The Millett MiniMAX is a terrific amp, especially if you were able to pick it up for $150. That's a steal!
I've been comparing a MiniMAX, Schiit Asgard, and a MAD Ear+ for the last couple weeks (been in the process of upgrading my system for the last couple months -- even had an EF2a a few months ago too).
The Asgard is great for the price, but the MAD Ear+ beats it in every area, except maybe build quality. I bought the Ear+ used and it arrived broken, so maybe I have a little bias there. The MiniMAX is a different animal altogether.
I actually like some aspects of the MiniMAX better than the Ear+. It definitely brings out a lot more detail than the Asgard or Ear+, but it just doesn't have the tubey warmth of the Ear+. I like the warmth -- find it more fun of a listen.
Tubes seem to play a huge part in the sound of the amp for the MiniMAX. The pair that came with it (bought it built, used), RCA 12FK6 were waaaay too bright to listen to with Grado SR-225s. I ordered another pair from Beezar, Tung Sol 12FM6, and these pair great with Grados (both SR-225 and RS-2). I still find the amp maybe a bit too bright for use with Grados. I thought it sounded fantastic with Sennheisers, but I bet a good OTL amp like the Bottlehead might be a better match. And even though the MAD Ear+ was supposedly voiced for Senn 600s, I didn't like the combination.
So in the end, I believe I'll be keeping the MAD Ear+ and getting rid of the MiniMAX and Asgard. Especially with the ability to upgrade the Ear+ to an Ear+ HD where things apparently get even better. I'd like to keep the Asgard as it will eventually match so nicely with the Bifrost I have on order, but ... gotta go with what sounds best I suppose, and I have no need for multiple amps :)
