Hey guys, so I kind of jumped the gun and decided to go into making a PCB version of Rene Schmitz YARM+ and finally got them and assembled them. But I kind of ran into a problem where it doesn’t seem I am getting a signal from the Y input even after testing the continuity of the voltages to ensure everything is connected and they are. Also I am wondering if I strictly need 47k trimpots or can use any other value as the ones I have aren’t the multiturn and only got a certain distance. Can anyone offer some help?
It would help if you supplied a link to the source
https://www.schmitzbits.de/vca.html
and/or the schematic
I spot one error, your R11 should be 100k, not 10k. It’s also possible other values may need to be adjusted for 12 V although I would guess probably not.
Probably the 47k trim pots could be 20k or 10k or maybe 100k. (I assume you’re using 50k since 47k pots are pretty much extinct these days — if not, 50k would be fine.)
Note it says input range is 3.5 Vpp — that’s quite small. Most synth signals these days are 10 Vpp. In the description it says
And here is a version with higher gain, which allows you to obtain 5Vpp waveforms on the output when using 5Vpp on the input. The limits given in the schematic are meant for preventing the output to clip you may not exceed 3.5V simultaneously at both inputs. However as long as the product is lower than the clipping level, you can drive the inputs above 3.5V.
but even 5 Vpp is small. Edit: And that’s with ±15 V; with ±12 V presumably the input range is even smaller. End edit You will probably need attenuators on the inputs.
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