Originally Posted by Krazywaffle
Would it be ideal to use 518 to reduce gain so that 568.2 runs closer to 87 (unity)? Is this reduction in gain by 518 any different than just reducing the output volume from computer source (only digital source with volume control)?
Best practice for gain is to maximise the channel use and only attenuate when needed, so keep the levels high to maximise S/N and attenuate at the end.
I beleive the processors use a hybrid analogue / digital attenuation; once you drop the level a few dB, analogue attenuation is applied and the digital signal is put back up to 0dB, keeping the the benefit of all the bits.

Originally Posted by Krazywaffle
To clarify, when DTS sources trigger Bypass (via DTSCD setting) in Type 1 this still applies twin PLL de-jittering to signal? On page 20 of 518 manual it states: “Bypass transmits all 24 bits on the input to the output without any processing”.
The twin PLL de-jittering is always applied, the processing is gain / dither etc.

Originally Posted by Krazywaffle
So it seems the question is: is DTSCD mode (DTS displayed on front panel) the same as Bypass mode (wherein all front panel controls are disabled)? If so, then it seems that the 518 does not de-jitter DTS signals as these are automatically bypassed.
See above.

Originally Posted by Krazywaffle
For example, does switching from Emphasis to Gain via front panel actually apply this change to the signal?
Yes; you may need to double check some of the settings in the set-up to make sure they are enabled correctly (been a few years since I've set up a 518!)

Originally Posted by Krazywaffle
Switched mine to Gain mode tonight and can’t hear any audible difference when switching from Flat to Shape A. Haven’t listened closely to High Pass or Shapes B-E yet.
To be honest, even with critical listening I couldn't hear the differences between the dither settings; maybe the 568 afterwards negates the differences and if the 518 was used straight into a DAC they may be more noticeable...

Originally Posted by Krazywaffle
Rearranged my setup and now have a different DAC connected to 518 via AES/EBU using XLR-to-RCA interconnect. Looking forward to A/B comparisons of this DAC (PS Audio Digital Link III; 24/48 input up-scaled to 24/96) versus 568.2mm (also up-scales 24/48 from 518 to 24/96)
The 568 will go 24/44.1 to 24/88.2, it doesn't look like the PS Audio does 88.2 or 176.4, so it may not sound as good as the 568, but it may well do a good job of non integer upsampling.

All the best,

Steve