The John Hardy Company M-2 Mic Preamp Two Channel with 20 OHM MIC by RobAnderson
The John Hardy M-2 is simply one of the best-sounding mic amps I have used. It is configurable in many ways. The package I have includes a 20-ohm mic switch and the optional metering and Jensen output transformers.
The main features of this particular mic amp are the Jensen mic input transformers and the Jensen 990 op amp. I heartily recommend the Jensen output transformer as well. You can order an empty 4-slot single RU frame and fill it as you like, so if ordering four channels with all the trimmings is out of your budget, you could simply start with one or two channels and fill in the rest later.
There are individual and chassis ground-lift switches that can be a life-saver in the live recording realm. Also the better CMRR performance offered by a good input transformer over a straight-up electronic differential input in this sort of situation is an added benefit. The mic amps themselves are quiet even with gobs of gain, and the headroom is quite good. They sound great even when pushed quite hard. Because there is no shared motherboard, the crosstalk between channels is basically non-existent.
The sound quality is astounding. These mic amps are equally at home amplifying a classical main pair (the 16-position stepped gains are quite handy for stereo recording) or being driven to their limits on close mic's - they excel for drum overheads or for winds and brass, and for vocals as well. It sounds wonderful on strings. I hate to use such metaphors, but they seem to induce a juicy fatness to everything that passes through them.
The 20-ohm mic switch can be replaced with a pad instead - something worth considering as the lowest gain setting is +15 dB. I ordered mine with the 20-ohm switch because it helps to optimize the input impedance for very low-z microphones such as Schoeps, which is my primary use for this mic amp. The difference is very subtle, but there seems to be some increase in clarity when it is engaged with these low-z mic's.
The only thing this mic amp does not excel at is dirty guitars - it sounds too good! if you are looking for aggressive Neve-ish or API-ish coloration, it will not deliver. Nor will it give the unforgiving etched detail of a Millennia. It has its own sound somewhere in the middle - a clean, glossy, deep shine as opposed to the sparkly brilliance of the Millennia, and a pleasant beefy smoothness in the mids, not so aggressive as an API.
I can't wait for a 500-series version, which is reportedly on the way. Kudos to John Hardy for making such an outstanding product.