What is the best 2A3 SET Amplifier?

Hello all,
I am searching for the best 2A3 SET Amplifier for my Avantgarde 2.1. Please advice.

I own a Triode Lab 2a3i FFX that I simply love. The sound is pure, clear and unforced. It's quick and no frequencies are rolled off. I have a hybrid D class integrated with a tube front end if I'm feeling the need for a power player.

I don’t see there are any corelation between them and the current designers or copiers.

@edle The US was first to move away from SETs because superior technology appeared, developed in the US. Although SETs can be fun, they really don’t stand up to a other, later technologies, even on easy to drive speakers like the Duos. If you are looking for the nth degree in neutrality and musicality look elsewhere.

One problem is any SET that is zero feedback has only about 20-25% usable power with respect to full output. This is because if pushed past that power level, any zero feedback SET will start to sound ’dynamic’ due to distortion appearing on the leaded edge of musical transients. This is a problem unique to SETs. In a smaller room this would allow Duos to work with a 2A3 amp depending on the music.

Another problem is poor bandwidth, which results in phase shift at either end of the audio spectrum. Phase shift in the bass is heard as a lack of impact in the bass. Phase shift in the highs is heard as a darkness. Usually 2A3s are pretty good about bandwidth, but to really get it right without feedback you need full power bass response to 2Hz (to prevent phase shift at 20Hz) and the highs need to go to 100KHz (to prevent phase shift at 10KHz).

There are tube amps that can do 2Hz full power but they aren’t transformer-coupled.

That said, Whammerdyne hasn’t been mentioned yet and is one of the best 2A3 SETs I’ve heard.

But you can do better than any SET on the Duos. There are even class D amps that more than give SETs a run for the money- every bit as smooth, more detailed, yet relaxed and involving.


Whammerdyne hasn’t been mentioned yet and is one of the best 2A3 SETs I’ve heard.

I was just going to post that my Whammerdyne DGA-1 uses ultrawide bandwidth output transformers. I think it sounds glorious. Running NOS tubes.