sontec 1 RU build thread

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dagoose

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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

<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>
 

Igor

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UPDATE: HERE YOU CAN FIND ALL DOCS:

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

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.

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.


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...
 

Grooveteer

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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.
 

crisotop

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probably post my questions better here instead of the order thread:

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
 

bearblock

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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...
 

keefaz

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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)
 

dagoose

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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.
 

crisotop

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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...
 

Grooveteer

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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
 

dagoose

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[quote author="Grooveteer"]Looks like PCB mounting the XLR's will not work with my case either. (also a Tat case). No big deal, though.[/quote]

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.
 

crisotop

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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!

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
 

Igor

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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!
 

crisotop

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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
 

Ghengis

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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
 

crisotop

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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
 

Grooveteer

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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
 

crisotop

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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
 

Igor

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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.
 
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