I know this is sounds crazy and insufficient power for subs, but if I were buying a "cheap" amp for my passive sub, but want something very high quality that could last 30 years, I would get the ATI AT1202 amp for $680 shipped new (dealer) or b-stock for $600 + s/h on CAP. It is rated for 180W into 4 ohm @ 0.03% THD, so 1% THD would be closer to 300W, which to me is more than enough.
It does have 12V trigger and gain/volume control for each of the Ch.
And it is ATI - the company that makes amps for Mark Levinson, Lexicon, Theta Digital, Cary Audio.
Should last you 30 years.
