Audio-GD Master 9

[Nayyte]

Channel imbalance disappeared? That's interesting, indicating faulty decoder chip. Do you have U2/U2Pro version with standard oscilators?

DAC's balanced design will only filter portion of noise entering power supply of A/D converter and output buffers. There is also noise affecting clock frequency. Balanced design won't fix jitter, so there is still a room for improvements. If you read a U2/U2Pro Poorman DDC thread, discussion is now focused on using USB isolators. Investment in the $50 dongle is never wasted when a source is PC. $100 device is probably optimal.

Yes I have the U2pro version. The sound quality improvement overall is immense vs. the older USB input on the Ref-5. I was getting +1 DB on the left channel before that I software corrected. With PC noise, all I know is that I hear it very loudly when listening to tube amps and that I hear none at all with the master-9p. Oh I meant balanced design of my amp not DAC.

 

[sajunky]

Yes I have the U2pro version. The sound quality improvement overall is immense vs. the older USB input on the Ref-5. I was getting +1 DB on the left channel before that I software corrected. With PC noise, all I know is that I hear it very loudly when listening to tube amps and that I hear none at all with the master-9p. Oh I meant balanced design of my amp not DAC.

And I meant both, but it was not a reason of my response. Modern USB receivers (XMOS /Amanero) introduce lower jitter, but implication on the sound are different to a noise you can hear from a tube amp. The original USB receiver is probably defective. U2Pro is just OK, a version with standard oscilators can be improved by installing better oscilators. It is what I suggest.

Further improvements can be achieved both in jitter and a noise you hear on the tube amp by powering U2Pro from the LPS. It will redirect ground loops from the PC to the external power source. And the latest USB isolators are very effective. Check it out, it is worth to try. The old DAC has no effective galvanic isolation. U2Pro has none.