Thanks for the IDE cable pointer; my unit is still completely original, including the "warranty void if broken" seal! Guess the time has come to break the seal...

With regards to extra step for external inputs (aux, tuner) I figured that, in order for EQ and other stuff to work, these analogue sources would be converted to digital first.

I noticed that voladj or time alignment don't work with either tuner or extrernal input, thought this was perhaps a limitiation of Hijack...

So, this means that tone control for tuner and HD is done in analogue domain?

If I can't get the sound quality to improve, I'll have to consider Eutronix' digital output kit and a small outboard A/D converter...