Sontec x 8 Build Thread

[SKJGProject]

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?

 

[zayance]

no cap tester :-(

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

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

i already installed the 14 0.1 uf:

Still 98 to Go  ;D

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....

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  , well if you don't want to waist too much time....

 

[Holger]

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.

 

[zayance]

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?

 

[Holger]

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.

 

[zayance]

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...

 

[radiance]

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 ....

 

[zayance]

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...

 

[Holger]

...Does anyone have a source for these pots? I might want to replace some in my unit ....

Maybe good old Alphastat?
http://alphastat.de/

 

[radiance]

Thanks!

I'll check if it's worth it to order 8 pots from them....what are considered high shipping costs from Alpha?

 

[Holger]

IIRC I paid 9,50€ inside Germany. I don't think that it will be more than 20€ inside EU.

 

[SKJGProject]

ok did some research on the sontec thread:

• 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?
• where can i get these molex connectors (x)?

my board so far:

 

[SKJGProject]

*bump*

 

[zayance]

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...

 

[radiance]

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...

 

[zayance]

haha, i was thinking about the Caps/resistors, but right i should be more precise... ;D

 

[Igor]

    * 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.

    * 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)

 

[skidmorebay]

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

 

[Igor]

No kits anymore, sorry. I have last 9 boards at my storage and Purusha case.
The boards are different than stereo version.

 

[skidmorebay]

OK, thanks. Please PM me with the price for a board and case if they are still available for purchase. Thanks!
JS