Using a mixer as a pre-amp is acceptable, but i dont think it would be as good quality as buying a standalone pre. You would get a much better tone..unless you maybe you bought a really good mixer
Mixers have their own preamp in every mic inputs, but the quality may be a little less compared to stand alone pre amps. So it depends on your project and budget.
Well i hope there's a difference. I'm using $165 aus mixer for my pre's and am about to buy a Sp VTB-1 pre-amp which is around $500..so i'm hoping it sounds alot better!
Good mixers have good pre's. If you want to tap just the pre-amp then run your signal into a channel, via an xlr or 1/4inch plug and insert a 1/4 inch cable in until the first click on the insert plug for that channel. **** this assumes that your board has inserts on the channels (insert = single jack with send and return) and that they can be used as direct out's, tapping into the signal after the pre-amp and before the eq and fader****
This leaves you with one or two adjustments on your board before you tap the signal. On most boards you are left with just a "trim" or "pre-amp" adjustment. I think some NICE!! boards have a low cutt/hi pass control in the pre section. This woiuld be to cutt the very low frequencies that create rumble.
Anyway, good luck.
F.S.
PS you can run your signal through the whole board but most frown on that. to put it simple cause I'm tired, the signal is not as pure when ran though the whole board.
Without comparing specific models this thread is next to worthless
Some mixers preamps are better than some stand alones and vice versa. If you are talking about a Behringer mixer than most stand alone pre's are better.