Depends where you want to use it.
...and the effect you wanna get.
The SM57 has been mentioned as it's often used in studios
for that purpose, and it's cheap. It'll get the job done.
...but it has drawbacks
1) Shure mics are inconsistent to an extent that's unusual in
a mic considered to be a standard. There's a lot of variation
in how they sound. (to be fair, part of that's down to their
reputation for robustness...they tend not to get looked after, then they degrade)
2) A mic that colors the sound so considerably works best if it's only used for
one or two elements in your final mix.
3) It's not a good option as an all round mic, in case you wanted to
use it other stuff too.
4) If you want to try the mic at a further distance from the amp
to capture ambience, and get an alternative tone for recording, then
a less colored mic would be better.
Of course, none of those drawbacks is necessarily a deal breaker.
An alternative would be a decent small diaphragm condenser, something
by Rode, Octava, Beyer Dynamic. That would give you a more accurate
representation of the amp (not necessarily what you want), and
could be also be used for recording more or less anything.
Make sure you spend time finding the best mic placement, that
makes all the difference. Distance, position and angle.
My favourite is to use a condenser about an inch away on the edge of the speaker cone.
Paul Richards wrote:
In the past, I've always had guitar amps with some output capability to route the signal to a looper, recording device, et al. I'm about to get a small wattage Marshall (Class5 - 5W) with no output feature which means I will have to mike it up. Any suggestions on a reasonably priced microphone? THX!