Anemic Musical Fidelity A300

Thanks to everyone for the input. Back to AA it goes!

With 85db and 88db speakers with a normal load, the volume at 12 would make you deaf sitting 10 feet away. I'd say call AA immediately.

Don't know about your amp in particular, but FWIW I have had an experience buying an MF demo piece from AA and having it show up with an operational defect (which I returned for AA to fix themselves, but they didn't succeed and I had to do it myself - and my problem might well have been simpler than yours seems likely to be).

I have an A300 and I don't recall ever having to turn it halfway up to get decent volume though, frankly, I don't listen to music as loudly as I did when I was younger. I have B&W N804's and don't know the relative sensitivities are or how loud you like to listen, but it sounds odd to me.

As for breaking in, I would have thought that a demo unit would have already been broken in. Doesn't AA have a 30 day return policy that they are pretty good about? May be worth talking to them.

This amp does take some time to break in, but the volume issue is a little strange. At 12 o'clock it should play very loud with 88dB/W/m speakers (like the ones you have).
Assuming all the connections are correct, the next place I'd look would be the input. What source do you use? If it's a TT, is the right phono input selected (the MM/MC switch on the back?) If it's another source, does it have a proper output level? If you have any other components connected to the tape or preamp outs, try and disconnect them and see if it helps.
At any rate, this does not look normal. You should probably contact the vendor.