"normanstrong" wrote in
news:gg9tb.151521$ao4.482861@attbi_s51:

I have 3 AKG C451's, 2 Nak CM-300's and 3 RadShack PZM's. No Shure
mikes.

So far as I can tell, mikes vary in noise level, frequency response
and output impedance. As long as the preamp has the right impedance
level for the mike used, has a smoother and more extended frequency
response than the mike, and adds little noise to the self noise of the
mike, it should be good enough. Anything else falls into the
category of mystery; I don't do mystery. If you feel I've missed
something pertinent, please feel free to correct me.

I have 451's and traded up from Mackie to Great River preamps. There is an
audible difference, particularly at quiet levels.

Things that better preamps do better (that you can easily measure):
* More headroom. Lets you stretch beyond 20 dB gain without breaking up
* Better loading. Get more out of dynamic and ribbon mics.
* Better phantom power. Produces more gain and runs more mics.

If you're recording a loud, noisy source on a single condenser mic close
up, the Mackie will sound almost as good as a Great River.

What you can't easily measure is the lower distortion and noise levels that
let you pull more detail out of the microphone. Anything with subtle
nuances, like a single voice in a quiet studio, benefits from the clarity a
better preamp produces. The difference is more noticeable when the source
being recorded is familiar to the listener (again, like the sound of a
human voice). Accuracy counts.