I've completed the QRV-08 a few months ago and it has playing happily ever since. You weren't kidding when you said it reveals poor recordings. I'll post a picture when I get around to taking one.
I've found the standard gain of 4 to be too high with an AMB gamma 3 and a set of HD650s. Which resistors should I change to reduce the gain, and what values would you recommend for a gain of 2 or 1 respectively?
R14 and E14 can be changed. 330 ohms will set the gain to 2.
Do 330 ohms impact anything else besides the gain?
No...