GroupDIY

Project Specific Discussions => Filters/Equalizers => Topic started by: norman_nomad on June 17, 2008, 07:16:57 PM

Title: Sontec x 8 Build Thread
Post by: norman_nomad on June 17, 2008, 07:16:57 PM
Hey Folks,

I just thought I'd start a build thread for those folks taking on Igor's 8 x Sontec project.

A couple of simple things that I stumbled on that you might benefit from after PM'ing Igor.

1.  If Igor gave you 1.5uf caps, you can use them in place of the 2.2uf caps in the low filter without any issue.  You can also use 1uf caps in the DC servo although 2.2uf is better.

2. You don't need the 150pf caps with the 604 or Forssel opamps

3. Channel bypass seems to work if you just link 1 and 3 on J6

4. The input/output 1 - 3 tags on the boards do NOT correspond to the XLR pins 1 - 3 (I stupidly assumed this).  Check the schematic for correct wiring.


Other than these things I had a very easy time with the build and actually managed to put the PSU inside of the case (all mounted against the back panel).

I tested one of the channels the other night and WOW what a great sounding EQ.  It's much like you'd expect.  Very clean and accurate sounding.  I think it will be a nice compliment to the more colored EQ's I have at my disposal.  

Thanks Igor for such a great project!  :grin:   :thumb:   :guinness:


I made some sound clips of unprocessed and processed... I'm using some meager Firebox converters to test, so they probably don't show the full potential of this EQ, but it will give you a general idea of what the EQ sounds like.  I also included clips with the 604's in the in/out position and some JLM99v's in the in/out for comparison.



Examples --> http://www.musicianssamples.com/SontecSamples/
Title: Sontec x 8 Build Thread
Post by: Igor on June 18, 2008, 03:40:45 PM
Great, thanx!
Title: Sontec x 8 Build Thread
Post by: JW on July 15, 2008, 04:54:28 PM
Hey guys.

I've searched forever for the Igor 8 channel build thread, and it appears this is it!

Anyway, if there is a future for this thread maybe someone could answer a couple questions for me.

As I have almost an entire kit on the way to me, I'll be starting soon on this project, but would like to know what kind of power transformer I should get.

I have an extra Mnats 1176 p.s. board and would like to use that. I'm assuming a 24-0-24 transformer would be good, but what amp rating should I be looking at?

Also, is there a schematic for Igor's version anywhere?

Thanks.
Title: Sontec x 8 Build Thread
Post by: JW on July 17, 2008, 06:51:50 PM
Bump.

Anybody want to point me in the right direction?
Title: Sontec x 8 Build Thread
Post by: JW on July 18, 2008, 09:28:05 PM
Thanks Pat! Are you saying this is the original transformer Sontec used (I'm guessing not) or the one that Igor used in the 8 channel unit? Just curious. That's probably not the one I'll end up with in any regard.
Title: Sontec x 8 Build Thread
Post by: Brad McGowan on July 25, 2008, 09:21:22 PM
I'm hoping Igor or someone else can shed more light on why there are six pads for the bypass switch connection.  What's supposed to go where?  I buy 1 and 3 get connected for operation, but what about all those other connections?

thanks,
Brad
Title: Sontec x 8 Build Thread
Post by: drpat on July 25, 2008, 11:17:59 PM
JW,

Yes, that's the original transformer that Sontec used...
Title: Sontec x 8 Build Thread
Post by: Brad McGowan on July 30, 2008, 05:57:45 PM
Are any of you guys using XLR's for your Sontecs?  I'm not at home and don't have access to the BOM right now...I'm wondering if someone can tell me what XLR fits on the board and whether or not they line up with the rear holes (I'm pretty sure they do).

thanks,
Brad
Title: Knobs
Post by: analogical on October 05, 2008, 03:36:33 PM
Any Part numbers for knobs would be much appriciated. Using Igor's pots.

Edit: found them on the other "sontec 8 build thread"  

Might want to merge these two.
Title: Re: Sontec x 8 Build Thread
Post by: SKJGProject on May 22, 2011, 11:23:32 AM
is there another build thread? i'm stuck atm and need some help with my sontec8
Title: Re: Sontec x 8 Build Thread
Post by: SKJGProject on May 22, 2011, 12:38:58 PM
i bought pcb, case and lots of parts from some member here and now
i don't know where to put the following parts:

- 100 k2k (seems to be CAPACITORS SILVER MICA/POLY/COG
4   5p        C2.5/2          CF1.2, CF2.2, CF3.2, CF4.1 because i have 32 pieces but 100 is the wrong value???)

-the 220µf elkos are rated 25v, should i get new ones or can i use them for C1 & C22

-the 3.9MOhm Resistors are 5% not 1% is it important or can i use the 5% ones

-i got 5.62k instead of 7k5 , how much boost/cut will i get when i use these for rf1b, rf1c etc.?

Title: Re: Sontec x 8 Build Thread
Post by: SKJGProject on May 25, 2011, 12:04:38 PM
which trafo is needed?
Title: Re: Sontec x 8 Build Thread
Post by: zayance on May 25, 2011, 12:47:25 PM
which trafo is needed?

Depends on Opamps used, I used OPA604 and 2604 all the way at +/-24V, so a 2*25V, and 100VA iirc....
Title: Re: Sontec x 8 Build Thread
Post by: SKJGProject on May 26, 2011, 10:00:30 AM
thx, any help for the other questions?

in my bag there were also the caps missing for CLF2 (4u7), CLMF2 (0.47) and C59(100)...which caps should i get? WIMA FKP3 for the filters?

which PS board should i get?
Title: Re: Sontec x 8 Build Thread
Post by: radiance on May 26, 2011, 01:37:54 PM


which PS board should i get?

Any PSU with LM317  &  LM337  will do.
Title: Re: Sontec x 8 Build Thread
Post by: SKJGProject on June 01, 2011, 09:53:47 AM
which trafo is needed?

Depends on Opamps used, I used OPA604 and 2604 all the way at +/-24V, so a 2*25V, and 100VA iirc....

i will use the same opamps and luckily i already have some 2x25v 340va toroid...i can use any rating above 100va, right?
Title: Re: Sontec x 8 Build Thread
Post by: zayance on June 01, 2011, 02:52:39 PM
OVERKILL but why not? The thing must be FAT and HEAVY tough  ;D :)
Title: Re: Sontec x 8 Build Thread
Post by: SKJGProject on June 05, 2011, 02:32:43 PM
i don't know where to put the following parts:

- 100 k2k (seems to be CAPACITORS SILVER MICA/POLY/COG
4   5p        C2.5/2          CF1.2, CF2.2, CF3.2, CF4.1 because i have 32 pieces but 100 is the wrong value???)

-the 220µf elkos are rated 25v, should i get new ones or can i use them for C1 & C22

-the 3.9MOhm Resistors are 5% not 1% is it important or can i use the 5% ones

-in my bag there were also the caps missing for CLF2 (4u7), CLMF2 (0.47) and C59(100)...which caps should i get? WIMA FKP3 for the filters?

-i got 5.62k instead of 7k5 , how much boost/cut will i get when i use these for rf1b, rf1c etc. which value gives +-12db?



*bump*

any help?
Title: Re: Sontec x 8 Build Thread
Post by: zayance on June 07, 2011, 05:08:28 AM
Quote
100 k2k (seems to be CAPACITORS SILVER MICA/POLY/COG

Pictures? If your guess is right then maybe a 100nF (0.1uf) any cap tester in hand?

Quote
4   5p        C2.5/2          CF1.2, CF2.2, CF3.2, CF4.1 because i have 32 pieces but 100 is the wrong value???)

100 for 100nf and so 0.1uF i guess?, a cap tester could be nice, on visual check of the printed layout i see 14 x 0.1uF so that makes 112 needed in total (minus PSU), better check twice, but you could be short on that one if it's the case.....

Quote
the 220µf elkos are rated 25v, should i get new ones or can i use them for C1 & C22

C1 & C22 are Bypass PSU Caps (see Schemo) so Electrolytics, better be over 25V if you're using 2x24V, i'd go for 50V.

Quote
-the 3.9MOhm Resistors are 5% not 1% is it important or can i use the 5% ones

All is good....

Quote
-in my bag there were also the caps missing for CLF2 (4u7), CLMF2 (0.47) and C59(100)...which caps should i get? WIMA FKP3 for the filters?

Any good poly would do, Epcos, Wima etc.....

Quote
-i got 5.62k instead of 7k5 , how much boost/cut will i get when i use these for rf1b, rf1c etc. which value gives +-12db?

From the Sontec Thread Igor's response:

Quote
Hi, 4k7 will give exactly +/-12db.

Yes the Sontec Stereo Thread will help you also.

Hope this helps?
Title: Re: Sontec x 8 Build Thread
Post by: SKJGProject on June 07, 2011, 07:46:17 AM
no cap tester :-(
but i still got the 100k2k
Title: Re: Sontec x 8 Build Thread
Post by: SKJGProject on June 07, 2011, 08:42:35 AM
oh and btw i just realized this AFTER soldering some of the alphas into place:

is it possible to cut the pot shafts after soldering with a dremel without damaging the pot?
Title: Re: Sontec x 8 Build Thread
Post by: zayance on June 07, 2011, 09:11:49 AM
Quote
no cap tester :-(


:( Get a cheap DMM that has Cap tester from Conrad, always usefull.

Quote
i have  16 of these left (seems to be CAPACITORS SILVER MICA/POLY/COG
2   12p       C7.5/3          C23, C57 CAN BE 12-33PF: right?)

hmm picture is too blurred, what is the writings on the Blue COG Caps, 150J  COG100? if yes then these are 15pF J for (+/-5%) Caps i think, so yes for C23 etc....

http://www.wjoe.com/capacitorinfo2.htm


Quote
i already installed the 14 0.1 uf:

Still 98 to Go  ;D

Quote
but i still got the 100k2k

What do they look like? My stupid logic would say, 100k like for the resistors, so 100000pF, and so 100nF and so 0.1uf....


Quote
oh and btw i just realized this AFTER soldering some of the alphas into place:

is it possible to cut the pot shafts after soldering with a dremel without damaging the pot?

Yes possible, but screw the Alpha on the frontpanel, protect the front panel with some cooking plastic or so, and cut, better to cut when you have the knobs in your hands so you have an idea of the exact dimension to cut, just my 2 cent.
After cutting, if the dimension is correct, well just use the cutted shaft length to duplicate on all others without soldering on PCB, mark them with a black pen or something, that's what i did, so cutted all at same time and at right size, like i said the build is a little like working in a factory  :D, well if you don't want to waist too much time....

Title: Re: Sontec x 8 Build Thread
Post by: Holger on June 07, 2011, 09:16:48 AM
oh and btw i just realized this AFTER soldering some of the alphas into place:

is it possible to cut the pot shafts after soldering with a dremel without damaging the pot?

I would say NO. I did that on one build and due to too much frictional heat I killed some pots. I would recommend to cut them with a saw, not with a dremel.
Title: Re: Sontec x 8 Build Thread
Post by: zayance on June 07, 2011, 09:20:14 AM
oh and btw i just realized this AFTER soldering some of the alphas into place:

is it possible to cut the pot shafts after soldering with a dremel without damaging the pot?

I would say NO. I did that on one build and due to too much frictional heat I killed some pots. I would recommend to cut them with a saw, not with a dremel.

Did all of mine with dremel, all was good, i used there High Speed cutting disk, with alpha on a vise and straight cutted them without forcing, Brass got cut like butter, i always believed that the manual Saw would actually give to much mechanical effort on them, going back and forth, not if you press the shaft on the vise tough of course...
Heat killing pot is logical, but it's still possible to be gentle, cut slowly all around for example without forcing on one side only....
All went well on my side and for more than 60 pots, maybe saw is better yes for not having any suprise, maybe i got lucky?
Title: Re: Sontec x 8 Build Thread
Post by: Holger on June 07, 2011, 09:31:08 AM
zayance, what can I say  ;)
Two men, two different experiences. You're right regarding the mechanical stress, but for me it was bad to realize that two pots went crazy. You know how time consuming it is to dis-assemble the entire EQ and exchange some pots.
Title: Re: Sontec x 8 Build Thread
Post by: zayance on June 07, 2011, 09:43:18 AM
zayance, what can I say  ;)
Two men, two different experiences. You're right regarding the mechanical stress, but for me it was bad to realize that two pots went crazy. You know how time consuming it is to dis-assemble the entire EQ and exchange some pots.

Of course, better be safe than sorry as always...
Title: Re: Sontec x 8 Build Thread
Post by: radiance on June 08, 2011, 05:34:19 AM
Well, saw or dremel....I think it's best to cut the pots before soldering them.
Put the shaft in a clamp and use a saw or dremel. This way no force will be put on the pot itself, only on the shaft.
Just catch the pot in time when done....

And btw, those alpha pots are weak...I probably had 5 dodgy ones with broken conductive paths, especially the middle ground path gets damaged easily.
Does anyone have a source for these pots? I might want to replace some in my unit ....
Title: Re: Sontec x 8 Build Thread
Post by: zayance on June 08, 2011, 05:40:20 AM
Quote
And btw, those alpha pots are weak...I probably had 5 dodgy ones with broken conductive paths, especially the middle ground path gets damaged easily.
Does anyone have a source for these pots? I might want to replace some in my unit ....

You mean you had them from the beginning as is?

Unfortunatly the only Source, is the Source itself, some Alpha's are sold on Conrad.de, but not the ones needed here.
But Mr Kirchhoff is an "ok" guy, of course his service is better when you ask for hundreds of pots...
Shipping is expensive from Alphastat, as always dealing directly with factory, something like 16 euros...

PS: Best way to deal with Alphastat is on GB i think, last one i did went smoothly, and all pots seemed to be just fine, all came quick etc...
Title: Re: Sontec x 8 Build Thread
Post by: Holger on June 08, 2011, 05:43:43 AM
...Does anyone have a source for these pots? I might want to replace some in my unit ....

Maybe good old Alphastat?
http://alphastat.de/
Title: Re: Sontec x 8 Build Thread
Post by: radiance on June 08, 2011, 10:31:38 AM
Thanks!

I'll check if it's worth it to order 8 pots from them....what are considered high shipping costs from Alpha?
Title: Re: Sontec x 8 Build Thread
Post by: Holger on June 08, 2011, 10:51:18 AM
IIRC I paid 9,50€ inside Germany. I don't think that it will be more than 20€ inside EU.
Title: Re: Sontec x 8 Build Thread
Post by: SKJGProject on June 09, 2011, 07:32:32 AM
ok did some research on the sontec thread:


my board so far:

(http://dl.dropbox.com/u/499952/sontec8.png)
Title: Re: Sontec x 8 Build Thread
Post by: SKJGProject on June 22, 2011, 07:09:52 AM
*bump*
Title: Re: Sontec x 8 Build Thread
Post by: zayance on June 22, 2011, 08:25:52 AM
iirc i've installed those 5p (1-2-3-4), and doesn't seem to be a problem for me, You can try it out on one channel and see how it goes...

For the CLF2', i think it was just a paralled or in series connected space for if you have hard time finding the 4u7 or to tweak, not sure tough, check the PCB traces....
I've installed a 4u7 on CLF2 and that's that....

For CLMF2 and CLMF1 i went with the values showed, and used Poly Wimas iirc...


Concerning Molex, here is a thread for infos about them:

http://www.groupdiy.com/index.php?topic=44197.0



BTW did you check if the DIL8 will pass between those big blue Epcos Caps? Not sure if it will? Just an observation.....

EDIT: If you're tight on space, you can of course solder the components on the other side, no prob...
Title: Re: Sontec x 8 Build Thread
Post by: radiance on June 22, 2011, 03:23:21 PM
EDIT: If you're tight on space, you can of course solder the components on the other side, no prob...

Yeah, bend all opamp pins and hope they don't break... ;D
No lettering will remain visible...it will be the secret opamp...

Title: Re: Sontec x 8 Build Thread
Post by: zayance on June 22, 2011, 04:04:56 PM
haha, i was thinking about the Caps/resistors, but right i should be more precise... ;D

Title: Re: Sontec x 8 Build Thread
Post by: Igor on August 02, 2011, 04:34:31 PM
Quote
    * is it correct that i can leave out all 5p caps (1,2,3 ) except cf4.1 (4) and use other values like 10p there?

Yes, it is possible to use 5...15pf at 1,2,3, and 5pf at 4.

Quote
    * where can i get these molex connectors (x)?

Farnell/Mouser/Digikey, or connect the wires directly to pcb.

Farnell p/n's for MOLEX 3 PIN 2.5MM PITCH CONNECTORS:

#1675755, #1675765, #1675781

BTW, here are updated docs for both 5 band and 4 band EQ's:

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

(unrar, check for sontec8_docs_1,2,3)
Title: Re: Sontec x 8 Build Thread
Post by: skidmorebay on November 08, 2011, 09:25:59 PM
Hello,
Are there any 8-channel Sontec kits out there? Is this just a matter of buying four stereo PCB's, or is there anything else I should know?
thankya,
JS
Title: Re: Sontec x 8 Build Thread
Post by: Igor on November 09, 2011, 03:41:54 AM
No kits anymore, sorry. I have last 9 boards at my storage and Purusha case.
The boards are different than stereo version.
Title: Re: Sontec x 8 Build Thread
Post by: skidmorebay on November 10, 2011, 06:43:09 PM
OK, thanks. Please PM me with the price for a board and case if they are still available for purchase. Thanks!
JS
Title: Re: Sontec x 8 Build Thread
Post by: spase on December 04, 2011, 11:11:01 AM
can you pm the price for that 8 sontec boards please.Thank you
Title: Re: Sontec x 8 Build Thread
Post by: zayance on December 05, 2011, 11:43:10 AM
can you pm the price for that 8 sontec boards please.Thank you

The price is about 240euros iirc.

But i remember you asking me questions about the Sontec builds, prices etc...
And you were a little shoked about the overall costs of a Sontec 8....
Title: Re: Sontec x 8 Build Thread
Post by: radiance on December 05, 2011, 01:32:10 PM
At the time we had group buys for almost all expensive parts and still the costs were about 1000 euro for a unit.
Title: Re: Sontec x 8 Build Thread
Post by: jensenmann on August 28, 2012, 01:47:29 PM
It took me only five years, but finally here it is:

(http://www.twin-x.com/groupdiy/albums/userpics/normal_000_0548.JPG)

Title: Re: Sontec x 8 Build Thread
Post by: dandeurloo on August 28, 2012, 02:00:07 PM
nice!  I just ordered a pair.  Hopefully it wont take as long to build but who knows.
Title: Re: Sontec x 8 Build Thread
Post by: Igor on September 08, 2012, 05:37:53 PM
It took me only five years, but finally here it is:

(http://www.twin-x.com/groupdiy/albums/userpics/normal_000_0548.JPG)



Hurray!!!! Happy to see it here. Sonic impressions? ;)
nice!  I just ordered a pair.  Hopefully it wont take as long to build but who knows.

Dan: don't mess Sontec 8 and stereo unit with MS ;)
Title: Re: Sontec x 8 Build Thread
Post by: jensenmann on September 11, 2012, 06:58:14 AM
We compared it to a real MEP250C and MES462 here: http://www.24-96.com/ . My version (everything OPA604/2604) has not the soft tone of a 250C but comes sonically very close to the MES462. The famous high shelv does it´s magic thing, though. The original 250 high shelv goes a bit higher in frequency and is a bit more "invisible". My Sontec has a tiny tiny little bit more controlled lowend. All in all it´s an impressive precision tool. Well done, Igor!!!
Title: Re: Sontec x 8 Build Thread
Post by: Igor on September 13, 2012, 11:02:01 AM
Awesome looking studio! And very good description of sound. +1 :)
Title: Re: Sontec x 8 Build Thread
Post by: jensenmann on February 20, 2019, 12:16:11 PM
just for the record a bump for this thread: some years later I ripped my Sontec clone apart and changed a few things. The reason is that over time it turned out that the high band didn´t sound as good as the original 250 HF band and the general boxtone is not as pleasing and soft as I know it from original Sontecs. I had a bunch of originals on my bench in the meantime, with enough time to compare and play with them next to another. That made the difference too obvious. So I though that there´s some potential for improvement.
 What I found is:
I´ve installed a smaller filtercap in the HF band because it pulled up some gritty frequencies when pushed at it´s highest position.
Using polystyrene filter caps helped to come closer to the original boxtone, too.
A bunch of electrolytics and film caps have been replaced with tantals, like in the original 250. That softened the sound a bit in a good way.
I did an extensive comparison of opamps in the circuit. It turned out that changing the servo or filter opamps didn´t change anything. But the input and summing opamps, being OPA604 in Igor´s design, made a difference. I decided to use LT1007 here. They sounded more natural, more relaxt and less aggressive. They run on +/-22V, so the PSU hat to be adjusted.