I've just finished building a x0xb0x from xoxshop.de and while the rest of the box seems fine I'm having trouble with the filter at high resonances. I'm not sure this qualifies as the filter warble mentioned in the troubleshooting faq. I've posted a recording of me playing some notes in Keyboard mode and moving the resonance and cutoff around (later on I move the envelope too) at https://dl.dropbox.com/u/781826/WeirdFilterProblem.mp3
I built some test projects and a Shruthi-1 before tackling the x0xb0x and kinda unfortunately they worked first time so I got no practise debugging! I have borrowed an old analogue oscilloscope which I can use for testing but I'm not sure what to check.
Anyone heard this problem before and/or can give me advice on what I should be checking? I've tried with another PSU and that didn't seem to make any difference.
TIA - Chris