Best SET power amp below $5,000

@saulh 

I'm not trying to be cynical or argumentative, but to what 2022 designs are you referring? One way or another, current tube amps' designs are based on 1930 - early 1960 designs. Components may be upgraded, but the designs are hardly space age. And in the end, many still look for throwbacks, especially for tubes.

For about $5000, you can get a new Cary 300SEI SET running 300Bs. And as previously pointed out, Dennis Had who designed this amp when he was at Cary, has a line of SET amps for under $5000.

Audion has several SETs "around" your price point. The Elekits get good reviews are are relatively inexpensive.

I am down to one SET that is specifically matched to the speakers it powers. The rest of my amps are PP and are more interchangeable with other speakers allowing me to "adjust" the sound a bit.

What don't t you like about the sound you have?

curious if there is any technology advantage in newer products, holding their condition constant (ie comparing a 1950s era SET amp to a 2022 design, both in mint condition).

+1

The original was $6K(?) in early 2000, Now the Art Audio PX25 MK2 is $16K!

Like @larryi , there are very nice, if properly designed, push pull amps out there.  I'm using decware, which you have to buy on the secondary market if you don't want an 18 month wait.  I had an SE34I.5 which was excellent SET.  I upgraded to their ZMA, a push pull amp that is hard to distinguish sonicly from an SET.  Very happy with it.  While it can provide more power, the magic still happens in the first watt.  Stay away from the mass produced push pull amps. 

Low power SET amps are among the oldest circuit designs, with little new ground broken other than new cases, perhaps better choices of parts and sometimes less ideal tubes used as more common ideal tubes have their good old stocks used up be expensive to supply. So I certainly wouldn’t think aboit newer versus older too much, focus more on the quality of the company or person making the amp.   Older amps can have some caps get old and need some servicing to play music well.

Go to Amazon, search: single ended 300b 805 845 amplifier, and select display as highest priced first.