Sontec x 8 Build Thread

[norman_nomad]

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/

 

[Igor]

Great, thanx!

 

[JW]

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.

 

[JW]

Bump.

Anybody want to point me in the right direction?

 

[JW]

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.

 

[BradM]

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

 

[drpat]

JW,

Yes, that's the original transformer that Sontec used...

 

[BradM]

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

 

[analogical]

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.

 

[SKJGProject]

is there another build thread? i'm stuck atm and need some help with my sontec8

 

[SKJGProject]

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.?

 

[SKJGProject]

which trafo is needed?

 

[zayance]

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....

 

[SKJGProject]

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?

 

[radiance]

which PS board should i get?

Any PSU with LM317  &  LM337  will do.

 

[SKJGProject]

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?

 

[zayance]

OVERKILL but why not? The thing must be FAT and HEAVY tough  ;D

 

[SKJGProject]

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?

 

[zayance]

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?

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.....

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.

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

All is good....

-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.....

-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:

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

Yes the Sontec Stereo Thread will help you also.

Hope this helps?

 

[SKJGProject]

no cap tester :-(
but i still got the 100k2k