Most desirable vacuum tubes for SET amps

The best sounding SETs are the ones with the least amount of power. This is due entirely to the output transformer- the differences people talk about between the various tubes has more to do with the output transformer than the tubes themselves. Once you get over about 7-8 watts of power it gets extremely difficult to build an output transformer that has full frequency bandwidth- and as a result many have compromised bass response on that account.

So back in 1990 there was a mystique around the 300b; by 2000 the 2A3 had ascended the throne and these days its the type 45.


If you really want to hear what any SET does, that will best be done with a set of loudspeakers that are efficient enough that the amplifier is never asked to make more than about 20-25% of full power. This is to prevent distortion, in particular the higher ordered harmonics, from showing up on the transients present in all music. The ear uses the higher ordered harmonics to sense sound pressure, so when they show up on transients it tends to make the system sound 'dynamic' but its really distortion masquerading as dynamics.

+1 testpilot. Any one of the listed tubes can sound truly excellent if careful attention is given to speaker selection. The higher power transmission output tubes such as 845 and 211 can be magnificent  sounding in the hands of a talented/skilled builder.

Same is true of low watt 45,50,2A3 etc tubes. Ultimate results are fully dependant on the designer/builder and quality of the parts utilized. I just do not believe that any one single tube can be declared the absolute best. There are a multitude of factors to be considered.
Charles

yep, the best one is the one that sounds the best to you, the best implemented in the amp, the best matched to your speakers, to your room...

asking these questions -- what is the best speaker, what is the best dac, what is the best cable

ugh

Thanks everyone for these wonderful responses. I feel, 300B got a cult status & many folks are waiting for another batch from Western Electric.

on a side note, I didn’t ask opinion for ‘best’. I’m looking for opinion about desirable tubes. The ‘one’ which everyone is after. It could be for academic purpose.  Need not be the best. Again, it doesn’t matter whether it sounds the best in my system. The desirability has nothing to do with it. It’s what the general public ‘wants’ !!

Many swear by NOS 300B Western Electrics. But they have become rare and upwards of $5000+ a pair. My favorite are 45s in general the lower the power the more magic. But at 1 1/2 watts you need super sensitive speakers.