sontec 1 RU build thread

[crisotop]

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.

 

[Siegfried Meier]

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

 

[Siegfried Meier]

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

 

[user 10827]

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

 

[SIXTYNINER]

BOM (with PSU at the bottom of the document)

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

 

[rrs]

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.

 

[1234]

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 ???

 

[kambo]

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

 

[Igor]

Enjoy
I have to update whole Sontec build thread-it is disappeared from forum...

 

[mikeyB]

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

 

[Igor]

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.

 

[mikeyB]

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!

 

[Igor]

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.

 

[1234]

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)?

 

[slowbass]

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

 

[mikeyB]

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!!

 

[slowbass]

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....

 

[SIXTYNINER]

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

 

[slowbass]

Thanks, I will follow this site !

 

[Igor]

@ 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.