Where in my sound chain to put the DSP box?

[One and a half]

@992Sam, the DG-58 is now replaced with the DG-68, the new Accuphase model has some very worthwhile improvements, sometimes, it's not so drastic. For instance the 2020 pre-amps have improvement to the S/N some  5db or more, that's considerable on paper, would you hear this..some would suppose :)

 

The Accuphase product is designed for the long term, 15-20 years about the minimum expectation, my vintage E-205 (bought 1988) integrated amp still works. Don't feel that the new model is a must have I need to point out, once an Accuphase model is no longer available from the factory, that's the end, no exceptions, they draw the line in the sand, and keep what's left for spare parts.

 

Your dealer may offer a very good price for the DG-58, hopefully more in line with the list JPN or AU prices. The US prices for Accuphase are way too high artificially, another topic. Even if there is a AD/DA conversion, that impact is minimal. What would be worse (IMHO) is to place DSP at the source computer, despite the infinite number of taps, digital domain bits is bits blah blah.  When playing DSD, the DSP needs to convert to PCM on the fly, so more processing, creating more noise. That system is completely bypassed when listening to SACD/CD in your case. 

 

The HS-Link is 'beyond transparent'. When playing SACD on a DP-720 and DC-950 DAC at home connected by HS-Link, regular digital (Roon/Lumin etc.)  can't come anywhere near the sound-stage, detail resolution and fatigue free, there's just no noise.  Was very close to pulling the trigger on a DG-58/68, but then Covid came along....