, 12:10:19 PM
thats exactly what understood from Igors post...
my individual band in/out switches are there... so, it must be it...
Title: Re: sontec 1 RU build thread
Post by: syn on February 19, 2010, 09:27:21 AM
Hi
    I'm oredering parts for the build, and have a couple of Qs:
No need for the 50k pots to be center detent if switches used for individual band bypass?
and
Could some one decipher this, please:
22R R-EU_0207/10
100R R-EU_0207/15
10k REU_0207/12
Thank you
 
Title: Re: sontec 1 RU build thread
Post by: haima on February 19, 2010, 10:31:11 AM
i'm pretty sure these would just be standard 1/4" metal film resistors (with part numbers for a distributor... like farnell?)

22R R-EU_0207/10 = 22ohms
100R R-EU_0207/15 = 100ohms
10k REU_0207/12 = 10k ohms

hope that's correct, and answers your question...
Title: Re: sontec 1 RU build thread
Post by: kambo on February 19, 2010, 10:48:41 AM
Syn, those are just European codes, not farnell etc codes...

center detent pot : no need if you use switch...
Title: Re: sontec 1 RU build thread
Post by: boji on February 22, 2010, 09:56:27 AM
Would someone mind explaining the difference between the Sontec 8 and the Sontec U19's  Input / Output signal flow?

Are they the same? I ask becuase the 2ch sontec has that pretty seperate amp card.

Would the Sontec 8's beneifit from using that?
Title: Re: sontec 1 RU build thread
Post by: boji on February 22, 2010, 10:05:12 AM
I suppose If I could find a copy of the sontec 8 schema I could compare it with the 2ch version, I just don't see the 8 build's schema floating around.  Any help would be appriciated, thanks.
Title: Re: sontec 1 RU build thread
Post by: kambo on February 22, 2010, 01:11:38 PM
8ch is 4band..
stereo version is 5 band mastering version...etc
Title: Re: sontec 1 RU build thread
Post by: dagoose on February 22, 2010, 03:13:44 PM
Today i added a nice dual pole on/off/on switch for the 6/12db/bypass per band and it works like a charm. So up is 6db, down is 12db and middle is bypass the band for left and right at the same time.
I ended up using 39k for the 6db and the standard 20k for the 12db.
So far only the low band and one mid band has a switch because i didn't have more switches in stock but it's a start and it looks quite ok as well.
The switch fits exactly in the middle of the purusha panel between the freq and gain pot, just drill a hole on the white line and your fine! (will take pics when done)
Title: Re: sontec 1 RU build thread
Post by: kambo on February 22, 2010, 05:13:15 PM
i have wired switches for boost_or_cut  ;)
Title: Re: sontec 1 RU build thread
Post by: boji on February 23, 2010, 08:46:56 AM
Quote
8ch is 4band..
stereo version is 5 band mastering version...etc

I am asking about the inputs and outputs; I'd like a little explanation on the difference between the 1u and the sontec 8.

Thanks.
Title: Re: sontec 1 RU build thread
Post by: zayance on March 27, 2010, 06:09:31 AM
Just curious anybody build this one using stepped attenutor? Will it be risky, in terms of catching durt on the way, to put good quality wire from boards to pots? Like 3mm gotham or mogami cable.
I was thinking using the alphastat but could be cool doing this one with stepped attenuator, well for now, will see the fonds when there  :)
Thanks.
Title: Re: sontec 1 RU build thread
Post by: bobine on March 27, 2010, 04:01:19 PM
Has anyone from the U.S. ordered from Alphastat? How did you pay? What were shipping costs? How did you communicate?

sorry if I've missed this info elsewhere

thanks

b
Title: Re: sontec 1 RU build thread
Post by: bobine on March 27, 2010, 04:03:13 PM
I'd consider making a switched unit, but I think the cost of the Elma or Grayhill switches far exceeds the cost of the pots. I haven't seen any posts regarding the model Elma switches that have been used, just some basic specs: 24 pos, shorting... What model number Elmas will work? Is there a Lorlin equiv that could be considered?

again, apologies if this has been discussed...

b
Title: Re: sontec 1 RU build thread
Post by: SIXTYNINER on April 09, 2010, 11:40:56 AM
...for case ... any skeme about
cut-boost switch (as in "mazz-pazzive") ?
 :)
Title: Re: sontec 1 RU build thread
Post by: muffy1975 on April 24, 2010, 11:24:30 AM
Hi Team Sontec,

Michael
Title: Re: sontec 1 RU build thread
Post by: muffy1975 on April 25, 2010, 10:45:51 AM
Ok,

my last post was dumb. 1st one for this project.

Now here's a question for y'all.

Does the BOM suggest either mica or polystyrene caps for those 5 values?

3n3
2n7
100p
150p
330p

Can I use polystyrene here? Do they sound any good in these positions

Michael
Title: Re: sontec 1 RU build thread
Post by: zayance on April 25, 2010, 11:19:22 AM
Quote
Ok,

my last post was dumb. 1st one for this project.

Now here's a question for y'all.

Does the BOM suggest either mica or polystyrene caps for those 5 values?

3n3
2n7
100p
150p
330p

Can I use polystyrene here? Do they sound any good in these positions

Michael

Your choice, that's what the BOM suggests, any of both will do the job, some would prefer Silver Mica but the price is high tough, i'll go WIMA FKP series on my side....

Anyway here is PRR's tought on Mica i found some time ago...

Quote
>  impression that mica are probably the best for filtering higher frequencies...

No.

First: mica are only (usually) available in very small values. Too small for audio coupling or filtering. Maybe big enough for a treble tone-control capacitor.

When capacitor technology was very crude, mica gave the lowest losses in radio tuned circuits. This type of loss is usually unimportant in audio; sometimes (in supply bypassing) "too low" loss is actually bad.

Mica is a rock, found in odd corners of the earth, and much of the good stuff is already mined. Meanwhile very very good plastics and ceramics have been developed.

These days the main reason to go mica is "nostalgia".

While on the subject: "ceramic" is NOT one single type of cap. You can make flower-pots or engine-pistons with modern mechanical "ceramics", and the range of electrical ceramics is even larger. Below 1,00pFd "ceramic" is usually a glass-like mix, and so very very nearly perfect that it largely replaced both Mica and Glass caps. Above 0.01uFd they use some very different stuff, all doped with polar salts, very goofy electrical properties. I can hear a 0.02uFd ceramic coupling cap, whereas I can't hear most other cap-types. OTOH for many bypass chores, the exact capacitance does not matter and the types of losses are complementary to the needs of bypassing.

And here is something interesting:

http://www.reliablecapacitors.com/pickcap.htm
Title: Re: sontec 1 RU build thread
Post by: muffy1975 on April 25, 2010, 07:38:27 PM
thank you broseph.

Am really considering polystyrene caps in these positions like those xicon styrene caps that Mouser do! We used them on the Ez1290 project. Any thoughts on those puppies? Order code 23PS110

Michael

( freaking out at the cost of them knobs)
Title: Re: sontec 1 RU build thread
Post by: Igor on April 25, 2010, 08:10:44 PM
Xicon styrenes are cheap price-wise, but should be good capacitors.
I love silver mica on highs, BTW, can post photo of 91nF/400V mica cap,
tell me they don't have high values :)
Polyprops or styrenes will work fine as well. All this is matter of taste.
Most people prefer styrenes versus mica soundwise. I prefer mica's.
To get right a/b test, you need some relays and good accoustic room
with perfect monitoring, converters etc.
Even in this case difference will be very, very subtle.
Title: Re: sontec 1 RU build thread
Post by: muffy1975 on April 26, 2010, 05:45:37 AM
 :D

Thanks Igor. That's really clear now for me. Might just go Mica for the high end, but of course I have a dead room and £300 speakers and wool in my ears.

Now I have no need of relying on the I Ching/Oracle for his/her/it's opinion on capacitor choices. Maybe when it says 'move away' it's talking about audio in general. Who knows?

Oh I can't wait for my sontec pcbs ( said like fat kid starring a piece of cake )

Michael
Title: Re: sontec 1 RU build thread
Post by: Igor on April 27, 2010, 06:37:26 PM
Hi people, I updated second post of this thread, in case of whatever:

HERE YOU CAN FIND ALL DOCS:

http://twin-x.com/groupdiy/thumbnails.php?album=399
Title: Re: sontec 1 RU build thread
Post by: haima on April 27, 2010, 09:03:59 PM
awesome! thanks igor  :)
Title: Re: sontec 1 RU build thread
Post by: boji on May 13, 2010, 02:07:12 PM

Quote
MrZpliff
Best way of running the Calrec EQ unbalanced ?
« on: March 07, 2008, 06:02:56 pm » Quote  
--------------------------------------------------------------------------------
Hi !
What's the best way to run Gyraf's DIY version of the Calrec EQ unbalanced. Me think's disconnect pin 3 on both input and output and just connect pin 2(+) and ground.  :?
--------------------------------------------------------------------------------
gyraf Reply
Ground -input, leave -output floating..

Sontec seems to be the opposite of this, correct?
Which is to say the sontec8 is built to be unbalanced out...
(http://i184.photobucket.com/albums/x320/donbosse/Mixer/sontecout.jpg)




 
Title: Re: sontec 1 RU build thread
Post by: Igor on May 13, 2010, 03:09:35 PM
Exactly. Instead of adding balanced line driver running at +/-18V max, I left it unbalanced.
This EQ runs on +/-24V, and there's a plenty of headroom.

From the other side, I personally prefer gear with high power supply rails, balanced input and
"balanced-ground-compensated" output, like here.
You can add output transformer to Sontec to make output balanced, it is easy.
JT-11 (IIRC) should work fine here as well as any other 1:1 or 1:(1...2) ratio trunny.
Title: Re: sontec 1 RU build thread
Post by: boji on May 14, 2010, 12:50:58 PM
Thanks Igor for the feedback!
Title: Re: sontec 1 RU build thread
Post by: xarolium on May 17, 2010, 09:54:39 AM
Dear diyer,

i would like to know if i could use this DAO http://www.audiophonics.fr/burson-audio-opamp-aop-simple-p-3715.html for the output and input stage or which other DAO could i use?

thank you
Title: Re: sontec 1 RU build thread
Post by: Igor on May 18, 2010, 08:24:21 AM
You mean, DOA (Dead On Arrival or Discrete-Op-Amp), right?
:)
Can't read french, but this opamp seems have different pinout than 990* etc.
I like OPA604 at input stage and fast Fred Forssel's opamp (993) at summing circuit.
Title: Re: sontec 1 RU build thread
Post by: RedNoise on May 18, 2010, 11:01:36 AM
Isn't this Burson a DIP8 pin compatible?
Title: Re: sontec 1 RU build thread
Post by: Harpo on May 18, 2010, 11:42:53 AM
compatible in DIL8 configuration for some chips maybe, but dimensions 48 x 22 x 24 mm ?
At least you'll have to cut some windows in your 1HE case lid to make them fit thru. Not reliable, but might look funny with the DOA ends sticking out like a tube amp ... ::) 
(Why can't they give some chip data, at least say being bipolar or fet type DOAs)
Title: Re: sontec 1 RU build thread
Post by: RedNoise on May 18, 2010, 11:49:25 AM
might look funny with the DOA ends sticking out like a tube amp ... ::) 

 ;D ;D ;D
Title: Re: sontec 1 RU build thread
Post by: Igor on May 19, 2010, 03:43:16 PM
I'd stay out of company selling gold-plated USB cables.
/just kidding/

Nice looking op-amp, but useless here.
Title: Re: sontec 1 RU build thread
Post by: king-rb on June 15, 2010, 03:28:04 PM
is it posible to get the boost/cut to 5db? i know the values for 6db but im not sure if the best way is to decrease r18-r21 or rf1c aso.. + rf18 aso..
Title: Re: sontec 1 RU build thread
Post by: Igor on June 20, 2010, 12:21:51 PM
It is possible to increase R18...R22 to 47k, r21 to 22k (closer standard values).
Title: Re: sontec 1 RU build thread
Post by: bobine on June 23, 2010, 06:05:25 PM
A new EQ was born today...

Aside from a few bad solder joints in a couple of bands and a ground problem to fix with the freq pots, everything works on paper:
(http://i941.photobucket.com/albums/ad258/otrabobine/Sontec/eq1LF100hzrangehiQ-1.png)
(shouldn't the overall gain remain at the baseline when a band is raised or lowered?)

(http://i941.photobucket.com/albums/ad258/otrabobine/Sontec/EQ2LFFreqrangeHiQ.png)
(http://i941.photobucket.com/albums/ad258/otrabobine/Sontec/eq2LFQcontrol.png)

But it sounds terrible...when the gain goes above +9 it suddenly sounds like a ring modulator...both channels, every band. In this pic, the green is just before distortion and the others just after. Weird.

Edit: It sounds great. I changed the source and lowered the input levels and now the unit is behaving...I was apparently overdriving something when I raised band gain levels... not sure where since the output levels always seemed fine. ???   End Edit.

I used OPA604s for input & summing and OPA2604s elsewhere.
Anyone else have this happen? I may try limiting the gain to +6 to avoid this if cleaning up the ground problems doesn't fix it.

Otherwise, this was a lot of fun to build and play with...  :)


Title: Re: sontec 1 RU build thread
Post by: dagoose on July 10, 2010, 09:16:34 AM
Just wondering, what would be the ideal DOA's for this sontec?
I already have one running with opa's but i'm going to build another one now with stepped switches and DOA's.
So... what (DIY prefered) DOA's are the best to use?
Title: Re: sontec 1 RU build thread
Post by: haima on July 10, 2010, 11:19:03 AM
i think igor likes the forssell 993...

(me is a big fan of Forssell newer fast (993) opamps,
I think they UNBEATABLE by any other amplifier in this Sontec).
They are ideal opamps with very nice color.
Title: Re: sontec 1 RU build thread
Post by: Igor on July 13, 2010, 05:50:39 PM
Hi Bobine, the graphs looks a bit strange for me. The overall gain should not change when boosting/cuting. And, seems like an oscillation at >15k? Let me know which soft was used to take these graphs,  and maybe it is good to put it on scope. I don't trust to soundcard-based analyzers :) Let us know if everything works fine after the fix.

Ultimate op-amp. Forssell's 993 is a cherry at summing circuit, IMHO.
Title: Re: sontec 1 RU build thread
Post by: dagoose on July 14, 2010, 12:28:03 PM
Yep, forsell 993's it will be :)
OK.. now trying to find some decent 24 steps switches, elma's will be a 'bit' expensive maybe, i need 20.  ;)
Title: Re: sontec 1 RU build thread
Post by: zayance on July 14, 2010, 12:44:35 PM
I bought 20 chinese stepped attenuator on ebay for my Sontec the dealers name is hampton if i remember correctly, got me a good price for them, they are Vishay i believe.
Seems like we will be building same sontec, i went for forsell also ;-)
Title: Re: sontec 1 RU build thread
Post by: Holger on July 20, 2010, 10:12:31 AM
My third:

(http://audiofor.tv/diy/sontech/front.jpg)

(http://audiofor.tv/diy/sontech/oben.jpg)

I can really recommend this EQ. Jump on this as long as Igor stocks it...
Title: Re: sontec 1 RU build thread
Post by: haima on July 20, 2010, 10:15:10 AM
sweeeet!

i really should finish mine soon... argh. too many projects!
Title: Re: sontec 1 RU build thread
Post by: Holger on July 20, 2010, 01:34:58 PM
Igor, as mentioned earlier
http://www.groupdiy.com/index.php?topic=27972.msg369988#msg369988 (http://www.groupdiy.com/index.php?topic=27972.msg369988#msg369988)
the knobs are Sifams, available from Sibalco. Send me a PM if I can do something for you.
Title: Re: sontec 1 RU build thread
Post by: Igor on July 20, 2010, 03:54:39 PM
:)
Thanx!
Title: Re: sontec 1 RU build thread
Post by: abechap024 on July 20, 2010, 04:18:52 PM
Hi ,

First of all Thanks Igor, great project!
Quick question. I've seen lots of great talk on the 4 pin molex, but I have a question on the 5 pin molex, I see from pcb and pic the spacing is smaller. I just want to be sure before I order is it the .1" spacing for the 5 pin?
Thanks!
AC
Title: Re: sontec 1 RU build thread
Post by: Igor on July 20, 2010, 07:00:10 PM
Hopefully, logged as Igor :)
4-pin connector has 3.81mm spacing
5-pin connector has 2.54mm spacing
In case crimping/soldering the wires to Molex pins seems hard, another opt:
http://il.farnell.com/jsp/level5/module.jsp?moduleId=en/230246.xml
this is for 2.54 mm,
for 3.81:
http://il.farnell.com/phoenix-contact/1727036/terminal-block-pcb-3-81mm-4way/dp/3704592

I personally hate screw terminals, but seems, it is same thing as Word Cup :)

POST Nr 1272!!!!!!!
Title: Re: sontec 1 RU build thread
Post by: dagoose on July 21, 2010, 03:12:30 AM
My boards for my second sontec came in yesterday and this one is going to be a bit more special.
It will be a 3u version with all stepped controls (elma's i think.. though very expensive), forsell 993's and it will also have left controls on the left and right controls on the right.
I was thinking of cutting the filterboards in 2 or maybe even 5 parts so that i can mount them vertically next to the switches.
This way every secion will have it's own filterboard and practically the board can 'handle this', it even has a mark where to cut it on the bottom.  ;)
I will only have to connect a couple of wires to make it work, basically psu, ground and busses so fast thinking 6 wires per board.

Just wondering, will i run into other poblems then just some extra wiring? Don't think so myself but want to make sure.
Personally i think it might be a good idea to have the summing together near/on the IO boards.
Title: Re: sontec 1 RU build thread
Post by: RedNoise on July 21, 2010, 04:49:23 AM
POST Nr 1272!!!!!!!
but you edited it , and then it's 1279... :-X
Title: Re: sontec 1 RU build thread
Post by: dagoose on July 21, 2010, 08:57:06 AM
OK, have been having a better look at the board and it's not real easy to cut the board in 5 pieces but at least doable in 2 pieces.
You can cut in 2 between the LMFfreq and MQ pot, exactly on the IJ Research logo (sorry Igor).
You can also cut the HF section apart, there is only a 10k resistor that has to be taken care of.
OK, we'll see..First find a nice source for a lot of elma's or equivalent. (anyone?)
Title: Re: sontec 1 RU build thread
Post by: dagoose on July 21, 2010, 11:10:33 AM
I bought 20 chinese stepped attenuator on ebay for my Sontec the dealers name is hampton if i remember correctly, got me a good price for them, they are Vishay i believe.
Seems like we will be building same sontec, i went for forsell also ;-)
Please tell me more! (concerning the switches that is) :)
Title: Re: sontec 1 RU build thread
Post by: Igor on July 21, 2010, 11:26:52 AM
@ Rednoise: Good for you, you have more posts :)
Cutting my logo!!!! Will never forgive you!!!  :P  ;D
Regarding the ELMAS. I did some boards to solder resistors on PCB,
not to ELMA contacts. Can post a picture here. Useful.
If there are too many people who wants mastering version...
Let's see what is possible :)
Title: Re: sontec 1 RU build thread
Post by: zayance on July 21, 2010, 06:27:22 PM
I bought 20 chinese stepped attenuator on ebay for my Sontec the dealers name is hampton if i remember correctly, got me a good price for them, they are Vishay i believe.
Seems like we will be building same sontec, i went for forsell also ;-)
Please tell me more! (concerning the switches that is) :)

let me get back to my desk and i'll send you the ebay link :-)
Title: Re: sontec 1 RU build thread
Post by: zayance on July 21, 2010, 08:12:10 PM
Dagoose you have a PM  ;)
Title: Re: sontec 1 RU build thread
Post by: dagoose on July 22, 2010, 03:45:37 PM
Thinking about the stepped switches; for frequency i'm going to use the calculations as vitalahde describes so with semitones instead of regular log. Has anybody done that already?
For the Q i will go for 12 steps switches because i think that is more then enough and for the gain i will also use 24 steps switches.
Both Q and gain are lin so i guess it's just a matter of deviding it in all the same values, so for gain it's something like 2k per step x 24 steps = 48k (almost 50k) and the centre will also be 0 automatically. Am i correct here or do i miss something?
Elma's will be a bit to much i guess so i will probably go for the switches from uraltone, about 1/10 of the price.
Title: Re: sontec 1 RU build thread
Post by: Pieter001 on July 22, 2010, 05:37:10 PM
Does someone have a BOM with farnell s/n? Like to order the right good quality components and it saves a lot of time.

Thanks
Title: Re: sontec 1 RU build thread
Post by: dagoose on July 23, 2010, 10:37:58 AM
Thinking about the stepped switches; for frequency i'm going to use the calculations as vitalahde describes so with semitones instead of regular log. Has anybody done that already?
For the Q i will go for 12 steps switches because i think that is more then enough and for the gain i will also use 24 steps switches.
Both Q and gain are lin so i guess it's just a matter of deviding it in all the same values, so for gain it's something like 2k per step x 24 steps = 48k (almost 50k) and the centre will also be 0 automatically. Am i correct here or do i miss something?


Anyone?  ???
Title: Re: sontec 1 RU build thread
Post by: Harpo on July 23, 2010, 12:11:29 PM
Thinking about the stepped switches; for frequency i'm going to use the calculations as vitalahde describes so with semitones instead of regular log. Has anybody done that already?
For the Q i will go for 12 steps switches because i think that is more then enough and for the gain i will also use 24 steps switches.
Both Q and gain are lin so i guess it's just a matter of deviding it in all the same values, so for gain it's something like 2k per step x 24 steps = 48k (almost 50k) and the centre will also be 0 automatically. Am i correct here or do i miss something?


Anyone?  ???
I only did the calculation in the excel sheet, dunno about Jaakos calculation. It's simply his idea translated into numbers, his values probably not that different from mine.
For your 24 steps and center, sure about 24 steps (does something like this exist?), not 24 positions? else you'll be missing the center position for +/-0dB. All/most 24 position switches, like Uraltone or Chiefdom RCL 370, other than Elma series04, don't come with end stop, that could kill yor monitors when dialing from electrical full ccw position one step further ccw to full cw. The ones I know that come with end stop or don't dial thru only have 23 positions/22 steps for 15° angle of throw. 
Title: Re: sontec 1 RU build thread
Post by: MrShhh on July 23, 2010, 02:07:41 PM
Re stepped gain controls: I got around this by using 24 step switches with steps 1&2 tied together. That way you can't have the switch 'fall off the end' into an unconnected step. The center tap point is then step 13 and you have 11 steps either side of this (actually 12 on the 'anti-clockwise' or minus side but 2 are tied together with a zero ohm link). Done this way, you need 22 x 2k2 resistors giving 48k4 total which is only 3.2% off 50k.

What's really needed is a 25 position switch as then you'd have 12 positions either side of zero (the center tap point at step 13), giving +/- 12dB nicely. Or of course, use actual 23 position switches giving +/-11dB.






Title: Re: sontec 1 RU build thread
Post by: dagoose on July 23, 2010, 03:51:46 PM
thanks! i was thinking in the right direction with the gain switches. :)

I just ordered 20 switches from uraltone this afternoon, they are indeed 24 steps but it's really easy to make 'm 23 steps which i'm going to do.
All you have to do is drill a 1.5mm hole in the plastic and put in a metal pin and it's a 23 steps switch, done this a couple of times before, needs some practice but now i know where to drill.  ;)
I will make a pic of the place wher to drill a hole and put the pin in, hard to explain, you have to see..

23 steps will also give the 0 position at the centre indeed, nice! Now it's time to order a lot of 2k2 resistors and start soldering..  :-*
I'm still thinking about the freq switches but that will also work out well i think. Can't wait to hear and work with my stepped DOA sontec.  ;D


Title: Re: sontec 1 RU build thread
Post by: bruno2000 on July 23, 2010, 04:17:32 PM
Re stepped gain controls: I got around this by using 24 step switches with steps 1&2 tied together. That way you can't have the switch 'fall off the end' into an unconnected step. The center tap point is then step 13 and you have 11 steps either side of this (actually 12 on the 'anti-clockwise' or minus side but 2 are tied together with a zero ohm link). Done this way, you need 22 x 2k2 resistors giving 48k4 total which is only 3.2% off 50k.

What's really needed is a 25 position switch as then you'd have 12 positions either side of zero (the center tap point at step 13), giving +/- 12dB nicely. Or of course, use actual 23 position switches giving +/-11dB.

Then you can truthfully say that youe EQ goes to "11"  ;-)
Bruno2000







Title: Re: sontec 1 RU build thread
Post by: zayance on July 23, 2010, 06:24:36 PM
Quote
I will make a pic of the place wher to drill a hole and put the pin in, hard to explain, you have to see..

Thanks for posting i'd really like to see.
Title: Re: sontec 1 RU build thread
Post by: Igor on July 23, 2010, 09:39:02 PM
Regarding stepped gain controls.
Use less resistance at center, i.e. kinda S-curved control for
exact db steps.
I.e. 2k7-2k7-2k4-2k4-2k2-2k2-2k-1k8-1k5-1k3/0/-1k3-1k5-1k8-.....2k7.

Added:

BTW, what is the deal with uraltone switches?

6 positions for Q is enough/IMHO
Take a look at Mass***9500.
This way, you can have 2x6 pos switch for low shelve etc.
Q is kinda "lin" pot, 10x499r, or 5x1k, or 4x1k27 is fine there.

I used rev-log pot calculator for first stepped Sontec, then, the values were bit changed,
gigathanx to my friend Charles for his ears and guys from Bardo and Hook&High mastering studios
who working with my gadgets some years.
http://www.hooknhigh.co.il/english/index.html
http://www.bardostudios.co.il/studios/mastering
Title: Re: sontec 1 RU build thread
Post by: dagoose on July 24, 2010, 02:38:08 AM
Thanks Igor,

It is indeed really that simple when i look at it this way.
The Q will be 11 steps, not much more work then 6 steps but i think that 6 is indeed enough but i want to fill the steps on the panel. :)
I was thinking that for the low shelf i need a 2 deck switch, 1 deck for resistors and the other deck lowest position for the low shelf/peak switching.

I got the 'uraltones' 24x2 for 8,15 euro's each.
They don't have the feel of a elma indeed but they are almost a 10th of the price of an elma!
Title: Re: sontec 1 RU build thread
Post by: zayance on July 24, 2010, 04:29:20 AM
Quote
I got the 'uraltones' 24x2 for 8,15 euro's each.

The seller on ebay, got me those for 7.5dollars  ;), that makes them for about 6euros, that was the price break for 20 pots order when i asked.

Quote
BTW, what is the deal with uraltone switches?

Mine are not from uraltone but that's what it is:

http://cgi.ebay.com/1-PC-Selector-Switch-24-step-2-pole-Attenuator-Pot-New-/270581450882?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item3effe94882#ht_603wt_1138
Title: Re: sontec 1 RU build thread
Post by: MrShhh on July 26, 2010, 08:17:54 AM
Regarding stepped gain controls.
Use less resistance at center, i.e. kinda S-curved control for
exact db steps.
I.e. 2k7-2k7-2k4-2k4-2k2-2k2-2k-1k8-1k5-1k3/0/-1k3-1k5-1k8-.....2k7.

Does anybody have the formulas for working out the above resistance curve? Is it a standard kind of log curve or something else specific to this eq?
Title: Re: sontec 1 RU build thread
Post by: Pieter001 on July 26, 2010, 11:32:10 AM
Hello,

Im ordering the parts for the sontec right now but don't understand something from the Bom.

1 rx+ 3k6 2% for 24v
1 rx- 3k6 2% for 24v

(200R/1.25V)=(Rx/(Ux-1.25V))
Rx in Ohms

What are the right value i need to order?
3k6?

Pieter
Title: Re: sontec 1 RU build thread
Post by: Harpo on July 26, 2010, 12:37:51 PM
Im ordering the parts for the sontec right now but don't understand something from the Bom.

1 rx+ 3k6 2% for 24v
1 rx- 3k6 2% for 24v

(200R/1.25V)=(Rx/(Ux-1.25V))
Rx in Ohms

What are the right value i need to order?
3k6?
depending on what supply voltage your opamps can take
Quote
http://www.groupdiy.com/index.php?topic=27972.msg403084#msg403084
Your chips might only stand +/-18V or +/-22V, so you can rescale the needed value from 3K6 for +/-24V to the allowed supply voltage for your opamps.
Title: Re: sontec 1 RU build thread
Post by: Pieter001 on July 26, 2010, 02:10:34 PM
Thanks for the reply. Didnt see the post back in the thread.

Title: Re: sontec 1 RU build thread
Post by: dagoose on July 30, 2010, 10:05:26 AM
Did some calculating and things for the switches and i come up with 21 steps which is nice becaus eon the gain you have 10x up and 10x down and step 11 = 0
I'm wondering concerning the freq switches, why is it that the high shelf switch has different values for the resistors then the other switches when you calculate them?
Is it because of the highest freq for shelf will be to high if you use the same values? step 21 is 365r with low/mid/hi but with the shelf the value is 576r.

I came up with this for thefreq pots/switches.

FREQ band = 101k total

1
   20k
2
   15k4
3
   12k4
4
   10k5
5
   8k25
6
   6k8
7
   5k36
8
   4k64
9
   3k6
10
   2k94
11
   2k4
12
   1k96
13
   1k54
14
   1k3
15
   1k07
16
   820r
17
   681r
18
   560r
19
   442r
20
   360r
21


Gain switches 48k2 total amount

1      -12db
3k9
2
   3k3
3
   3k
4
   2k7
5
   2k4
6
   2k2
7
   2k
8
   1k8
9
   1k5
10
   1k3
11       MID position =0
   1k3
12
   1k5
13
   1k8
14
   2k
15
   2k2
16
   2k4
17
   2k7
18
   3k
19
   3k3
20
   3k9
21      +12db


 
Title: Re: sontec 1 RU build thread
Post by: Harpo on July 30, 2010, 02:27:32 PM
Did some calculating and things for the switches and i come up with 21 steps which is nice becaus eon the gain you have 10x up and 10x down and step 11 = 0
I'm wondering concerning the freq switches, why is it that the high shelf switch has different values for the resistors then the other switches when you calculate them?
Is it because of the highest freq for shelf will be to high if you use the same values? step 21 is 365r with low/mid/hi but with the shelf the value is 576r.
Different frequency ratio between lowest and highest position for your high band.
For your resistor values, I only had them calculated for E96 and E48 type resistors (http://www.hausverwaltung-heger.de/al_leck_trick/SontecCalc_Igor.xls). Anything lower values per row ie.E12 or E24 would have to use a lookup table for historical reasons.
Title: Re: sontec 1 RU build thread
Post by: dagoose on July 30, 2010, 04:25:11 PM
Did some calculating and things for the switches and i come up with 21 steps which is nice becaus eon the gain you have 10x up and 10x down and step 11 = 0
I'm wondering concerning the freq switches, why is it that the high shelf switch has different values for the resistors then the other switches when you calculate them?
Is it because of the highest freq for shelf will be to high if you use the same values? step 21 is 365r with low/mid/hi but with the shelf the value is 576r.
Different frequency ratio between lowest and highest position for your high band.
For your resistor values, I only had them calculated for E96 and E48 type resistors (http://www.hausverwaltung-heger.de/al_leck_trick/SontecCalc_Igor.xls). Anything lower values per row ie.E12 or E24 would have to use a lookup table for historical reasons.

OK, what i expected indeed. :)
Concerning the values, i just went trough all values at RS and picked the closest values to the original calculation. ok.. i skipped some because i don't need 5000 x one value.  ;D
I came pretty close to the values compared to the excell sheet!
Now up for some soldering when the switches and R's  come in, i think about 800 resistors? pure zen.  :-*
Title: Re: sontec 1 RU build thread
Post by: dagoose on July 31, 2010, 08:51:37 AM
Today i had a better look at the filterboard concerning chopping it up and it's quite easy and will turn out quite nicely i guess.

The 2x low band are real easy to chop apart so that you have 2 boards for the low bands that i can mount vertically near the switches which is really nice.
Then you have the 2x mid/high section with the main inputs/outputs/psu and they are not 'cutable' without messing up the board so these have to stay together as one board. Then the hi shelf is also quite easy, only thing is that the 10k summing resistor 'has to go' because that is where the board is going to be cut but that is just a matter of moving it somewhere else. The summing resistors will all have 2 values for a 12/6db gain switch so that had to be modded anyway.
That gives 4 filterboards in total and the mid/high baord will still be the mainboard where all connctions are made and then the 2x low and 1x hishelf board will have their connections  made to the 'mainboard'.

The panel is going to be great! Peter/grandmaster audio is working on it, pretty much excited about this!
Now for some nice knobs.. i think big metal knobs but not sure yet.  ;D
Title: Re: sontec 1 RU build thread
Post by: dagoose on August 02, 2010, 04:04:59 PM
i couldn't resist, a glimpse of the frontpanel.
(http://www.dagoosemusic.nl/temp/sontec.jpg)
Title: Re: sontec 1 RU build thread
Post by: zayance on August 02, 2010, 04:06:08 PM
Looking good  :)
Title: Re: sontec 1 RU build thread
Post by: muffy1975 on August 04, 2010, 10:40:25 AM
Dear Igor and Team Sontec EQ,

my dual eq worked 1st time. No hum ( gosh it's quiet ) just a great signal.

My only concern are the rails. The + rail = 24.2V and the - rail = -23.6V.

Is this OK team? I believe I put two equal 3.6k resistors in the PSU. Is this what I need to change to get them both at 24v ish?

Regards and many smiles

Michael de Albuquerque
Oxford
England
Title: Re: sontec 1 RU build thread
Post by: dagoose on August 04, 2010, 11:53:52 AM
I don't think it will do any harm but what you can do is use a trimpot instead of the 3k6 resistor so that you trim them both to 24v.
Title: Re: sontec 1 RU build thread
Post by: haima on August 04, 2010, 08:02:51 PM
i wouldn't worry about it Michael - it will surely be of little consequence IMHO.

congrats on the working build! ;)
Title: Re: sontec 1 RU build thread
Post by: MrShhh on August 05, 2010, 01:13:45 PM
Hey dagoose, how would I go about calculating the gain switch values if I want to use 23 positions instead of your 21? I had all the switches soldered up in linear fashion with 2k2 resistors which of course, does not work as intended (nothing's ever as simple as it seems!) Thank you!

Title: Re: sontec 1 RU build thread
Post by: kambo on August 05, 2010, 03:43:58 PM
i am back people..  :)
super busy lately...

MrShhh : check back some pages... there were detailed info on switches....
Title: Re: sontec 1 RU build thread
Post by: dagoose on August 08, 2010, 07:24:21 AM
Concerning modding the 24 steps 'uraltone' switches, check here. http://www.groupdiy.com/index.php?topic=40384.0
Title: Re: sontec 1 RU build thread
Post by: electrisizer on August 13, 2010, 06:40:30 AM
high guys!
is there another (perhaps german) order option for the 5k lin pot sw and the 5k lin pot?

im not in the USA.

does it matter how much "watt" the pots have or could i even take some with more watt?

thanks
Title: Re: sontec 1 RU build thread
Post by: MrShhh on August 19, 2010, 09:46:45 AM
Hi electrisizer,

You can get the exact pots from Banzai Music GmbH  ;):

http://www.banzaimusic.com/CTS-270-SW-5k-LIN.html (http://www.banzaimusic.com/CTS-270-SW-5k-LIN.html)
http://www.banzaimusic.com/CTS-270-5k-LIN.html (http://www.banzaimusic.com/CTS-270-5k-LIN.html)

Remember they have a 3.18mm diamater shaft and to get the right knobs!

Title: Re: sontec 1 RU build thread
Post by: electrisizer on August 20, 2010, 08:09:42 AM
great man thanks a lot!

EQ is nearly finished  :D
Title: Re: sontec 1 RU build thread
Post by: zayance on August 20, 2010, 08:30:37 AM
Just make sure before by mail that they have it in stock, because if not then lead time could be terrible, happened to me once dealing with Banzai, they have great stuff, but no way of seeing stock status.
Just for info, Digikey has free shipping for orders over 65 euros, and tax will be payable when fedex send you the invoice of it.
Title: replacement pot
Post by: jwk1 on August 25, 2010, 07:19:21 PM
Hi,

I'm just building one of these, using the pots supplied as a kit, and the exposed leg has snapped off one of my gain pots (50k centre tap centre detent).  Does anyone know where I might be able to get a replacement pot from?

Thanks very much for any help,

Josh
Title: Re: sontec 1 RU build thread
Post by: buschfsu on September 10, 2010, 01:07:32 PM
any chance of ordering the alphastat pots in the us? I need a supplier for...

10 - 50k CTPOT
2207 RD1601-20F4-30R
ALPHASTAT 63250-01610/B50K 50K LIN CENTERTAPCENTERDETENT

10 - 100K RLOG DUAL_ALPHA_2
4196 RD1602-20B4-30R
ALPHASTAT 63256-02600/C100K 100K REV-LOG

Anyone?  i will order outside us if i have to.

thanks
Title: Re: sontec 1 RU build thread
Post by: zayance on September 10, 2010, 01:14:44 PM
Quote
any chance of ordering the alphastat pots in the us?

I don't think so, that's why the feeler Yosh made and i took care of, the PITA with Alphastat is their Shipping charges, they make some crazy amount for shipping to US directly, but maybe i can help you out, just PM me, don't have to give away, but i'll be doing one order from them, for an idea of the prices, check the feeler, of course a set of Sontec will cost my friend that's for sure....
Title: Re: sontec 1 RU build thread
Post by: electrisizer on September 10, 2010, 02:19:44 PM
one question left:

where do i have to place the one 5K Lin POT and the 3x 5k Lin POT SW? LF, MF1-3?
Title: Re: sontec 1 RU build thread
Post by: zayance on September 10, 2010, 02:25:37 PM
Quote
where do i have to place the one 5K Lin POT and the 3x 5k Lin POT SW? LF, MF1-3?

You Mean the 3xLin Pots, and the Lin Pot with switch:

http://i251.photobucket.com/albums/gg291/diy33609/P1020023.jpg
Title: Re: sontec 1 RU build thread
Post by: electrisizer on September 11, 2010, 05:22:09 AM
 :-\
thats what ive suspected...

its a mistake in the BOM:

3 5K LIN POTSW
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=CT2204-ND

1 5K LIN POT
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=CT2226-ND

im wondering noone has observed.

can i place the swich pots instead of normal pots too?
Title: Re: sontec 1 RU build thread
Post by: zayance on September 11, 2010, 05:46:29 AM
Quote

thats what ive suspected...

its a mistake in the BOM:

3 5K LIN POTSW
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=CT2204-ND

1 5K LIN POT
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=CT2226-ND

im wondering noone has observed.

can i place the swich pots instead of normal pots too?

Yes a Typo mistake i know and saw that, but the link clearly sends you to the right one so....., and the picture gives proof to what's needed, so i think nobody bothered saying, hey typo there, i tought about you buying wrong ones when asking question, but this is electronics, better check twice before everything, got caught in your situation too for different things, i don't think you can stick the SW ones in the linear places ??? But maybe actually, the pads seems to fit also, anyway if not, then think about it this way you'll have spares for other Sontecs....
Title: Re: sontec 1 RU build thread
Post by: electrisizer on September 12, 2010, 06:01:27 AM
hm i dont even understand why the Q of the LO-F is switchable in this design.
so i cant decide if its sensible to make other Qs switchable too.

the mounting is not a problem. the pots fit everywhere...

perhaps can igor give an advice?
Title: Re: sontec 1 RU build thread
Post by: haima on September 12, 2010, 07:52:26 AM
isn't the switch to engage the "shelf" mode?
Title: Re: sontec 1 RU build thread
Post by: zayance on September 12, 2010, 07:56:45 AM
Yes low shelf switch
Title: Re: sontec 1 RU build thread
Post by: Joe_caithness on September 18, 2010, 04:54:58 AM
Hello,
(http://img.photobucket.com/albums/v687/joe_caithness/Front.jpg?t=1284460029)

Built by Mark Watson... m.a.watson at hotmail.co.uk

Slutty info:

- It has EQ in and out switches on each band
- It's stereo, but fixed in linked mode
- It has a 6 or 12 dB switch, so that's 6dB at 0.5 steps or 12 at 1dB steps
- All other controls are switched for maximum recall.
- It looks the same as my compressor, aka like a tank!

Some basic operating info:

Individual bypass switches:

Up
+/-11dB gain in 1dB steps (bands 1 to 4)
+/-5.5dB in 0.5dB steps (band 5 - hi-shelf)

Middle
Off

Down
+/-5.5dB gain in 0.5dB steps (bands 1 to 4)
+/-2.75dB in 0.25dB steps (band 5 - hi-shelf)

So band 5 has half the gain range of bands 1 to 4 just because I could think of no earthly reason why anyone would need a +/-12dB shelf in a mastering eq.

IN switch (top right)
Bypasses all channels for quick A/B testing.

Low Shelf
On the original, this only worked when the Q knob was turned all the way to the left and the pot switch was engaged. In your model, it can be used at any Q value giving some more sound shaping options (which may or may not be desirable, worth playing around with it).

Hi Shelf Slope Switch
Switches between 12dB/octave & 6dB/octave slope. This is a subtle change but still useful.

Q switches
Continuous rotary switches so you can go from Q=1 to Q=12 in 1 step.
I used 12 steps in the end as 24 would have been total overkill. 6 steps would have been more than adequate looking back.
Title: Re: sontec 1 RU build thread
Post by: Igor on September 27, 2010, 05:23:07 PM
Nice panel. What's inside?

For all guys here who want this EQ steped.
I hate the idea with cutting my logo on PCB with dremel tool :)
To be more accurate and let you all have nicer stepped EQ's
without cutting the PCB's with dremel.

I almost finished mastering version of PCB set which will be offered soon.

Here is what I did about 5 years ago:

http://www.bardostudios.co.il/studios/mastering
(check the animated picture, and re-load site to play it again).
Title: Re: sontec 1 RU build thread
Post by: zayance on September 27, 2010, 05:26:32 PM
Quote
I almost finished mastering DIY-able version of PCB set.

ha, you just never stop  :), well you know what i'm going to say then.....
Title: Re: sontec 1 RU build thread
Post by: Igor on September 27, 2010, 05:33:33 PM
:)
I have about 200 of audio projects.

About 40 were finished.

8 of them were done many times by other people,
like 33609, TG, (ops :), 2254C, Sontec, etc.
This is my fun to receive a message kinda "Igor, built your 2254C about a year ago,
working with it daily, today it sounded cool on drums and just writing this to let you know".

About 30-40 are drawn in my PC and were breadboarded (I never simulate).
About 100 projects are in my had.
Anyway, I hope new mastering version of Sontec PCB's will be right in!

edit: sorry, i am not good in mathematics :)
Title: Re: sontec 1 RU build thread
Post by: Matthew Jacobs on September 27, 2010, 06:14:38 PM

I almost finished mastering version of PCB set which will be offered soon.


Damm! and I just bought a Sontec board from you today! Ahhh anyway, it will be fun to chop it up....
Title: Re: sontec 1 RU build thread
Post by: Igor on September 27, 2010, 10:35:22 PM
@Matthew, we figured this out, or this wasn't you?
I completely lost in mails and forum names!
@Mark: thanx! Have a fun with your Sontec!

Some other projects will come soon......hopefully :)
Title: Re: sontec 1 RU build thread
Post by: electrisizer on September 28, 2010, 04:23:47 AM
hi igor i finished my sontec yesterday - it works nearly from first powerup. just still waiting for "one" poor cap thats missin. i hope supplier hurries up...

but i have to say that its an exiting unit that sounds great. not a colorful EQ like my old british EQs from 80s soundcraft desk... it sounds clean but not harsh. im very interested in a mastering version then i use my normal sontec in the bus. thank you for the project  :D
Title: Re: sontec 1 RU build thread
Post by: horvitz on September 28, 2010, 06:56:40 AM
For all guys here who want this EQ steped.
I hate the idea with cutting my logo on PCB with dremel tool :)
To be more accurate and let you all have nicer stepped EQ's
without cutting the PCB's with dremel.

Not so fond of cutting, myself!  But I'm curious, are you thinking of any real functional changes or just going to change the layout so that it's on multiple boards?

  Brian
Title: Re: sontec 1 RU build thread
Post by: Igor on October 17, 2010, 12:34:17 PM
Quote
But I'm curious, are you thinking of any real functional changes or just going to change the layout so that it's on multiple boards?

There will be motherboard and filter's boards....
Finally, after 95% (rough nr, anyway :) finishing the motherboard,
I got a crazy idea about adding MS and output level trim.....
/never counted myself normal, cough :)
The EQ can be build in "vertical" and "horisontal" front arrangement,
i.e. left channel at left side/right chann. at right side, or
left channel top/right channel bottom. Just...some time, it is there.
Title: Re: sontec 1 RU build thread
Post by: horvitz on October 17, 2010, 11:16:50 PM
Now, where's the fun in normal?  ;D

But, interesting stuff!  I was going to get working on your 1RU boards, but I think I'll hang out and see how this develops.  M/S is a neat idea.
Title: Re: sontec 1 RU build thread
Post by: mrcase on October 20, 2010, 05:17:54 PM
hi all!

did someone test piers app99f substitute for the JE990 in this circuit?
Am I good to go with these for my sontec?
Title: Re: sontec 1 RU build thread
Post by: mrcase on November 03, 2010, 04:14:13 PM
ok. one more...
still sourcing parts.
What kind of wimas are you guys using? Am I good to go with "normal" MKS types or should I care for polypropylenes ones?
any other good hints regarding caps to make this eq sound killer?  ;D

thank you all!
cheers
martin
Title: Re: sontec 1 RU build thread
Post by: mrcase on November 14, 2010, 08:31:46 AM
Hi all!

a question regarding the bom. are the R-EU_0207/15 resistors supposed to be carbon resistors?

cheers
Title: Re: sontec 1 RU build thread
Post by: Pieter001 on November 20, 2010, 12:58:27 PM
Hello,

I want to know for sure if i wired the toroid the right way in my sontec. The color of the wires:

BLK 0v
RED 25v

ORA 0v
YEL 25v

I connected the black wire to ~1 on the pcb, the red and orange wires to ~AB and the yellow wire to ~2
Is this right? ???

Thanks
Title: Re: sontec 1 RU build thread
Post by: zayance on November 20, 2010, 03:41:02 PM
Hello,

I want to know for sure if i wired the toroid the right way in my sontec. The color of the wires:

BLK 0v
RED 25v

ORA 0v
YEL 25v

I connected the black wire to ~1 on the pcb, the red and orange wires to ~AB and the yellow wire to ~2
Is this right? ???

Thanks

Sounds good
Title: Re: sontec 1 RU build thread
Post by: deuc224 on November 21, 2010, 05:07:51 AM
Im looking for the jfet 993s and they arent on the foressell site, they only havethe schematic in he schematic section. Discontinued? ???
Title: Re: sontec 1 RU build thread
Post by: zayance on November 21, 2010, 03:35:27 PM
Im looking for the jfet 993s and they arent on the foressell site, they only havethe schematic in he schematic section. Discontinued? ???

http://www.forsselltech.com/products/jfet993.html
Title: Re: sontec 1 RU build thread
Post by: UNIVAC on November 21, 2010, 03:51:24 PM
Quote
But I'm curious, are you thinking of any real functional changes or just going to change the layout so that it's on multiple boards?

There will be motherboard and filter's boards....
Finally, after 95% (rough nr, anyway :) finishing the motherboard,
I got a crazy idea about adding MS and output level trim.....
/never counted myself normal, cough :)
The EQ can be build in "vertical" and "horisontal" front arrangement,
i.e. left channel at left side/right chann. at right side, or
left channel top/right channel bottom. Just...some time, it is there.

it is a MS - DECODER
Title: Re: sontec 1 RU build thread
Post by: Pieter001 on November 23, 2010, 02:39:19 PM
Powerd up my sontec today. D19 got realy hot and the transformer warms up too.
Measure little more than 20v at ~1 and ~2 from my 25v transformer. On the wires on the other side of the psu pcb i measure a realy low voltage.
There is something wrong with my psu but i cant find the thing. Could it be a bad diode? ???

Thanks
Title: Re: sontec 1 RU build thread
Post by: zayance on November 23, 2010, 05:26:33 PM
Quote
Powerd up my sontec today

It's better to test the PSU always first before connecting to the boards, so you know it's doing fine before feeding the Main boards with IC out and checking again, just saying maybe you've done this anyway, not sure tough.

Quote
D19 got realy hot and the transformer warms up too.

Transformer getting hot is a sign of a short somewhere If i'm correct, or transformer maybe underated in terms of VA?, did you install the Diodes the right way around? Any bad soldering underneath the PCB...
And of course little voltage at the other end is sign of something wrong, check everything as always, it's small mistake most of the time...
I'm not a pro but maybe this can help???  :)
Title: Re: sontec 1 RU build thread
Post by: 1234 on November 28, 2010, 04:01:40 AM
I have just finished soldering my Sontec PCB. It works perfect! thank you Igor!
Very good sounding EQ - transparent, big, but with sweet hint...the noise is quite low too. Sometimes one can forget that there it is EQ in the sound path...very natural sounding equalisation. Found it wery useful on channel.
And for information - I have tried it with old first generation Forsell DOAs from the schematics on their site (a friend has rolled them for me) on input and output on one channel and AB tested it with 604 ICs on the other channel. I consider the variant with DOAs superior sounding - better detail, more animated sound, silkier too. But do not think 604 is bad  - actualy it is very nice sounding and it is quite close in quality to DOA variant. Noise does not change significantly in both variants, probably its origin in this topology is not OP Amp dependant.
Title: Re: sontec 1 RU build thread
Post by: electrisizer on November 28, 2010, 05:23:16 AM
thats interesting to hear! when igor release the mastering version i will go with DOAs too... but im still very happy with this IC beast :)
perhaps the only wish thats left for me would be a more detailed control range for the low frequences... 50hz-120hz
Title: Re: sontec 1 RU build thread
Post by: Igor on November 29, 2010, 06:54:45 PM
1234: thanx for the info and enjoy!
Yes, those small 604's aren't bad sounding, hehe...
I absolutely agree about Forssell's op-amps. I used both older version and 993, and, IMHO, this is best sounding opt.

electrisizer: I finishing the new version proto PCB design, with stepped control;
here, you can expand or squeeze control range as you want, and have 23 steps in 50-120 hz :)
 
Title: Re: sontec 1 RU build thread
Post by: electrisizer on November 30, 2010, 04:35:01 AM
here, you can expand or squeeze control range as you want, and have 23 steps in 50-120 hz :)

oh yeah its christmas  ;D
Title: Re: sontec 1 RU build thread
Post by: Igor on November 30, 2010, 09:26:46 AM
lol
Title: Re: sontec 1 RU build thread
Post by: gandhalf3 on November 30, 2010, 04:12:30 PM
Hello, I'v finished my Sontec, and he is not working well. I v'got two problemes :

1. When I turn the Gain on a band clockwise, the level of the band is decreasing, and when i turn counter clockwise is increasing. (Same probleme on each band)

2.  I'v Got MF3 on each channel don't working. strange. (In fact when I Turn the knob full CCW I'v got a boost of all the spectrum about 0,5db and CW a -0,5db on all the spectrum.)

I need your help.

Thanks  8)
Title: Re: sontec 1 RU build thread
Post by: gandhalf3 on December 01, 2010, 06:04:57 AM
Hello, I'v finished my Sontec, and he is not working well. I v'got two problemes :

1. When I turn the Gain on a band clockwise, the level of the band is decreasing, and when i turn counter clockwise is increasing. (Same probleme on each band)

2.  I'v Got MF3 on each channel don't working. strange. (In fact when I Turn the knob full CCW I'v got a boost of all the spectrum about 0,5db and CW a -0,5db on all the spectrum.)

I need your help.

Thanks  8)

Please help !  :'(
Title: Re: sontec 1 RU build thread
Post by: kante1603 on December 01, 2010, 06:48:33 AM
Hello, I'v finished my Sontec, and he is not working well. I v'got two problemes :

1. When I turn the Gain on a band clockwise, the level of the band is decreasing, and when i turn counter clockwise is increasing. (Same probleme on each band)

2.  I'v Got MF3 on each channel don't working. strange. (In fact when I Turn the knob full CCW I'v got a boost of all the spectrum about 0,5db and CW a -0,5db on all the spectrum.)

I need your help.

Thanks  8)



Please help !  :'(


Hello gandhalf,

seems that all of your gainpots are reversed meaning you have the in and out of each pot swapped (the both outer pins).
This can only be achieved if you have mounted them off board (swapped the outer wires-easy fix!) or mounted them on the wrong side of the pcb!
It would be helpfull if you can show us a picture of your pot-mounting.
For your MF3-issue (do you mean the third band from the left?) I can not help at the moment,but this is a differnt thing-maybe we can see more when we have the pics.

Hope to have helped,

Udo.
Title: Re: sontec 1 RU build thread
Post by: gandhalf3 on December 01, 2010, 08:30:34 AM
Hello, I'm talking about the 4th from left.


here are the pics :

(http://farm6.static.flickr.com/5205/5223722290_dc7d0c33ac_z.jpg)

(http://farm5.static.flickr.com/4091/5223125813_fab9c4fedd_z.jpg)

(http://farm5.static.flickr.com/4126/5223722580_d80008c6ce_z.jpg)

http://farm6.static.flickr.com/5288/5223126101_cc23d61c00_b.jpg (http://farm6.static.flickr.com/5288/5223126101_cc23d61c00_b.jpg)

http://www.flickr.com/photos/[email protected]/5223127255/in/photostream/  (http://www.flickr.com/photos/[email protected]/5223127255/in/photostream/)
Title: Re: sontec 1 RU build thread
Post by: dagoose on December 01, 2010, 08:43:22 AM
I think you swapped 2 wires from the filterboards to the summing boards (see schematic), otherwise i don't know what's wrong.
Concerning MF3, make sure you have the right caps in there, could be that it's boosting and cutting at 100khz instead of 1khz.  8)
Title: Re: sontec 1 RU build thread
Post by: kante1603 on December 01, 2010, 09:14:05 AM
Hi again,

after having seen your pics (always very helpfull!!!)  I think dagoose is right-must be the connections from eq to op/summing-even more easy to fix ;)

Good luck to you-and do not forget to check the cap values on MF3 (super good tip of dagoose again).

Udo.
Title: Re: sontec 1 RU build thread
Post by: gandhalf3 on December 01, 2010, 12:37:13 PM
thanks for your help.



Here are the pictures of the condo in the High/medium frequecy band. (the 4th from left.)

(http://farm5.static.flickr.com/4104/5223682785_edebf30071_b.jpg)

(http://farm5.static.flickr.com/4103/5224280780_9dbb9b941c_b.jpg)

(http://farm6.static.flickr.com/5089/5224281160_8de3cf6f3c_b.jpg)

(http://farm6.static.flickr.com/5128/5223683931_eb983d7eae_b.jpg)


Title: Re: sontec 1 RU build thread
Post by: gandhalf3 on December 01, 2010, 02:08:27 PM
is my CHMF3 0,15 or 150 ?  ???
Title: Re: sontec 1 RU build thread
Post by: kante1603 on December 01, 2010, 03:32:43 PM
Hi gandhalf,

CHMF3 seems to be wrong.
I do not know the (black) caps you used but if it is the code written on it then 150 means 15pF.
Not 100 percent sure but looking at the schemo it will be wrong then(says 0.15).
If this is it then also check CHMF4 because code 100 will mean 10pF (schemo says 100).
The rest of the caps look o.k. on the first sight.
Maybe dagoose or Igor can clear it up?

And did you have success with swapping wires?

Udo.
Title: Re: sontec 1 RU build thread
Post by: Harpo on December 02, 2010, 07:04:08 AM
is my CHMF3 0,15 or 150 ?  ???
your dipped mica cap  (http://www.cde.com/catalogs/STD-DIPPED.pdf) looks like 150pF.
You want a 0.15uF = 150nF cap in this place. (this will not be a mica type)
Title: Re: sontec 1 RU build thread
Post by: gandhalf3 on December 02, 2010, 03:42:45 PM
thanks a lot for your advises. I'll try with a new cap. and for the polarity problem I think that my measuring software switched the reference curve with the measured one. so polarity switched.

Title: Re: sontec 1 RU build thread
Post by: kante1603 on December 03, 2010, 01:27:28 AM
thanks a lot for your advises. I'll try with a new cap. and for the polarity problem I think that my measuring software switched the reference curve with the measured one. so polarity switched.



Good to hear that you have the first problem solved,but it seems to me therefore that you have only measured your eq with some measuring software and did not listen to it?
If so may I give you an advice-TRUST YOUR EARS (you would have heard that....) ;D

Now you are on track I think....thanks to harpo for clearing the cap issue-did not know these types so it was very helpfull for me either as I  am about to build some of them in the near future (...if my work does not kill me before that ;).

Cheers,

Udo.
Title: Re: sontec 1 RU build thread
Post by: dagoose on December 03, 2010, 11:30:05 AM
I know almost 100% sure it's the caps, i had the same thing. Check this thread, i think 3rd post from the top: http://www.groupdiy.com/index.php?topic=40648.msg507967#msg507967
Title: Re: sontec 1 RU build thread
Post by: gandhalf3 on December 03, 2010, 03:28:13 PM
well done boys. I'v changed the presumed 0,15U who was in fact 150p.  Now all bands work great, sound good. but i found the noise floor a little bit high (i'v put the OPA604 )

here are some curve. If someone could say if they are right. i' have some doubt about the LF band in shelf mode.

(http://farm6.static.flickr.com/5241/5229895716_8834cd1c65_z.jpg)

higher resolution http://farm6.static.flickr.com/5241/5229895716_8834cd1c65_b.jpg (http://farm6.static.flickr.com/5241/5229895716_8834cd1c65_b.jpg)

(http://farm6.static.flickr.com/5043/5229895462_9eb377ae5f_z.jpg)

higher resolution http://farm6.static.flickr.com/5043/5229895462_9eb377ae5f_b.jpg (http://farm6.static.flickr.com/5043/5229895462_9eb377ae5f_b.jpg)

(http://farm6.static.flickr.com/5209/5229302867_809f7a690c_z.jpg)

higher resolution http://farm6.static.flickr.com/5209/5229302867_809f7a690c_b.jpg (http://farm6.static.flickr.com/5209/5229302867_809f7a690c_b.jpg)



Title: Re: sontec 1 RU build thread
Post by: gandhalf3 on December 04, 2010, 05:18:55 AM
adding some more wires to the star ground  to th PCBs could help to reduce the noise floor ?
Title: Re: sontec 1 RU build thread
Post by: briomusic on December 05, 2010, 09:56:46 AM
Hi Igor/group,
I am wondering if it is possible/smart to vary the resistors next to the gain potentiometers to compensate for the 20% tolerance of these pots. Basically, what I am trying to achieve is that at its center-detent position the pot really doesn't have any boost or gain. However, measuring my pots it turns out most of them are pretty far off value, for example 52k from left to right leg, and 24k from left to tap (at center detent) and 28k from tap to right. For this pot, shouldn't I use a higher (than 4k75) resistor for RFxC and a lower one for RFxB? In this example, I would chose 5k75 for RFxC and 1k75 for RFxB.

The ideal case sum of resistors is: 4k75+50k+4k75 = 59k5

My real world sum of resistors is: 5k75+52k+1k75 = 59k5, (which it wouldn't be if I had stuck to the spec resistors)

Also the resistance from the CUT and BOOST buss to the potentiometer tap is more evened out, at center detent position.

Is this a good thing to do?
Thanks
Briomusic

ETA: I can't get hold of 1n5400 diodes is there another diode i can use? what is the disadvantage using normal 1n400x types? cheers
Title: Re: sontec 1 RU build thread
Post by: Igor on December 09, 2010, 02:53:48 PM
Brio: gain potentiometers already have CENTERTAP grounded,
and it doesn't matter so much 45K or 55K total resistance, and 0db will be exactly at center.
The DB/versus rotation angle may be bit different, but hey,
you want an action of precision 21-pos switch from potentiometer, which
in any case will be weared a bit within 3-5 years and give even more tolerance.
Title: Re: sontec 1 RU build thread
Post by: briomusic on December 09, 2010, 04:58:00 PM
Ah, that's what the 4th pin on those pots is for. How exactly does it work?

Anyway, I will build a switched-resistor sontec at some point in the future, just wanted to bash one out cheaply and quickly, mainly for tracking purposes. I guess instead I will just use similar pots for the left and right channels respectively, so rotation angles are roughly matched (even if not accurate to silk screening).

Thanks,
Brio
Title: Re: sontec 1 RU build thread
Post by: analogica on January 04, 2011, 11:08:19 AM

 hi everyone....

  i need some help, sorry about my stupid questions if the they are....i ve done several proyects but im a bit lost in electronics.

   1. how do i have to solder the toroid ??? i have an 2 x 24 V 50VA

     ive read in the forum  :

RED 25v
ORA 0v
YEL 25v
I connected the black wire to ~1 on the pcb, the red and orange wires to ~AB and the yellow wire to ~2
 
  But my trafo has 2 black wires , 2 red wires and 2 blue.....so how do i have to solder them???? and please i cant find ~1 and ~2 on the board, where are  they????


  2.which caps do you recomend for 33 uF ????   panasonic??? philips ???  elna????

  3.if my trafo is 24V i have to solder 3K6 on rx + and rx - , is that right???

  4.ive soldered all the 7K5 resistors on the pcb, do you recomend to change for 4K7 on the LF part????

  5.i have the 0,15 cap empty, which one works best on there????

  6.that resistor on the pots pcb.....FB 0...is that a jumper???? waht do i have to put on there????

  7. Where can I find a wiring overlay of the `proyect????  im completely lost about the cables, and the IEC power socket....

    thanks so much for your help

 
Title: Re: sontec 1 RU build thread
Post by: Harpo on January 04, 2011, 02:22:00 PM
   1. how do i have to solder the toroid ??? i have an 2 x 24 V 50VA
     ive read in the forum  :
RED 25v
ORA 0v
YEL 25v
I connected the black wire to ~1 on the pcb, the red and orange wires to ~AB and the yellow wire to ~2
 
  But my trafo has 2 black wires , 2 red wires and 2 blue.....so how do i have to solder them???? and please i cant find ~1 and ~2 on the board, where are  they????
Colour coding of transformers is NOT standarized. Without giving a hint on manufacturer and type of YOUR transformer, no one can seriously help you. Updating your profile with your location might further indicate, this info is needed for 115V, 230V, 240V or whatever AC mains from your wall outlet.

Quote
  3.if my trafo is 24V i have to solder 3K6 on rx + and rx - , is that right???
Maybe, maybe NOT. http://www.groupdiy.com/index.php?topic=27972.msg497711#msg497711 (http://www.groupdiy.com/index.php?topic=27972.msg497711#msg497711)

Quote
  5.i have the 0,15 cap empty, which one works best on there????
A 150nF cap with the correct pin spacing.
Title: Re: sontec 1 RU build thread
Post by: MrShhh on January 06, 2011, 08:01:38 AM
2.which caps do you recomend for 33 uF ????   panasonic??? philips ???  elna???? 
Panasonic FM works well.

Quote
4.ive soldered all the 7K5 resistors on the pcb, do you recomend to change for 4K7 on the LF part????
4K7 gives +/-12dB gain, depends if that's what you want for the LF band (or any other band). Up to you.   

Quote
6.that resistor on the pots pcb.....FB 0...is that a jumper????
Yes. Or a ferrite bead.
Title: Re: sontec 1 RU build thread
Post by: analogica on January 06, 2011, 10:50:35 AM

 thanks indeed guys!!!!

   im looking for my trafo on internet but i cant find the info...

    EYRA 230 V 50/60 Hz  sek: 2 x 24 50VA  as i said , 6 wires , two blacks , 2 blue, 2 reds   has somebody the same???

    which value do i need then for rx resistors???? variable trim is the better choice or 3K6 just works for it????


     thanks again
 

   
Title: Re: sontec 1 RU build thread
Post by: Harpo on January 06, 2011, 11:32:29 AM
  im looking for my trafo on internet but i cant find the info...

    EYRA 230 V 50/60 Hz  sek: 2 x 24 50VA  as i said , 6 wires , two blacks , 2 blue, 2 reds   has somebody the same???

    which value do i need then for rx resistors???? variable trim is the better choice or 3K6 just works for it????
Answer is depending on what supply voltage your opamps can take.
Your chips might only stand +/-18V or +/-22V, so you can rescale the needed value from 3K6 for +/-24V to the allowed supply voltage for your opamps.
Your 'EYRA' might be a typo and manufacturer iswas 'ERA' for real.
For usual, all needed info is printed on a label at your whatever toroid-/block-/EI-core- ..transformer.
Title: Re: sontec 1 RU build thread
Post by: MrShhh on January 06, 2011, 12:23:36 PM
I'd like to add 6dB input & output trim. Is this as simple as varying the feedback resistors in the input & output amplifiers from 20k down to 10k given that G = Rf/Rin. I figure changing both feedback resistors at once in the differential input amp would preserve the common mode rejection and give the correct gain reduction...For the inverting output only one resistor would need to be variable.

This would save me messing around with bridged T or "unbalanced floating" attenuators etc.

Is there some snag to varying the gain via the feedback resistors?



Title: Re: sontec 1 RU build thread
Post by: analogica on January 10, 2011, 03:21:44 PM


    thanks guys....i really need you,more doubts:

   1.i read this :somewhere   :   BYPASS PCB:  1m cap = 1.8uF - 2.2uF is fine there....is that right??? can i use in the 100m caps on filter board????

   2.i cant find the eyra or era trafo on internet....can somebody help me with the wires????

       My OPs are the 604, so how do i solder it???  i have 2 red wires, 2 blue and 2 black, which one goes to 1 , to 2 or to grnd ????

   3.And about the wiring inlay....im trying to understand the pcbs and the arrows but im lost,

 
  Sorry to be a pita guys but this is mi first proyect without a manual....

    thanks indeed

Title: Re: sontec 1 RU build thread
Post by: Harpo on January 11, 2011, 08:44:16 AM
1.i read this :somewhere   :   BYPASS PCB:  1m cap = 1.8uF - 2.2uF is fine there....is that right??? can i use in the 100m caps on filter board?
Please include a reference number (such as C12, R123, IC-2, ..) for a part in question, so we're talking about the same object. Your question is probably related to the 1m=1uF cap (C in) on Input/Summing PCB. If so, 1.8uF - 2.2uF is fine as well, if you can make this larger sized cap fit on PCB.
I have no idea what you are asking about the 100uF caps on filter board.

Quote
2.i cant find the eyra or era trafo on internet....can somebody help me with the wires????
Why don't you read the sticker applied to this whatever type transformer and post this. A close up picture from this label might help as well. If this label says 'ERA' or 'era Elektrotechnik', this german company now is owned by 'Pulse GmbH'.

Quote
My OPs are the 604, so how do i solder it???  i have 2 red wires, 2 blue and 2 black, which one goes to 1 , to 2 or to grnd ????
Only two (or 4 for stereo) of your opamps are the OPA604. The remaining ones are NOT.
If all of the remaining dual opamps are OPA2604, +/-24V supply voltage would fit, so Rx is 3k6.
If at least one of the remaining dual opamps is an AD706, NE5532 or another one with lower max.supply rating, +/-24V supply voltage would/might blow this opamp.
Title: Re: sontec 1 RU build thread
Post by: briomusic on January 11, 2011, 04:38:19 PM
I would like to add a post-gain control to my sontec, to compensate for level differences caused by eq-ing. Can i replace the 20k resistor in the feedback path of the output opamp with a 10k resistor and a 20k variable resistor in series? Would I need a lin or log pot?
original:
(http://img.photobucket.com/albums/v426/brio/gain_ctrl_before.gif)
pot added: (http://img.photobucket.com/albums/v426/brio/gain_ctrl_after.gif)
Title: Re: sontec 1 RU build thread
Post by: MrShhh on January 12, 2011, 05:08:31 AM
Hi briomusic, this is similar to what I asked 4 posts ago.

Unless I'm mistaken, you'd need a log pot and would have between -6dB and +3.5dB of gain if you did things this way. I don't know what issues (if any) changing the feedback resistance might cause....

Rf        Rin      Rf/Rin dB
10.00   20.00   0.50   -6.0
10.62   20.00   0.53   -5.5
11.25   20.00   0.56   -5.0
11.91   20.00   0.60   -4.5
12.62   20.00   0.63   -4.0
13.36   20.00   0.67   -3.5
14.16   20.00   0.71   -3.0
14.99   20.00   0.75   -2.5
15.88   20.00   0.79   -2.0
16.83   20.00   0.84   -1.5
17.82   20.00   0.89   -1.0
18.88   20.00   0.94   -0.5
20.00   20.00   1.00   0.0
21.18   20.00   1.06   0.5
22.45   20.00   1.12   1.0
23.78   20.00   1.19   1.5
25.17   20.00   1.26   2.0
26.68   20.00   1.33   2.5
28.25   20.00   1.41   3.0
30.00   20.00   1.50   3.5
Title: Re: sontec 1 RU build thread
Post by: briomusic on January 12, 2011, 07:02:04 AM
Hi MrShhh,
yes i noticed your similar question, and was trying to bump the thread (with additional pictures to get attention)  ;D
can i ask you, why are you keen on variable input gain as well? this seems to be asking for trouble in terms of CMRR...? I am mostly worried about overloading the converter input post eq, if there is a lot of boosting going on.
cheers
Briomusic.

p.s. I like your formulas/tables and that would be exactly the gain range i am after! I think I am just going to give it a try the next time the case is open...
Title: Re: sontec 1 RU build thread
Post by: analogica on January 12, 2011, 07:05:19 AM
 sorry about the last post..theres a problem on my replys

 Danke schön Harpo!

   the reference of the 100m caps in think they are C1 - C22  or  C2 - C51, i have the old schematics...but they are the couple next to the ferrite bead, i soldered 220 uF, is that right on there???
   
the name of the trafo is EYRA, so i cant find the info, im still searching...i guess 2 red are the hots, 2 blue are the cold, and 2 black the ground...but which goes to ~1  ~2  or  ~AB...
 
and yes my ops are 2604 ap...so 24V should work

   thanks
Title: Re: sontec 1 RU build thread
Post by: MrShhh on January 12, 2011, 10:24:54 AM
Hi MrShhh,
can i ask you, why are you keen on variable input gain as well? this seems to be asking for trouble in terms of CMRR...?
It's just an idea at the moment to add flexibility, not as useful as output trim but if it's simple enough...I think it's possible to preserve the CMR of the input but you have to change resistors R3 & R4 at the same time to match each other. It could be done with a stepped attenuator to get a good match at all settings. I'm not 100% sure if this is a good thing to mess around with, or if my reasoning is correct!

On a bit of a tangent, according to P9 of the IC Op-Amp Cookbook:

Common mode gain of a diff amp = 4d[Rf/(Rin+Rf)]
where d is the fractional unbalance of the resistors (1.0% = 0.01).

So if we have a 1% resistor mismatch in the unity gain diff input amp then:

CM gain = 4*0.01*[20k/(20k+20k)] = 0.02

This seems really high?? Is it wise then to use 0.1% matched resistors or better? Practically speaking, it probably doesn't matter, I'm just interested in the theory...

(http://i985.photobucket.com/albums/ae333/MrShhh_2009/MS250/250InputAmp.jpg)
Title: Re: sontec 1 RU build thread
Post by: Harpo on January 12, 2011, 10:45:12 AM
the reference of the 100m caps in think they are C1 - C22  or  C2 - C51, i have the old schematics...but they are the couple next to the ferrite bead, i soldered 220 uF, is that right on there???
These will work if they are rated for at least 24V. Comon value would be 220uF/35V. Watch out orientation of these polarized parts.
   
Quote
the name of the trafo is EYRA, so i cant find the info, im still searching...i guess 2 red are the hots, 2 blue are the cold, and 2 black the ground...but which goes to ~1  ~2  or  ~AB...
Still you give no further information or pics of your transformer, but your guess will be wrong. This is a transformer, not a battery. 6 leads comming in/out and stating, its a dual secondary, would be one wire pair for primary winding, further connecting to mains switch - fuse - IEC-connector - 230VAC wall outlet, the remaining two wire pairs are your 2x separate windings 24VAC each. This isn't a center tapped transformer, but it can be wired to behave as such.

Get a multimeter, switched for measuring ohms and sort out the 3 pairs (or read the sticker applied to your transformer. If there is the manufacturers name EYRA printed on, there will be other/all information as well as symbols/signs/dots ::)). Your measuring result might come up with the pairing black/black- and red/red-, blue/blue- or red/blue, red/blue or another permutation. Looking close to the wire insulation, you might notice a thin white or black stripe at one of the black, red and blue wires, indicating the cold or out-of-phase wire end of this winding connection. 

For your 230:24+24 stepdown transformer, the primary winding wires (wild guessing maybe the black/black- wire pair) most often come with a smaller diameter (more turns, less current) than the secondary winding wires. If all wire diameters are the same, you want to be absolutely sure which pair connects to AC mains side before picking a wrong pair and have the transformer connected backwards (giving a frightening 2300VAC secondary instead). A VariAC or a small low voltage transformer (doorbell transformer,...) in front could help to sort this out with less lethal voltages.

For examples sake, assuming the secondary pairs as red/red- and blue/blue-, you want both of your 24VAC secondary windings connected in series, giving a single 48VAC secondary winding with this series connection being the center tap. This now combined single secondary winding has a hot/in-phase end (red) and a cold/out-of-phase end (blue-), each further connecting to either '~1' or '~2'. The transformers center tap junction (red- linked to blue) is further connecting to '~AB'.
Title: Re: sontec 1 RU build thread
Post by: analogica on February 07, 2011, 11:31:23 AM

 Hi friends, im almost there....

  I have a few questions about the wiring...

  1. how do i have to solder the XLR boards???  what i see on the pictures is PS to filter board, and PS 2 to
      power board, is that right???    so i just have to follow the numbers from 1 to 4, right???

      I cant see it so clear,

   2.i have to solder XLR board ground to GRD on the power board, and add the the input ground on the plug, right???

   3. how do i have to solder the toroid to a ON/OFF switch???, just the AB wires ???

  sorry if my questions are silly, im lost

     thanks again
Title: Re: sontec 1 RU build thread
Post by: analogica on February 09, 2011, 12:58:24 PM

 come on guys, im stuck, pleaseeeeee.....
Title: Re: sontec 1 RU build thread
Post by: zayance on February 09, 2011, 07:39:15 PM
Quote
1. how do i have to solder the XLR boards???  what i see on the pictures is PS to filter board, and PS 2 to
      power board, is that right???    so i just have to follow the numbers from 1 to 4, right???

      I cant see it so clear,

Just connect PSU board to PS, and go from PS2 to Filter board. For making sure the + to - follow the traces on the board.
Quote
2.i have to solder XLR board ground to GRD on the power board, and add the the input ground on the plug, right???

If you take a closer look under the summing board, you will see that there are two different plane grounds, one for the XLR's that has to be connected to your star ground, and the other that is connected to your PSU ground.
Do a star ground hooked to the chassis with a steardy knut and a screw, and it's better to take out the paint where you connect this star ground, powder coating can make a bad contact, and here you will connect the IEC Ground, the PSU ground, and the Audio (XLR) Gnd.

Quote
3. how do i have to solder the toroid to a ON/OFF switch???, just the AB wires

First make sure this and that you're using the toroid the right way:
http://www.diyfactory.com/data/transformer_connections.gif


Normally you would like to cut the Phase ( L in the file above) of the Main IEC. Some like to cut both neutral and Phase.
Meaning you have 3 points on the back of your IEC, one that must be the neutral, one that must be GND (Goes to Star Gnd), and the Phase that is connected to your fuse if you have a fuse inlet IEC Socket? Check wich is wich.
From the phase you go to your switch, and from there you connect the phase of your toroid.
The neutral of the toroid goes to Neutral of the IEC Socket.
This is for if your IEC socket has the fuse inside, if not then you have to connect the Phase from the IEC socket to the fuse socket (has two solder hears for that) and from the fuse socket to the switch etc...

All this means you cut the primary section not the secondarys of your transformer, you said AB, but that is the connections of the secondary "Center Tap" to the PSU board, be carefull.
You understand that when the primary is feeded, then you have power on secondary, so if you cut secondary, then that means main power always on and toroidal always feeded  :o...

IF you still feel lost, then look at some pictures here and there, you'll get the point.

ANd Last but not least, don't fit any of the IC's and no DOA's, until all voltages are checked at all MAJOR points.

I personnaly like to start by checking the PSU first, and there you can check if your switch wiring is ok for you in example and you wire to main boards after checking if the PSU outputs are correct and at the right points.

Hope this helps???

EDIT: Make sure the switch you use handles 250V and more than 1A, don't use tiny dc switches for that purpose, maybe that you knew, but better be safe than sorry...
Title: Re: sontec 1 RU build thread
Post by: diezel_addict on February 11, 2011, 04:31:21 AM
Hi All

I just checked out the ALPHASTAT 50K gain pot on my sontec that I built and the pin above and slightly to the right of pin 3 which I thought was the center tap doesn't :

A) short to ground on the PCB

B) short to the wiper when at center detent position

however it does short to the outside of the pot.

Am I missing something here???  can someone else check with a multimeter to confirm this?

would be great if someone can shed some light on this.

thanks in advance
Title: Re: sontec 1 RU build thread
Post by: Igor on February 12, 2011, 07:45:46 PM
Are you talking about potentiometer case pin?
The PIN4 is center tap, it is locared at the left side of pot if you looking from front.
Title: Re: sontec 1 RU build thread
Post by: diezel_addict on February 13, 2011, 03:25:03 AM
Hi Igor

Thanks for the reply.

I just checked it again and the reason it didn't show continuity was because there was 68 ohms difference between the two pins.  All good.

If I was going to use a non center tapped pot for a build of this circuit, would it work ok if the wiper was just switched to ground when you want it out of circuit?
Title: Re: sontec 1 RU build thread
Post by: zayance on February 14, 2011, 12:11:47 PM

 I only have 24 V on pin 3 both, on the power supply board, is that correct???? do i have - 24 V on pin both pin 4????

  thanks

Pin 3 correct, Pin 4 must be -24V Obviously...
Title: Re: sontec 1 RU build thread
Post by: brennyb on February 15, 2011, 10:04:14 PM
any news on the mastering version kit... price/differences?

cheers- Bren.
Title: Re: sontec 1 RU build thread
Post by: briomusic on February 16, 2011, 05:06:20 AM
this thing just saved my life rescueing a really badly recorded vocal (verse and chorus recorded in different studios etc).
can't wait to have a switched version to use confidently in stereo!  :)
Title: Re: sontec 1 RU build thread
Post by: analogica on February 23, 2011, 01:58:09 PM

 hey fellows....i have problems again

  the unit is finished and working but the channels doesnt work the same way,

  1. the unit off has a small hum sound when I put the plug on the power socket, so it seems a ground problem, ...the screw to hold the toroid is the same where i place the main ground star....do you think it can be the problem¿???¿?....where can i check then???

 2.in the first channel if i turn down a pot it affects to signal more than on the other....so the signal is more muddy and smaller(almost dissapear) than on the other channel
 
 And if I amplify on the other channel the sound is brighter always...wheres the problem????

 If turn ON the EQ on both channels with the pots on 0, the signal is the same...so is that a problem on the summing board???? i have no clue how or where to check this.

  hope you can help me...thanks guys
 
Title: Re: sontec 1 RU build thread
Post by: bpucekov on February 23, 2011, 02:05:30 PM
1. definitely yes, never use toroid screw for this purpose
Title: Re: sontec 1 RU build thread
Post by: analogica on February 23, 2011, 06:05:10 PM

 buuuuuuuuuuuut, could you explain me why....im na ignorant, cuz the screw never touch nothing more than ground wires and the metal rack....

 thanks
Title: Re: sontec 1 RU build thread
Post by: kante1603 on February 24, 2011, 04:24:04 AM

 buuuuuuuuuuuut, could you explain me why....im na ignorant, cuz the screw never touch nothing more than ground wires and the metal rack....

 thanks

Hi analogica,

as bpucekov stated:Never do it-you might end up in magnetic short!This is also given when the screw touches the bottom and top of a metall housing because you create a one-winding coil arround the transformer-HORROR!!!

So may I suggest to move your starground somewhere else-please ;)

Best,

Udo.
Title: Re: sontec 1 RU build thread
Post by: analogica on February 24, 2011, 07:50:54 AM

 thanks everyone for your help...

  ive changed the main ground from there to another place...but the hum is still there, is not a big noise but more than on the other analog stuff i got...

 where can i check??? 

  i have no clue how to solve this and how to make the unit sound equal and even...

   thanks for your patience
Title: Re: sontec 1 RU build thread
Post by: analogica on February 28, 2011, 02:20:24 PM

 HELPPPP

   One channel do not reduce or dim the signal if I turn down the dbs pot,    it amplifies ...slightly different to the other channel but it doesnt reduce , or is something really really unnoticiable.

 do you think thats a problem on the summing board????

   thans fellas , i need your help
Title: Re: sontec 1 RU build thread
Post by: analogica on March 02, 2011, 07:14:15 AM

 Hi again guys...

  i ve tested the unit again...let see what happens now.

   1.As i said to you If i turn on the EQ on both channels with all gains on 0, the signal doesnt change, right?.

      -but If I remove PS 2 wires from the filter board and turn on the EQ switch the signal amplifies and sound so distorted on mediums i think...and if I move the pots then, nothing changes

      If I do the same on the other channel(the one which amplifies and reduce right)the signal doesnt amplify, and if i move the pots the signal changes a bit.

  As I said, one channel seems to work well, and the other doesnt reduce when I move all gains on all frequencies, and amplifies very bright to me ears.

  Dont you think thats something on the summing board????  what can i do ?????


  thanks guys , im waiting for an answer to solve this



   is so strange....
Title: Re: sontec 1 RU build thread
Post by: briomusic on March 02, 2011, 07:21:06 AM
I don't quite understand your test procedure....

wouldn't it be easier to swap the filterboards around (at the 5 pin connector) to see if the problem follows the filterboard or stays with the amp board?
Title: Re: sontec 1 RU build thread
Post by: analogica on March 02, 2011, 08:05:18 AM

 i have to desolder everything then....but ill do, ill say what happens
Title: Re: sontec 1 RU build thread
Post by: briomusic on March 02, 2011, 08:34:56 AM
I know the feeling.....

now I always use molex connectors, so much easier to troubleshoot!
Title: Re: sontec 1 RU build thread
Post by: analogica on March 02, 2011, 10:37:35 AM

 it works!!!!!!

   it was a bad connection on the 5 pin wires, thanks for your help.

   the pmly thing left is to get rid of that hum....
Title: Re: sontec 1 RU build thread
Post by: analogica on March 03, 2011, 07:49:41 AM

 Hi,

   ive resoldered the main star ground and the hum is a bit quieter but is still there,

   I didnt notice that all pins 2 on the unit goes to ground.,.......?????, is that correct????

   Should be better to solder a ground lift on the XLR to get rid of that hum ????

    thanks
Title: Re: sontec 1 RU build thread
Post by: analogica on March 07, 2011, 06:56:48 AM

 pleaseeeee, can somebody help me with the ground?????   I guess should be normal to have some noise if pin 2 goes to ground....is that correct????

 what should i do?
Title: Re: sontec 1 RU build thread
Post by: Sylvain D. on March 16, 2011, 04:03:47 PM
This may be a noob question but: ::)

Is there any use in getting "film" caps in higher voltage than the circuit can swing i.e +- 24V=48V  (headroom maybe...) or is it useless to buy 250, 630 volts etc... caps?

Will 63V caps suffice in a filter function? (specifically in this EQ)

Sylvain

Title: Re: sontec 1 RU build thread
Post by: benlindell on March 16, 2011, 09:04:59 PM
Extra voltage is definitely not nessecary for the filter.
Title: Re: sontec 1 RU build thread
Post by: Sylvain D. on March 23, 2011, 07:25:21 PM
Is it just me, or are some of these caps really hard to find?

like the ones bellow... I have found many of these values but in the 7 mm or 7.5 mm width. Can I cheat and use these instead of 6 mm width?

CAPACITORS-POLY ETC.

1 0.15U C-10-15/6
2 0.47U C-10-15/6
8 1U C-10-15/6
1 2U2 C-10-15/6
1 1U C-10-15/6
2 2u2 C-10-15/6

1 4u7 C-10-15/6

Anyone...?


Thanks
Sylvain
Title: Re: sontec 1 RU build thread
Post by: daggertX on May 10, 2011, 05:04:11 PM
Forsell JFET 993 discontinued  :'(    now what ??? 

I am okay with using 604s but has anybody had good results with any discrete opamps?
Title: Re: sontec 1 RU build thread
Post by: sonicwarrior on June 08, 2011, 04:49:13 PM
The BOM says:

POTENTIOMETERS
3 5K LIN POTSW (CTS 270X232A502B1A1)
1 5K LIN POT (CTS 270X232A502B1B1)

But the B1A1 variant ist the one without a switch and the B1B1 is the one with a switch. Do I need 3 with or without switch?
I looked at the schematic but I didn't see any pot there with a switch.  ???
Title: Re: sontec 1 RU build thread
Post by: zayance on June 08, 2011, 06:45:15 PM
You need 1 with switch (For the LF Shape(Q)/Shelf Position), all the 3 others are without, and that for one channel.
Check first picture on page 1 for having an idea....
Title: Re: sontec 1 RU build thread
Post by: sonicwarrior on June 09, 2011, 03:21:44 PM
I checked the pictures before and now again but I still don't see a clue anyware that there should a pot with a switch.
Or is the 'shelf' the clue?
Title: Re: sontec 1 RU build thread
Post by: zayance on June 09, 2011, 04:12:33 PM
I was reffering to the picture just for confirming my statement and have a visual of it that the LF shape(Q) is the switched position that's all...
The inner picture where you see the CTS pots From up view gives you the answer also, for if you had the pic of the CTS on Digikey for ex, the switched one is different than the "normal" ones...
Title: Re: sontec 1 RU build thread
Post by: earl on June 28, 2011, 02:09:51 AM
can other pots be used on this project besides alpha? for U.S. ?
Title: Re: sontec 1 RU build thread
Post by: Lowfreq on August 16, 2011, 11:53:12 PM
I've got a quick question. I've got the 4k7 on the underside of the board so I can have 12dB boost/cut, but I'm only getting 6dB boost/cut.

I've made sure I've got 4k7's in there, and I've even tried lower and higher values on there. The most I can get is 9dB boost/cut with a wire bridge connection.

I've compared to my trident EQ and even to my plugin EQ's, and they're giving me the amount of boost they're telling me.

It's the same on both channels of the sontec...... so besides the 4k7 area, what else should I be looking at to resolve the problem?
Title: Re: sontec 1 RU build thread
Post by: Igor on August 21, 2011, 03:38:58 PM
There may be some issues like:

- Check if the GAIN pots are 50k, lin, centertap;
- Check the summing resistors R18-R22 are 20k and r21 is 10k;
- Check the values of CLF1/2, CLMF1/2, etc, they should be in 5% range.

Check for mistakes, wrong placed components, etc. If gain pots are 50k, they should give +/-12db with 4k7.
Title: Re: sontec 1 RU build thread
Post by: glazer56 on September 15, 2011, 02:46:37 AM
Thanks for sending the boards Igor, the build is humming along!
Wondering... What are the three small boards attached to the I/O board for? I looked back in the forum archives but didn't see anything. Many thanks!
Title: Re: sontec 1 RU build thread
Post by: Igor on September 15, 2011, 07:11:57 AM
Put them below the switches mounted on PCB, if using case from Purusha.
Title: Re: sontec 1 RU build thread
Post by: cstella on December 06, 2011, 10:30:57 PM
Hi there.

I am looking forward to this build. The boards are on the way and I have managed to secure most of the parts.

I have a question about the power transformer. Would 30VA suffice for +/-24V As I am thinking of getting this one from Hairball.

http://hairballaudio.com/shop/product_info.php?products_id=37&osCsid=9f5e8f09df1061774567eb8d0b4432cd

Any help is greatly appreciated.

Thanks, Charles
Title: Re: sontec 1 RU build thread
Post by: G-Sun on December 08, 2011, 09:02:05 AM
Project looking excelent :)

Molex: Is that Mini-Fit?
http://www.molex.com/molex/products/group?key=minifit_products&channel=products
Title: Re: sontec 1 RU build thread
Post by: marshman on December 18, 2011, 06:21:25 PM
Hey guys,

I had a 50k pot disintigrate on me.

Anyone got a spare or two I could purchase?

Thanks,

mm
Title: Re: sontec 1 RU build thread
Post by: glazer56 on December 23, 2011, 11:53:49 PM
Greetings!
I seem to have an interesting problem with my Sontec. Everything is working as advertised EXCEPT that the boost/cut volume will change depending on the Q setting  :o I've ran a signal through it and into a spectrograph and the wider the Q setting, the lower the bell is. I don't get it. Anyone know what may be causing this?? I have wired this EQ as a mastering EQ with all stepped switches (24 position for gain and freq, 6 for Q) and have not cut the board as others have done. I'm stumped with this one.. any help would be appreciated!
Title: Re: sontec 1 RU build thread
Post by: glazer56 on December 24, 2011, 01:37:38 AM
Aha.... I think I debunked my problem. Checking the resistors around the Q pot, I found that RF*.2 (1.2, 2.2 ect...) was 54.9OHM, not 54.9K!! ( I couldn't find a 55, so I ordered a 49.5). I'll have to pick up some resistors tomorrow and swap them out to see if that's the only problem, but it looks like it is. I'll post results.
Title: Re: sontec 1 RU build thread
Post by: cstella on December 25, 2011, 05:22:34 PM
Hey Mark.

Interesting seeing your post this morning as I just started putting the PS together. I got the hairball transformer which I think should be fine too.

I also bought those heat sinks in the BOM from Mouser. I ended up mounting the 100UF's on the bottom of the board and have the heat sinks slightly off the board so they make no contact with any parts. This is working well and my standoffs are a little taller than the caps on the bottom.

I just checked my DOA pins and they are the .062's from Mouser #575-034420. They do fit into those holes.

Looking forward to finishing this up. Just waiting on the pots from Alphastat.

Good luck on your build!

Charles





Title: Re: sontec 1 RU build thread
Post by: glazer56 on December 25, 2011, 05:30:51 PM
For what it's worth, these are the TO-220 Heatsinks I ordered. Fit perfectly on The PS Board
Mouser: 567-637-10ABP
Title: Re: sontec 1 RU build thread
Post by: gda on December 26, 2011, 07:43:28 AM
Hi! I would like to ask a (maybe silly) question: In the BOM says resistors
10x 1m
1x  2m
1x 3m9     Are Mega or mili ohms? Should be 1/4 Watt or any other Watt can do the job?.....maybe a mouser code?
For 55k can i use 20k and 35k in series?
Title: Re: sontec 1 RU build thread
Post by: zayance on December 26, 2011, 08:01:00 AM
Hi! I would like to ask a (maybe silly) question: In the BOM says resistors
10x 1m
1x  2m
1x 3m9     Are Mega or mili ohms? Should be 1/4 Watt or any other Watt can do the job?.....maybe a mouser code?
For 55k can i use 20k and 35k in series?

Welcome,

- Mega 1/4  1%

- Of course
Title: Re: sontec 1 RU build thread
Post by: Sylvain D. on December 26, 2011, 10:16:40 AM
Hey guys,

I've finally got arround to putting together this eq and on first power-up, voltage tested good at PS output (+/- 23.9). But when I connect the PS to output boards, RPS3(22r) smoked on one channel only.  (btw, I have red boards)

(I read the post about "inversed PS polarity output" but that seems odd to me)

Anyone have any thoughts? ???

Title: Re: sontec 1 RU build thread
Post by: zayance on December 26, 2011, 11:09:14 AM
Hey guys,

I've finally got arround to putting together this eq and on first power-up, voltage tested good at PS output (+/- 23.9). But when I connect the PS to output boards, RPS3(22r) smoked on one channel only.  (btw, I have red boards)

(I read the post about "inversed PS polarity output" but that seems odd to me)

Anyone have any thoughts? ???

I don't know what's that inversed polarity thing...
just make sure you have positive rail wired to the positive PS input of all the other boards, same for Negative and voila... EDIT: and Grounds of course...
Follow PCB traces if you have a doubt...
Title: Re: sontec 1 RU build thread
Post by: Sylvain D. on December 26, 2011, 06:24:59 PM
Wired up my first channel and got smoke from the 22R resistors, it seems the PSU markings on the filter board have + and - reversed. Once I traced through the schematic and hooked it up correctly all is fine.

Great EQ! Amazing level of precision.


I was refering to the post above on page 4.

But, merçi Zayance.  I will take a closer look.

Title: Re: sontec 1 RU build thread
Post by: Sylvain D. on December 26, 2011, 11:15:04 PM
Got it!!

I had reversed one of the +/- pairs going from the PS to one of the I/O boards.
One of those late nite solder sessions... I should have gone to bed earlier. ;D
Title: Re: sontec 1 RU build thread
Post by: gda on January 04, 2012, 06:19:58 PM
All of my opamps are OPA2604 or OPA604. My transformer is 2x25Volt, 30VA.
Should Rx 3k6 be fine?
My transformer has red, orange, black, yellow wires (which as mentioned are going straight on the suply board) and one black and one brown. Are they going on the main switch and from the switch straight to the 220Volt socket? What about fuse? should I use one and how should I connect it?
What about grounds? As you understand I have problems with the "outboard wiring"...it's my first "big" project....please help! Thank you a lot!You really helped me a lot with all your posts guys...be well!
Title: Re: sontec 1 RU build thread
Post by: atticmike on January 05, 2012, 06:55:31 PM
Does this in the bom mean I can either run it:

with 1 X ad706 OR OPA2604(24V PS) 'CAN BE OTHER LOW OFFSET DUAL OPAMP,

OR

2 X times OPA604 OR JE990 ETC 'CAN BE OTHER LOW DIST FAST HIGH CURRENT OPAMP,

OR

5 X OPA2604 OR OP275 ETC 'CAN BE OTHER LOW DIST FAST DUAL OPAMP

?

What are my benefits with each setup?
Title: Re: sontec 1 RU build thread
Post by: atticmike on January 06, 2012, 02:41:04 AM
My third:

(http://audiofor.tv/diy/sontech/front.jpg)

(http://audiofor.tv/diy/sontech/oben.jpg)

I can really recommend this EQ. Jump on this as long as Igor stocks it...

what op amps are you using?
Title: Re: sontec 1 RU build thread
Post by: Holger on January 06, 2012, 02:48:58 AM
2604/604
Title: Re: sontec 1 RU build thread
Post by: atticmike on January 06, 2012, 03:02:26 AM
2604/604

thanks, makes sense with their low noise floor :)

Do you also happen to have the cart of your resistor / capacitor / parts purchase for stuffing the boards?

I've seen you quite built a lot of units and all of em look really proper.

Would you mind to share the info?

-

Also Igor, I couldn't find a mono version of this EQ, nor the faceplate you are using on this build?
Title: Re: sontec 1 RU build thread
Post by: atticmike on January 06, 2012, 05:27:48 PM
Hoping for a quick favor from a kind soul with a working build.

I'm having some problems with my cut's / gain structure in my build.

http://www.groupdiy.com/index.php?topic=27972.msg593590#msg593590

I get healthy AC voltage on PIN 1 (Boost bus) of the I/O - EQ board connector but low voltage on PIN 3 (Cut buss) which I think may be the problem.

If you inject a line level 1khz tone on the input, with the boost/cut control centered and the EQ IN; what are the AC voltages present on PIN 1 and PIN 3. I'm guessing they should be around the same level, but I'm not sure.

This would help me track down this last gremlin.

Regards,
Mark

Have you checked the opamps yet?
Title: Re: sontec 1 RU build thread
Post by: Harpo on January 06, 2012, 06:30:14 PM
I get healthy AC voltage on PIN 1 (Boost bus) of the I/O - EQ board connector
Assuming healthy=unity gain, polarity inverted=0dB at pin1 with 0dB input signal feed.

Quote
but low voltage on PIN 3 (Cut buss) which I think may be the problem.
I've checked levels on each of the 20K summing resistors and when I apply full boost centered at 1khz I'm getting around 1.5Vac of signal before the resistor and about 1/10th of that after the summing resistors.
My output OPA604's are running super hot as well, not sure if that's normal.
When disconnecting the filter board, output of IC6 or XLR-out pin2 will read same level and polarity as input level and opamp will stay cool, else IC6 or servo IC10a might be blown.
What is the voltage reading at servo out IC10a-pin1? Might as well be a bad cap C62 that died from too long soldering on and servo now running open-loop.
IC6-pin3 will be close to 0V and a working IC6 will try its best to keep its inverting input pin2 (virtual ground node) at this same level as pin3, not at 'about 1/10th of around 1.5Vac'.
Title: Re: sontec 1 RU build thread
Post by: Harpo on January 07, 2012, 03:53:26 PM
My pleasure.
My remaining problem is an oscillation in the individual bands. High bands are more suseptible than the low bands but I can get every band ringing like a bell. High bands will start after about 3db of boost.

I'm using verified good OPA2604's for each band. I went through an added the 5pf compensation caps to each band (which Igor doesn't recommend for 2604's) with no difference. Moved wires around with no difference.

Not sure if this could this be power supply decoupling issues or more of a frequency compensation issue.
Just run the numbers for maybe CF5.1 to know why your 5pF wouldn't make a difference ... ( 1/(2PI*11K*5E-12) LPF at 2.9MHz wouldn't help that much when opamp runs out of GBW). A 47pF might be a better fit. The 12pF comp.caps C23 and C57 across the 20Ks at 660kHz are on the high side as well. Wouldn't go lower than 27pF, but as always YMMV.
Title: Re: sontec 1 RU build thread
Post by: atticmike on January 07, 2012, 07:26:31 PM
Hi, I bought opa604's last time from digikey, but for now seems they
 doesn't have them. Farnell is another option.
Regarding resistors, R-EU_0207/12 means 1/4w, 12 mm pitch.
I.e. common 1/4w resistor.
I used to draw pcbs in Eagle, really good prog ,but bom-wise, it is bad ;)

Pitch as in length or diameter?

what about the lead spacing?

So you are saying 0207 and 0204 are the same? 207 is just a building type and 207 & 204 are 1/4 therewith?

I thought 204 were the ones that small ones that easily roll off your board?

Mike
Title: Re: sontec 1 RU build thread
Post by: Kingston on January 07, 2012, 07:43:35 PM
It seems strange that no one is having this problem with their 2604's.

using LME49860 here because quite frankly OPA2604's suck. Even NE5532 sounds better, try it.

If concerned about headroom, 15V vs. 24V rails will give you a whopping 4dBu more. LME49860 can do 22V rails by the way. Excellent pairing with some decent DOA's.
Title: Re: sontec 1 RU build thread
Post by: Kingston on January 07, 2012, 07:59:38 PM
12-5pF as in the schematic worked for all opamps I tried (OPA2604, LME and NE parts). Never had oscillation in the filter boards.

Using just about any DOA's on the I/O board was oscillating like mad. 47pF tamed them all. Maybe it was more, say 100pF. My approach was pretty hands on, increase feedback pF range capacitance as much as it takes. Filtering boards bypassed. Who cares what happens in the +200khz range, right? (apparently igor and his dolphins do)

I'm using LME parts as the servos as well by the way.

Do you perhaps have some exotic or non-standard PSU configuration that might be the cause of your oscillation problems?
Title: Re: sontec 1 RU build thread
Post by: Kingston on January 07, 2012, 08:09:04 PM
Nice, the GBW is almost triple that of the 2604 and the slew rate is 5/Vus slower than the 2604.

Manufacturers always lie. Testing conditions are rarely disclosed in detail. Sure you have this and that bandwidth with whatever slewrate, but at what distortion and at what frequency range.

The only thing that's reasonably trustworthy for us audio folks is Samuel Groners opamp catalog.

We're already running very close to 22v rails with the 22 ohm PS "fuse" resistors installed, no big deal to adjust those slightly.

They are not just fuse. Standard LM regulators have white noise issues. These droppers will take care of that. Also, if using the OPA's you can tune your PSU so that rails are 24V after the droppers. (will be more like 25.5V at the PSU outputs)
Title: Re: sontec 1 RU build thread
Post by: atticmike on January 08, 2012, 02:46:11 PM
Hi, I bought opa604's last time from digikey, but for now seems they
 doesn't have them. Farnell is another option.
Regarding resistors, R-EU_0207/12 means 1/4w, 12 mm pitch.
I.e. common 1/4w resistor.
I used to draw pcbs in Eagle, really good prog ,but bom-wise, it is bad ;)

Pitch as in length or diameter?

what about the lead spacing?

So you are saying 0207 and 0204 are the same? 207 is just a building type and 207 & 204 are 1/4 therewith?

I thought 204 were the ones that small ones that easily roll off your board?

Mike

can anybody assist me with my question ? :)
Title: Re: sontec 1 RU build thread
Post by: zayance on January 08, 2012, 03:23:24 PM
Hi, I bought opa604's last time from digikey, but for now seems they
 doesn't have them. Farnell is another option.
Regarding resistors, R-EU_0207/12 means 1/4w, 12 mm pitch.
I.e. common 1/4w resistor.
I used to draw pcbs in Eagle, really good prog ,but bom-wise, it is bad ;)

Pitch as in length or diameter?

what about the lead spacing?

So you are saying 0207 and 0204 are the same? 207 is just a building type and 207 & 204 are 1/4 therewith?

I thought 204 were the ones that small ones that easily roll off your board?

Mike

can anybody assist me with my question ? :)

http://www2.mouser.com/Passive-Components/Resistors/Through-Hole-Resistors/Metal-Film-Resistors/_/N-7h7zb?P=1z0vod7Z1z1414h&Keyword=Xicon&FS=True

https://docs.google.com/viewer?url=http://www.mouser.com/catalog/specsheets/XC-600046.pdf&pli=1
Title: Re: sontec 1 RU build thread
Post by: atticmike on January 10, 2012, 01:31:24 PM
What is the voltage rating for these parts of the bom?

CAPACITORS-POLY ETC.

1 0.15U C-10-15/6
2 0.47U C-10-15/6
8 1U C-10-15/6
1 2U2 C-10-15/6
1 1U C-10-15/6
2 2u2 C-10-15/6

1 4u7 C-10-15/6 (PITCH UP TO 35MM, POSSIBLE TO USE 2 CAPS IN PARALLEL)
1 ** C-10-15/6

--

Also, 1 ** is still in question

--

Also, I have issues with the 2k pf mica capacitors

CAPACITORS-SILVER MICA OR POLY

1 3n3 C-7-10/5
2 2n70 C-7-10/5
1 100P C7.5/3
1 150P C5/2.5 NOT NECESSARY WITH OPA604
2 330P C7.5/3


CAPACITORS-SILVER MICA OR COG
5 5p C2.5/2
2 12p C7.5/3

--

I'm sorry but I seriously doubt there will be a 2.7k pf mica with a width of 5 mm ...

they mostly start at twice the value (10 mm).
Title: Re: sontec 1 RU build thread
Post by: abechap024 on January 10, 2012, 04:52:16 PM
I don't think you could find any of those parts in a low enough voltage value for it to be a problem. You want to have them rated at least the amount of the highest possible voltage they will see in the given circuit. No harm in getting a capacitor rated at a higher voltage though.

Most people run into problems when they order a bunch of low voltage electrolytic and put them in a power supply rated over the max voltage of the electrolytic capacitor and before long...pop! Film and ceramic on the other-hand usually are at least rated at 50v and unless you are building some high voltage tube stuff, you are going to always be fine.
Title: Re: sontec 1 RU build thread
Post by: atticmike on January 10, 2012, 05:37:03 PM
I don't think you could find any of those parts in a low enough voltage value for it to be a problem. You want to have them rated at least the amount of the highest possible voltage they will see in the given circuit. No harm in getting a capacitor rated at a higher voltage though.

Most people run into problems when they order a bunch of low voltage electrolytic and put them in a power supply rated over the max voltage of the electrolytic capacitor and before long...pop! Film and ceramic on the other-hand usually are at least rated at 50v and unless you are building some high voltage tube stuff, you are going to always be fine.

Well, I suppose with op-amps operating at 24v, capacitors with anything just above that would be probably fine (68V)?

And about the 2.7k pf mica with a width of 5 mm ... ? I searched mouser in every mica corner and couldn't find anything that'd match a width of 5mm.
Title: Re: sontec 1 RU build thread
Post by: cstella on January 11, 2012, 02:21:26 PM
Anything 35V and above should be fine for caps.

Here's a 2700pF Mica from Mouser 598-CD16FD272JO3

http://www.mouser.com/Search/ProductDetail.aspx?R=CD16FD272JO3virtualkey59850000virtualkey598-CD16FD272JO3

Charles
Title: Re: sontec 1 RU build thread
Post by: cstella on January 11, 2012, 03:04:08 PM
50V on the Power Supply Caps!
Title: Re: sontec 1 RU build thread
Post by: cstella on January 12, 2012, 12:27:54 PM
Hi all

I am trying to get one channel of the Sontec up and running. I am running into some problems with the star ground. I was under the impression that I should star ground to chassis the AC ground, PS ground and the XLR ground on the Summing board. When I did this I blew a fuse (500mA Slow Blow). If I just connect the AC ground or the AC and XLR Grounds the voltage is fine. If I try the PS ground and AC ground only it drops my voltage to just under 5V.  :-[

Yesterday when I had only the AC ground connected I was able to safely power one channel with all IC's and 2 DOA's. I will try this with now with the XLR and AC connected at the star ground.

What have successful builders used as a grounding scheme? Any help would be greatly appreciated!

Thanks, Charles
Title: Re: sontec 1 RU build thread
Post by: cstella on January 12, 2012, 07:08:49 PM
Hi Mark

Thanks for your response. Here's a picture of the PS. The black wire that is in the center connects PS ground to the star ground. Nut not attached in photo! As I said earlier the PS works fine unless these two points are connected and then it does not.

Because of huge heat sinks 100uF caos are mounted on the bottom.

Thanks, Charles
Title: Re: sontec 1 RU build thread
Post by: Harpo on January 12, 2012, 07:57:27 PM
Double check your transformers colour coding of your center tap connection. For the usual suspects it is not black+orange.
Title: Re: sontec 1 RU build thread
Post by: cstella on January 12, 2012, 08:08:35 PM
Thanks. I am using the Hairball 30VA

http://hairballaudio.com/shop/product_info.php?cPath=33&products_id=37

Secondary is orange and black for 0V and Red and Yellow for 25V. On the primary side I have them setup in parallel.

Does that sound right?

Thanks, Charles
Title: Re: sontec 1 RU build thread
Post by: Harpo on January 12, 2012, 08:25:39 PM
No. http://www.avellindberg.com/transformers/tech_notes/tech_notes_comp.htm (http://www.avellindberg.com/transformers/tech_notes/tech_notes_comp.htm)
You want your secondary windings connected in series. Exchange the black with red, so orange+red is your transformers secondary center tap connection to pcb.
Title: Re: sontec 1 RU build thread
Post by: cstella on January 12, 2012, 08:39:50 PM
Aha! Cool. Thanks for the help!

 :D
Title: Re: sontec 1 RU build thread
Post by: Kingston on January 12, 2012, 09:05:22 PM
And about the 2.7k pf mica with a width of 5 mm ... ? I searched mouser in every mica corner and couldn't find anything that'd match a width of 5mm.

There aren't small mica's available, they're big, clumsy and high voltage. But that's ok, they don't sound very good in filters, you don't want there here anyway. Use c0g or np0 ceramic caps everywhere. Technically these are the best option.
Title: Re: sontec 1 RU build thread
Post by: cstella on January 13, 2012, 10:39:52 AM
No. http://www.avellindberg.com/transformers/tech_notes/tech_notes_comp.htm (http://www.avellindberg.com/transformers/tech_notes/tech_notes_comp.htm)
You want your secondary windings connected in series. Exchange the black with red, so orange+red is your transformers secondary center tap connection to pcb.

Thanks Harpo! I switched the secondaries this morning and now it works as expected! The transformer gets pretty hot though.
Title: Re: sontec 1 RU build thread
Post by: cstella on January 13, 2012, 04:38:09 PM
I was using a 1A slow blow fuse on the power supply and it works now but I was concerned that is too high for my 30VA 600mA transformer. The transformer was working but seemed to get hot. When I switched to 500mA Slow Blow it just blew the fuse. What are people using for US voltage on there Sontec?

Thanks, Charles
Title: Re: sontec 1 RU build thread
Post by: cstella on January 13, 2012, 04:57:39 PM
Hi Mark

Thanks for responding. 500mA should be fine right.

The heatsinks are raised of the board and not in contact with anything. They are also isolated from the regulators.

You are using the Hairball transformer right? I have the primaries wired in parallel brown+grey and blue+violet. Secondaries are as harpo corrected orange+red for CT. Is that what you have?

Thanks, Charles

Title: Re: sontec 1 RU build thread
Post by: cstella on January 13, 2012, 05:19:12 PM
Thanks Mark for the picture.  ;)

That's what I originally had as my CT (orange + black). I just disconnected the PS and the transformer is still blowing fuses with orange+ red CT.

I'll try to switch it back and see what happens.

Thanks! Charles
Title: Re: sontec 1 RU build thread
Post by: cstella on January 13, 2012, 06:38:36 PM
OMG! I figured out what the problem has been. The transformer I have has some cuts in the tape exposing some of the windings and shorting itself to my case. I'm surprised it was brand new. I have re-taped it and now no shorts and I can ground AGND to power ground!

Thanks for everyone's help. Mark the pics helped a lot!

Charles
Title: Re: sontec 1 RU build thread
Post by: cstella on January 13, 2012, 07:54:19 PM
Well after all that the first channel works perfectly so far. OPA2604's on the filter board and the servo and Forssell DLR on the input and JFET990-2 on the output.

Now on to the next channel!  :)

Title: Re: sontec 1 RU build thread
Post by: cstella on January 13, 2012, 09:45:40 PM
Nice! In some great company there.

I hope to be joining you soon!

Thanks for your help.

Charles

Title: Re: sontec 1 RU build thread
Post by: rocksure on January 13, 2012, 10:18:08 PM
Thanks for everyone's help. Mark the pics helped a lot!
Charles

Awesome, glad you got it sorted Charles.

Here's my baby all dressed up and ready to rock, hangin' with some friends.

Regards,
Mark

Looks great! How does it sound? I have never used a Sontec EQ, kind of interested to know your experiences with it in use have shaped up.
Title: Re: sontec 1 RU build thread
Post by: Nobieesd on January 16, 2012, 02:29:35 AM
Hey guys,
I'm totaly new in this DIY audiogear-thing :D
but my brain doesn't stop working since I have seen this awesome Project, so i have decidet to build also one sontec eq :)
I have really no idea how to start with such a project, maybe someone could help me ?

- Should i start with searching for the parts from the BOM-list ?
- or first read the whole thread ?
- and, where can i get a cheap PCB for this projekt ?, this is it or not?:
http://market.diyrecordingequipment.com/red-sontec-stereo-pcb-set,name,100290,auction_id,auction_details
seems a bit expensive...

and sorry for my bad english, i'm from germany and haven't spoken or written this language since 2 years :D
thanks ahead for your help
cheers, Nobieesd
Title: Re: sontec 1 RU build thread
Post by: cstella on January 17, 2012, 12:16:12 PM
Just finished the Sontec! It all checks out on the scope and meter. Headed to the studio to put it through the paces. Still short a couple .1 bypass caps but they should come today.

After the power supply issues it all came together very smoothly.

Thanks Igor for a great project and Dan at Collective Cases for a beautiful enclosure. And thanks to the group for the build support!

 
Title: Re: sontec 1 RU build thread
Post by: cstella on January 17, 2012, 12:17:28 PM
and the guts...
Title: Re: sontec 1 RU build thread
Post by: sonicwarrior on January 17, 2012, 01:52:09 PM
Looks great.

Btw.: Was it hard to get the potentiometers from Alphastat?
I still haven't bought them.
Title: Re: sontec 1 RU build thread
Post by: benlindell on January 17, 2012, 02:12:02 PM
Looks great.

Btw.: Was it hard to get the knobs from Alphastat?
I still haven't bought them.
I was just about to ask where the knobs are from, I'd be curious to hear about them as well.
Title: Re: sontec 1 RU build thread
Post by: sonicwarrior on January 17, 2012, 02:16:36 PM
I meant the potentiometers.  :-[
Title: Re: sontec 1 RU build thread
Post by: cstella on January 17, 2012, 02:24:04 PM
Looks great.

Btw.: Was it hard to get the knobs from Alphastat?
I still haven't bought them.

I assume you mean the pots from Alphastat? They were not hard to get but a bit expensive. It took about 3 weeks to get them. You should have an easier time being in Germany I would think.

Looks great.

Btw.: Was it hard to get the knobs from Alphastat?
I still haven't bought them.
I was just about to ask where the knobs are from, I'd be curious to hear about them as well.

The knobs are Elma Classic Collet's 14.5mm's. I got them directly from Elma US in Fremont, CA.

http://www.elma.com/Americas/English/Products/RotarySwitches_4/Knobs_31/137.aspx
Title: Re: sontec 1 RU build thread
Post by: Igor on January 23, 2012, 05:58:43 PM
Awesome guys. I love these eq's by one simple reason: don't have to give any support, all works ;)
Happy to see your units.

Regarding the PCB's pricing: I am more than happy to sell them lower,
but, to bring the price down, I have to order MOQ of 100 PCB's.
In case of 3-4 stereo pcb sets sold monthly, impossible.
You can organize group buy for say 20 stereo sets, the price will be 40% lower.
Title: Re: sontec 1 RU build thread
Post by: Nobieesd on January 24, 2012, 07:40:40 AM
Regarding the PCB's pricing: I am more than happy to sell them lower,
but, to bring the price down, I have to order MOQ of 100 PCB's.
In case of 3-4 stereo pcb sets sold monthly, impossible.
You can organize group buy for say 20 stereo sets, the price will be 40% lower.

ok, it was just because at diy-recording-equip. it's written it should cost 90$ and at the market it was 130
however, i have bought your pcb some days ago over the diy-rec.-market :)

already i have found nearly all parts wich i need for the hole eq... just the pot's and the case make a problem... (for the case it will need 3 more customer from diy-racked... and i cant find the alphastats or any other pot with 5K
the amusing part:
it seems, the pot's of alphastat are manufactured in germany but nobody sell them here :D
is there maybe someone out of germany who know i can buy them ?
cheers, Nobieesd
Title: Re: sontec 1 RU build thread
Post by: cstella on January 24, 2012, 09:58:12 AM
You can buy them from PS Potentiometer in Germany

http://www.alphastat.de/

Title: Re: sontec 1 RU build thread
Post by: kante1603 on January 24, 2012, 01:48:56 PM
You can buy them from PS Potentiometer in Germany

http://www.alphastat.de/
Exactly-although they´re a bit slow sometimes (in my case they were...but it worked with being patient).
Translation:
Genau-aber manchmal sind die ein bischen dröge....so war´s jedenfalls bei mir (funktioniert aber...Geduld).

Udo.
Title: Re: sontec 1 RU build thread
Post by: Nobieesd on February 08, 2012, 01:16:11 AM
oh thx, i will write to them...
now i have read the half thread ... and it seems all my questions are answered
:)

*YeY*
and it beginns...
Title: Re: sontec 1 RU build thread
Post by: Paultec on February 08, 2012, 10:32:46 AM
Igor,

Did you get anywhere with  the mastering version pcbs?

Regards

Paul
Title: Re: sontec 1 RU build thread
Post by: cstella on February 08, 2012, 10:47:05 AM
Igor,

Did you get anywhere with  the mastering version pcbs?

Regards

Paul

A bit of of turn but It's happening here:

http://www.groupdiy.com/index.php?topic=47454.0
Title: Re: sontec 1 RU build thread
Post by: Paultec on February 08, 2012, 11:59:37 AM
Ah, cool...!

Thanks cstella...

 :)
Title: Re: sontec 1 RU build thread
Post by: gda on February 15, 2012, 06:12:07 AM
Hi to all! I would like to ask how do I connect the eq to an unbalanced piece of gear. I suppose, I should solder new wires...should I solder two of the three XLR pins to a mono jack and leave the one left unconnected or should I connect two of the three XLR pins together?
Title: Re: sontec 1 RU build thread
Post by: cstella on February 15, 2012, 11:29:14 PM
Hi to all! I would like to ask how do I connect the eq to an unbalanced piece of gear. I suppose, I should solder new wires...should I solder two of the three XLR pins to a mono jack and leave the one left unconnected or should I connect two of the three XLR pins together?

Typically you would tie  pin1 (ground) and 3 (-) together to ground and use  pin 2 as your signal to connect unbalanced.

Title: Re: sontec 1 RU build thread
Post by: gda on February 17, 2012, 03:21:21 PM
Today I first powered up my Sontec....the RPS2 and RPS3 (22Ohm) resistors of the in/out board of one of the channels burned. :( I found that I had put upright the OPA2604 (the middle IC as we see it). Bear in mind that I used 604s and 2604s. I put it correctly, I changed the resistors, powered it up and everything seemed ok.... and I have problem again. When I check the XLR out of the board between pin 1 and pin 2 I found that I have 1.5Volts, while on the other channel I have 0 Volts. Please help..what is the correct one? From the power supply board in both channels I have 24Volts coming out..so that board seems ok...
Title: Re: sontec 1 RU build thread
Post by: sonicwarrior on February 19, 2012, 09:04:07 AM
For 55k can i use 20k and 35k in series?

I'm currently trying to source that, too, but 22k and 33k in series makes more sense to me as these are E12 standard values while 35k is almost as hard to get as 55k.

using LME49860 here because quite frankly OPA2604's suck.

I thought the LME49860 are SMD only but Mouser has a DIP version in stock that is even cheaper than the OPA2604 so I'll give them a try.

Did you use them in the AD706 position, too, and used a +/- 22 V PSU with Rx = 3.48K?
Title: Re: sontec 1 RU build thread
Post by: dagoose on February 19, 2012, 02:07:20 PM
I was thinking of replacing/trying the OPA's with LME49860 but Since i have forsell 993 DOA's in the output if they run on 22v or do they really need 24v?
I tried searching the foreselltech site but Fred doesn't sell the DOA's anymore and all info seems to be gone as well.
Title: Re: sontec 1 RU build thread
Post by: hop.sing on February 19, 2012, 04:45:37 PM
Today I first powered up my Sontec....the RPS2 and RPS3 (22Ohm) resistors of the in/out board of one of the channels burned. :( I found that I had put upright the OPA2604 (the middle IC as we see it). Bear in mind that I used 604s and 2604s. I put it correctly, I changed the resistors, powered it up and everything seemed ok.... and I have problem again. When I check the XLR out of the board between pin 1 and pin 2 I found that I have 1.5Volts, while on the other channel I have 0 Volts. Please help..what is the correct one? From the power supply board in both channels I have 24Volts coming out..so that board seems ok...
The middle opa2604 is acting as a servo for both opa604 in and output opamps. That means it corrects dc offset from the audioopamps so that there is no electrolytic in and output cap necessary. Having dc on pin 2 means probably, that the servo opamp (opa2604) does not work anymore because it is fried. Change it and things should be fine again.
Title: Re: sontec 1 RU build thread
Post by: cstella on February 19, 2012, 05:14:43 PM
I've successfully used the Forssell DOA's at 15v. So 22v should be fine.
Title: Re: sontec 1 RU build thread
Post by: gda on February 20, 2012, 03:49:06 PM
Thank you hop.sing! well I changed the opa2604 and I still have the voltage...I connected the eq and passed signal through it and it works! I realized also that that opa gets really hot in contrast with all the others...can't find any bad connection...what is happening...?should I leave it? the other channel doesn't get such hot...
Title: Re: sontec 1 RU build thread
Post by: hop.sing on February 21, 2012, 02:29:23 PM
Thank you hop.sing! well I changed the opa2604 and I still have the voltage...I connected the eq and passed signal through it and it works! I realized also that that opa gets really hot in contrast with all the others...can't find any bad connection...what is happening...?should I leave it? the other channel doesn't get such hot...
Well, that opamp is not really (just a little bit) in the signal path, so the channel will still kind of work with it malfunctioning.
Getting hot could be a sign of oscillation, if you have a scope you can verify that, otherwise check all the surrounding components for values and solder joints again, I bet you will find the problem there.
But I would try to solve that problem, not leave it as it is, some gear does not like dc on its input (Think of transformers, dc between pin 2 and 3 will degrade their performance) and if it is oscillating, the audio opamps in the signalpath will probably be affected, too.
Title: Re: sontec 1 RU build thread
Post by: gda on February 21, 2012, 02:37:34 PM
Thanks again! I will check for another time the nearby components...may be I will replace them too...will see...
Title: Re: sontec 1 RU build thread
Post by: ptron on March 05, 2012, 03:00:51 PM
hello! well i just jumped in both legs first into this got 2 stereo sets.. i really need this eq in my life!! anyways ... i was looking now into pots. i seen the ones on digikey..
http://search.digikey.com/us/en/products/270X232A502B1A1/CT2204-ND/203785
http://search.digikey.com/us/en/products/270X232A502B1B1/CT2226-ND/203807?cur=USD

thing is.. i already ordering a massive list for a gssl and some parts for a 2254 on mouser and would really like to source em there..

i found some bourns pots and honeywell ones 5k lin ... i wanted to ask.. are these ok and suitable for audio purposes?
http://mx.mouser.com/ProductDetail/Bourns/PTD902-2215K-B502/?qs=sGAEpiMZZMsYXAobifOWHHsvVlmygg1PJ15czyNNTvQ%3d
http://mx.mouser.com/ProductDetail/Honeywell/585SX4Q25F502SP/?qs=sGAEpiMZZMsYXAobifOWHABmzPQ018zT6tcr500YAG4%3d

this one says AUDIO but does this mean is a Log one? or just good quality?
http://mx.mouser.com/ProductDetail/Bourns/PTD901-2015K-A502/?qs=sGAEpiMZZMsYXAobifOWHHsvVlmygg1PSRrH8DJbHc4%3d

the 5k with switch i cant find on mouser.. i sent an email to alphastat.de to ask about prices but before all that happens i wanted to know if anyone has 2 stereo sets of pots here? would be great!

anyways thanks a lot ill be coming to hassle to this thread more often

:D
Title: Re: sontec 1 RU build thread
Post by: zayance on March 05, 2012, 04:51:05 PM
I give you a hint: Copy/Paste Manufacturer Part number from Digikey in Mouser's Search field  ;)
Title: Re: sontec 1 RU build thread
Post by: ptron on March 06, 2012, 04:43:39 AM
http://mx.mouser.com/ProductDetail/CTS/270X232A502B1A1/?qs=GxOUx7aO6nwVwavGBMqnkg%3d%3d so 3 per channel?

http://mx.mouser.com/ProductDetail/CTS/270X232A502B1B1/?qs=GxOUx7aO6nyHwVWMNHDkQg%3d%3d 1 per channel?

:) thanks a lot zayance
Title: Re: sontec 1 RU build thread
Post by: zayance on March 06, 2012, 06:07:30 AM
yes
Title: Re: sontec 1 RU build thread
Post by: ptron on March 06, 2012, 10:49:38 PM
the other 10 pots i defo got to order to alphastat then i guess? .. they havent replied yet
Title: Re: sontec 1 RU build thread
Post by: Leonardo_007 on March 07, 2012, 02:20:41 PM
Hi,
currently i face a problem with the sum amp...
i'm stuck because i don't know how to deal with the area around the OPA604 (+24, GND,-24, +in, -in, out).
on the photos i've seen of the old version, there is a further stage set up  on this area which has not been part of the red pcb set.
can you help?
thanks in advance.
best
Leo
Title: Re: sontec 1 RU build thread
Post by: Leonardo_007 on March 08, 2012, 06:31:36 AM
AAAAAH ok.... i think i understood...

these pins seem to be provided for those people who use other op amps than OPA604!?

alright.... and the mounted stage above on the "older" version is a discrete (maybe J99) type of op amp... alright alright...

so in other words - to conclude - i wouldn't have to do anything on these slots when using the OPA 604, right?
Title: Re: sontec 1 RU build thread
Post by: cstella on March 08, 2012, 09:59:36 AM
Yes that is correct. You can also omit C59 150p as per the BOM.

Title: Re: sontec 1 RU build thread
Post by: Leonardo_007 on March 08, 2012, 11:09:43 AM
alright,thanks!

another question on the intern capacitor (hard left side on the sum amp, indicated with 1mF value):

i saw that several dudes used a wima polyester capacitor, mks4...
normally, they are not available with 1mF... i ordered an electrolythic cap instead...
is it really 1mF value this CIN???

concerning grounding, i'd only need to establisch ONE star-ground point on the chassis, right? this is where i need to connect 4 points: the ps, the transformer and the two sum amps, right?
Title: Re: sontec 1 RU build thread
Post by: cstella on March 08, 2012, 11:31:40 AM
Sure they are. Look for 1uF

http://www.mouser.com/ProductDetail/WIMA/MKS4D041002F00KSSD/?qs=sGAEpiMZZMvOcEq4GH1AAlUs2Fayh3j%2fqBV5lAHCsAo%3d

Regarding the star ground and sources you are correct.
Title: Re: sontec 1 RU build thread
Post by: Leonardo_007 on March 08, 2012, 12:35:56 PM
ok and this is what i do not understand, because due to the pcb, the cap indicated as CIN does show a value of 1 mF and not 1 uF.

so is it in fact 1uF instead of 1mF? i didn't get that out of the thread...

thanks in advance, cstella.

bw,
Leo
Title: Re: sontec 1 RU build thread
Post by: cstella on March 08, 2012, 12:47:09 PM
Yeah it's confusing the way it is listed since the other 1's all say 1U.

1uF is 1 microfarad hence 1mF.

Thanks, Charles
Title: Re: sontec 1 RU build thread
Post by: Leonardo_007 on March 08, 2012, 01:02:02 PM
oh ok!

thanks for having shared this information, it may be a helpful one for the pcb creator as well in order solve this issue with version 1.7, thanks Charles.
i may get back to you when it comes to transformer connection...
the rest should be manageable, assuming i did a reasonable job on the soldering...
best wishes from germany,
Leo
Title: Re: sontec 1 RU build thread
Post by: druu on March 12, 2012, 07:05:52 AM
Igor still about? Ordered a set of boards from his site and haven't had a response yet?
Title: Re: sontec 1 RU build thread
Post by: RATMNL on March 12, 2012, 07:14:30 AM
I think I read somewhere he's bound to get back from holidays any day now...
Title: Re: sontec 1 RU build thread
Post by: Leonardo_007 on March 13, 2012, 01:28:49 PM
yeah, Igor is currently on vacation...

my unit works now! it's just wow!

i own now a mastering eq which are being sold for several thousand dollars!

awesome job has been done on the pcbs!

to be honest... i waited some time for them to come... but the payoff has been extremely satisfying!
Title: Re: sontec 1 RU build thread
Post by: Aleguitarpro on March 14, 2012, 11:32:52 AM
Hi!
I've finished to find all the components for my Sontec.
I've found this power transformer, that suites the specs of the real sontec POWER DETAILS:

http://www.musikding.de/product_info.php/info/p2884_Toroidal-transformer-230V----2x-24V-10W.html

In the Sontec specs I've found:

Power - 240 VAC    21VA
Fuse  -  0.15 [email protected]

Could I use that toroidal (0,21 A for each secondary) or it's too less powerful??

I'll use OPA2604-OPA604-OP275.

The only option that I've, is to find another toroidal in MOUSER site...but which??

Thanks!

p.s. I'm from italy and here it's very difficult to find something useful to this kind of project...
Title: Re: sontec 1 RU build thread
Post by: cstella on March 14, 2012, 11:58:35 AM
That may be a hair on the small side. Add up all the current requirements of your IC's and see.

I used this one in my build and it works great. It's a bit more powerful.

http://hairballaudio.com/shop/product_info.php?cPath=33&products_id=37

Thanks, Charles
Title: Re: sontec 1 RU build thread
Post by: Aleguitarpro on March 14, 2012, 12:06:17 PM
Thanks, I've used that transformer in my 1176 clone.
I'm trying to find something here in Europe (that transformer 25$+ shipment+customs taxes+21%taxes cost me a lot...)

Anyone has bought a similar toroid here in europe??
I prefer to find one suitable to this application in mouser...any code suggestion?? :)
Title: Re: sontec 1 RU build thread
Post by: cstella on March 14, 2012, 12:19:39 PM
I did not have much luck at Mouser when I was looking. I know some people used these from Farnell. Not sure if their Italian branch works fro you or not.

http://it.farnell.com/multicomp/mcfe030-25/trasformatore-30-va-2-x-25-v/dp/9531750?Ntt=MCFE030/25

http://it.farnell.com/multicomp/mcfe050-25/trasformatore-50-va-2-x-25-v/dp/9531807?Ntt=MCFE050/25
Title: Re: sontec 1 RU build thread
Post by: Aleguitarpro on March 14, 2012, 03:41:25 PM
After 1 day of research, I've found this one (25VA):

http://it.mouser.com/Search/ProductDetail.aspx?R=VPT48-520virtualkey55310000virtualkey553-VPT48-520

and this one (50VA):

http://it.mouser.com/Search/ProductDetail.aspx?R=VPT48-1040virtualkey55310000virtualkey553-VPT48-1040

It's not very clear the searching options in mouser... :S

Thanks for help!
Title: Re: sontec 1 RU build thread
Post by: cstella on March 14, 2012, 04:08:26 PM
cool!
Title: Re: sontec 1 RU build thread
Post by: ptron on March 19, 2012, 09:59:35 PM
sorry to bother yall! i just checkin here wanted to see if these are good for our cause. im gettin the case from tat

(MALE)
http://mx.mouser.com/ProductDetail/Neutrik/NC3MD-H-BAG/?qs=sGAEpiMZZMv0W4pxf2HiV0%252bKdhvD8lQR7TrIC38bFrM%3d
or
http://mx.mouser.com/ProductDetail/Neutrik/NC3MD-V-BAG/?qs=sGAEpiMZZMv0W4pxf2HiV0%252bKdhvD8lQRZfW6%252bHEjzvA%3d

and (FEM)
http://mx.mouser.com/ProductDetail/Neutrik/NC3FD-H-BAG/?qs=sGAEpiMZZMv0W4pxf2HiV0%252bKdhvD8lQRVxgm65Gvs8w%3d

-- i can see from the drawing of these neutriks they are horizontal i thought the pins had to go down vertically to mount to pcb?

do i need metal standoffs so to get grounded from pcb?

will the pcbs hold themselves from the pots and I/O XLR`s respectively without standoffs in case previous question is no? (except power supply)

just checking what else i need to get!!

thanks a lot for your help
Title: Re: sontec 1 RU build thread
Post by: ptron on March 21, 2012, 01:30:46 AM
thanks a lot! ill ask tat again.

he sent me to the bom to check which ones the project needed, i guess ill know soon enough what cutout they have :)

thanks again!
Title: Re: sontec 1 RU build thread
Post by: ptron on March 21, 2012, 08:18:51 PM
i asked Tat and theyre fine for the cutouts of the case.. i just dont know if they will fit into the pcb nicely or i will have to wire the good ol hard way? id prefer the pcb style termination

would any be able to tell me if these are it?
 there is H and V type of both male and female neutriks. do i need the V" kind so the pins are vertical? im not sure
thanks a lot!
Title: Re: sontec 1 RU build thread
Post by: ptron on March 21, 2012, 10:22:53 PM
i asked Tat and theyre fine for the cutouts of the case.. i just dont know if they will fit into the pcb nicely or i will have to wire the good ol hard way? id prefer the pcb style termination

I installed the XLR's and used Shielded Mogami hookup wire for connector to board.

You can use pretty much any Neutrik XLR using this method.

You might want to contact Igor, if the connector type that you want to use isn't specified in the BOM.

Regards,
Mark

thank you very much!! :)
will contact him right away. got a question about the 2254 trannies too :)
Title: Re: sontec 1 RU build thread
Post by: sedit1 on March 27, 2012, 08:04:19 AM
Hi!

I would love to build a stereo sontec and I would like to use it for mastering duties. I'm no mastering engineer but many of my clients (smaller bands) wants me to master their demos/ep's so I would like to have a decent eq for that job.

The stepped version would of course be the better option but it seems like too much work to me at this time.
Do you think that normal pot version would be suitable for mastering duties/how many of you guys are using the normal version for mastering?

Thanks!
Title: Re: sontec 1 RU build thread
Post by: Leonardo_007 on March 27, 2012, 10:12:42 AM
Hi!

I would love to build a stereo sontec and I would like to use it for mastering duties. I'm no mastering engineer but many of my clients (smaller bands) wants me to master their demos/ep's so I would like to have a decent eq for that job.

The stepped version would of course be the better option but it seems like too much work to me at this time.
Do you think that normal pot version would be suitable for mastering duties/how many of you guys are using the normal version for mastering?

Thanks!

Hi!

congratulations! very good idea. Igor's sontec is unquestionable the best diy mastering eq out there! incredible value for money.
i finished the sontec around 2 weeks ago and this unit has greatly enriched my existing gear arsenal!
yes! this unit works brilliantly for mastering!
i'm aware of eq techniques for mastering, but in this case i have to say: no matter what you do with this eq, which knob in which direction: it simply sounds so much better than before!
there may certainly different opinions on the stepped version out there, in my opinion: the non-stepped version is totally sufficient for mastering. the stepped version would - as you already assumed - mean a substantial increase on your diy efforts!
it maybe a nice to have but for me (i use to evaluate sound-wise, only): not justifying the extra effort (if you realize what other remarkable diy adventures are also currently available, also from Igor: the 2254, CRM kit, 33609, mnats 1176, even a u47 clone, 1084 etc. pp...) - my advice: save resources you do not really need to spend on comfort that add only little value on your goal no. 1: SOUND
just do it like this: the midrange is the key! in order to identify disturbihng frequencies cut the lows and highs off.
then boost through the midrange and if you found the poor dog, just make a cut of ca. 3db. you can do this with all 3 midrange knobs. if you are done with the midrange, just add a lil air and balls and there we go.
best wishes.
Title: Re: sontec 1 RU build thread
Post by: ptron on March 28, 2012, 02:13:09 AM
thought of it a while. the stepped one seems the right choice if you really want control over the frequency you wanna treat and not messing up stereo image but it is bit more work..
Title: Re: sontec 1 RU build thread
Post by: ilfungo on April 11, 2012, 10:34:16 AM
sorry
I would like to build this equalizer
there is a cheaper alternative to Alphastat pot?
Can anyone tell me the approximate cost for the stereo version?
thanks
Title: Re: sontec 1 RU build thread
Post by: cstella on April 11, 2012, 12:07:25 PM
Hi

The board is designed around those specific pots so for a clean build you really need to use the alphastats. You could use other pots of the same values but they would have to be mounted off board (lots of extra wiring, noise etc). Also with the correct case they act as the mounting for the PCB to front panel.

I spent about $800 US on mine not counting the DOA's which I already had.

Thanks, Charles
Title: Re: sontec 1 RU build thread
Post by: ilfungo on April 11, 2012, 01:11:29 PM
Thanks!!!
Title: Re: sontec 1 RU build thread
Post by: Siegfried Meier on April 11, 2012, 09:56:00 PM
Where are you guys taking voltage for a mains power LED?  I've read through the thread, and maybe I've missed it, but I can't see anything here.  I've measured a few spots and there's plenty of 23v going on, but nothing low that I can use.

Any ideas much appreciated,
Thanks!
Sig
Title: Re: sontec 1 RU build thread
Post by: cstella on April 11, 2012, 10:03:12 PM
Hi

Use JP1 on the power supply board. That's what it was designed for. There's 10k resistor in series to pad 2.

Charles.
Title: Re: sontec 1 RU build thread
Post by: Siegfried Meier on April 11, 2012, 10:48:07 PM
Huh?  Where's JP1?

All I see are 2 pads that are joined together, but labelled +3 and Ground.  Are these what you mean?

I tried using them as they're labelled, but nothing...

Ohhhhhhh you must mean the actual spot labelled LED on the PSU board.  Doh, I actually stuck the LED in place on the PSU as an indication of whether it was powered up.  I shouldn't have done that.  I'll remove, do it right.

PS - what are these other 2 pads for?

Thanks!
Sig
Title: Re: sontec 1 RU build thread
Post by: cstella on April 11, 2012, 10:57:03 PM
It's marked JP1 on the schematic. On the pcb it's labeled LED+ and LED -. Is this the PCB you have? +3 and ground are AGND.
Title: Re: sontec 1 RU build thread
Post by: cstella on April 11, 2012, 11:05:18 PM
I see you updated your post. Yes exactly!! You might be able to see it better on the front panel  ;).
Title: Re: sontec 1 RU build thread
Post by: cstella on April 11, 2012, 11:07:20 PM
ANGD is connected to your star ground on the chassis.

Title: Re: sontec 1 RU build thread
Post by: Siegfried Meier on April 11, 2012, 11:13:18 PM
Haha indeed.  I actually fed off the bottom of the PCB so now I am using BOTH led's...ya I'm crazy.

Ahhh ok, I wondered about that for star ground.  Awesome thanks!
Title: Re: sontec 1 RU build thread
Post by: cstella on April 11, 2012, 11:17:45 PM
Cool. Enjoy the rest of the build. It's an awesome eq!

Charles
Title: Re: sontec 1 RU build thread
Post by: Siegfried Meier on April 12, 2012, 10:51:42 AM
Thanks!

1 more quick question - do the XLR IO boards have to also be attached to star ground?  I didn't do it, and my unit it pretty damn quiet.

Thanks!
Sig
Title: Re: sontec 1 RU build thread
Post by: Leonardo_007 on April 12, 2012, 11:34:27 AM
usually you would do so, yes (as i did it for my sontec as well)

but who cares..!? - if it works - it works and seems to be a minor issue (as you deal with 24v only).
Title: Re: sontec 1 RU build thread
Post by: cstella on April 12, 2012, 12:24:40 PM
It is designed to be attached to the star ground at CHAS on the I/O board. That's how I did it. You could measure the noise level with and without to see if it makes any difference. I think mine is around -107dB.

Charles
Title: Re: sontec 1 RU build thread
Post by: Siegfried Meier on April 12, 2012, 12:58:42 PM
Awesome, you rock thanks!
Title: Re: sontec 1 RU build thread
Post by: atticmike on April 13, 2012, 06:16:27 PM
I'd appreciated a lot if anybody around here would post either their digi or mouser bom :D
Title: Re: sontec 1 RU build thread
Post by: sedit1 on April 14, 2012, 12:41:02 AM
Hi guys!

I decided to go with the rotary switch route, but I have few newbish qustions regarding the rotary switches :)
So i'm kind of new with all the rotary switch thing and I havent recieved the pcb's yet so can you help me? 

-For the freq range how are you supposed to wire the rotary, the pot is dual rev log and the pcb has 6 holes.
 and should the rotary then be 2 pole rotary? I'm using harpos xls

-Low shelf, what kind of switch do you need to have the normal rotary+the shelf switch

-Gain switch for 0 position do you just tie -1/+1 resistor legs together to the center lug?

Thanks!
Title: Re: sontec 1 RU build thread
Post by: atticmike on April 16, 2012, 07:26:25 AM
Does also anybody have a rough figure on how much they spent on the passive parts / components to be soldered onto the boards?

Without the expenses of either enclosure, frontplate, xlr connectors, cables and such?

And again, a simple buying list, of all the to be soldered components onto the pcbs, would help people's rather rare occasion of build undertakings and therefore their targetet parts procurement tremendously.
Title: Re: sontec 1 RU build thread
Post by: Aleguitarpro on April 17, 2012, 04:42:49 AM
Does also anybody have a rough figure on how much they spent on the passive parts / components to be soldered onto the boards?

Without the expenses of either enclosure, frontplate, xlr connectors, cables and such?

And again, a simple buying list, of all the to be soldered components onto the pcbs, would help people's rather rare occasion of build undertakings and therefore their targetet parts procurement tremendously.

Hi.
For the passive components+toroidal power transformer I've spent about 200 euro (mouser+musikding.de).
I can't say it with precision, because I've bought a lot of passive components in that order, but it's not more than 200 euro, only for sontec.
Only for the alpha pots, the cost is about 135 euro.
For the case, I've spent 75 euro on diy-racked.
The you have to buy knobs with 6,3 mm and 3,2 mm axis (CTS pots).


Now, I've a problem with my power transformer: after a short test to see if everything was good, I've switch off my Sontec.
The day after, I've switch on it and it broke my fuse.
I've repeat the test, isolating the problem (I've made a test without the summing+filter boards) and then, without the psu: always the same...
I've broken 6 fuse...
I isolate the transformer and I think that it has lose the isolation in the primary.
It's possible? This is the first time I find this problem!
I don't know if it is a problem of THIS particular transformer or if I change it, I'll burn another transformer!
The secondary seems to be ok... How can I test it?
I think the problem is in the primary, because also with the secondary disconnected it burn the fuse.
The transformer is this one:
http://it.mouser.com/Search/ProductDetail.aspx?qs=wkKrz7WmEgNNyd%2Fvat7D2Q%3D%3D
I've used a 150 mA fuse with it, according to the specific of sontec...

Thanks.
A.
Title: Re: sontec 1 RU build thread
Post by: wolfgang on April 17, 2012, 05:59:03 AM
I think your fuse is set to low since this is a 50VA transformer.
50/230 is about 220mA. i would go with 250mA to 315mA for inrush current.

I hope my calculation is right!

regards,
Wolfgang
Title: Re: sontec 1 RU build thread
Post by: Aleguitarpro on April 17, 2012, 06:52:20 AM
I think your fuse is set to low since this is a 50VA transformer.
50/230 is about 220mA. i would go with 250mA to 315mA for inrush current.

I hope my calculation is right!

regards,
Wolfgang

Oh, sh*t!
You're right...
50/220= 0.227 mA (fuse)
But I don't remerber if I've to oversize the primary fuse respect to the amperage...
150% it's ok?
es.

50VA/220=0.22 x 150% = 0.33 mA

It's ok?

It's possible that I've damaged the circuit, too, or I've "just" burn the transformer?
Title: Re: sontec 1 RU build thread
Post by: atticmike on April 17, 2012, 07:31:32 AM
Does also anybody have a rough figure on how much they spent on the passive parts / components to be soldered onto the boards?

Without the expenses of either enclosure, frontplate, xlr connectors, cables and such?

And again, a simple buying list, of all the to be soldered components onto the pcbs, would help people's rather rare occasion of build undertakings and therefore their targetet parts procurement tremendously.

Hi.
For the passive components+toroidal power transformer I've spent about 200 euro (mouser+musikding.de).
I can't say it with precision, because I've bought a lot of passive components in that order, but it's not more than 200 euro, only for sontec.
Only for the alpha pots, the cost is about 135 euro.
For the case, I've spent 75 euro on diy-racked.
The you have to buy knobs with 6,3 mm and 3,2 mm axis (CTS pots).


Now, I've a problem with my power transformer: after a short test to see if everything was good, I've switch off my Sontec.
The day after, I've switch on it and it broke my fuse.
I've repeat the test, isolating the problem (I've made a test without the summing+filter boards) and then, without the psu: always the same...
I've broken 6 fuse...
I isolate the transformer and I think that it has lose the isolation in the primary.
It's possible? This is the first time I find this problem!
I don't know if it is a problem of THIS particular transformer or if I change it, I'll burn another transformer!
The secondary seems to be ok... How can I test it?
I think the problem is in the primary, because also with the secondary disconnected it burn the fuse.
The transformer is this one:
http://it.mouser.com/Search/ProductDetail.aspx?qs=wkKrz7WmEgNNyd%2Fvat7D2Q%3D%3D
I've used a 150 mA fuse with it, according to the specific of sontec...

Thanks.
A.

But still, if it shows what parts you've procured, it'd be hell of a help :D
Title: Re: sontec 1 RU build thread
Post by: Aleguitarpro on April 17, 2012, 03:35:29 PM

But still, if it shows what parts you've procured, it'd be hell of a help :D

FROM MOUSER:

- CTS pots
3 5K LIN POTSW
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=CT2204-ND

1 5K LIN POT
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=CT2226-ND
(you have to copy the product code in Mouser)

- power transformer
- neutrik xlr
- not common european value resistors
- 2604 OPA
- some ceramic capacitor

FROM ALPHASTAT:
- 5 50k CTPOT
2207 RD1601-20F4-30R
ALPHASTAT 63250-01610/B50K 50K LIN CENTERTAPCENTERDETENT

- 5 100K RLOG DUAL_ALPHA_2
4196 RD1602-20B4-30R
ALPHASTAT 63256-02600/C100K 100K REV-LOG

FROM MUSIKDING (a place in europe in which you could find passive components for a very good price...supposing you're from europe...)

- all resistors 0.6 W
- OPA 604
- OPA 275
- capacitors (WIMA, tantalum, etc.)
- connectors (MOLEX)
- power connector
- wirings
- led
- diodes
- heatsink
- etc.

CASE from DIY-RACKED for 75 euro.

Hope this could help you.

A.
Title: Re: sontec 1 RU build thread
Post by: wolfgang on April 18, 2012, 03:23:30 AM
Quote
Oh, sh*t!
You're right...
50/220= 0.227 mA (fuse)
But I don't remerber if I've to oversize the primary fuse respect to the amperage...
150% it's ok?
es.

50VA/220=0.22 x 150% = 0.33 mA

It's ok?

It's possible that I've damaged the circuit, too, or I've "just" burn the transformer?

I would go with 150%. so 315mA is a standard-value in that range that should work.
If something else is gone ? can happen but dont have to! I would  connect the PSU-Board only and check the DC-Voltages. Then you will see!

regards,
Wolfgang
Title: Re: sontec 1 RU build thread
Post by: Aleguitarpro on April 18, 2012, 03:52:01 AM
Quote
Oh, sh*t!
You're right...
50/220= 0.227 mA (fuse)
But I don't remerber if I've to oversize the primary fuse respect to the amperage...
150% it's ok?
es.

50VA/220=0.22 x 150% = 0.33 mA

It's ok?

It's possible that I've damaged the circuit, too, or I've "just" burn the transformer?

I would go with 150%. so 315mA is a standard-value in that range that should work.
If something else is gone ? can happen but dont have to! I would  connect the PSU-Board only and check the DC-Voltages. Then you will see!

regards,
Wolfgang

Yes, but maybe I haven't explain well my problem.
When I finished my sontec, I've tested the power supply and was ok.
Then, I connect the rest and check the equalizer.
OK.
The day after, I've tried to switch on my eq and the 150mA fuse burned.
I've changed the fuse with a 400mA new one, and burned.
Obiouvsly I've disconnected all the filters and summing pcbs from PSU pcb but always the same behaviour.
Then, I've tried to isolate the problem, thinking about a bad trasformer isolation: yes, the problem is a bad isolation in primary of the toroidal.
But the BIG QUESTION is: why the primary is shorted?
Why it lose the isolation?

Because in a first moment it has worked.
It depends on a too small fuse I used the first time (150mA)?
I've burn the transformer or it's possible that I've bought a defected transformer?
I thought that the amperage of the fuse depends on the absorption of the circuit (the secondary) and don't regards the primary.
Title: Re: sontec 1 RU build thread
Post by: cstella on April 18, 2012, 01:49:27 PM
I had a similar problem that drove me crazy! I was blowing fuses and had other strange behavior. I had a new transformer but some how the protective film had been broken and the transformer was shorting out against the chassis mount screw. I removed the transformer and covered it with electrical binding tape. No more shorts and the Sontec works great!

Maybe that helps.

Thanks, Charles
Title: Re: sontec 1 RU build thread
Post by: atticmike on April 19, 2012, 11:43:14 AM
Is it that 0207 are 0.4 resistors and 0204 equals 0.25?
Title: Re: sontec 1 RU build thread
Post by: kante1603 on April 19, 2012, 12:42:48 PM
But the BIG QUESTION is: why the primary is shorted?
Why it lose the isolation?
Hi,

this often occurs when overtightening the mounting screw.I had exactly that in a different built.Also don´t mount them with the wires running from the bottom of the torroid;I know it looks better but it´s possible to break one.Mount them correctly with all the mounting parts like a rubber sheet and the metall pieces etc.
I´m sure you know that the mounting screw shouldn´t touch both the bottom and the top of the case because this will cause a magnetic short by creating one single winding-that´s a killer.

Hope to have helped,

Udo.
Title: Re: sontec 1 RU build thread
Post by: atticmike on April 19, 2012, 07:17:41 PM
From what I've understand, you employ two ics for every channel.

Which ones would you recommend? Thankfully with referring to an online source where I can get em.

Mike

Still, are the 0207 as well 1/4 0.25 watt resistors, kind of curious because they're listed separately?
Title: Re: sontec 1 RU build thread
Post by: Leonardo_007 on April 19, 2012, 08:11:14 PM
maybe it will depend on your selected sources for procurement but i would definitely recommend the combination OPA 604 / 2604 as they will provide the best value for money ratio and you won't have to calculate with different values for the resistors. they are robust (even work w/o sockets) and you can get along with 24v.
Title: Re: sontec 1 RU build thread
Post by: Leonardo_007 on April 20, 2012, 06:59:48 AM
just for official clarification.. the codes "0207" "0204" on resistors are size indications in mm, for instance: "0207" means the resistor is 2mm wide and 7mm long.
Title: Re: sontec 1 RU build thread
Post by: ilfungo on April 20, 2012, 09:50:44 AM
hi Igor
Any news about stepped sontec?
Thanks
Title: Re: sontec 1 RU build thread
Post by: ptron on April 20, 2012, 02:58:28 PM
hi Igor
Any news about stepped sontec?
Thanks

i think this project has moved on with the name of Uni-Q
Title: Re: sontec 1 RU build thread
Post by: atticmike on April 20, 2012, 08:56:25 PM
just for official clarification.. the codes "0207" "0204" on resistors are size indications in mm, for instance: "0207" means the resistor is 2mm wide and 7mm long.

but that'd mean I could just take regular 1/4 resistors since you can stretch em anyways by the lead?
Title: Re: sontec 1 RU build thread
Post by: Harpo on April 21, 2012, 12:38:30 AM
just for official clarification.. the codes "0207" "0204" on resistors are size indications in mm, for instance: "0207" means the resistor is 2mm wide and 7mm long.
Look up the resistors datasheet for the 0204 and 0207 types to get the difference (parts size / power rating / voltage), maybe from this manufacturer ...
http://www.yageo.com/documents/recent/Leaded-R_MF0_2011.pdf (http://www.yageo.com/documents/recent/Leaded-R_MF0_2011.pdf)

Use ohms law to check, if it matters for a specific part in question.
(hint: with a +/-24V supply, 0.25W rated resistors with value lower than 2K3, 0.4W rated resistors with value lower than 1K4 or 0.6W rated resistors with value lower than 960R might need a 2nd look, if their power rating will be sufficient in a specific spot in this application)
For this EQ build, RPS1...5 (and R16 in a shorted output condition by maybe connected broken XLR cable) better have a higher power rating than 0.25W or 0.4W.
Title: Re: sontec 1 RU build thread
Post by: atticmike on April 21, 2012, 03:50:09 AM
just for official clarification.. the codes "0207" "0204" on resistors are size indications in mm, for instance: "0207" means the resistor is 2mm wide and 7mm long.
Look up the resistors datasheet for the 0204 and 0207 types to get the difference (parts size / power rating / voltage), maybe from this manufacturer ...
http://www.yageo.com/documents/recent/Leaded-R_MF0_2011.pdf (http://www.yageo.com/documents/recent/Leaded-R_MF0_2011.pdf)

Use ohms law to check, if it matters for a specific part in question.
(hint: with a +/-24V supply, 0.25W rated resistors with value lower than 2K3, 0.4W rated resistors with value lower than 1K4 or 0.6W rated resistors with value lower than 960R might need a 2nd look, if their power rating will be sufficient in a specific spot in this application)
For this EQ build, RPS1...5 (and R16 in a shorted output condition by maybe connected broken XLR cable) better have a higher power rating than 0.25W or 0.4W.

Xicon resistors, even at values such as 68R maintain the following specifications:

Power Rating:   250 mWatts (1/4 Watt)   
Voltage Rating:   250 Volts   
Temperature Coefficient:   50 PPM /

For a person who is not that much of an expert but does their homework, it'd be nice to know where or what these spots / resistors are by simply indicating a higher mWatts Power Rating you'd only attain by getting the respective bigger values.

It is not that I'm asking and won't do nothing, I've put the BOM together so far but lacking the knowledge I need to be 100 % sure of my choices. Also, with projects that lack a clear BOM, for people like me, I always provide the community with my mouser BOM.
Title: Re: sontec 1 RU build thread
Post by: Harpo on April 21, 2012, 05:26:57 PM
Look up the resistors datasheet for the 0204 and 0207 types to get the difference (parts size / power rating / voltage), maybe from this manufacturer ...
http://www.yageo.com/documents/recent/Leaded-R_MF0_2011.pdf (http://www.yageo.com/documents/recent/Leaded-R_MF0_2011.pdf)

Use ohms law to check, if it matters for a specific part in question.
(hint: with a +/-24V supply, 0.25W rated resistors with value lower than 2K3, 0.4W rated resistors with value lower than 1K4 or 0.6W rated resistors with value lower than 960R might need a 2nd look, if their power rating will be sufficient in a specific spot in this application)
For this EQ build, RPS1...5 (and R16 in a shorted output condition by maybe connected broken XLR cable) better have a higher power rating than 0.25W or 0.4W.

Xicon resistors, even at values such as 68R maintain the following specifications:

Power Rating:   250 mWatts (1/4 Watt)   
Voltage Rating:   250 Volts   
Temperature Coefficient:   50 PPM /

For a person who is not that much of an expert but does their homework, it'd be nice to know where or what these spots / resistors are by simply indicating a higher mWatts Power Rating you'd only attain by getting the respective bigger values.

It is not that I'm asking and won't do nothing, I've put the BOM together so far but lacking the knowledge I need to be 100 % sure of my choices. Also, with projects that lack a clear BOM, for people like me, I always provide the community with my mouser BOM.
Mike, you know from your +/-24V supply rails, voltage will not exceed this +24V or -24V value, so the voltage limits of your Xicon resistors with 250V rating won't be a problem. Your 1/4W rated resistors can stand a current flow of 0.25W/24V=0.010417A=~10mA. In a short condition (IE solder blob, broken cable), this make or break point will be 24V/0.01A=2K4 ohm. Using a lower resistor value than 2K4 might exceed the resistors power rating, so rating of this part will need a 2nd look, but knowing this value limit, you can simply ignore all resistors with a parts value higher than 2K4. (3/4 of all resistors in this circuit have a value higher than 2K4, so most of this work is already done)
Looking at the schematic, 1st resistor in circuit with value lower than 2K4 is the 100R R7. This has the 20K R8 in series connected, so total resistance is 20K1, more than the 2K4 limit, no problem with 1/4W rating. This R7 also branches to J1-1, further going to the 'boost' rail. This has some 7K5 in series with the 50K center tapped pots in parallel connected. 100R + this paralleled series string doesn't exceed the 2K4 limit, so no problem from this side of the branch as well.
R15 is the same for the 'cut' rail so same as previous branch test and no problem as well.
R9 connects thru J1-5 to the output of the filter stages, each with a 20K or 10K in series in between, no problem expected as well.
R11 connects in series to the 10K R13. No problem.
The 68R R16 connects to XLR-pin2. No problem for usual operation, but if the resistor feeding opamp is steady clipping and can swing up to the voltage rails from a boosted signal and XLR-pin2 gets shorted to gnd by a broken connected cable, there is only a voltage divider forming 10R R23 in between, so your 1/4W resistor power rating will be exceeded, maybe on purpose, acting like a fuse. (Required rating might go up to (24V/(68R+10R)*68R)^2/68R=6.44W for this extreme condition, if your opamp -more unlikely- could deliver this 300mA current draw and the fusible resistors RPS1...RPS4 for whatever reason don't blow up first).
For the 10R R23, Igor already suggested a 0.6W rated 0207 type, where a (24V/(68R+10R)*10R)^2/10R=0.95W would be required to stand this extreme, but a 0.25W or 0.6W rated R16 or more likely the RPS1...RPS4 would blow first, protecting this R23.
No problem for the impedance balancing 68R R17 expected.
The 392R RF1.4...RF4.4 have high enough series resistors connected, so no problem as well.
The 1K6 RF1.9...RF4.10 have a cap in series connected, blocking DC condition and max.voltage will not exceed 24V/sqrt(2). Rating required 0.18W, no problem.
The current limiting/fusible RPS1...5 have to stand the power consumption of all connected opamps. Igor already suggested a 0.6W rated 0207 type.
So all resistors -except RPS1...RPS5- can be fitted with your 0.25W Xicon resistors. As always YMMV.
Title: Re: sontec 1 RU build thread
Post by: atticmike on April 22, 2012, 06:51:33 PM
Look up the resistors datasheet for the 0204 and 0207 types to get the difference (parts size / power rating / voltage), maybe from this manufacturer ...
http://www.yageo.com/documents/recent/Leaded-R_MF0_2011.pdf (http://www.yageo.com/documents/recent/Leaded-R_MF0_2011.pdf)

Use ohms law to check, if it matters for a specific part in question.
(hint: with a +/-24V supply, 0.25W rated resistors with value lower than 2K3, 0.4W rated resistors with value lower than 1K4 or 0.6W rated resistors with value lower than 960R might need a 2nd look, if their power rating will be sufficient in a specific spot in this application)
For this EQ build, RPS1...5 (and R16 in a shorted output condition by maybe connected broken XLR cable) better have a higher power rating than 0.25W or 0.4W.

Xicon resistors, even at values such as 68R maintain the following specifications:

Power Rating:   250 mWatts (1/4 Watt)   
Voltage Rating:   250 Volts   
Temperature Coefficient:   50 PPM /

For a person who is not that much of an expert but does their homework, it'd be nice to know where or what these spots / resistors are by simply indicating a higher mWatts Power Rating you'd only attain by getting the respective bigger values.

It is not that I'm asking and won't do nothing, I've put the BOM together so far but lacking the knowledge I need to be 100 % sure of my choices. Also, with projects that lack a clear BOM, for people like me, I always provide the community with my mouser BOM.
Mike, you know from your +/-24V supply rails, voltage will not exceed this +24V or -24V value, so the voltage limits of your Xicon resistors with 250V rating won't be a problem. Your 1/4W rated resistors can stand a current flow of 0.25W/24V=0.010417A=~10mA. In a short condition (IE solder blob, broken cable), this make or break point will be 24V/0.01A=2K4 ohm. Using a lower resistor value than 2K4 might exceed the resistors power rating, so rating of this part will need a 2nd look, but knowing this value limit, you can simply ignore all resistors with a parts value higher than 2K4. (3/4 of all resistors in this circuit have a value higher than 2K4, so most of this work is already done)
Looking at the schematic, 1st resistor in circuit with value lower than 2K4 is the 100R R7. This has the 20K R8 in series connected, so total resistance is 20K1, more than the 2K4 limit, no problem with 1/4W rating. This R7 also branches to J1-1, further going to the 'boost' rail. This has some 7K5 in series with the 50K center tapped pots in parallel connected. 100R + this paralleled series string doesn't exceed the 2K4 limit, so no problem from this side of the branch as well.
R15 is the same for the 'cut' rail so same as previous branch test and no problem as well.
R9 connects thru J1-5 to the output of the filter stages, each with a 20K or 10K in series in between, no problem expected as well.
R11 connects in series to the 10K R13. No problem.
The 68R R16 connects to XLR-pin2. No problem for usual operation, but if the resistor feeding opamp is steady clipping and can swing up to the voltage rails from a boosted signal and XLR-pin2 gets shorted to gnd by a broken connected cable, there is only a voltage divider forming 10R R23 in between, so your 1/4W resistor power rating will be exceeded, maybe on purpose, acting like a fuse. (Required rating might go up to (24V/(68R+10R)*68R)^2/68R=6.44W for this extreme condition, if your opamp -more unlikely- could deliver this 300mA current draw and the fusible resistors RPS1...RPS4 for whatever reason don't blow up first).
For the 10R R23, Igor already suggested a 0.6W rated 0207 type, where a (24V/(68R+10R)*10R)^2/10R=0.95W would be required to stand this extreme, but a 0.25W or 0.6W rated R16 or more likely the RPS1...RPS4 would blow first, protecting this R23.
No problem for the impedance balancing 68R R17 expected.
The 392R RF1.4...RF4.4 have high enough series resistors connected, so no problem as well.
The 1K6 RF1.9...RF4.10 have a cap in series connected, blocking DC condition and max.voltage will not exceed 24V/sqrt(2). Rating required 0.18W, no problem.
The current limiting/fusible RPS1...5 have to stand the power consumption of all connected opamps. Igor already suggested a 0.6W rated 0207 type.
So all resistors -except RPS1...RPS5- can be fitted with your 0.25W Xicon resistors. As always YMMV.

Thanks Harpo, I cannot express how grateful I am for your assistance and the info about how to narrow down my choice of resistors. Hadn't done it without your help.

Although is 10R really part of the build since it is not listed on the BOM provided by Igor? But yeah, I threw a glance at the schematic / drawings and saw that indeed 10R is indicated. Is it just a drawing culprit or really missing on the BOM?

Furthermore, here is my mouser BOM I've put together so far. Anything is on there except the following parts which I already included in my previous mouser order:

Neutrik XLR In / Output

CONNECTORS

POTENTIOMETERS

MISC

DIODES

HEATSINKS

I'd greatly appreciated it if someone could check it for mistakes, it'd be a huge help for anybody as inept as I am :D

I also have to add that creating a substitute for R55k, I chose two variants since I wasn't so sure which would be the smartest choice of em all:

1. 271-48.7K-RC & 271-1.3K-RC
2. 271-49.9K-RC & 271-100-RC

http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=f65d170554
Title: Re: sontec 1 RU build thread
Post by: Harpo on April 22, 2012, 08:44:08 PM
I also have to add that creating a substitute for R55k, I chose two variants since I wasn't so sure which would be the smartest choice of em all:
1. 271-48.7K-RC & 271-1.3K-RC
2. 271-49.9K-RC & 271-100-RC
Sorry, but I'm missing how your suggested substitute will add up to 55K. Just fit a 54K9 and be done with it. The 0.18% difference on paper is within parts tolerances.
No idea why BOMs aren't banned. Most often these are partly wrong, are missing essential parameters or are simply outdated because a vendor changed some order-IDs. You could learn so much more alongside by looking at datasheets when selecting parts of your desire. YMMV.
Title: Re: sontec 1 RU build thread
Post by: atticmike on April 23, 2012, 02:37:25 AM
I also have to add that creating a substitute for R55k, I chose two variants since I wasn't so sure which would be the smartest choice of em all:
1. 271-48.7K-RC & 271-1.3K-RC
2. 271-49.9K-RC & 271-100-RC
Sorry, but I'm missing how your suggested substitute will add up to 55K. Just fit a 54K9 and be done with it. The 0.18% difference on paper is within parts tolerances.
No idea why BOMs aren't banned. Most often these are partly wrong, are missing essential parameters or are simply outdated because a vendor changed some order-IDs. You could learn so much more alongside by looking at datasheets when selecting parts of your desire. YMMV.

Hah, I was dumbstruck at first too since I couldn't make sense of my 50k composure but I've stumbled across the culprit. I put 50k on my piece of jotting paper and transferred it onto my BOM. Will get fixed as soon as I've put the final list together :D

Why would the BOM be wrong if I asked for assistance from the experienced members of this board and I'm not going to mince matters just because I want to whitewash my weak points.

Even if it was outdated, people would still get to see the parts of a working build someone put together prior to their efforts which will make their ensuing parts procurement a lot easier.

I'm getting the point that you want folks to throw a glance at the build first and try to understand it. I didn't do anything any different by that matter. But it'll be still nice to have someone apt to throw a last glance at it and support the other's effort.

Especially with the Mica capacitors, I wasn't quite sure whether I've done everything correct with my choice of Mica caps.

I will just list everything accordingly to the bom's structure in this thread to avoid your loathed BOM scheme:


OP-AMP


1 x ad706 OR OPA2604(24V PS) 'CAN BE OTHER LOW OFFSET DUAL OPAMP

http://www.reichelt.de/ICs-NE-SA-/OPA-2604-AP/index.html?ACTION=3&GROUPID=2915&ARTICLE=13662&SHOW=1&START=0&OFFSET=16&&SID=10TwCoZ38AAAIAAGkrnrM5241d7b48719e2f0439021072ba7654c&LANGUAGE=EN

2 x OPA604 OR JE990 ETC 'CAN BE OTHER LOW DIST FAST HIGH CURRENT

http://www.reichelt.de/ICs-NE-SA-/OPA-604-AP/index.html?;ACTION=3;LA=444;GROUP=A218;GROUPID=2915;ARTICLE=13669;START=0;SORT=artnr;OFFSET=16;SID=10TwCoZ38AAAIAAGkrnrM5241d7b48719e2f0439021072ba7654c

5 x OPA2604 OR OP275 ETC 'CAN BE OTHER LOW DIST FAST DUAL OPAMP

Same OPA2604 as number one: http://www.reichelt.de/ICs-NE-SA-/OPA-2604-AP/index.html?ACTION=3&GROUPID=2915&ARTICLE=13662&SHOW=1&START=0&OFFSET=16&&SID=10TwCoZ38AAAIAAGkrnrM5241d7b48719e2f0439021072ba7654c&LANGUAGE=EN


---


RESISTORS


Anything Xicon 1/4 metal film except these parts:

R68 - 0.6 W

http://www.reichelt.de/Metall-0-1-5-10-Ohm-82-5-Ohm/MPR-68-0/index.html?;ACTION=3;LA=2;ARTICLE=13047;GROUPID=3102;artnr=MPR+68%2C0;SID=10TwCoZ38AAAIAAGkrnrM5241d7b48719e2f0439021072ba7654c

R22 - 0.6 W

http://www.reichelt.de/Metall-0-1-5-10-Ohm-82-5-Ohm/MPR-22-0/index.html?;ACTION=3;LA=2;ARTICLE=12871;GROUPID=3102;artnr=MPR+22%2C0;SID=10TwCoZ38AAAIAAGkrnrM5241d7b48719e2f0439021072ba7654c

2 x 200R 2%

http://uk.mouser.com/Search/ProductDetail.aspx?R=CCF07200RGKE36virtualkey61300000virtualkey71-CCF07200RGKE36

1 x rx+ 3k6 2% for 24v

http://uk.mouser.com/Search/ProductDetail.aspx?R=RL07S362GB14virtualkey61300000virtualkey71-RL07S-G-3.6K

1 x rx- 3k6 2% for 24v

Same as the one above: http://uk.mouser.com/Search/ProductDetail.aspx?R=RL07S362GB14virtualkey61300000virtualkey71-RL07S-G-3.6K

Still, I'm not sure whether R10 is part of the build since it list not listed under the parts list.

Anyways, there we got R10 - 0,6W, 0,1%, 10,0 Ohm

http://www.reichelt.de/Metall-0-1-5-10-Ohm-82-5-Ohm/MPR-10-0/index.html?;ACTION=3;LA=2;ARTICLE=12769;GROUPID=3102;artnr=MPR+10%2C0;SID=10TwCoZ38AAAIAAGkrnrM5241d7b48719e2f0439021072ba7654c


Do you think it'd be smart to just get all the resistors at 0,6W with a tolerance of 0.1%? That'd be almost 0.9 percent lower compared to Xicon and it'd cover the headroom mentioned earlier everywhere?



---


CAPACITORS-ELECTROLYTHIC


2 x 100U CPOL-EUE Pitch: 5 mm Width: 10.5 mm

http://uk.mouser.com/Search/ProductDetail.aspx?R=UES1H101MHMvirtualkey64700000virtualkey647-UES1H101MHM

2 x 100U CPOL-EUE Pitch: 5 mm Width: 13 mm

http://uk.mouser.com/Search/ProductDetail.aspx?R=UFG1H101MPMvirtualkey64700000virtualkey647-UFG1H101MPM

4 x 33U CPOL-EUE Pitch: 5 mm Width: 6 mm

http://uk.mouser.com/Search/ProductDetail.aspx?R=UKW1H330MDDvirtualkey64700000virtualkey647-UKW1H330MDD


---


CAPACITORS-CERAMIC


17 x 0.1U 5MM PITCH CERAMIC POWER SUPPLY BYPASS

http://uk.mouser.com/Search/ProductDetail.aspx?R=RPER71H104K2K1A03Bvirtualkey64800000virtualkey81-RPER71H104K2K1A03


---


CAPACITORS-POLY ETC.



1 x 0.15U C-10-15/6

http://uk.mouser.com/Search/ProductDetail.aspx?R=160154J250E-Fvirtualkey53900000virtualkey539-160154J250E-F

2 x 0.47U C-10-15/6

http://uk.mouser.com/Search/ProductDetail.aspx?R=160474J63D-Fvirtualkey53900000virtualkey539-160474J63D-F

8 x 1U C-10-15/6

http://uk.mouser.com/Search/ProductDetail.aspx?R=160105J63E-Fvirtualkey53900000virtualkey539-160105J63E-F

1 x 2U2 C-10-15/6

http://uk.mouser.com/Search/ProductDetail.aspx?R=MKS4C042204C00JSSDvirtualkey50520000virtualkey505-MKS42.2%2f63%2f5P15

1 x 1U C-10-15/6

Chose the same one as 8 x 1U since I didn't know what difference it'd make since it was listed separately: http://uk.mouser.com/Search/ProductDetail.aspx?R=160105J63E-Fvirtualkey53900000virtualkey539-160105J63E-F

2 x 2u2 C-10-15/6

Chose the same one as 1 x 2u2 since I didn't know what difference it'd make since it was listed separately: http://de.mouser.com/Search/ProductDetail.aspx?R=MKS4C042204C00JSSDvirtualkey50520000virtualkey505-MKS42.2%2f63%2f5P15

1 x 4u7 C-10-15/6 (PITCH UP TO 35MM, POSSIBLE TO USE 2 CAPS IN PARALLEL)

http://uk.mouser.com/Search/ProductDetail.aspx?R=MKS4C044704D00JSSDvirtualkey50520000virtualkey505-MKS44.7%2f63%2f5

1 ** C-10-15/6

I presume that " 1 ** " indicates the possibility to use 2 caps in parallel?



---


CAPACITORS-SILVER MICA OR POLY



1 x 3n3 C-7-10/5

http://uk.mouser.com/Search/ProductDetail.aspx?R=CD19FD332JO3Fvirtualkey59850000virtualkey598-CD19FD332JO3F

2 x 2n70 C-7-10/5

http://uk.mouser.com/Search/ProductDetail.aspx?R=CD16FD272JO3Fvirtualkey59850000virtualkey598-CD16FD272JO3F

1 x 100P C7.5/3

http://uk.mouser.com/Search/ProductDetail.aspx?R=CD5FC101JO3virtualkey59850000virtualkey5982-5-300V100

1 x 150P C5/2.5 NOT NECESSARY WITH OPA604 2 330P C7.5/3

http://uk.mouser.com/Search/ProductDetail.aspx?R=CD5FA151JO3virtualkey59850000virtualkey5982-5-100V150

2 x 330P C7.5/3

http://uk.mouser.com/Search/ProductDetail.aspx?R=D105F331JO3virtualkey59850000virtualkey5982-10-500V330

---


CAPACITORS-SILVER MICA OR COG



5 x 5p C2.5/2

http://uk.mouser.com/Search/ProductDetail.aspx?R=CD5CC050D03virtualkey59850000virtualkey598-CD5CC050D03

2 x 12p C7.5/3

http://uk.mouser.com/Search/ProductDetail.aspx?R=CD5CC120JO3Fvirtualkey59850000virtualkey598-CD5CC120JO3F


---


DIODES


4 x 1N4004 D20, D21, D22, D23

http://uk.mouser.com/Search/ProductDetail.aspx?R=1N4004G-Tvirtualkey62110000virtualkey621-1N4004G-T

4 x 1N5400 D16, D17, D18, D19

http://uk.mouser.com/Search/ProductDetail.aspx?R=1N5400G-Tvirtualkey62110000virtualkey621-1N5400G-T


---


IC'S


1 x 317 LM317 IC1

http://uk.mouser.com/Search/ProductDetail.aspx?R=LM317HVT%2fNOPBvirtualkey56960000virtualkey926-LM317HVT%2fNOPB

1 x 337 LM337 IC3

http://uk.mouser.com/Search/ProductDetail.aspx?R=LM337T%2fNOPBvirtualkey56960000virtualkey926-LM337T%2fNOPB


---


PS Ceramic Caps


4 x CERAMIC CAPS 0.1UX50V PITCH 2.5MM

http://uk.mouser.com/Search/ProductDetail.aspx?R=FK16C0G1H104Jvirtualkey52130000virtualkey810-FK16C0G1H104J


---


ELECTROLYTHIC CAPS 50V


4 x 100u CPOL-EUE3.5-8 PITCH 3.5MM

http://uk.mouser.com/Search/ProductDetail.aspx?R=UKW1H101MPDvirtualkey64700000virtualkey647-UKW1H101MPD

2 x 3300u CPOL-EUE7.5-18 PITCH 7.5 OR 10MM

http://uk.mouser.com/Search/ProductDetail.aspx?R=UKW1H332MHDvirtualkey64700000virtualkey647-UKW1H332MHD


---
Title: Re: sontec 1 RU build thread
Post by: colombian on April 23, 2012, 09:02:43 PM
Hey Guys,

Thanks to Christoph (crisotop), I Just finished reading the whole thread and I think I am motivated to build this precious, maybe two of them, Need to check if anyone  in US (I am in Dallas, TX) is interested in getting the alpha pots and maybe we can order a bundle and split shipping charges, I can re-ship via USPS ?  Or perhaps someone in Germany could receive them for me and re-ship to us?



Please send me a PM or an email to ludwing at usmastering dot com ASAP if you are interested

Wish me luck!!!

Ludwing
Title: Re: sontec 1 RU build thread
Post by: ptron on April 24, 2012, 03:57:21 AM
the shipping isnt as bad as the actual cost of the pots :D
Title: Re: sontec 1 RU build thread
Post by: atticmike on April 24, 2012, 07:11:07 AM
Anybody available to take part in checking the parts of my list?
Title: Re: sontec 1 RU build thread
Post by: colombian on April 24, 2012, 12:20:42 PM
atticmike, I will have check to very soon!  :P

yeah, pots are a bit pricey.... but I wrote them an email and they can send me twice the amount for same shipping price ($30 eu) to US.    I am just waiting for Igor to respond my email before proceeding to order them.

By the way, who ordered diy-racked cases from USA?  how long did they take?  The ones from collective cases are nice but a bit more expensive than the Europeans

Thanks!
Title: Re: sontec 1 RU build thread
Post by: ptron on April 24, 2012, 02:34:45 PM
atticmike, I will have check to very soon!  :P

yeah, pots are a bit pricey.... but I wrote them an email and they can send me twice the amount for same shipping price ($30 eu) to US.    I am just waiting for Igor to respond my email before proceeding to order them.

By the way, who ordered diy-racked cases from USA?  how long did they take?  The ones from collective cases are nice but a bit more expensive than the Europeans

Thanks!

i got cases from Tat... im in Mexico and in less than 2 weeks they were in my doorstep. he is a legend
Title: Re: sontec 1 RU build thread
Post by: colombian on April 24, 2012, 04:12:42 PM
Gracias Patron!!! :)

me alegra que un Latino tambien este en esto!  ya terminaste el tuyo?  si puedes dame tu email para escribirte!

Un abrazo!
Title: Re: sontec 1 RU build thread
Post by: colombian on April 24, 2012, 06:11:48 PM
Actually, I have to correct myself.  Tat's and Dan's cases are about the same price.

Thank you
Title: Re: sontec 1 RU build thread
Post by: druu on April 26, 2012, 12:35:21 AM
I emailed Alphastat about pots a month or so ago and was quoted 45 eu for postage, emailed him recently and was quoted 30 eu. Glad I held off for that 15 eu saving hehe..
Title: Re: sontec 1 RU build thread
Post by: sedit1 on April 26, 2012, 01:13:53 AM
Still one silly question about stepped switches  :)

How do you wire the gain switch? Ok the center is 0r but are you supposed to connect the -1/+1 resistor legs to center lug or just leave the center empty and jump the -1/+1 over the lug? In alpha pots it seems that there is 4 legs and one of them goes to ground, do I need also ground the center lug of the stepped switch?

Thanks!
Title: Re: sontec 1 RU build thread
Post by: Harpo on April 26, 2012, 06:15:02 AM
3 connections to your 'center lug' (maybe pin12 from a 23 position rotary switch).
Both +/-dB resistor legs next to the +/-0dB step position and 0V reference voltage.
Title: Re: sontec 1 RU build thread
Post by: sedit1 on April 26, 2012, 08:02:46 AM
3 connections to your 'center lug' (maybe pin12 from a 23 position rotary switch).
Both +/-dB resistor legs next to the +/-0dB step position and 0V reference voltage.

Great thanks again!

And just to clarify before stuffing the resistors (using 21 position rotary):

For freq I'm using Harpos xls I stuff the both decs (2x21) as 100k rev log, one side of the resistors connected to a switches throw lug and all resistors other side to a common ring?

For Gain, 0.5db steps 20x2.5k connected in a series string and change summing resistor from the boards twice as higher 40k/20k?

Title: Re: sontec 1 RU build thread
Post by: atticmike on April 26, 2012, 09:32:11 AM
on the pcb_io it says ad706, does that mean it is better to employ ad706s for that purpose or can I stick with an OPA2604 since on the bom, it says  "ad706 OR OPA2604"?

Placed in between the two 604s.

Also, what options are there to procure the front panel?

Anything European by any chance? Wouldn't mind to import from the states also though.
Title: Re: sontec 1 RU build thread
Post by: Harpo on April 26, 2012, 09:35:38 AM
And just to clarify before stuffing the resistors (using 21 position rotary):
Don't miss the line 'Update the cap.values in the red cells with measured real world capacitance of your fitted parts' before ordering resistors for your frequency setting rotary switches (caps come with tolerances from +/-2% up to +80%/-20%).

Quote
For freq I'm using Harpos xls I stuff the both decs (2x21) as 100k rev log, one side of the resistors connected to a switches throw lug and all resistors other side to a common ring?
Single resistors, connecting to a common ring, require a MBB switch to prevent an open loop. I'd prefer the calc right next to it for strings of series resistors (adding up to a total of about 100K), so either MBB or BBM switches could be used. YMMV.
Title: Re: sontec 1 RU build thread
Post by: sedit1 on April 26, 2012, 09:54:07 AM
And just to clarify before stuffing the resistors (using 21 position rotary):
Don't miss the line 'Update the cap.values in the red cells with measured real world capacitance of your fitted parts' before ordering resistors for your frequency setting rotary switches (caps come with tolerances from +/-2% up to +80%/-20%).

Quote
For freq I'm using Harpos xls I stuff the both decs (2x21) as 100k rev log, one side of the resistors connected to a switches throw lug and all resistors other side to a common ring?
Single resistors, connecting to a common ring, require a MBB switch to prevent an open loop. I'd prefer the calc right next to it for strings of series resistors (adding up to a total of about 100K), so either MBB or BBM switches could be used. YMMV.

Will do so.
Great advices especially the importance of measuring the caps.
Again thanks a ton!
Title: Re: sontec 1 RU build thread
Post by: sedit1 on April 26, 2012, 11:27:22 AM
And just to clarify before stuffing the resistors (using 21 position rotary):
Don't miss the line 'Update the cap.values in the red cells with measured real world capacitance of your fitted parts' before ordering resistors for your frequency setting rotary switches (caps come with tolerances from +/-2% up to +80%/-20%).

Just measured capacitances. Allmost all the values were in line with eatchother but how colose do you need to match the channels?
My 0.47uf caps were littlebit off 3x~0.47 and one 0.49uf. Is it better to order more 0.47uf and try to match the caps better?

Title: Re: sontec 1 RU build thread
Post by: Harpo on April 26, 2012, 12:17:25 PM
Just measured capacitances. Allmost all the values were in line with eatchother but how colose do you need to match the channels?
My 0.47uf caps were littlebit off 3x~0.47 and one 0.49uf. Is it better to order more 0.47uf and try to match the caps better?
This 20nF difference with all other parts spot on will change frequency range from 125.8/7,987Hz to 123.2/7,822Hz. You could overwrite the '0.49' uF value with this '0.49' in maybe cell F15 to see the consequnces and if these matter to you.  Ordering more 0.47uF (or paralleling 22nF caps to the 3 remaining 0.47uF) might be the easiest way for a better match. You could as well decrease Rx.9 and Rx.10 to 1K567 and decrease the substituted pots resistance for this specific band to 98K instead of 100K for Rfreq.1 and Rfreq.2 to get you back on track.
Title: Re: sontec 1 RU build thread
Post by: sedit1 on April 26, 2012, 01:08:24 PM
Just measured capacitances. Allmost all the values were in line with eatchother but how colose do you need to match the channels?
My 0.47uf caps were littlebit off 3x~0.47 and one 0.49uf. Is it better to order more 0.47uf and try to match the caps better?
This 20nF difference with all other parts spot on will change frequency range from 125.8/7,987Hz to 123.2/7,822Hz. You could overwrite the '0.49' uF value with this '0.49' in maybe cell F15 to see the consequnces and if these matter to you.  Ordering more 0.47uF (or paralleling 22nF caps to the 3 remaining 0.47uF) might be the easiest way for a better match. You could as well decrease Rx.9 and Rx.10 to 1K567 and decrease the substituted pots resistance for this specific band to 98K instead of 100K for Rfreq.1 and Rfreq.2 to get you back on track.

So ordering more it is  :) Thanks!
Title: Re: sontec 1 RU build thread
Post by: atticmike on April 26, 2012, 02:17:50 PM
Is there a 1u front-panel for sale?
Title: Re: sontec 1 RU build thread
Post by: Seditionary on April 27, 2012, 06:37:13 AM
Seems like there is a lot of sontec orders... But no group buy on the pots necessarily to build it?  Who is down? GROUP BUY, GROUP BUY, GROUP BUY!  You guys who are building them in the states... Is there any other kind of pot we could substitute? 

Also, any kind of pot which would be easier to build stepped gain with?

Thanks ! 
Title: Re: sontec 1 RU build thread
Post by: colombian on April 27, 2012, 02:23:56 PM
any idea where to get the Forssell 990 DOA in US?  I have been unable to source them!
Title: Re: sontec 1 RU build thread
Post by: cstella on April 27, 2012, 02:37:01 PM
any idea where to get the Forssell 990 DOA in US?  I have been unable to source them!

None of the 99x DOA's are made by Mr. Forssell any longer. :-[ I had inquired about it to him awhile ago. Apparently the parts are no longer available. Sometimes they come up for sale on this forum. I had a couple of his 992's around and I used those. They really sound great in this circuit.

Charles
Title: Re: sontec 1 RU build thread
Post by: colombian on April 27, 2012, 02:56:06 PM
Hey Charles!  Thanks for replying!!

Yeah, very hard to get, I looked everywhere and I am a good searcher!   I did find these:

http://johnhardyco.com/990OpAmpDetails.html

Seem like they are based on the old JE990 and have the same Pinout that could potentially fit in the board for the summing section.  They are $50 a piece and I am thinking to build it with 604s first and then try a couple of those.....  after I am sure it lights up fine!  :)

regards

Ludwing
Title: Re: sontec 1 RU build thread
Post by: cstella on April 27, 2012, 03:10:18 PM
Hi!

Yes the Hardy 990's will work on the summing boards. The pin out is the 990 standard. They are not JFET based as the Forssell's but use a matched Bi-polar transistor. They sound great just different. You may need to play with the compensation cap value to use these though.

Charles
Title: Re: sontec 1 RU build thread
Post by: Igor on April 29, 2012, 06:19:04 AM
OK.... Ready?

http://www.groupdiy.com/index.php?topic=48527.0
Title: Re: sontec 1 RU build thread
Post by: sonicwarrior on April 29, 2012, 08:21:56 AM
Will you make the holes for the DOAs bigger on this one to fit the standard size female pins?
Title: Re: sontec 1 RU build thread
Post by: Igor on April 29, 2012, 09:11:51 AM
Those will fit fine:

http://il.farnell.com/harwin/h3161-01/socket-pcb-tin-knurled-1mm/dp/149318?Ntt=149318
Title: Re: sontec 1 RU build thread
Post by: sonicwarrior on April 29, 2012, 10:01:28 AM
Ah, they are available at Mouser, too: 855-H3161-01
Title: Re: sontec 1 RU build thread
Post by: ptron on April 30, 2012, 11:17:10 PM
OK.... Ready?

http://www.groupdiy.com/index.php?topic=48527.0

there should be a like button here in the forum ehehehe :)
Title: Re: sontec 1 RU build thread
Post by: sonicwarrior on May 04, 2012, 04:55:48 PM
Those will fit fine:

http://il.farnell.com/harwin/h3161-01/socket-pcb-tin-knurled-1mm/dp/149318?Ntt=149318

They definitely don't fit! Maybe you've changed your boards in the meantime, mine are Rev 1.6.

Mouser No. 575-032620 barely fits, but I have to force them in. :(
Title: Re: sontec 1 RU build thread
Post by: sonicwarrior on May 06, 2012, 10:52:10 AM
I'll try to us the male pins soldered to the female pins as a workaround. That's a bit loosely but at least it fits without having to drill anything and destroy the contacts:

(http://www.sdiy.de/DOA-Workaround-4-Sontec_Forssell.jpg)
Title: Re: sontec 1 RU build thread
Post by: sonicwarrior on May 06, 2012, 05:18:19 PM
Those look backwards, that's probably why they didn't fit.

I don't get it. Backwards?
The smaller side doesn't fit, so obviously the bigger side doesn't fit, too. By using the gold plated males as seen in the picture it fits but the DOA sits very high.
Title: Re: sontec 1 RU build thread
Post by: sonicwarrior on May 07, 2012, 02:20:01 PM
Yeah, looks like my description kind of sucked. ;)

The issues with the drilling made me think about this workaround. The downsides are that it's a bit more expensive and the DOA sits ca. 5 mm higher than with just the female pins. But I don't care much for both.
Title: Re: sontec 1 RU build thread
Post by: druu on May 09, 2012, 03:16:22 AM
Would this particular switch work for a stepped version? I think they have a few options and $38 for a prepopulated switch doesn't seem too bad?

http://www.analogmetric.com/goods.php?id=1000
Title: Re: sontec 1 RU build thread
Post by: Harpo on May 09, 2012, 05:19:27 AM
Would this particular switch work for a stepped version? I think they have a few options and $38 for a prepopulated switch doesn't seem too bad?

http://www.analogmetric.com/goods.php?id=1000
Might work when you use the "Please contact to our sales for other customized values" for a reverse log increase for the rheostats (not ladder attenuators), or you only use the switches Rg part and are comfortable with having the rotation reversed from usual behaviour ...
Title: Re: sontec 1 RU build thread
Post by: zayance on May 09, 2012, 05:41:53 AM
OR build it yourself :), EDIT: "i guess" they are using 1% resistors, and you might get to their same price using 0.1% ones tough (SMD)
There is a Log Excel file here that harpo and AndreasS were kind enough to provide to the community.
Takes that away in the equation also.

http://www.groupdiy.com/index.php?topic=48566.0
Title: Re: sontec 1 RU build thread
Post by: analogica on June 07, 2012, 03:00:15 PM

 the thread seems alive!!!...just a question, is there a MOD for the low end section??? I check on both channels that the pots doesnt affect to the signal so much around 60 HZ....do you khow about it guys????
Title: Re: sontec 1 RU build thread
Post by: Kingston on June 10, 2012, 05:22:45 PM
I did a DOA shootout to confirm several things I had suspected. I used the Igor Sontec and a modified PRR176 compressor that has the same input stage, but with a decoupling cap instead of a servo.

My hunch was that the input de-balancing DOA stage is much more sensitive to opamp changes than the summing/output stage.

So I gathered all different types of DOA's I have and started testing.

gar2520, ppa APP2050, ppa APP2055 (FET input) and ppa's latest APP992. They all measure the absolute same frequency response just as expected. The differences can be seen with high resolution FFT distortion measurements as slightly different shaped distortion spread. The differences are very subtle. I had better success seeing what was happening with square waves and oscilloscope but those results were tainted due to RME sound card band-limiting artifacts.

I wish I had a better way of actually seeing what is happening, because especially when chaining channels where more than one opamp is changed, the difference is very easy to hear on transients especially. And yet the differences between distortion plots are very minimal.

gar2520 is smudgy and had obviously most distortion of all these, even midrange-harsh at times. I guess that's one of the reasons why people want to mix rock through API gear. APP2050 is very similar but more transparent, a good work horse I would say. APP2055 does something interesting to transients and imaging. There seems to be a bit more 2nd order distortion, but this sounds cleaner than APP2050. This is a sound I have not heard from FET input chip opamps. gar2520 sounds even "lofi" in comparison.

Then there's the APP992. This is highest mastering grade stuff. Best opamp I've heard, chip or DOA. It goes beyond the transients and imaging of the fet APP2055 and even adds some bass punch. It's also FET input, but seems just about everything has been improved compared to APP2055.

[edit]

Again, I wish I had some quantifiable method to *show* what is happening. I will get a signal generator one day and redo this test with proper square waves. Guess I should get some more exotic DOA's and see what they do as well. To be honest I did not expect differences this significant.
Title: Re: sontec 1 RU build thread
Post by: hop.sing on June 12, 2012, 01:04:02 PM
I just built the igor 250 Eq for a friend and since we had no discrete opamps available at the time, I used signetics 5534 in the input and output stages (they take +-22v), the EQ and servo stages have LME 47860 installed. After receiving the app992 we where surprised about the differences we heard. The 5534 sounds kind of harsh in the upper midrange compared to the app 992. On our listening chain (mytek conversion and psi 215 speaker), that was very audible.
I could not measure any significant differences, like you, but I trust my ears in this case. It would be very interesting to know what is going on there. Those distortion levels (very close to the noisefloor with levels around +4dBu) should theoretically make no difference.
Tobias
Title: Re: sontec 1 RU build thread
Post by: i3j0rn on June 18, 2012, 09:37:04 AM
Hi! I've just finnished building two units.
Works fine!
Sounds Great!
It was also my first DiY project. So...
Thank you so much Igor. Many thanks to everyone for your contribution to this thread! And thanks Tat for the nice case...

(http://img138.imageshack.us/img138/2397/sontecx3.jpg) (http://img15.imageshack.us/img15/9067/sontecinside2.jpg)
(http://img694.imageshack.us/img694/4971/sontecx3side.jpg)

I just have to find some good looking knobs and it will be perfect.
Title: Re: sontec 1 RU build thread
Post by: cstella on June 18, 2012, 01:31:24 PM
Looks great! Congrats!  ;)
Title: Re: sontec 1 RU build thread
Post by: sonicwarrior on June 18, 2012, 01:47:27 PM
Wow, that's a tough beginners project (at least regarding the sourcing of the parts).
Title: Re: sontec 1 RU build thread
Post by: i3j0rn on June 19, 2012, 07:10:38 AM
Wow, that's a tough beginners project (at least regarding the sourcing of the parts).
Fortunately there is a lot of usefull informations around here!  :)
It was great help.
Title: Re: sontec 1 RU build thread
Post by: Igor on June 19, 2012, 11:14:45 AM
My favorite support thread. The project is very straight-forward, so, I really don't need to do anything here ;)
Title: Re: sontec 1 RU build thread
Post by: druu on June 24, 2012, 08:29:35 AM
Right, I didn't realize those cutoff it's on the IO pcb's were supposed to be used to raise the switches to for a Tat case. Anyway I tried to desolder a switch and two pads lifted (furthest two from the front of the switch). Any ideas what I should do to remedy this? I can't read schems properly yet so any advice appreciated!

I think for the other 3 switches I'll snip off at the legs and replace. :s
Title: Re: sontec 1 RU build thread
Post by: ptron on June 25, 2012, 10:55:56 AM
How many DOA's are neededon each stereo unit? (it seems like every IO board requires 2?)

Also, i thought it did but, bypass, would i need some bypass pcb's for it? I thought it was included on the IO boards too!

Title: Re: sontec 1 RU build thread
Post by: ppa on June 26, 2012, 03:50:47 PM
many thanks for the comments on my DOA's!
Another many thanks go to Igor, because if the my DOA's performed very well is even beacuse  Igor's eq permits to my opamps to do so, being this eq a very nice item.
Title: Re: sontec 1 RU build thread
Post by: Majestic12 on June 28, 2012, 12:22:34 AM
Finished mine today....

(http://i50.tinypic.com/s1p3qa.jpg)

(http://i45.tinypic.com/2gujza9.jpg)
Title: Re: sontec 1 RU build thread
Post by: sonicwarrior on June 28, 2012, 10:52:21 AM
Impressive.  :)

Is that a Mu metal shield?
Title: Re: sontec 1 RU build thread
Post by: hop.sing on June 28, 2012, 11:29:44 AM
Looks very professional :)
But the sheet is not really necessary, even without ours has no measurable hum, just a very low wideband noisefloor.
Title: Re: sontec 1 RU build thread
Post by: Kingston on June 28, 2012, 11:47:01 AM
(http://i45.tinypic.com/2gujza9.jpg)

wow, super clean build! good job.

I have a very similar plastic casing transformer and can't measure any 50hz hum above the general noise floor. That PSU shield looks great but might be unnecessary.
Title: Re: sontec 1 RU build thread
Post by: Majestic12 on June 28, 2012, 11:54:06 AM
Yeah propably I wouldn't need it. But usually I put some shield around the power supply just to be on the save side. It's easy and not much work to install the shield when I'm doing the metalwork on the case.
Title: Re: sontec 1 RU build thread
Post by: hop.sing on June 28, 2012, 12:24:31 PM
One thing I notice is, that there might not be enough room for discrete opamps because of the large caps in the servo cirquit, but maybe it is just the angle of the picture. Good opamps make a difference there!
Tobias
Title: Re: sontec 1 RU build thread
Post by: Majestic12 on June 28, 2012, 12:55:06 PM
Well, I consider OPA2604 to be "good" opamps, unit sounds great. I don't have the intention to put in any discrete opamp stuff....
Title: Re: sontec 1 RU build thread
Post by: Igor on June 28, 2012, 02:35:27 PM
He, funny 2u2 caps! Actually, there is no need for audiofullery cool types, every polyester or polyprop will work fine.

I found that I always prefer opa604 in summing circuit over 2520, 1731, and 990;
however, the best sounding for me is Forssell 993 or our based on cascode topology discrete op - amp.
Title: Re: sontec 1 RU build thread
Post by: Majestic12 on June 28, 2012, 03:03:48 PM
In fact...I just bought the big, round 2u2 caps because they where cheap (something like 0,70 cents) and availiable :). I don't care about the "audiophile" printing.

I used 2604 + 604 opamps in this build.

The only things I'm not quite sure about are the 5pF blocking caps on the 2604 and the 150pF on the I/O board. I think you don't recommend them Igor, but I can't measure any difference with or without them.
Title: Re: sontec 1 RU build thread
Post by: Igor on June 28, 2012, 03:17:05 PM
The difference for 150pf is high frequency stability (pole compensation) for discrete op-amps used in "original" build.
It is possible to completely avoid these 150pf with fast op-amp.
Title: Re: sontec 1 RU build thread
Post by: Majestic12 on June 28, 2012, 03:18:56 PM
Well, right now I have the 150pF and 5pF caps in the circuit. Don'T think theres any need to remove them.
Title: Re: sontec 1 RU build thread
Post by: kante1603 on June 28, 2012, 03:26:13 PM
Sehr schön und sauber gebaut-Respekt!

Udo ;)
Title: Re: sontec 1 RU build thread
Post by: kante1603 on June 28, 2012, 03:30:41 PM
Hi,
The transformer,is that a fully sealed type from Schuro Electronics?

Thx,

Udo.
Title: Re: sontec 1 RU build thread
Post by: Igor on June 28, 2012, 03:52:27 PM
Tonleitungsubertrager faterland!

Ah yep. I finished another one with MS option few days ago...
Title: Re: sontec 1 RU build thread
Post by: druu on June 28, 2012, 06:56:30 PM
Builds look great!

Nearly finishe mine, just did some testing with the psu board. I'm new to this stuff, is the power LED supposed to take a while to switch off? I found some spare from an old project and no idea of the voltage but it's the right size for the front panel. How can I make it switch off immediately?
Title: Re: sontec 1 RU build thread
Post by: Kingston on June 28, 2012, 07:59:20 PM
Nearly finishe mine, just did some testing with the psu board. I'm new to this stuff, is the power LED supposed to take a while to switch off?

It happens if you use especially big electrolytic caps on the PSU and if the unit isn't big on drinking current. I like it personally, same for the delayed clickety-clack of relays in a similar case.
Title: Re: sontec 1 RU build thread
Post by: druu on June 28, 2012, 08:33:42 PM
Yeah I guess it's a good notification of when it's safe to touch the boards if required. I don't mind it, just used to instant off's hehe.
Title: Re: sontec 1 RU build thread
Post by: ptron on June 29, 2012, 08:09:45 PM
Hi guys! Just checkin here.. Im just finished populating boards im really excited! (igor i sent u the list of missing stuff, a tag to your 2254 pictures also eheheh, to your email and payed for the shipping :) )

i got to finish reading the thread, ill post doubts if any but at the moment all is very self explanatory!

Just one question... The frequency pots... The pcb has 6 holes, the pots have 7 legs, 6 stacked like the pcb and an extra one behind... What do i do?

Theyre alphastat pots from the BOM just with detent positions..
thanks
All the best!
Patricio
Title: Re: sontec 1 RU build thread
Post by: Majestic12 on June 30, 2012, 03:27:05 AM
The 7th pin on the pot is just a ground connection to its metal housing. You have to remove it with a wire clipper.
Title: Re: sontec 1 RU build thread
Post by: ptron on June 30, 2012, 04:35:28 AM
Thanks for the quick reply! :)
Title: Re: sontec 1 RU build thread
Post by: druu on July 07, 2012, 09:32:08 PM
Having a hard time trying to find some knobs for my EQ. Farnell (Element14 in Australia) or RS don't seem to have the right type I want. :s
Title: Re: sontec 1 RU build thread
Post by: ptron on July 08, 2012, 02:06:09 AM
i been thinking of knobs... (dont laugh hehe)...

.. damn hard to pick
Title: Re: sontec 1 RU build thread
Post by: kante1603 on July 08, 2012, 02:12:02 AM
i been thinking of knobs... (dont laugh hehe)...

.. damn hard to pick
Hmmmm.....Sifam?Or are you searching for a special look?

Udo.
Title: Re: sontec 1 RU build thread
Post by: druu on July 08, 2012, 02:53:41 AM
Tell me about it ptron, i've literally spent two days so far trying to figure out what to get!

I think i've settled on some though, ones from RS that dagoose used on his stepped EQ. Thing is, there's not a lot available that match that type that have a 1/8" shaft for the shape controls. :(
Title: Re: sontec 1 RU build thread
Post by: i3j0rn on July 08, 2012, 08:54:57 AM
Sifam knobs are all right and not so expensive. Ordered It from sibalco.de. Holger putted the right references previously in this thread.
Quote
The article # is 3001768 for the 15mm and 3000195 for then 10mm knobs
By the way thanks Holger for thoses references ! =)

Title: Re: sontec 1 RU build thread
Post by: rmaier on July 08, 2012, 12:10:18 PM
Tell me about it ptron, i've literally spent two days so far trying to figure out what to get!

I think i've settled on some though, ones from RS that dagoose used on his stepped EQ. Thing is, there's not a lot available that match that type that have a 1/8" shaft for the shape controls. :(

You might use reducers to open up your choices: http://ca.mouser.com/ProductDetail/TE-Connectivity/KR104/?qs=uxvR3OIxFgcf%2fvZL7XsX4Q%3d%3d (http://ca.mouser.com/ProductDetail/TE-Connectivity/KR104/?qs=uxvR3OIxFgcf%2fvZL7XsX4Q%3d%3d)
Title: Re: sontec 1 RU build thread
Post by: ptron on July 15, 2012, 08:02:30 PM
wow guys thanks a lot!! this is tons of info :P i can see some of u have spent some time looking for these  damn things... 
 
rmaier, thanks a lot! didnt even know those existed !!! :D

j3j0rn, i thought sifam was overly expensive! ill give em a shot, thanks a lot. since holger already done the work for us... (thanks holger!)

druu... i feel ya mate... theyre so many shaft sizes..

Udo, i dont know! a bit of myself would like it to have the nice colorful look u know.. easy to get the right parameter like this... up for anything tho, i mostly like the knob to feel heavy.. not light... (i feel this makes it easier to control with heavy knobs rather than lighter ones)

btw.. did any of u order tat`s case?? i found the gain pots`holes are a bit smaller than the actual thread of the pot... so had to chew a bit on those holes.. and the toggles... i thought they were ok to solder right against the board but theyre off by a mm or so... mm might have to chew a bit of those too..

thanks a lot guys!!
Title: Re: sontec 1 RU build thread
Post by: dryman on July 18, 2012, 01:28:34 PM
i have a question about the resistors RF 1/2/3 B/C (and RF4B/C1) on the BOM the resitors should be 7.5k, but there is a note, that i can use 4.7k for more gain. Do i have +/- 12db with 4.7k and +/- 6db with 7.5k?
Title: Re: sontec 1 RU build thread
Post by: Harpo on July 18, 2012, 04:32:22 PM
i have a question about the resistors RF 1/2/3 B/C (and RF4B/C1) on the BOM the resitors should be 7.5k, but there is a note, that i can use 4.7k for more gain. Do i have +/- 12db with 4.7k and +/- 6db with 7.5k?
No. With perfect value center tapped pots (they won't be perfect), 4.7K resistors will give you a +/-12dB range of boost/cut. Using 7.5K resistors instead in these voltage dividers will decrease this range to +/-11.3dB. If you want halve of this +/-12dB range, double up the resistor values of R18 ... R21 for a +/-6dB range of cut/boost.
Title: Re: sontec 1 RU build thread
Post by: dryman on July 18, 2012, 07:01:34 PM
No. With perfect value center tapped pots (they won't be perfect), 4.7K resistors will give you a +/-12dB range of boost/cut. Using 7.5K resistors instead in these voltage dividers will decrease this range to +/-11.3dB. If you want halve of this +/-12dB range, double up the resistor values of R18 ... R21 for a +/-6dB range of cut/boost.

Thanks
Title: Re: sontec 1 RU build thread
Post by: colombian on July 25, 2012, 12:22:03 PM
there, another baby is born.......  Thanks to Igor for creating this project and his patience with my post office complaining!   It was worth the wait!!  Also thanks to Cstella for his help, PTRON for his cool idea about detented pots!

Good Luck in your build, now have to get back to work to pay for the $1100 us it cost me to build this baby.

Saludos!!

Ludwing
Title: Re: sontec 1 RU build thread
Post by: ptron on July 25, 2012, 01:00:04 PM

dude, Ludwing... looks great!!! :) im glad u liked the detented story! did u measure the pots before installing? was a pain in the ass but i got mine with the pots somewhat matched between detent pos.
my builds have been delayed.. the DOA`s havent arrived yet and ill be off for 2 months in about a week... i hope i can finish before that time but im uncertain!!

best for u and all the sontec enthusiasts :D

(btw are those sifam knobs???)

Title: Re: sontec 1 RU build thread
Post by: colombian on July 26, 2012, 11:44:00 AM
Hey PTRON,

what DOA are you using? why don't you build with 604s and then replace once you get the DOA?  In all Honesty, I think 604 do a very good job!


yes, Sifam knobs!  I have a contact in US in case you need them

Thanks!

Title: Re: sontec 1 RU build thread
Post by: ptron on July 26, 2012, 03:32:54 PM
i might go with those knobs man! they look very nice.. indeed close to the original, not quite but great looks.

i would keep going with 604`s i might try one unit with them but in this moment, the 604 havent been sent with the kit, alongside with the DOA`s and a couple of extras for other builds... im about to leave to a short but demanding tour thru europe and asia.. gonna be hard to get it done now.

about this sifam dealer in USA.. sounds great! thanks a lot ludwing!! ive had a few weeks to think about this.. only thing, do they feel solid or theyre flimsy thin plastic knobs? like mackie`s hehe .. id like some solid heavy knobs sort of story

thanks a lot!!!
Title: Re: sontec 1 RU build thread
Post by: druu on July 27, 2012, 06:16:25 AM
Is there any way to add a hardware bypass? The new board Igor offers won't fit in Tats case unfortunately.
Title: Re: sontec 1 RU build thread
Post by: dryman on July 27, 2012, 06:23:12 AM
Yes, you can use any bypass solution. For example from Igor:

http://www.ij-audio.com/store/pcbs/byp_60m/ (http://www.ij-audio.com/store/pcbs/byp_60m/)

http://www.ij-audio.com/store/pcbs/byp_54mm/ (http://www.ij-audio.com/store/pcbs/byp_54mm/)

Another possibility is to use a deeper case and change the frontpanel.
Title: Re: sontec 1 RU build thread
Post by: druu on July 27, 2012, 06:41:33 AM
How about this?

http://www.ij-audio.com/store/pcbs/msbypass-board/

The new sontec board would be good but if this will fit I'll be happy. :)
Title: Re: sontec 1 RU build thread
Post by: skidmorebay on July 29, 2012, 12:40:19 AM
Hello-
Could anybody share what it cost them to complete their Sontec 2U build in the U.S.?
Trying to decide how many pennies I might need to save to take this project on...
thanks!
JS
Title: Re: sontec 1 RU build thread
Post by: Igor on July 29, 2012, 01:34:58 PM
@dudes who want to use new MS/bypass/power supply board: you need to ask for 250mm case from Tat.
@JD: between $800-1300; complete and tested from us, with MS and our DOA's... feel free to ask (Skype, mail, Facebook, etc).
Title: Re: sontec 1 RU build thread
Post by: andydiy on August 01, 2012, 03:10:09 AM

Hi!

Can someone give me a sontec New Bom information?
Title: Re: sontec 1 RU build thread
Post by: ArnauTS on August 01, 2012, 09:53:43 AM

Hi!

Can someone give me a sontec New Bom information?
You have the docs at the first page of the thread
Title: Re: sontec 1 RU build thread
Post by: Igor on August 03, 2012, 11:41:49 AM
http://ij-audio.com/downloads/SONT_MS_UPGR.rar
Title: Re: sontec 1 RU build thread
Post by: druu on August 03, 2012, 11:30:06 PM
Still waiting for AD706's to arrive from RS but here she is so far.. really itching to test it out!

(http://www.amnet.net.au/~amunday/random/IMG_1296.JPG)

(http://www.amnet.net.au/~amunday/random/IMG_1300.JPG)
Title: Re: sontec 1 RU build thread
Post by: Igor on August 04, 2012, 11:08:52 AM
Very nice work. You can use OPA2604 or other low dc offset jfet opamp instead of AD706...it is just a dc servo, after all :)
What are the knobs you used?
Title: Re: sontec 1 RU build thread
Post by: druu on August 04, 2012, 11:41:17 AM
Thanks igor! I've been told the chips are arriving early this week so fingers crossed!

Knobs are 16mm and 19mm aluminium ones from RS, same ones dagoose used on his stepped Sontec. I wanted a more modern approach instead of the multicolored scheme. ;)
Title: Re: sontec 1 RU build thread
Post by: ptron on August 06, 2012, 12:31:21 AM
wow those knobs look really nice!!! were they overly expensive? RS don't deliver to mexico but would be good to know anyways!!!

great work! i hope mine looks half as good as that!!

btw.. did u have a problem with the toggles? being a bit too low for the faceplate when fitted on pcb`s bottom? i found mine being a tiny bit down.. about 1 or 1.5 mm... and the gain pots, the thread don't go thru the FP either! .. for a moment i thought i ordered the wrong pots heheh

anyways! looking good man! respect
Title: Re: sontec 1 RU build thread
Post by: druu on August 06, 2012, 07:43:37 AM
Thanks mate!

With the toggles, you need to use the snap off boards that were originally joined to the amp pcb's (there are about six of them). This will give you the right height for the switches.

Title: Re: sontec 1 RU build thread
Post by: druu on August 07, 2012, 02:43:50 AM
Anybody have issues with noise? Any suggestions on points to check with my grounding?

Thanks.
Title: Re: sontec 1 RU build thread
Post by: dryman on August 08, 2012, 05:14:45 AM
I want to use DOAs (APP992), does it make any other parts obsolete?
Title: Re: sontec 1 RU build thread
Post by: ilfungo on August 11, 2012, 08:12:30 AM
which toroidal x stereo sontec + new M/S PCB?
2x22v 30va?
Thanks
Title: Re: sontec 1 RU build thread
Post by: ilfungo on August 13, 2012, 11:19:35 AM
???
Title: Re: sontec 1 RU build thread
Post by: ArnauTS on August 13, 2012, 11:44:32 AM
which toroidal x stereo sontec + new M/S PCB?
2x22v 30va?
Thanks
Wich opamps you are using or going to use?
Title: Re: sontec 1 RU build thread
Post by: ilfungo on August 13, 2012, 12:02:04 PM
OPA2604
 
OPA604   

and  IGOR Doa


Thanks
Title: Re: sontec 1 RU build thread
Post by: Igor on August 16, 2012, 05:43:21 PM
2x22 or 2x25V AC, 30 VA, power supply's are +/- 23.5 and +/- 16V
Title: Re: sontec 1 RU build thread
Post by: ilfungo on September 04, 2012, 06:07:58 AM
Hi
someone can give me the code (RS or Mouser) for Knobs?
thanks
Title: Re: sontec 1 RU build thread
Post by: zayance on September 04, 2012, 06:38:29 AM
Hi
someone can give me the code (RS or Mouser) for Knobs?
thanks

What type of knobs?

Most RS and Mouser won't have the ones seen on first post.

Farnell have those Elma's, but not sure of all types tough.
http://fr.farnell.com/jsp/search/browse.jsp?N=2014+202401&Ntk=gensearch&Ntt=Elma&Ntx=mode+matchallpartial&locale=fr_FR&appliedparametrics=true&getResults=true&originalQueryURL=/jsp/search/browse.jsp%3FN%3D2014%2B202401%26Ntk%3Dgensearch%26Ntt%3DElma%26Ntx%3Dmode%2Bmatchallpartial%26No%3D0%26getResults%3Dtrue%26appliedparametrics%3Dtrue%26locale%3Dfr_FR%26divisionLocale%3Dfr_FR%26catalogId%3D%26skipManufacturer%3Dfalse%26skipParametricAttributeId%3D%26prevNValues%3D2014%2B202401


Electrochronic has them also, check with him:

https://sites.google.com/site/diypartsstore/catalog/catalog-page-2


T.
Title: Re: sontec 1 RU build thread
Post by: ptron on September 07, 2012, 01:04:15 PM
Hey! Im back from hell!! Good to have like 2 days to finish some of this :)
I just have a quick question.. The op amps, are u using the DOA for output and the 602 604 (sorry) for input ? Or viceversa? :)

Thanks a lot!
Title: Re: sontec 1 RU build thread
Post by: Igor on September 08, 2012, 06:36:54 PM
DOA's for out, 604 for input.
Title: Re: sontec 1 RU build thread
Post by: ptron on September 08, 2012, 10:02:10 PM
Thanks igor
Title: Re: sontec 1 RU build thread
Post by: ptron on September 09, 2012, 04:11:04 PM
Ah one question! The kit came with traffo 2x24v 0.6A ..
1- Do i need to connect secondaries in series and just go from black to ~1 and yellow to ~2 on PSU pcb?

2 - what is this "G2 AB~" point on pcb for? And the +3 / ~G (are those for testing before plugging into the I/O boards?)

3- is there any grounding point that i might not be aware of? (i can only see those 2 G spots heheheh)

Traffo model: noratel TA030/25

Stereo sontec, without ms and without relay bypass.

Thanks a lot!
Title: Re: sontec 1 RU build thread
Post by: Harpo on September 09, 2012, 05:09:43 PM
1- Do i need to connect secondaries in series and just go from black to ~1 and yellow to ~2 on PSU pcb?
2 - what is this "G2 AB~" point on pcb for? And the +3 / ~G (are those for testing before plugging into the I/O boards?)
3- is there any grounding point that i might not be aware of? (i can only see those 2 G spots heheheh)
Traffo model: noratel TA030/25
1- transformer secondaries black to ~1 and yellow to ~2 on PSU pcb.
2- transformer secondaries red+orange to "G2 AB~" (just have a look at "P1000010.jpg" and "ps_sch.JPG" in the .zip files from pg.1 of this thread 'Here you can find all docs' (http://twin-x.com/groupdiy/thumbnails.php?album=399))
3- you might use the "+3 / ~G" for 0V reference voltage/grounding.
Title: Re: sontec 1 RU build thread
Post by: ptron on September 10, 2012, 12:43:41 PM
as always, thanks a lot harpo. i thought that GND point wouldve been for grounding with chassis! im glad i asked first!

all the best

and again, thanks a lot for the quick reply
Title: Re: sontec 1 RU build thread
Post by: Igor on September 20, 2012, 11:22:22 AM
http://ij-audio.com/downloads/SONTEC_RED.rar
http://ij-audio.com/downloads/SONT_MS_UPGR.rar

for the updated docs, as well
Title: Re: sontec 1 RU build thread
Post by: ncl|usl on October 05, 2012, 05:42:09 AM
hi, noob question...
in this  sontec eq is possible to add voltage control to any parameters? to use like a voltage control comb filter?
thanks in advances
Title: Re: sontec 1 RU build thread
Post by: Igor on October 06, 2012, 10:35:00 AM
hi, noob question...
in this  sontec eq is possible to add voltage control to any parameters? to use like a voltage control comb filter?
thanks in advances

Nope)

From the oter side, possible to use VTL5C3/2 to control frequency; for the gain controls, check net for VCA use in digitally controlled eq's..
Title: Re: sontec 1 RU build thread
Post by: ncl|usl on October 06, 2012, 04:45:46 PM
ok so is possible only for frequency . and for the q control ?
how it can be implemented? do you know some circuit to add for cv controll?
thanks igor, sorry i'm a newcomer in this forum!
Title: Re: sontec 1 RU build thread
Post by: Igor on October 06, 2012, 07:19:22 PM
Welcome and have fun.

Well, this VCA question is a bit OT. After all this is build support thread. In any case.

VCA's won't work for Q control for Sontec filters. Should be pot. Or it becomes bit complicated. For gain, see further.

I used relays in DC Uni-Q, fully digitally controlled universal EQ, and got good results with prototyped Sontec filters.
VCA's have many benefits, but not for every EQ's filter app.
Very nice paper on use of VCA's in EQ's:
http://www.thatcorp.com/datashts/AES13-031_Digitally_Controllable_Audio_Filters.pdf

However. After prototyping and listening.... VCA's can be cool for GAIN control - as in  fig 12 and 17, it worked for me; even possible to bring bit of 2nd harmonic for nice color.
For freq control, it is not ideal thingy. After all, vca's are hooked arround SVF, on high freqs, slowed transients are audible (what you guys call "harshness on highs).
With the relays, the quality of sound limited to quality of opamps/capacitors/right pcb layout/etc. With vca's, it is very flexible and relatively simple. The final app dictates the topology.
Title: Re: sontec 1 RU build thread
Post by: ncl|usl on October 07, 2012, 08:51:47 AM
ok, thank you igor!
i will waith for the new project DC Uni-Q !
i also see the buchla 296e and its touch sensor-grafic equalizer
can be mounted in this layout ?  :-[
Title: Re: sontec 1 RU build thread
Post by: Igor on October 07, 2012, 06:56:21 PM
Kinda different things.
I cannot answer on this question, try to open a topic in lab section of forum ;)
Title: Re: sontec 1 RU build thread
Post by: cstella on October 29, 2012, 12:58:05 PM
Hi Group!

I am having a strange problem with my Sontec and hopefully someone here can help. Everything is working ok except the HF band on the second channel. The band works but as the frequency control is turned more counter-clock-wise a hum develops. It's ok until about 6K but any more to the left and it gets bad. Flipping the Shape toggle to 12dB increases the hum even more. The pot is also a little scratchy to. I have checked connections and re-flowed the solder joints in that area but no luck. I have also swapped all the power and signal connectors with the other channel and I still get this problem. So i am pretty sure it is isolated to that board and band. Any help would be greatly appreciated!

Thanks, Charles
Title: Re: sontec 1 RU build thread
Post by: Holger on October 30, 2012, 06:28:21 AM
Try to increase the 5pF CF5.1 to something like 22pF or 27pF
Title: Re: sontec 1 RU build thread
Post by: cstella on October 30, 2012, 12:49:15 PM
Thanks Holger. I put a 22pf in parallel with CF 5.1 and still the same problem. The second channel is fine. I tried swapping out the opamp but that did not help either.

Thanks, Charles
Title: Re: sontec 1 RU build thread
Post by: dandeurloo on November 09, 2012, 02:30:11 PM
any chance of ordering the alphastat pots in the us? I need a supplier for...

10 - 50k CTPOT
2207 RD1601-20F4-30R
ALPHASTAT 63250-01610/B50K 50K LIN CENTERTAPCENTERDETENT

10 - 100K RLOG DUAL_ALPHA_2
4196 RD1602-20B4-30R
ALPHASTAT 63256-02600/C100K 100K REV-LOG

Anyone?  i will order outside us if i have to.

thanks

Does anyone have a USA source for these?
Title: Re: sontec 1 RU build thread
Post by: ptron on November 14, 2012, 04:54:12 AM
another sontec was born today! flawless (this one was, but the first one gave me some trouble...)
it sounds awsome!!
DOA on output 604 on input.. its a beast!

(http://i1088.photobucket.com/albums/i340/tron888/DSC_0545.jpg)

(http://i1088.photobucket.com/albums/i340/tron888/DSC_0547.jpg)


THANKS A LOT IGOR!
Title: Re: sontec 1 RU build thread
Post by: druu on November 14, 2012, 05:20:58 PM
Nice! No internal shots? ;)

You should trim the pot shafts, will make it look even better!
Title: Re: sontec 1 RU build thread
Post by: ptron on November 18, 2012, 01:41:32 PM
Ill take some porn shots today or tomorow :) its really super clean design ... Igor really simplified it i love this eq!
One thing.. With hi Q the eq starts kinda whistling over the noise floor...  I asume this is normal
Aah about the shaft trimming, you think a dremel and one of those coarse discs will do the job or i need tungsten carbide tip?

Thanks A lot guys! Your help was priceless
Title: Re: sontec 1 RU build thread
Post by: druu on November 22, 2012, 09:14:33 AM
I've just been testing the right channel on my stepped version and getting some weird measurements. I have +/-12dB selection and testing sweeps through the 1k1 frequency selection from -12 to +12 on the HF band (L/R mode). Any idea what's causing the problem when going into +12db range?

(https://dl.dropbox.com/u/3228830/SontecMeasure.png)
Title: Re: sontec 1 RU build thread
Post by: druu on November 23, 2012, 05:22:49 AM
Seems to be happening on all bands. The above was swept at 96khz, 44.1khz is much more prominent.

Any ideas? Tested same filter board on the left channel of the io board and same problem.
Title: Re: sontec 1 RU build thread
Post by: dagoose on November 23, 2012, 01:30:52 PM
Seems to be happening on all bands. The above was swept at 96khz, 44.1khz is much more prominent.

Any ideas? Tested same filter board on the left channel of the io board and same problem.

what about distortion? try it with a lower input and see what happens.
Title: Re: sontec 1 RU build thread
Post by: druu on November 23, 2012, 05:31:01 PM
Hmm that's sorted it! Must be very sensitive to input as I did have the input quite low already, didn't think to lower it as I wasn't monitoring the sweeps. Thanks dagoose!

Meanwhile everything checks out fine now. :) On with the other channel..
Title: Re: sontec 1 RU build thread
Post by: duantro on November 23, 2012, 05:38:32 PM
Ill take some porn shots today or tomorow :) its really super clean design ... Igor really simplified it i love this eq!
One thing.. With hi Q the eq starts kinda whistling over the noise floor...  I asume this is normal
Aah about the shaft trimming, you think a dremel and one of those coarse discs will do the job or i need tungsten carbide tip?

Thanks A lot guys! Your help was priceless
Hey Ptron, looks great! I used a thin bladed jewelers saw to cut pot shafts. I think I suggested a dremel and disc previously, but I was referring to doing this to the plastic pots that were use on other builds. I'm still waiting on parts to finish this project. glad to hear that you like it! 8)
Title: Re: sontec 1 RU build thread
Post by: druu on November 23, 2012, 05:56:12 PM
A dremel with cutting disc works well and is quick, but make sure you mask of everything carefully as the shavings can get everywhere. Use some tape to cover the gap so nothing gets inside the pot.
Title: Re: sontec 1 RU build thread
Post by: dagoose on November 24, 2012, 01:40:18 AM
Hmm that's sorted it! Must be very sensitive to input as I did have the input quite low already, didn't think to lower it as I wasn't monitoring the sweeps. Thanks dagoose!

Meanwhile everything checks out fine now. :) On with the other channel..
I think it's the input of your soundcard distorting instead of the EQ itself. You're boosting quite a lot which means more gain = higher output voltage driving the input of your soundcard.
Title: Re: sontec 1 RU build thread
Post by: druu on November 24, 2012, 07:17:51 AM
I think you're right. A bit annoyed I didn't pick that up sooner!
Title: Re: sontec 1 RU build thread
Post by: Igor on November 24, 2012, 08:43:50 AM
Oh, you, soundcard testers! ;)
Take used Boonton 1120, HP8903, and enjoy! Why do you complicate your life? ;)
BTW,
http://www.pmillett.com/hp_8903_software.htm
Title: Re: sontec 1 RU build thread
Post by: druu on November 24, 2012, 08:51:54 PM
I've been considering some proper test equipment but I've only just started DIY gear this year (this project is my second build). Maybe once things become more serious then yes, will definitely invest in something. :)
Title: Re: sontec 1 RU build thread
Post by: Igor on November 24, 2012, 10:38:29 PM
druu: this is not even a matter of investment, today, just look on surplus stores or ebay,
for $300-500 you can have both used Tectronix scope and HP8903 analyzer, even with dual lab power supply on top.
More matter of space and... been lazy, I'd say :)
Title: Re: sontec 1 RU build thread
Post by: cstella on November 25, 2012, 07:07:00 PM
Hi Group!

I am having a strange problem with my Sontec and hopefully someone here can help. Everything is working ok except the HF band on the second channel. The band works but as the frequency control is turned more counter-clock-wise a hum develops. It's ok until about 6K but any more to the left and it gets bad. Flipping the Shape toggle to 12dB increases the hum even more. The pot is also a little scratchy to. I have checked connections and re-flowed the solder joints in that area but no luck. I have also swapped all the power and signal connectors with the other channel and I still get this problem. So i am pretty sure it is isolated to that board and band. Any help would be greatly appreciated!

Thanks, Charles
Title: Re: sontec 1 RU build thread
Post by: cstella on November 25, 2012, 07:08:51 PM
I am still trying to sort out the above problem. Any help is greatly appreciated!
Title: Re: sontec 1 RU build thread
Post by: Igor on November 25, 2012, 09:47:52 PM
Hi Group!

I am having a strange problem with my Sontec and hopefully someone here can help. Everything is working ok except the HF band on the second channel. The band works but as the frequency control is turned more counter-clock-wise a hum develops. It's ok until about 6K but any more to the left and it gets bad. Flipping the Shape toggle to 12dB increases the hum even more. The pot is also a little scratchy to. I have checked connections and re-flowed the solder joints in that area but no luck. I have also swapped all the power and signal connectors with the other channel and I still get this problem. So i am pretty sure it is isolated to that board and band. Any help would be greatly appreciated!

Thanks, Charles

Front panel and gain, freq potentiometers should be grounded.
Power transformer can be the source for EMF. Try to move power transformer out of box
(be carefull, high voltages; good insulation on wires, attention, etc).

All EQ's I built are relatively quiet, if 0db is 1V RMS, at the input, test conditions - S/N, Boonton 1120, no filters,
the thrashy noise etc was always about or lower -80 db with all gains at 0 and EQ ON
(this way, filters outs are going to summing circuit).
With EQ switch off, I measured about -92...-98 db. In perfect lab conditions, maybe, it will be even better.

Ah yep. Trick: increase input signal till the EQ is 0.5 db below clip, you will get even better results, like some manufacturers do/claim in manuals ;)

I have BTW some noise from somewhere on electricity at my workshop, it starts at the morning and goes about 2 at night... kill all humans!!!
T4 lamp on my workbench adds some noise, too - when it closed and it is night here, all measurements looks almost perfect. Well, OT.
Please post what was the noise source for HF.... just a human curiosity ;)
Title: Re: sontec 1 RU build thread
Post by: cstella on November 27, 2012, 11:32:46 AM
Thanks Igor!

I will check the grounding and also report back on the noise. It sounds like a 60 cycle type hum. It is only present on the HF band of one channel though so it seems like it has to be something around there. The other channel is fine.

More soon!

Thanks, Charles
Title: Re: sontec 1 RU build thread
Post by: peskado on November 27, 2012, 03:07:28 PM
I had the same problem
made ground for front panel and pot
now it work perfect
Title: Re: sontec 1 RU build thread
Post by: dagoose on November 28, 2012, 09:49:48 AM
Most of the times if the frontpanel is not grounded is that because there is paint on both the panel as well as the case, which is quite a good isolator. So sand of the paint on the edges where your frontpanel touches the case and most of the times that is enough. Be aware that blank metal can/will oxidate after a while..
Title: Re: sontec 1 RU build thread
Post by: cstella on November 28, 2012, 10:58:52 AM
Thanks guys! I will try this for sure as soon as I can.

Best, Charles
Title: Re: sontec 1 RU build thread
Post by: sedit1 on December 07, 2012, 07:01:45 AM
Hi,

I have a problem. Just finishing my sontec rev 1.7 black boards..I fired up the first channel but in filter pcb my c22 bypass cap stared to smoke up...
I cheked the orientation and the +24v coming from 22r rps4 resistor goes straight to c22 - minus polarity when the cap is connected like in the silkscreen...

So what am I missing here???

Thanks!
Title: Re: sontec 1 RU build thread
Post by: sedit1 on December 07, 2012, 07:56:46 AM
Hi,

I have a problem. Just finishing my sontec rev 1.7 black boards..I fired up the first channel but in filter pcb my c22 bypass cap stared to smoke up...
I cheked the orientation and the +24v coming from 22r rps4 resistor goes straight to c22 - minus polarity when the cap is connected like in the silkscreen...

So what am I missing here???

Thanks!

Found the solution...It seems that In filter pcb the -24v/+24v have switched places if you just follow the silkscreen...Reminder to self always check the schematics..
Title: Re: sontec 1 RU build thread
Post by: Igor on December 08, 2012, 02:57:55 PM
Strange.... What revision of boards?
Title: Re: sontec 1 RU build thread
Post by: sedit1 on December 09, 2012, 08:39:09 AM
Strange.... What revision of boards?

Hi Igor! The i/o pcb is Rev.1.6 and the filter pcb is rev.1.7. If you look at the silkschreen in i/o pcb (PS/PS2)there are markings G + - when you look at filter pcb the +- markings are reversed, G - +.

It might be that I'm missing something, not that experienced :) But got it worked out and the eq works great and the sound is amaizing!! Thanks for a great project!
Title: Re: sontec 1 RU build thread
Post by: Igor on December 11, 2012, 08:39:12 PM
Ah yep... the silkscreening was reversed, but pinout is correct. 1 goes to 1, 2 to 2, etc. Yes, this is one of my favorite EQ's too. Enjoy! :)
Title: Re: sontec 1 RU build thread
Post by: Igor on December 11, 2012, 08:44:16 PM
Most of the times if the frontpanel is not grounded is that because there is paint on both the panel as well as the case, which is quite a good isolator. So sand of the paint on the edges where your frontpanel touches the case and most of the times that is enough. Be aware that blank metal can/will oxidate after a while..

I soldering the wire from starground to one of pots, so, it works.
The cases I use have good contact between parts, front is always grounded like Butters, for SP fans.... so I had no this prob. But was interesting to read ;)
Title: Re: sontec 1 RU build thread
Post by: pieca on December 14, 2012, 12:40:02 PM
Igor,
no more PCB in stock on your website?
Title: Re: sontec 1 RU build thread
Post by: Igor on December 15, 2012, 12:32:00 AM
What the heck! After we moved site to new faster hosting, things started to disappear! :)
Try this:
http://www.ij-audio.com/store/equalizers/sontec_pc/
Title: Re: sontec 1 RU build thread
Post by: steki on February 12, 2013, 03:13:47 PM
Hey guys, which ferrite bead for the FB 0R position instead of a jumper is the best for this project or is it indifferent what kind of ferrite I use?
Title: Re: sontec 1 RU build thread
Post by: dogma on February 20, 2013, 03:38:33 AM
Hi - I've emailed igor but have had no reply. I can't find the boards on his site nor on his white market page. I'm sure they where on his site a couple of weeks ago. I'm looking for a pcb for a stereo build. If igor or someone has or knows someone with some spare boards to sell please pm me or email me at thenewmandmshowAtgmailDOT.com - cheers, Matt
Title: Re: sontec 1 RU build thread
Post by: druu on February 20, 2013, 07:08:25 AM
I don't have boards but may have a complete EQ ready soon to sell, minus knobs possibly, if anyone is interested.
Title: Re: sontec 1 RU build thread
Post by: andydiy on February 24, 2013, 03:46:26 AM
Hi!

Ask the following ALPHASTAT, addition to the PS Potentiometer-Service GmbH something to buy, there are other places to buy it?

10x  50k CTPOT                                                                                                             
2207 RD1601-20F4-30R
ALPHASTAT 63250-01610/B50K 50K LIN CENTERTAPCENTERDETENT
10x 100K RLOG DUAL_ALPHA_2                                                                                   
4196 RD1602-20B4-30R
ALPHASTAT 63256-02600/C100K 100K REV-LOG

In addition, I want to buy Power Transformer, In Mouser company, Have one would be better Power Transformer?

My country is 220V.

Thank you!
Title: Re: sontec 1 RU build thread
Post by: ptron on February 25, 2013, 01:47:54 PM
Hi!

Ask the following ALPHASTAT, addition to the PS Potentiometer-Service GmbH something to buy, there are other places to buy it?

10x  50k CTPOT                                                                                                             
2207 RD1601-20F4-30R
ALPHASTAT 63250-01610/B50K 50K LIN CENTERTAPCENTERDETENT
10x 100K RLOG DUAL_ALPHA_2                                                                                   
4196 RD1602-20B4-30R
ALPHASTAT 63256-02600/C100K 100K REV-LOG

In addition, I want to buy Power Transformer, In Mouser company, Have one would be better Power Transformer?

My country is 220V.

Thank you!

I believe Alphastat is the only place to buy those pots... they are not standard stuff as u may know.

all the best!!
Title: Re: sontec 1 RU build thread
Post by: andydiy on February 26, 2013, 12:40:34 PM
Thank!

In addition, I want to buy Power Transformer, In Mouser company, Have one would be better Power Transformer?

My country is 220V.

Thank you!


Hi!

Ask the following ALPHASTAT, addition to the PS Potentiometer-Service GmbH something to buy, there are other places to buy it?

10x  50k CTPOT                                                                                                             
2207 RD1601-20F4-30R
ALPHASTAT 63250-01610/B50K 50K LIN CENTERTAPCENTERDETENT
10x 100K RLOG DUAL_ALPHA_2                                                                                   
4196 RD1602-20B4-30R
ALPHASTAT 63256-02600/C100K 100K REV-LOG

In addition, I want to buy Power Transformer, In Mouser company, Have one would be better Power Transformer?

My country is 220V.

Thank you!

I believe Alphastat is the only place to buy those pots... they are not standard stuff as u may know.

all the best!!
Title: Re: sontec 1 RU build thread
Post by: andydiy on February 26, 2013, 02:29:09 PM
Hi!

Someone can give me a complete BOM ?

If the to mouser best!

Thank !
Title: Re: sontec 1 RU build thread
Post by: SKJGProject on March 26, 2013, 09:36:07 AM
i have soldered 7k5 resistors on the backside, how much boost/ cut will result from this value?

 and i plan to add an 6/ off / 12 db switch to it, so if i don't want to desolder all the 7k5 resistors, which values should i use for r18-r22?
Title: Re: sontec 1 RU build thread
Post by: zayance on March 26, 2013, 11:07:30 AM
i have soldered 7k5 resistors on the backside, how much boost/ cut will result from this value?

 and i plan to add an 6/ off / 12 db switch to it, so if i don't want to desolder all the 7k5 resistors, which values should i use for r18-r22?

Start from reply#47
Title: Re: sontec 1 RU build thread
Post by: frazzman on April 23, 2013, 12:58:38 AM
Any one happen to have any of Igor's sontec Red boards around? I was really keen on building one of these but it looks like he's shut up shop and no prospect of getting my hands on any
Title: Re: sontec 1 RU build thread
Post by: druu on April 23, 2013, 01:20:18 AM
I have a complete unit that will be ready for sale soon once a few more parts arrive (and elma knobs).

Let me know if you're interested.
Title: Re: sontec 1 RU build thread
Post by: leadbreath on May 31, 2013, 05:19:09 PM
"Any one happen to have any of Igor's sontec Red boards around? I was really keen on building one of these but it looks like he's shut up shop and no prospect of getting my hands on any"

me too!! even though i dont really care what colour the pcb's are...
Title: Re: sontec 1 RU build thread
Post by: Screamer on June 25, 2013, 08:05:44 PM
Hi everyone!

Does any one have a "RED sontec stereo PCB" to sell for me? Or only the filter boards?

I bought the "Sontec/MS/hardware bypass/power supply upgrade board" but I didn't buy the "RED Sontec Stereo PCB Set"... The Igor's store is close now...
I can't finish my Sontec EQ...  :'(

Thanks,
ScreameR
Title: Re: sontec 1 RU build thread
Post by: Tudy on July 12, 2013, 05:16:36 PM
Hello,
I need change HF range to low frequency. Do you know formula for RC calculating please?
Or do you know, what is this HPF type?
Title: Re: sontec 1 RU build thread
Post by: andydiy on July 25, 2013, 07:53:08 AM
I intended to sell RED Sontec EQ accessories, the following is my list:

1. RED Sontec Stereo PCB

2. Collective Cases

3. Neutrik XLR (NC3FAH1 x2/ NC3MAH x2)

4. Switch Toggle 2PDT RA PCB x2

5. 5K Lin POTSW x6 / 5K Lin 5K Lin CTPOT


Current disposal value: $ 387 USD (Not calculate the shipping)



Title: Re: sontec 1 RU build thread
Post by: gda on August 25, 2013, 05:10:05 PM
Hello everybody!
It's been almost a year since I've finished my EQ and I have never been able to make it work correct. One of the channels has noise. The resistance in the output of one of the channels is 80.7 Ohm and the other 77,8 Ohm. Which is the correct value?
Also when I engage one of the channels I have a pop and one the other not. What is normal?
Please help...Thanks a lot.
Title: Re: sontec 1 RU build thread
Post by: Jordan on August 15, 2014, 11:20:25 AM
Hi,

I would like to know if anyone has the documents to make this EQ?
Documents page 1 are not downloadable ...

Thank you!
Title: Re: sontec 1 RU build thread
Post by: Trench Recordings on August 30, 2014, 02:20:35 PM
Also looking for any documentation for this and the M/S board. Thanks !
Title: Re: sontec 1 RU build thread
Post by: Zander on September 01, 2014, 04:18:52 AM
Also looking. Thanks
Title: Re: sontec 1 RU build thread
Post by: muffy1975 on October 10, 2014, 06:35:24 AM
there  is  documentation at the beginning of the the thread. The files are all there. Schematics layouts etc etc.

I have jus built myself the sontec from scratch using igor's layout as a guide . had the pcbs made for me and ...viola


This an amazing smooth eq.

Built stepped volume controls cos these need to be centre tapped and 50k lin centre taps don't really exist anymore....not without placing a large order etc etc.



I however do get some resonance when the Q 5k controls are sett to peak. Not sure why this should be inducing noise . When the Q is set to 2 octaves plus there is no noise.


But yeah what a great shelf and tight bass.....
Title: Re: sontec 1 RU build thread
Post by: phelar on January 08, 2015, 03:38:00 PM
Hi!
Does anyone have the sontec_red.rar file.  Need to look at the schematic etc.

Thanks!
Title: Re: sontec 1 RU build thread
Post by: druu on January 08, 2015, 11:38:04 PM
http://i251.photobucket.com/albums/gg291/diy33609/schem_upd.gif
Title: Re: sontec 1 RU build thread
Post by: Trench Recordings on February 28, 2015, 08:38:39 PM
all links dead ! no one has any files saved on their computer ? ???
Title: Re: sontec 1 RU build thread
Post by: druu on March 01, 2015, 03:02:17 AM
Gimme a tick and i'll upload them some place.
Title: Re: sontec 1 RU build thread
Post by: druu on March 01, 2015, 03:05:09 AM
https://www.sendspace.com/file/c0dlkk
Title: Re: sontec 1 RU build thread
Post by: Trench Recordings on March 01, 2015, 10:31:35 AM
Thank you so much  :)

You don't happen to have Igor's 33609 docs too ?
Title: Re: sontec 1 RU build thread
Post by: pH on March 20, 2015, 08:59:25 PM
I'm changing out the chips on the I/O board to discrete op amps (APP992), and the mill-max sockets I bought are too large on the solder end. Would anyone happen to have a mouser part number for the correct size?

Thanks,
Paul

Title: Re: sontec 1 RU build thread
Post by: Trench Recordings on March 22, 2015, 04:52:29 PM
Double check this with their product specs and measurements but i have a few spare harwin sockets and they fit igors board.

http://www.digikey.ca/product-detail/en/H3167-05/H3167-05-ND/3919400
Title: Re: sontec 1 RU build thread
Post by: tonedude on March 24, 2015, 03:56:19 AM
I did place the Mill-Max sockets on the pins of the DOA and then soldered the sockets in the right position on top of the i/o PCB, worked just fine!

I'm changing out the chips on the I/O board to discrete op amps (APP992), and the mill-max sockets I bought are too large on the solder end. Would anyone happen to have a mouser part number for the correct size?

Thanks,
Paul
Title: Re: sontec 1 RU build thread
Post by: pH on March 24, 2015, 11:45:20 AM
It looks like Igor suggested to solder the bottom of the pin onto the board like you did tonedude. I tried one and it seems to work fine.

Title: Re: sontec 1 RU build thread
Post by: tonedude on April 12, 2015, 12:21:33 PM
Hmmm....?

I wonder if my sontec is working as it should?

When I send in a mono signal (eg white noise...) in to both channels of my Igor Sontec, and try to cancel the signal out through phase shifting one of the returning channel, it doesn't null, not even close (I get about -30 dB or something).

When doing the same with my Behringer T1951, modified to something "close" to BP Net EQ spec, it almost nulls.

How can I understand this? Is there something wrong with my Sontec i/o board?
Title: Re: sontec 1 RU build thread
Post by: tonedude on April 13, 2015, 03:00:31 AM
Fixed....
Title: Re: sontec 1 RU build thread
Post by: Siegfried Meier on June 22, 2015, 01:50:21 PM
Hey guys,

I built up 2 of these over the years - a +/-6dB version a few years back, which sounds excellent and just now finished a +/-12dB version.  However, I have an odd hum with the mains cranked in the top end.  Even with the boost/gain at 0, when the freq is set to the lowest, around 1k, I hear the hum.  The trafo positioning and even one of Don Audio's toroid shields doesn't seem to do anything at all.  I put a ground wire on the back of the freq select pot and connected it to star ground and it got a little better, but still not as good as the other unit.  Could it just be that the different caps used in this unit are more sensitive?  But usually you'd hear a difference in boosting the frequency...in this case I'm not boosting at all, I'm simply selecting the frequency.  That's an odd one...both channels do it as well, which makes it double odd...

Any advice much appreciated.
Thanks!
Sig
Title: Re: sontec 1 RU build thread
Post by: Biasrocks on June 22, 2015, 04:35:27 PM
Hi Sig,

Mark from Sharktank here.

A few things to check.

Make sure the front panel is grounded and the pots are grounded to the panel.

Check with an meter.

You could try scraping away the finish around the pots and where the front panel connects to the enclosure.

Recheck your grounds on all the boards, makes sure you have zero ohms on your ground points to your main audio ground.

Barring that you may want to seperate audio ground and power ground until the last possible point, verify with a scope to make sure there's no hash on your audio ground.

Mark


I built up 2 of these over the years - a +/-6dB version a few years back, which sounds excellent and just now finished a +/-12dB version.  However, I have an odd hum with the mains cranked in the top end.  Even with the boost/gain at 0, when the freq is set to the lowest, around 1k, I hear the hum. 

Any advice much appreciated.
Thanks!
Sig
Title: Re: sontec 1 RU build thread
Post by: Siegfried Meier on June 23, 2015, 03:37:41 PM
Well, the only pots that are actually attached to the panel are the gain pots, and I feel that's the weakest part of this project - the design should have been so that all the pots bolt to the panel.  I took buss bar and attached it from the back of the hi freq pot to my star ground and it's made a significant difference.  Once the 2nd channel went in and the top was attached, it was actually pretty decent.  I'm probably audibly testing this a little bit unrealistic (mains and levels all cranked), but if I put my finger on the back of that pot, and touch that cap directly behind, I can get the hum to disappear 100%.  I'll do a bit more poking around when I get some free time, but for 99% of tracking purposes, it'll probably be just fine.

Thanks!
Sig
Title: Re: sontec 1 RU build thread
Post by: jefepeters on January 13, 2016, 04:20:10 PM
Hello,

Quite a few years back I picked up the I.J. Research PCBs for this project, but never got around to building it. Is it true the Alphastat pots specified in the BOM are no longer available? (Or only as a bulk special order?) If so, are there any other viable alternatives or am I out of luck?

Thanks,
Justin
Title: Re: sontec 1 RU build thread
Post by: mrcase on January 13, 2016, 06:11:47 PM
Hey!

I have the vice versa situation. I missplaced my pcb and can only find the pots I bought for it. I might sell them, if another search doesnt bring out the board.  pm me if you are interested.
Title: Re: sontec 1 RU build thread
Post by: Gold on January 22, 2019, 05:31:04 PM
I want to make a +/- 3dB version of this. To do this the gain set resistors (for example RF2B,RF2C)need to be about 68K Ω. I was wondering if the value of the pot could be lowered to reduce noise? Normally I'd just try it but I don't have center tapped pots in different values. If so is it worth doing?
Title: Re: sontec 1 RU build thread
Post by: Harpo on January 23, 2019, 03:40:06 AM
... To do this the gain set resistors (for example RF2B,RF2C) ...
for usual R18, R19, R20, R21 and R22 are the gain setting resistors ...
Quote
I was wondering if the value of the pot could be lowered to reduce noise?
yepp, as long as IC6 and IC8 can drive the then increased load of actually 6K5 (=5 x (50K/2 + 7K5) in parallel)
good luck
Title: Re: sontec 1 RU build thread
Post by: Gold on January 23, 2019, 03:24:34 PM
Thanks Harpo.

I was looking at your spreadsheet. I see you can enter the number of switch positions you want and it will tell you the resistor values for the range you have by evenly dividing the range. I was wondering if there is a way to enter the number of switch positions with the center frequency you want for each position and have it tell you the resistor values? In other words if I want 11 positions with the center frequencies being 20Hz, 40Hz, 75Hz, 100Hz, 125Hz, 150Hz, 175Hz, 200Hz, 250Hz, 300Hz, 350Hz. Can I enter those in to a spreadsheet and have it spit out resistor values?

I plan on figuring it out by measuring. I don't know Excel and I think it will be easier than using anRPN calculator a million times. I have a dual 25K pot. I'll make up the rest of the resistance with resistors. Hopefully that will give me enough resolution to measure.
Title: Re: sontec 1 RU build thread
Post by: Harpo on January 24, 2019, 02:33:35 AM
Paul, yepp, in cell C23 of 'SontecCalc_Igor.xls' you fill in the number of wanted step positions (in your case '11') and simply overwrite the evenly divided calculated frequencies in cells D26 ... H36 with your wanted target frequencies.
Just as a reminder, don't miss the sentence 'Update the cap.values in the red cells with measured real world capacitance of your fitted parts.'
Title: Re: sontec 1 RU build thread
Post by: Gold on January 24, 2019, 01:03:59 PM
Thanks Harpo, it worked! I got scared when I clicked on the cell and saw the equation the first time.
Title: Re: sontec 1 RU build thread
Post by: Gold on January 30, 2019, 02:36:01 PM
Now I'm not so sure it worked. Here is a link to the .xls file I used.  https://we.tl/t-8UnvDpSMlz    I made a rotary switch with 11 positions for the High Mid band using the values in the Series Resistance table.  I’m not using the  High Shelving band in this build. Just four bell bands. My High Mid is the second  0.47uf/330pf band.

Using the values in the table it looks like the center frequency is somewhat close but the available gain in the band is about half as much. With the 100K rev log pot and 68K gain range set resistors I was getting +/-3dBat a given center frequency. Now I'm getting about 1.5dB and the center frequency seems a bit off. The calculated values for 1K Hz seem to be closer to 1k3 Hz.

Shouldn't the overall resistance value from one end of the string to the other end of the string for the rotary switches be 100K? I tried lowering the value of the pot since I have the 68KΩ gain range set resistors. I tried a 10K pot but there was less gain available in the High Mid band I tried.
Title: Re: sontec 1 RU build thread
Post by: Gold on January 30, 2019, 05:06:04 PM
Here is what I got empirically. Way different than the spreadsheet. I must not understand something.

(http://www.saltmastering.com/Console/IJR_Sontec_HiMidValues.jpg)
Title: Re: sontec 1 RU build thread
Post by: Harpo on January 31, 2019, 05:54:55 AM
Now I'm not so sure it worked. Here is a link to the .xls file I used.  https://we.tl/t-8UnvDpSMlz    I made a rotary switch with 11 positions for the High Mid band using the values in the Series Resistance table.  I’m not using the  High Shelving band in this build. Just four bell bands. My High Mid is the second  0.47uf/330pf band.
Paul, you seem to have missed adjusting the parts values in rows 8 ... 17 for your desired range.

See attached file with updated parts values for your target frequencies ... http://www.hausverwaltung-heger.de/al_leck_trick/SontecCalc_PaulGold.xls (http://www.hausverwaltung-heger.de/al_leck_trick/SontecCalc_PaulGold.xls).
Title: Re: sontec 1 RU build thread
Post by: Gold on January 31, 2019, 01:32:30 PM
Harpo,

Thanks for taking the time to do that but I guess I still don't understand. Don't the resistor strings need to add up to 100K? Using the second band labeled Lo Mid in the spreadsheet the total resistance in the Series Resistance table is 11,129Ω. If I subtract 11,129 from 100,000Ω I get 88,871Ω. That's close to the measurement I got for the first switch position which was 88,580Ω.

It still doesn't make sense to me because the last switch position is 0Ω. If I put 88,871Ω before the first switch position then the last switch position can't be right as 0Ω should be the top of the range of the band which is about 8K Hz.
Title: Re: sontec 1 RU build thread
Post by: Harpo on January 31, 2019, 05:16:55 PM
Don't the resistor strings need to add up to 100K?
No. The equation for bandpass center frequency is set by 1/(2PI * SQRT( (RFx.9+pot.value) * Cfb *  (RFx.10+pot.value) * Cshunt) ).
Keeping cap values ratio from Sontec circuit and setting the substituted pot.values to zero ohms (CW end of pot travel) giving the upper end of the bandpass filter.
Your FI wanted 5,500 Hz for the 2nd low mid band requires a RFx of 2,323 Ohms instead of Sontec 7,987 Hz with RFx 1,600 Ohms. Increasing the pot.value to 11,129 Ohms (giving series resistance 2,323+11,129 Ohms) brings the BP center down to your wanted 950 Hz for the substituted potsCCW end instead of Sontec 100,000 Ohms for 126 Hz.
Quote
It still doesn't make sense to me because the last switch position is 0Ω.
The CW end of the substituted stereo pot with rev.log taper is zero ohms, setting the upper end of the BP center frequency with the remaining 2,323 ohms series resistors.
Title: Re: sontec 1 RU build thread
Post by: Gold on January 31, 2019, 06:50:42 PM
Your FI wanted 5,500 Hz for the 2nd low mid band requires a RFx of 2,323 Ohms instead of Sontec 7,987 Hz with RFx 1,600 Ohms. Increasing the pot.value to 11,129 Ohms (giving series resistance 2,323+11,129 Ohms) brings the BP center down to your wanted 950 Hz for the substituted potsCCW end instead of Sontec 100,000 Ohms for 126 Hz.The CW end of the substituted stereo pot with rev.log taper is zero ohms, setting the upper end of the BP center frequency with the remaining 2,323 ohms series resistors.

I think I'm starting to get it. To use the 11,129 series resistance calculated in the table I have to change both RF3.9 (1600Ω) and RF3.10 (1600Ω) to 2,323Ω.  To use the values from the series resistance table for the other three bands I have to change the RFx.9 and RFx.10 to the values in the top table. Lo = 4,260Ω LoMid = 14,200Ω  High = 2568Ω.
Title: Re: sontec 1 RU build thread
Post by: Harpo on January 31, 2019, 07:05:50 PM
yepp (or change cap values)
Title: Re: sontec 1 RU build thread
Post by: Harpo on February 01, 2019, 03:17:54 AM
Here is what I got empirically. Way different than the spreadsheet. I must not understand something.

(http://www.saltmastering.com/Console/IJR_Sontec_HiMidValues.jpg)
Cap values for the Low band are 4.7uF / 3.3nF and 470nF / 330pF for the LowMid and HiMid band. Your measured 4.69uF parts value for the HiMid band is a decade high. Just sayin'...
Title: Re: sontec 1 RU build thread
Post by: Gold on February 01, 2019, 04:13:25 PM
Cap values for the Low band are 4.7uF / 3.3nF and 470nF / 330pF for the LowMid and HiMid band. Your measured 4.69uF parts value for the HiMid band is a decade high. Just sayin'...

It's a typo. The cap is 0.47uF. The first two measured values are in reverse order too.

I've ordered resistor values that I didn't have to make the switches. They should be here Monday.

I have a lot of 0.1% 10K resistors. Is there any reason not to change R1-R4 in the Input/Summing board to 10KΩ for improved CMRR?

Would I see better level accuracy by using 0.1% 20K Ω resistors for R18-21? The band level summing resistors. What about using 0.1% resistors for R8/R12 in the Output/Summing section?

Title: Re: sontec 1 RU build thread
Post by: Harpo on February 03, 2019, 05:25:29 PM
I have a lot of 0.1% 10K resistors. Is there any reason not to change R1-R4 in the Input/Summing board to 10KΩ for improved CMRR?
IMHO no. Good move. I'd increase the 12pF for 663kHz LPF too optimistic compensation cap value of C57 (would rise to even more insane 1.3MHz LPF with your 10K R4) to maybe 68pF for 234kHz.

Quote
Would I see better level accuracy by using 0.1% 20K Ω resistors for R18-21? The band level summing resistors.
No, (the 100Ω resistors R9 and R15 already spoil the accuracy party by factor 5) and for your wanted +/-3dB boost/cut range, these 20Ks would increase by factor 4 anyway...
Quote
What about using 0.1% resistors for R8/R12 in the Output/Summing section?
Good move and decrease both to 10K in order to half the needed parts values of the summing resistors R18, R19, R20 and R22. Parts value of compensation cap C23 as described above.
As always YMMV.
Title: Re: sontec 1 RU build thread
Post by: Gold on February 03, 2019, 11:42:15 PM
Thanks Harpo. With any luck I’ll have pictures in a couple of weeks.
Title: Re: sontec 1 RU build thread
Post by: Gold on March 07, 2019, 06:15:27 PM
It's alive! It took close to 100 hours of bench time. This is a four channel EQ for vinyl mastering. It's for the A/B path console I'm building to master directly from tape to lacquer. All the PCB's are mounted on 3/8"x1/4" aluminum stock. The aluminum stock is mounted to the sides of the chassis. That way there is access from both the top and the bottom. I cut slots in the side of the case so the PCB's could slide back and forth for better access to the terminal blocks. The slots look really rough but when faced with the choice of spending fifteen minutes with an angle grinder and over an hour on the micro mill I went with the angle grinder.

(http://www.saltmastering.com/Console/TFEQ/TFEQA-1.JPG)

View looking through the unit.

(http://www.saltmastering.com/Console/TFEQ/TFEQA-2.JPG)

Starting to install the switches

(http://www.saltmastering.com/Console/TFEQ/TFEQA-3.JPG)

Switches installed

(http://www.saltmastering.com/Console/TFEQ/TFEQA-5.JPG)

I thought having all that braided shield packed in there might have a problem shorting to stuff. But I hoped against hope it would work. No dice. Have to put clear heat shrink over all the braided shield.

(http://www.saltmastering.com/Console/TFEQ/TFEQA-6.JPG)

Time to put it back together again.

(http://www.saltmastering.com/Console/TFEQ/TFEQA-7.JPG)

I had two channels that I put together with pots to work through all the choices. I worked out gain, frequency and Q ranges.

I built it like I think most others. I started out with OPA604/2604 OpAmps and Wima capacitors. When I started listening I wasn't happy. The EQ sounded hard and edgy. I figured I'd try swapping OpAmps and see if that helped. I tried some LME49710/20's. It helped a little but not nearly enough to turn my frown into a smile.

After thinking about it I figured the most likely culprits were the capacitors in the tuning circuit. I pulled the Wima's. I had some other brands of 0.47uF PP caps and some 330pF polystyrene caps. I redid the two mid bands and the improvement was dramatic. I now had a smile. I ordered a few different brands of PP caps to try for the larger value. I liked the polystyrene for the smaller value so I used what I had and ordered what I didn't.

Then I hand matched all the caps to within 1%. I of course had to order 3X what I needed to sort.

(http://www.saltmastering.com/Console/TFEQ/TFEQA-8.JPG)

Everything tested with IC's. Time to put in the DOA's. I decided to run the filter boards +/-15VDC and the In/Out/ Summing boards +/-24VDC. The console also has separate PSU's for Preview and Modulation channels. The power distribution is from the grey terminal blocks in the rear.

(http://www.saltmastering.com/Console/TFEQ/TFEQA-9.JPG)

Knobs on.

(http://www.saltmastering.com/Console/TFEQ/TFEQA-10.JPG)

Listening in the studio.

(http://www.saltmastering.com/Console/TFEQ/TFEQA-11.JPG)
Title: Re: sontec 1 RU build thread
Post by: scott2000 on March 07, 2019, 07:16:38 PM
Wow!
NIce!
Title: Re: sontec 1 RU build thread
Post by: john12ax7 on March 08, 2019, 12:44:14 AM
What PP cap did you end up with?
Title: Re: sontec 1 RU build thread
Post by: Gold on March 08, 2019, 01:21:53 AM
What PP cap did you end up with?

The low end is a Cornell Dublier. The two mid bands are Illinois Capacitor and the high band is TDK.

I didn’t spend a lot of time on it. I think the polystyrene may be doing the heavy lifting.

The original swap was  two Wima MKS4’s for a Cornell Dublier and a polystyrene.

I wasn’t able to make the 3n3 in the low band a polystyrene until I figured out I could use three 5000pf in series parallel to get the value. The large 4.7uF made a difference but when I put the polystyrene in it helped a lot.
Title: Re: sontec 1 RU build thread
Post by: john12ax7 on March 08, 2019, 01:41:47 AM
Thanks for the info.  Wima are generally pretty good but I do remember MKS to be rather bad for audio.  The MKP series should be better,  with the FKP even better,  but limited in capacitance size.
Title: Re: sontec 1 RU build thread
Post by: Gold on March 08, 2019, 02:02:41 AM
I don’t think the boards would take the footprint of an MKP. Since the leads are short you can’t shoehorn them in there. The smaller value was actually an MKP.

Edit: the smaller values were actually FKP to start with.
Title: Re: sontec 1 RU build thread
Post by: dagoose on March 12, 2019, 04:48:09 AM
wow! That's a real DIY sontec there! Cool looking panel, suits it. Congrats.  8)
Title: Re: sontec 1 RU build thread
Post by: 5v333 on March 12, 2019, 06:19:06 AM
applause!
Title: Re: sontec 1 RU build thread
Post by: Harpo on March 12, 2019, 07:16:18 AM
Congrats, that's some serious DIY.
Title: Re: sontec 1 RU build thread
Post by: Gold on March 12, 2019, 10:52:31 AM
Thanks guys. I don’t think I could have completed this build even a few years ago. 

I’m happy with the arrangement of controls. I oriented the controls vertically but in the horizontal order. It goes from left to right Lo Left, Lo Right, LoMid Left, LoMid Right, etc. It’s great for stereo or M/S but would be confusing for dual mono use.

I’m happy with the sound too.  I might call it YR-1 for Yaht Rock. It has that soft focus Super 8 kind of sound. That’s exactly what I was hoping to get out of it.

I’m working on the second unit for the console now. The only thing I’m going to change is some of the terminal blocks. I thought there would be better screwdriver access from the rear so I got angled blocks. It didn’t work very well so I’m using regular 90 degree blocks.

I put some shots of me making the faceplate in the Machine Shop.
Title: Re: sontec 1 RU build thread
Post by: Gold on March 12, 2019, 12:59:25 PM
I had a happy accident when building this. The Electroswitch C4's have D shafts. The OKW knobs are collett mount. I've had both the switches and the knobs for years. If you just try to tighten the colletts on the shaft they slip. My first thought was to get some 1/4" half round stock to make the D into an O. The flat of the shaft doesn't take up 50% of the shaft diameter so it's not a drop in solution. The next thought was to get some thin wall brass tubing and glue it over the shaft. That didn't work either because no tube wall was thin enough to get the collett over.

When testing this EQ out I didn't want to take the knobs on and off a million times so I used a pliers with teeth to rotate the switches. It gave me a good grip but tore up the switch shafts. I figured I could smooth them out later if necessary. When I went to put on the knobs I discovered I had inadvertently made a lock washer. The colletts were snug over the roughed up shafts and don't move. Problem solved!
Title: Re: sontec 1 RU build thread
Post by: Gold on May 29, 2019, 01:44:15 PM
This is Unit B. I ended up spending about as much time on this one as the previous one. I was able to tighten things up a bit. The frequency centers on Unit A were tightly matched between channels but didn't match the faceplate markings as closely as I'd like. On this unit I was able to trim them so they come pretty close to the faceplate markings and are still tightly matched. I had to trim the polystyrene caps which wasn't easy as there aren't too many values available anymore.

I put relay bypass boards in this one but didn't connect them. If I decide I want that in the future it won't be too difficult to install them. I forgot the LED's need a switch pole. The pushbutton switches are only 2 pole so I can only switch audio and not any LED's. I think I'm going to go with a 6 pole F style pushbutton switch so I can switch everything at once.

On the A Unit I used 31mm knobs for Frequency Select because they are 4 deck switches. These Electroswitch C4's are stiff. That didn't leave enough room for the legend. On this one I used 23mm knobs for everything. I think it looks better and the switch torque doesn't seem too much different than the others. Now I'll go back to Unit A and clean some things up.

(http://www.saltmastering.com/Console/TFEQ/TFEQ-B_1.JPG)


(http://www.saltmastering.com/Console/TFEQ/TFEQ-B_3.JPG)


(http://www.saltmastering.com/Console/TFEQ/TFEQ-B_4.JPG)


(http://www.saltmastering.com/Console/TFEQ/TFEQ-B_5.JPG)


(http://www.saltmastering.com/Console/TFEQ/TFEQ-B_6.JPG)