I hardly noticed AU-XII's heft in sound, compared with alpha 907 for instance, until I used it with a tube preamp with gains early last month. My AU-XII is now paired with Luxman SQ-38FD Mk II, which I was able to revive, in driving a pair of JBL 4430. The SQ-38 only had 30wpc (valve) power amp, which is too thin for my ears. When I paired it with the AU-XII, harnessed as power amp, the sound that came out of the 4430 was something else. SQ-38 has treble and bass gains plus turnover switches for low and high frequencies.
Congratulations! $180 is cheap for the AU-XII, I actually got mine at slightly lower price about 6 years ago. Me and Diego/EGP, here in Davao, have one unit each of AU-XII. Now we're three. I think there's also a guy in Laguna who once emailed me claiming he has this amp, but he's not a member of Pinoy DVD if I'm not mistaken.
A couple of years back, the guys in AK could hardly believe I have an AU-XII and that my unit has no oscillation problem. Some probably even thought I was the perennial scammer on US eBay trying to sell a ghost unit of AU-XII for a grand. I told them I'll never sell my unit (quite heavy and messy to peddle at US eBay) and that it is a common amp here in the Philippines.