I've done the following:
- Opamp changed to OPA1612A
- Caps changed 100%, used rubycons and nichicons from an old sony music system's mainboard from 1995
It sounds amazing!!!
But I bought this x-fi used, it has 2 years on it... It sounded great already when compared to the audigy SE I was upgrading from, but right off the bat there was something wrong with this x-fi, like not being able to get the calibration signal down to -1 dB as indicated by the program, only to about -2.5 or -2.2 dB, after that the left channel distorts quite badly.. it's in audio creation mode, all eax effects disabled, bit perfect mode activated.. as it should be.. have a look at the RMAA calibration graphs at 92%, 94% and 100% volume. It's the line out that's borked, the line-in's working fine.
92% | http://www.imagebam.com/image/9ff7ce114169363
94% | http://www.imagebam.com/image/ae2c81114169367
100% | http://www.imagebam.com/image/855e39114169372
RMAA graphs at 92% | http://www.imagebam.com/image/cc87b3114169384
RMAA results at 92% w/ audigy SE | http://www.imagebam.com/image/d7e8d8114169378
I've changed all the caps thinking there was a bad one somewhere causing all this, but unfortunately it wasn't the case. I thought maybe the stock opamp was doing things wrong, but it wasn't. It hasn't changed with all the mods applied.
I'm at a loss, clearly the left channel is ****ed up... I can't seem to find what's wrong with this card. Mind you, it sounds great to me, the best I've ever heard and much better than my old audigy SE, but it makes me uneasy to know that my card isn't right. What could be broken? the DAC chip? Any ideas folks?