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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.

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bruce19 OP
275 posts
 

Great input @glennewdick  on your tube experiences, I will be saving it for reference. The interstage transformer idea is a new one to me. I will be looking for examples of that implementation down the road if I fall under the 300B spell, but I have to be honest and say the cost of 300Bs is a deterrent, so I am liking what I am hearing about the 2A3.

Can I pose a broader question to you gentlemen of experiance with tubes? When considering the difference among different brands of a given tube such as the 300B or the 2A3 or Even the EL-84 would one reasonably expect to hear sonic differences closer to changing one's speakers or one's cables? In other words is the design of the tube more controlling of the sound produced or is it the execution represented by particular brands or models within a brand?

cfarrow's avatar
cfarrow
100 posts
 

I will chime in since you have already bought the piece of gear you are going to assemble.  I have 45’s, 2a3 and 300b amps-Triode Labs, 2a2, Yamamoto 45 and 300b and Coincident Frankenstein 300b and preferred the 2a3 over the 300b amps, better bass and treble and not far off a 300b on mids.  I used NOS RCA 2a3 and preferred them over any modern tube with better dynamics and better across the whole frequency band.  My favorite is the 45 but believe you can’t use that on your kit you will be assembling.   Congrats and good luck on the build!

sns
3,398 posts
 

Audio Note has IT 300B looks very nice.

jasonbourne71's avatar
jasonbourne71
1,256 posts
 

Check out the Bottlehead Stereomour 2A3 parafeed amp. There is quite a bit on diyAudio about this circuit topology.

kmtang's avatar
kmtang
25 posts
 

I used a simple transistor-MOSFET "Shunt regulator" to replace the RC (self-bias) in my 45, 2A3, and 300B SE amps. The sound quality improved significantly. All my audiophile buddies were amazed.

The very nice thing is that I can set the right amount of idle current of the power tubes. 

 

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