what do you mean bypassed?
as in traded for another pair of opamps (like you can do on Auzen cards), or bypassed as in wiring to the D/A's output (like some SPCH-1001 mods call for, or similar transport/player mods call for)?
why not just hook up to the digital outlet with a D/A that you can switch opamps on (like the Firestone Spitfire, for example) and change opamps until you find the sound you want?
going raw from the D/A's output, assuming you hit the right pins (not at all hard to do), and assuming you can cleanly wire it (this is tricky, unless you've got surgeon stable hands, in which case, again, won't be hard at all to do), will drop the signal quite a bit, the only concern I'd have with using an amplifier with the gain up that high, is clipping (will you push the amplifier into clipping, just to handle the lower signal, is what I'm concerned about), other than that, it probably should work quite normally
the only issue I forsee is the card still having the circuitry for the opamps, and still feeding them juice and signal (you can't actually remove the entire circuit path, since some of it is inside the card), so you might have some potential problems there (and I have no idea what to suggest as far as a fix)
SQ wise, well, that'd be interesting, I know on SPCH-1001 when people go raw from the D/A they note a slightly improved SQ, but the opamps on that aren't as good as the ones on the Juli@ (probably not by a long shot, given that we're talking about a 1996-1997 era gaming console), if you can afford to replace the Juil@ board, I'd say try it out and let us know what it does to the SQ, although I'm going to venture a guess, it won't do a whole lot the SQ, because you'll loose so much gain that all of the coloration/influence the opamps had, will be replaced with coloration/influence by whatever you use to bring the signal back up to a usable level
