300B, 2A3 experiances wanted


I took the plunge and bought an Elekit 8900 which I plan to assemble later this year when the weather here in the Northeast starts to get too nasty to be outdoors. I have not bought the tubes yet and would greatly appreciate hearing from any of you who have direct experiance with this amp and the tubes it takes. It will be played into, at different times, Klipsch Heresy 1's, homemade open baffles featuring Lii Audio F15 full range speakers with no crossovers and maybe even my KEF LS50s on occasion.

I like detail, texture and tone as well as a sense of space and air. Generally listen to acoustic instruments in the jazz and classical traditions, 80-85 db being plenty loud for me. I'm interested in what you think are the best bang for the buck tubes as well as some that might be on the aspirational side.

My prior tube experiance included a Dynakit ST-35 amp i build last winter and a Decware Zkit SE84 I put together the year before that. I find the Deware strangely enchanting but a bit noisy, and the ST-35 is clean and clear but, perhaps because it is a push-pull design and and not a SET, sometimes not as magical as the SE84. Kind of hoping that the third tube amp, Elekit TU8900,  with the right tubes might be the charm. I might mention that I plan to build it stock initally but might consider investing in alternate caps and output transformers if the vaunted 300B/2a3 lives up to it's legend.

Thanks for sharing your knowledge.

Ag insider logo xs@2xbruce19

Joe Boyd of Sound Practices liked the 45 better than the 2A3. He also liked the half-power sibling of the 45 - the 71A - good for a mere 3/4 of a watt! I have some in my tube collection.

@jasonbourne71 I think you're referring to Joe Roberts. Otherwise, all your comments about Sound Practices are right on target. A very worthwhile magazine and reference for the ages.

BTW, for those who might be reading this thread but unable or uninterested in building a kit, Alan Eaton sells beautiful sounding 45 amplifiers for a very reasonable price. I have a pair of his monoblocks, which IMHO is the way to go with his amps.

Lol, I was reading Joe Boyd and thinking he was the producer of the incredible string band and a bunch of other British folk rock type bands. Thanks for the clarification, of course there could’ve been more than one Joe Boyd, I suppose :-)

I apologize! It was Joe Roberts who was editor of Sound Practices. Joe Boyd was indeed a record producer. Blame it on my old brain which is not getting any younger!

I have had a 300B amplifier with a 6f6 driver for many years.

I upgraded and rebuilt it many times.

What was an essential upgrade is adding an interstage transformer between driver 300B instead of RC coupling.

My experience shows that monoblocks are not essential for good soundstage and imaging. It is enough to isolate right and left channel power supplies by LC or even by RC filter. It gives enough channel separation except sub bass that is not important for imaging. But sub bass isolation is super important for the driver to output power supply. Otherwise we get PS feedback between output and driver and as result motorboating that leads to loose bass. As a result, it is better to separate driver and output power supplies.

Another important subject is power supply capacitors quantity and quality. The same thing is important for cathode bypass capacitors.