In Reply to: possibly something wrong in power supply . . . posted by dave789 on December 11, 2014 at 03:33:09:
Hi,
I would not class anything below around 0.3% H2 and 0.1% H3 at full scale in a DAC as "defect" (in the light of for example the distortion in speakers or microphones), unless it is very frequency selective.
I suspect it could be something in the PSU, but this is less likely as the feedback would likely kill it. My bet is on a coupling cap.
With electrolytic's (and or certain ceramic's) you must keep the AC voltage across the cap very low, or distortion will result. If the cap is too small in value, you will get distortion only at very low frequencies, improving quickly as the frequency rises, even though there is no obvious LF rolloff.
Thor
At 20 bits, you are on the verge of dynamic range covering fly-farts-at-20-feet to intolerable pain. Really, what more could we need?
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- RE: possibly something wrong in power supply . . . - Thorsten 21:32:36 12/11/14 (3)
- defective active ground drive, for example - dave789 22:28:46 12/11/14 (1)
- RE: defective active ground drive, for example - Thorsten 22:59:06 12/11/14 (0)
- it is very frequency selective. - dave789 21:59:09 12/11/14 (0)