Yusynth ladder not sounding

[MapacheRaper]

Hi guys,

I have built a yusynth ladder VCF and Im getting no sound at all. It´s built from the originial soundtronics PCB.

I have checked the +V and -V at the tl072 and are correct but Im not sure what else to test. Is there any guide for troubleshooting this?.

Any table with voltages at pins or suggestions would be helpful

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[MapacheRaper]

the pcb

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[MapacheRaper]

When I matched the transistors, I got a pair with a very strange reading, Im guessing maybe I fried them.

Maybe.

Is there any way to check if the the trannies are working while they are soldered or I have to desolder them?

[murmeklis]

I have recently built this using soundtronics PCB as well, once I get the chance (expect a few days), I will post some voltage measurements, if you still think they are useful.

[MapacheRaper]

Hey murmeklis, thank you so much for your help!!

It happens that I was mixing 2n3906 matched ones with BC547C matched ones in the ladder!. So after desolder and put the correct ones, the filter is sounding like silk

So no need for these measurements (unless you want to do it for science). What I did found, though, is that R32 or R33 needs to be higher to get a nice output level.

If you are using eurorack voltages, you should read this thread:

http://electro-music.com/forum/topic-70376.html

So, thanks again and enjoy your new little baby!

[murmeklis]

thanks for your tip, I haven't even thought about the output level, seemed fine for me, but will definitely check. Glad you fixed it, enjoy!