I did some loopback testing on my Xonar U7 (non-MKII) to determine the optimal signal level to drive the ADC with, when I noticed that the right channel has a lot more noise than the left channel.
94dB vs 70dB is quite dramatic. Of course I switched cables and flipped the L and R signals driving the ADC around. The problem still persists.
With no signal present you'd think everything is okay:
Does anyone else here have a U7 that does this? Did I break mine? Can this be fixed? I'd love to hear what you folks think as I really like this interface otherwise.
94dB vs 70dB is quite dramatic. Of course I switched cables and flipped the L and R signals driving the ADC around. The problem still persists.
With no signal present you'd think everything is okay:
Does anyone else here have a U7 that does this? Did I break mine? Can this be fixed? I'd love to hear what you folks think as I really like this interface otherwise.
It gets more weird. Just unplugged the thing and plugged it back in again. The left channel got a lot better, the right channel got worse.
Sure looks like something's dodgy. But what could it be?
Sure looks like something's dodgy. But what could it be?
Is that card connected to the desktop computer with grounded connection?
Is that card connected to notebook with power supply connected to the grid? Your power supply for the notebook have ground connection?
Your measuring equipment have ground connection?
After this questions and answers you can conclude that maybe ground loop is present.
If maybe it is notebook try measurement without power supply connected.
Is that card connected to notebook with power supply connected to the grid? Your power supply for the notebook have ground connection?
Your measuring equipment have ground connection?
After this questions and answers you can conclude that maybe ground loop is present.
If maybe it is notebook try measurement without power supply connected.
Good call, I'll retest on battery power. I had just assumed that a ground loop would show up on both channels, not just on one, as the line input is a TRS jack with shared negative terminal. But I never actually bothered to test this. Thanks for the hint, I'll give it a try.
Why I was written this? Because I had something similar on my system when some noise is present on right channel and on the left it was much quiter. This noise was because of ground loop (when I removed second audio source from same power supply, the noise has gone, so I reconnected the audio source and the noise was present again, so I was sure). Audio gnd is from same point (RCA gnd is from same point) as your TRS connector.