Oh Datty, the match the level trick again, humm woe is me, you see this were a lot of decent cdp's/dac score, low level detail retrival & resolution if you have a transparent systems it's easily high lighted at the SAME matched levels, and yes Balanced outputs are up to 6 db higher for sure, but then I can't tell that I'm deaf!!!!!. I can tell an Arcam cd 23 from a CDs2 or a Cyrus cd 7 sir in the same system, there not expensive, granted the level trick is used by a lot of manufacturers to 'help all' the process of selling
Output stages, are more than just op amps, but the whole section, the strong part is the weakest link, now a lot of pro gear uses switch mode psu's, which by the inheirent nature are good for small enclosed spaces and tight sections, but can have 'interesting effects on the sound', pro gear is basical stripp down to the bear bones good stuff, minimum fuction alledged max preformanace in a small say 1 or 2u rack space to cope with the mounting of ADC/D-A's syn clock gennys, power suppiles /mixing desks, pro tools rigs, so quaint things are catered for, priorities lie in other areas I feel.
Oh, you be surprised at what we do, £70 dvd players, bang per buck they are fun, a lot can be extracted from these, not every thing is wadia my good man, we even do the naim
player

(Really)
I understand where your coming from, it's a fair point, but a lot of even half reasonable gear, does have it's own sonics even at lowish levels, granted if you were listen at very low volume levels, only a serious player would stand out, and then not by much.
However, at these listening levels, church mice would need tones ear trumpet I feel. Wm