TOPIC:

I just received a new SHD. I upgraded to the latest firmware and reset the unit. No Dirac live calibration attempted yet.

Trying to compare the Hegel H390 internal DAC to the SHD's DAC by comparing playback through Coax out -> Hegel Coax in vs XLR out -> Hegel XLR in. I noticed that one of the channels is significantly louder on XLR than the other, even though channel mapping and attenuation is set at 0 dB. Swapping the input plugs on the Hegel (left vs right) results in the opposite channel being louder compared to before swapping the plugs, so it's not the Hegel. Is this a hardware issue of the SHD or am I missing something?

I can't quite follow what you're saying... Is the coax out you're referring to digital whilst the XLR is analogue, or something else?

It is normal for RCA (unbalanced) analogue outputs to be at a lower voltage than XLR (balanced), and it's entirely possible for the output level for the same output type to differ between the two DACs. (I use and SMSL DAC with my SHD and there's about a 1.5 dB difference in XLR output level between the two.)

So you say XLR 1 out on the SHD is louder or quieter than XLR 2 out when using 0dB on both channels and nothing else configurated in the SHD plugin or the new device console on the SHD?

Try using RCA out (should be the same signal than the XLRs) and check if it's the same.

Thanks for replying. RCA out doesn't show this problem, both channels have the same volume. No such problem with coax (digital) out either. The issue only occurs with XLR out, where one XLR channel is much louder than the other XLR channel. I'm aware that XLR in general is louder than RCA, but there should be no volume difference between the XLR channels themselves. Hope that clarifies my question.

One of your interconnect cables is bad.  Probably missing either the + or - polarity.  That would yield a 6db reduction in volume on that channel and be quite noticeable.

Dave.

Spot on! Thanks Dave.

Interestingly enough, measuring the cables with a multimeter showed no problems, but when comparing the cables separately (i.e. cable 1 on DSP left out to amp left in, cable 2 not connected vs cable 2 on DSP left out to amp left in with cable 1 disconnected showed the 6 dB sound level difference you mentioned. Thanks for your help!

Eberhard

I'm confused by your explanation, but it seems like you found the issue.  Good deal.
The issue could be either a break or a short in the cable.  So, a pin-to-pin ohmmeter check might have shown okay, but a continuity check between Pin 1 or Pin 2/3 might show a short.
And, it could be intermittent too. 
It's important to approach this sort of thing methodically and not get confused when doing swap tests.

Dave.