Amps that don’t impersonate space heaters.

You need 1 very good watt to drive those speakers. Even Class A, 1-5 watts may remain extremely inefficient but if you you were to take say a 5w PX25 amp, it will burn off 15w x 2 instead of 90w.

Flea watt tube amps are the way to go.

A good class D amp can sound even better and despite being able to make considerably more power, actually draw less power at idle and at any power level the amps mentioned in this post can make. At the same time it can be stone cold to the touch even after running all day. Plus there’s a good chance a class D set of amps would take up less room and would certainly weigh less. Literally no downside.

One recurring theme I encountered in researching this phenomenon is that bass roll-off is a common trait among amps employing zero global feedback.

@helomech I've seen zero feedback amps that go full power to 1Hz and don't seem to lack any bass at all. IOW its not a common trait.

@hoosierinohio Agreed, but I run a class D because of its sound quality. The low heat and energy draw is a side benefit.

There have been some epically hot periods in metropolitan Chicago this summer. I have had a long running affair with a pair of Avantgarde Uno s2’s and don’t really require a great deal of power. I have two dissimilar but equally compelling amps (a Pass 30.5 and a BAT vk-56) both prodigeous producers of heat creating a sauna like environment in my library/listening room the HVAC system not withstanding. What, if anything, have you boys and girls found that might replicate the qualities of my beloved amps minus the potential for 3rd degree burns and heat prostration?

@williamjohnston If you don't like the heat consider a class D amp. There are some now that rival class A tube or solid state amps in terms of sound quality (with a very good first Watt)- no harshness and actually lower noise so no problem running on horns. I have a set on my speakers which are 98 dB. They replaced a set of class A triode OTLs. I don't miss the tubes at all.