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.
@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. |
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. |
Good point: the 300B driven by an interstage transformer is a completely different animal than a 300B driven by RC coupling. From that perspective, an IT is almost mandatory to hear the full potential of the 300B tube. By contrast, the 45 and 2A3 are much easier to drive, and RC coupling works a lot better. (RC coupling typically throws away 1/3 of the power of the driver tube, while transformer coupling is about 95% efficient. Big difference.) |
