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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
sns
3,265 posts
 

So many variables, difficult to have some overarching opinion. I run 845 and 300B amps, used to own 2a3 mono blocks. The 2a3 amps had this 'lit within' quality, read transparency the other SET's don't have quite as much of, but then 845 has massive drive the others can't match, 300B just right in my present setup, textured, so immediate, transparent, resolving, etc. IMO, transformers are most critical part in SET amps. I've also experimented with boutique caps and resistors, changes are easily heard in these minimalist circuits. My favs at this point are Duelund tin plated CAST, Texas Components TX2575 for clarity, resolving, Takman carbon film for musicality.

jasonbourne71's avatar
jasonbourne71
1,204 posts
 

The 6C6 is an older pentode (early 1930's) than the 6L6. The two are not interchangeable. Will Vincent (autospec) built my SET45 on an ST70 chassis using Emcron output trannies. A C6C drives a 45 for 1.75 watts out. Rectifier tube is a 5V4. I wanted a 45 SET after reading about the Yamamoto 45 in Stereophile some years ago. Will did an excellent job for half the price of the Japanese amp!

sns
3,265 posts
 

Neglected to mention power supplies as a major variable and critical part of any audio component. Look at internal photos of 300B, 2a3, 45 amps, you'll see relatively large discrepancies in capacity, large, stiff ps will be more authoritive, greater drive.  I tend to go with mono blocks for greater real estate and non-shared power trans. Any one example of these amps may or may not reflect others, ie, some 2a3 amps may drive speakers other 2a3 struggle with.

jasonbourne71's avatar
jasonbourne71
1,204 posts
 

I also have a Sanei 260A SET amp from Japan. In it I have a pair of gold-pin Electro Harmonix 2A3’s.

jasonbourne71's avatar
jasonbourne71
1,204 posts
 

A good source of knowledge about offbeat tube circuits/amps is Sound Practices magazine. Joe Boyd was editor. He liked flea-power amps (45, 2A3, 300B) with horn speakers like the Altec VOTT.

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