Looking To Match A Tube Amp With A Pair Of Audio Note AN-K/Spe

Have certainly decided that a 20-40W pentode design is a good path. Keeping in mind the K's are in a 12x26 room go with KT 66, 77, or 6L6 for an "EL-84 tactile and immediate" kind of sound?

If it were me I'd be looking for an amp with Ultra-Linear operation since UL allows the output section to have the same linearity as a triode. Or find an amp that is actually triode. Push-pull amps that are triode, even using Directly Heated Triodes do exist.

Ultra-linear is nice since the power tubes usually used are easy to find. Since you don't need all that much power a 6L6 or EL34 based amp would certainly do the job.

He however, is squarely in the SET camp and suggested Quests given my price range and need for a dedicated power amp.

@scottya118 SETs have this way of more and more limited bandwidth as you increase power. Usually this means 7-8 Watts (usually via a 300b) is as much power as you can get and still call it 'hifi'. Since output transformer bandwidth falls off with power (its not the tube's fault!) usually its the bass octave that suffers as bass response is usually the hardest to get when designing an output transformer.

That is why I recommended a push-pull amplifier! A 20 Watt or even a 60 Watt PP amp will have wider bandwidth (for example the H/K Citation 2 has bandwidth past 100KHz) and will have much lower distortion.

To give you an idea of the latter, a typical SET is 10% distortion at full power (which is why you usually don't want to run them past about 20% of full power...). A PP amp might be 1%. BUT- and this is a big one- the distortion of the PP amp is considerably lower at the power level that an SET makes at full power! Depending on the amp, by a couple of orders of magnitude.

Distortion obscures detail plain and simple. With a good PP amp its no problem making out detail in the rear of the sound stage that you can't with the best SETs.

I know Vu, we've shown at audio shows in the past and he's a good guy, but in this case I think he's giving you bad advice: your room is a bit on the large side- and the Audio Note speakers are not as efficient as they claim IMO. That's why I recommend a bit more power than will be practical with an SET.

Just to be clear since the K's are in a larger room (approx 30 x 12) you would prefer a push pull configuration.

Definitely! In a room like that I'd want 50-60 watts. Also you might consider a subwoofer system to break up standing waves in the room below 80Hz. To do this the subs have to be asymmetrically placed in the room so the standing waves are properly broken up- that's not something you can treat with bass traps or DSP room correction, although once the subs are in place and doing their job, those things can be helpful. 

The only other caveat is that on several occasions, I've heard a bit of noise coming from speakers hooked up to Atmasphere amps, but in all these cases, the speakers being used were quite a bit more efficient

@larryi 

If you've had high efficiency speakers you know how careful you have to be about setup to avoid noise! We have a number of customers using AvantGarde and other horns with no worries. For speakers like that we offer a gain reduction plug that replaces a tube in the voltage amplifier. thus reducing the gain of the amp and pesky noises that can manifest upstream from the amplifier.

would Manley Mahi's be worthy of consideration? Both have the same power tubes (EL 84). Oto is 10W SET, Hahi is configurable to triode mode at 20W. So what's more important in considering amp/speaker matching? Type of power tube or configuration? Is there a concern regarding distortion at 20W? Any and all thoughts on this are welcome.

@scottya118 Although that speaker is an easy load for nearly any tube amplifier, I think you'll find that unless you are in a smaller room that its like a bit of power that a push pull amplifier provides, which will be very welcome- and less colored; more transparent. This is simply because at the power levels most SETs play, the distortion of a push pull amplifier will be dramatically lower, allowing you to hear into the rear of the sound stage with greater ease.