Hey Chris, thanks for helping in this thread!
I've got a question about the input caps. This also relates to some other gear, like the Edirol UA5 and R04.
Sometimes I see a single cap, like the PR8. But I wonder if this is always correctly polarized. Take a look at C6 or C7. Ignoring phantom power, and letting the Base of Q1 and Q2 be approx. zero volts, it looks like a positive going input will correctly bias the cap, but a negative going signal will *reverse bias* it. I thought electrolytics only "work" when there is a positive bias (like a DC blocking cap). But I don't know what happens when they are reversed. In fact, many of the caps (C9, C5) seem to have ambiguous polarity.
Similar wierdness happens in the Edirol UA5, but in this case, they take two caps and put them "back to back". Again I wonder how this distorts because there will probably be one forward and one reverse biased cap.
I don't have a fear of electrolytics like some people do, but it seems like they are being *abused* often, and this might be why they distort.
Please enlighten me dude!
Richard
From the schematic it looks like most of the gain is comming from the transistors, I would reverse that replace the 4555 with a OPA2227A opamp and change the feedback loop on that opamp with a 15k resistor and get rid of the shit coupling caps. Replace all resistors in the signal path and else where to 1% metal film if not so already makes a huge sonic difference. Make sure left and right caps are all the same.