I do this quite a bit, but it requires an OBSCENE amount of time at sound-check...
If you're multi-tracking, just go out of the "DIRECT OUT" on each channel and ignore everything else below.
Assuming you're using an AH with enough AUX sends (2200 maybe?) and you can spare two of them, use AUX 1 for LEFT and AUX 2 for RIGHT (or 3&4, or 5&6). Plug the aux sends into your recorder...
These need to be POST fader - Flip that switch if you need to...
Once you can get a decent sound check, even if you're running the mix in mono, you can use the aux sends to build a separate, stereo mix. Both aux's will have to be at the same level to achieve a center (vocal, snare, kick, bass...), but you can manipulate the 2 sends like a "manual pan control" to build it up. Monitor the headphone out on the recorder. If you've got one handy, going through a bit of compression wouldn't hurt too much.
The taper on most AH potentiometers will give you unity at around "7" for full left or right (drum overheads, dual guitars, B-Vox wash). If you're sending mono, you'll get you level (BOTH knobs now...) at around "4.5" or "5" (stereo pan law... long story). Of course, if you want something "tilted" to the left or right, start at "3" on one and "6" on the other or so.
I know that 's a lot to take in if you've never tried it. But if you have the time, you'll love it.
This may not get you an "album quality" live recording, but it'll sure beat the FOH mix that you'd get through the tape-out.
John Scrip -
www.massivemastering.com