Compact ~20WPC Tube Amp

If you can find a Dynaco ST35, its a lot more linear amp than its bigger brother. But it makes about 17 Watts/channel.

SETs tend to have a limited amount of what I call 'usable power'. By that I mean its usually not a good idea to push them past 20-25% of full power. Based on your comments your speakers are nowhere near efficient enough to work with your SET.

If that 96dB number is real, your speakers are similar to mine which are 98dB. I find that I need a bit of power; at least 30 Watts. I have an average room, so I suspect you'll need at least that much.

So the amps you are looking for (if you stay with tubes) will be PushPull. They tend to have a much higher amount of 'usable power'; usually close to 95%.

The ST70 is not a bad suggestion in this range; the RM10 is another good one. Either should be properly refurbished. Another amp that might suit is the Harmon Kardon Citation 2 if you can find one refurbished. They make about 60 Watt/ch.

Another vote for Quicksilver.

And another for the Quicksilver Horn Monos!

agree with jasonbourne52 seek out a ST-70 properly refurbished.  I bought a new custom build recently from retroaudio on US audiomart for peanuts just to have a tube amp to rotate and it's more enjoyable in my system than my previous RM-10.  He's restored hundreds of Dynacos for decades and knows his craft.  He does ST-35's as well.

http://glowinthedarkaudio.com/chris-keller-st70.html

@atmasphere

Based on your comments your speakers are nowhere near efficient enough to work with your SET.

Which leads me to suspect that the 96 db sensitivity rating is exaggerated or (More possibly) the speaker’s impedance curve and load just isn’t suitable for an SET 300b.

My speakers are 94 db but a 14 ohm impedance with an appropriately designed/damped woofer to not require much amplifier DF (Damping Factor). They literally sing with my 300b SET mono blocks and replaced the previous 100 watt amplifier.

So, much depends upon speaker design and intended use.Push pull tube amplifiers will usually have lower output impedance and thus higher DF. Also generally they utilize some degree of NFB which increases DF.

Most SET amplifiers are zero NFB (Or very low) and will require different/compatible speaker loads. OP’s speakers just need a good quality push pull amplifier and they’ll do well.

Charles