Jedman said:
What makes a mixer able to be used as a multi - channel preamp, and what are some good value ones?...
Jed
Basically it depends what you want to do.
If money is no object you could just go out a buy a rack full of Avalons or whatever, but you haven't really made yourself clear.
If you just wnat to record one or two channels simultaneously then a two channel pre like
a Studio Projects VTB1 or the more expensive RNP will probably suit your needs.
If you want to record with a microphone then you need obviously need a preamp. How many preamps you need is dependant on how many microphones you need simultaniously to record with. Do you require EQ whilst tracking? Do you require flexible monitoring whilst tracking, do you want to add compression, limiting and FX etc whilst tracking. Will you need to mix a drumkit whislt tracking? If you do then you probably need some kind of mixer. As long it is not a line only mixer it will come with preamps.
Now to cut to the chase, all the references you've probably read about outboard pres stem from the fact the people either want higher quality pres (often only a couple) than the generic standard pres that come in most low to mid mixers, or they don't really need a mixer at all as they are just tracking direct into their PC etc and intend doing everything else in the digital domain.
However a rack of say eight fairly high quality pres will cost you more than an eight mic input Mackie or Behringer etc. and you won't have the flexibility of all the features a mixer offers... BUT you will probably have a better quality signal.
INSERT POINTS AND DIRECT OUTS!
Many mixers will allow you to access just the pres and bypass the rest of the signal chain if you tap into the insert point of the channel and then feed that direct to your DAW etc. This usually occurs before the EQ stage and while you can't tweek the EQ as a result, in the case of the Mackies with non-switchable EQ sections, will provide a better quality signal than going through then entire channel stage. Whilst the insert is usually used for patching a compressor or other device into the signal chain, the amplified mic signal can be accessed here and sent off to some other place thus avoiding any extra travel through unneccessary mixer circuitry that may not be required.
Other mixers have direct outs which are usally post fader and leave the EQ stage intact but won't improve the sonics that much compared with the direct out approach as the signal is passing through the entire channel strip anyway.
Another option over the standard Behringer/Mackie approach is something like an Alan & Heath Mixwizard. These are very flexible little consoles with nice sounding pres and EQ's and will give you both insert points AND direct outs to play with!
The Behringers and new Alto's are the cheapest but their bottom range units won't give you insert points or direct outs and they are really just entry level at the very least.
If you can scrape together the $$$ I'd consider something like a Mixwizard as it will give you enough quality features without going over board. Otherwise if you don't need more that a couple of channels simultaneously go for a decent quality outboard pre.
A word of warning though... two channels is NEVER ENOUGH!!
