It ain't that critical. Thirty watts will bee fine. Whether it is PMPO, PMPILS, RMS or average doesn't matter. An old Marantz receiver maybe, or some small Sansui or something from the 1970s or so. They are out there for reasonable money. some have been restored and go for big bucks but most of them will run alright for a long time without a restore. They are all of ever eBay, as long as the seller says that it is tested and working. If you don't fix **** obviously do not go for the ones that say "for parts or repair".

And Craigslist. If the guy says "You can hear it run at my house" it is not a robbery. When you first walk in there, leave your money in your car. And if you buy tell the guy the money is in our car, he can walk out there with you if he wants but you will be right back cash in hand. But all that **** is for high end items, you want a 30 watt amp you should spend, on an unrestored but working mid fi amp maybe fifty bucks.

There are makes and models that command alot more bucks but most people do not need them.

In the audiophile realm, there are 30 watt amps that go for five figures. If you were looking for that, you would not have asked the question you asked. So I am thinking of those mid end fi things that me and my "rich" friends shunned, but really did sound good. You would probably be happy with an MCS, which was a JCPenny house brand with some of them maybe being built by Rotel or whatever. Or a Radioshack, which seem to be gaining popularity among mid audiophiles.

Really, 30, 40, 50, even 100 watt amp, when you hear it start to stress out, back of the volume or you fry the speakers.