Okay, I'll explain my set-up, but don't make fun.
I track a guitar through a SansAmp (the cheap one), sometime distorted sometimes not.
I track a bass through a DI box.
I track an Alesis drum machine straight into the 424.
I track a Yamaha keyboard (the cheesie kind) through the DI box. The direct out from the keyboard is a little noisy, but it's the source of the 2nd gen problems
I track a melodica through an SM57 that's plugged into the 424
I track a harmonica through an SM57 that's plugged into the board.
Now I'm experiencing the 2nd generation problems on things that have 1, 2, 3, and/or 4 tracks. None of the masters have internally bounced tracks.
When I record a track, I do push the signal pretty high.
I'm mixing down to one of those Sony "Executive" mini component systems. I can't adjust levels on it. But if I just record a CD to a tape inside it, the tape sounds fine. I run from the RCA master outs to an MD/Video in on the Sony.
When I monitor the outs from the 424 on the Sony they sound great. I know the fidelity of cassette multi-tracks is never going to be great, but I also know there are a lot of people getting great results (P.J. Harvey, Tobin Sprout, etc.). And I've gotten to the point where I can imagine that. My guitar with no effects can sound really, really great on this... until mixdown.
I'm using Radio Shack c-60 tapes, I forget the particulars. But again, they sound great in the 424.
I'm more than willing to invest in a better mixdown deck (even if it would mean getting an amp and some monitor speakers... I'll need that eventually when I upgrade to digital).
Sorry to go on and on. Hope this helps.
Thanks,
Clark