The above-mentioned ST-35 would be a very good choice, IMO.
David Hafler-era's all-round best Dynaco amplifier IMO. PP EL84 so only about 15 watts per channel (Dynaco said "17.5", thus the "35" in "ST-35") -- fine for some of us, but not for everybody.
The other option, if one doesn't mind investing some sweat equity, is to re-hab a nice
vintage vacuum tube amplifier. There were oh-so-many good ones. A Fisher X-101, HH Scott 222c or EICO HF81 will put you in a good place -- again, if their relatively low output power works for you.
It is -- IMO/IME -- hard to make a bad sounding amplifier using EL84 power output tubes, be it single-ended or push-pull.
Another option, out on the wild frontier, is to acquire and re-hab the power amplifier from an old tube console hifi. These amps tend(ed) to be extremely simple but some of them are still pretty darned good. I am a fan of the old
Maggotbox Magnavox console 'hifi' amps... but unfortunately, so are many other folks, so they're not cheap any more. Still, one may stumble across an amp (or whole console) in unexpected
places ---
Chance favors the prepared mind, as Louis Pasteur said.
Here's one that passed through here years back -- this is a push-pull stereo 6V6 amp from a Magnavox console that has been gently rehabbed and housebroken enough to use as a standalone power amp
About 10 watts per channel, and almost breathtakingly cheaply/simply designed and built, but these rascals make the most of their modest design and construction (IMO).
P1020244 by
Mark Hardy, on Flickr
P1020247 by
Mark Hardy, on Flickr
As Gertrude Stein said,
There's no "there" there.
They lend themselves nicely to
customization, too.
Souped up Maggotbox from AA by
Mark Hardy, on Flickr
(This pp EL84 Maggotbox amp is not mine, unfortunately)
I
would recommend the Bottlehead "Stereomour II" stereo single-ended 2A3 amp kit in an instant except 1) it's too expensive (although on sale at the moment) and 2) at ca. 3 watts per channel, it does limit one's choice of loudspeakers, program material, or "listening geometry"
I have a pair of the monoblock precursors ("Paramour") -- they were very simple and straightforward (and
cheap) kits and sound very good for their profoundly modest complement of components (particularly iron).
www.bottlehead.com
FWIW, these are the Paramours my kids and I built in the late 1990s. This pair, in kit form, was only $500, back then! The trick was using a parallel-feed output topology (where the DC component from the plates of the output tubes is shunted though a choke), allowing a hyper-cheap (!) line matching transformer to be used (backwards!) as the OPT. Not elegant, and the LF rolloff is pretty substantial -- but these little amps sound surprisingly good full range -- and would be superb treble amps for an active crossover, bi-amplified loudspeaker system
paramours 112413 by
Mark Hardy, on Flickr
There are myriad other kit and semi-kit (i.e., you buy the PC board, stuff it yourself and add transformers, wiring, and enclosure) options -- see, e.g.,
https://diyaudiostore.com/collections/kits
Gratuitous opinion paragraph:
Most of the
affordable modern stuff -- strictly IMO, of course -- ain't worth the space it takes up (except as a toy/curiosity).