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.
I share the same preferences as cfarrow. I like the 45 too, but, as a tube for a SET amp, it can be used for only very efficient speakers. A dealer who builds his own house brand amps used to build his pushpull amps to run 2a3 tubes quite conservatively; those same amps were used by some customers to run 45 tubes. The 45 were being pushed hard—high B+ voltage—so they did not last long (about a year or so), but the amps did sound good.
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I have a TU-8900 with the Lundahl transformers and Gold Lion 300B's driving my AG Trios and am very happy with this combination, having had many amplifiers in the chain. At the price point of the TU-8900, nothing comes close. Despite the high efficiency of many horns, I have found (IMHO) that you really need more than 3 or 4 watts to drive them full range, hence the advantage of the 300B over the other tubes mentioned in this thread. Good luck with your project. |
Agreed on power needed for what would be a true full range sound(lubachl). I recently parted ways with a pair of Zu Druids V that were rated I believe at 101 db efficiency that I just didn’t get the sound I was looking for with my amps. I replaced them with a pair of hORNS Mummy’s rated at 93db and the sound opened up quite a bit for me in my listening room which is 18x14. It’s a fine line between having enough power with any of the tubes we are talking about and what speakers you use. I prefer a full range sound with in room dynamics of 65-80db. 300b’s will give you that extra power you need unless you sit in a more near field position. |
The TU-8900 is an excellent choice. I think I heard a stock version. Your plan to do subsequent upgrades if the basic amp sounds good to you is the right approach. The parts that the distributor--Victor Kung--offers and suggests are very good choices. I would start with a transformer upgrade--this, more than anything else determines the sound of an amplifier. The option of silver foil Audio Note caps is also enticing--these caps deliver a clear sound without sounding thin or harsh. |
@alexberger so you added an interstage transformer into a 300 B amp that originally did not come with it, if I understand correctly. What amp was it and what kind or what model transformer? Did you determine the specs for this or did someone else? I would like to learn more. |
