Gyraf GSL help needed

Hello, I am in the process of building the GSSL compressor, and I have some questions.

First of all, in all the parts lists I found on this forum, it reads that there are supposed to be nine 100pF caps on the main pcb, though on the schematic I see ten! Could anyone tell me where I am wrong? I made a little drawing, which is here:

http://134.2.42.41/~marten/ssl100p.gif

Then another thing would be how to bring the unit up for initial testing, has this been answered before? Can I leave out the IC's and measure for correct voltages first, or is there a preferred procedure?

I'd appreciate any help, I have looked through the ssl meta thread and found nothing.
Thank you and cheers from Germany, marT

Hi MarT,

Welcome to "The Lab"..

Yes, there may be some discrepancy between schemo and PCB. The PCB is known working, so trust that. And Please use the SSL-help-thread, so we can keep all questions and answers at one place. Makes it easier for other troublefixers.

Jakob E.

Hello Jakob,

thanks for your reply, I will post in the SSL-help-thread.

hello, a lot of the 100pf feedback caps can also be smaller down to around 22pf. I tried it and the ICs are stable(even if you use faster opamps like opa2604/opa627s) supposedly this will increase the bandwidth but I don't have the equipment to measure this. I really can't tell a difference by ear either, except when you get below 22pf when/if it starts to oscillate.


ah but trust the board silkscreen it's correct as Gyraf stated.

:thumb: