I just spotted, that JJ has started making the 2A3!
http://www.jj-electronic.sk/
Max rated at 40W, 100mA (cathode bias) and 450V
Curves looks nice too!!I wonder if it's a single plate construction... Hope so!
Anyone know the price?
http://www.jj-electronic.sk/
Max rated at 40W, 100mA (cathode bias) and 450V
Curves looks nice too!!I wonder if it's a single plate construction... Hope so!
Anyone know the price?
The JJ239 was developed on request from customers from Southeast Asia and Japan after the 2A3-40W tube was introduced..
The 2A3-40W showed as having the best sound in the group of power triodes.
Like the 300B, the 2A3 has perfect linearity due to the design of the internal geometry. The sound quality however, is even better because the cathode heater voltage is only 2.5V and the filament ends potential difference with respect to -Ug is smaller than in the 300B tube. Therefore, a much bigger cathode area is active during operation. (The maximum current flows at the positive filament end.)
The ideal cathode heating current Ig would be, for example, 50A at 0.1V. The sound difference between 2A3 and 6A3 is remarkable.
Found this text on the JJ239 SE 2A3 / ECC99 amp...
The 2A3-40W showed as having the best sound in the group of power triodes.
Like the 300B, the 2A3 has perfect linearity due to the design of the internal geometry. The sound quality however, is even better because the cathode heater voltage is only 2.5V and the filament ends potential difference with respect to -Ug is smaller than in the 300B tube. Therefore, a much bigger cathode area is active during operation. (The maximum current flows at the positive filament end.)
The ideal cathode heating current Ig would be, for example, 50A at 0.1V. The sound difference between 2A3 and 6A3 is remarkable.
Found this text on the JJ239 SE 2A3 / ECC99 amp...
Prices found on
http://www.thomsonaudiodesign.com/parts.html
site
But they also ask $AU425 for a pair of JJ300B...
If I look at the http://www.ae-europe.nl/buizen_jj.htm site
the JJ300B pair would cost around US$ 207 (including VAT)meaning the 2A3 would cost the same..meaning US$ 207 for a pair..
Thus from AE-europe they would cost € 207... (Would you believe I sucked at maths when I went to school?!?)
Better?
Cheers,
Bas
PS...That would alse mean that a complete set of JJ2A3 + Chokes, Power Transformer and output transformers from AE would set you back just €450.. NOW we are cooking!
http://www.thomsonaudiodesign.com/parts.html
site
But they also ask $AU425 for a pair of JJ300B...
If I look at the http://www.ae-europe.nl/buizen_jj.htm site
the JJ300B pair would cost around US$ 207 (including VAT)meaning the 2A3 would cost the same..meaning US$ 207 for a pair..
Thus from AE-europe they would cost € 207... (Would you believe I sucked at maths when I went to school?!?)
Better?
Cheers,
Bas
PS...That would alse mean that a complete set of JJ2A3 + Chokes, Power Transformer and output transformers from AE would set you back just €450.. NOW we are cooking!
Bas Horneman said:
Thanks for the info Bas, but I think I'll pass. I can get a matched <i>octet</i> of Sovteks for that, and there'd be a few other things I think I'd prefer to try first. They'd wanna be <i>really</i> good!
Classic 2A3 circuits won't be able to take advantage of their extra dissipation, though they'd go into circuits where the 2.5V TJ 300B will work, so they're really only applicable to DIYers or purpose optimised circuits.
Cheers
Well, then, it wouldn't be a secret any more, would it?
Anyway, some very linear options at $100 max/80 w min/pair would include paralleled 6550s (very nice connected in triode), triple paralleled EL34s (ditto), doubled 6336A, doubled 6528A (the last two allow the use of a lower turns ratio, higher-bandwidth xfrmer), and about a million RF output tubes. Not to mention triple paralleled 6080-family, those odd Russian 829B lookalikes, paralleled TV sweep tubes...
Of course, they can't do the "perfect linearity" thing, but the ones I use from this list come damn close, closer, I'll wager, than those overpriced fashion DHTs.
Julius Knew This Already...
Hi,
Yes, they can...only you guys never bothered to measure nor plot it or so it seems...
In a typical OTL operation, provided you chose a linear OP point, the curves are just equally spaced horizontal lines...which is why Julius Futterman went through the extreme effort and expense of regulating the outputstage, so they're kept at that point at most of the power output.
Nonetheless, a typical OTL output stage is as linear as you can get.
Cheers,
Hi,
Yes, they can...only you guys never bothered to measure nor plot it or so it seems...
In a typical OTL operation, provided you chose a linear OP point, the curves are just equally spaced horizontal lines...which is why Julius Futterman went through the extreme effort and expense of regulating the outputstage, so they're kept at that point at most of the power output.
Nonetheless, a typical OTL output stage is as linear as you can get.
Cheers,
If There's One Person...
Hi,
The 2A3s are definetely overpriced, and not by a small margin if I may say so.
And I sit with Brett here that the Sovteks are much cheaper and probably just as good.
What I meant was that once put into service in a typical OTL cct most tubes gain in linearity as would most CFs.
My comment wasn't addressed at you in person, SY, it was meant to make people aware of the extreme linearity that can be had from OTL circuits.
Rest assured, I do " know you better than that"...heck, I think you know more, measured even more than I'll ever do...
What I wanted to get across was, if you value fidelity than consider OTL for the output stage is as linear as you can ever achieve, you can still xformer couple that ( the zero comes to mind), or if you're paranoid, you can even capcouple the output to the speaker... it will most likely still sound superior.
What Julius Futterman was aware of IMO is that to maintain this linearity he had to regulate the ouput as well, now that part is going to be as expensive as the entire basic amp.
If any of you ever had the chance to listen to Gizmos' OTL 1 amps I think you'll all too much aware of the importance of proper regulation.
No free lunch there,
Hi,
The 2A3s are definetely overpriced, and not by a small margin if I may say so.
And I sit with Brett here that the Sovteks are much cheaper and probably just as good.
What I meant was that once put into service in a typical OTL cct most tubes gain in linearity as would most CFs.
My comment wasn't addressed at you in person, SY, it was meant to make people aware of the extreme linearity that can be had from OTL circuits.
Rest assured, I do " know you better than that"...heck, I think you know more, measured even more than I'll ever do...
What I wanted to get across was, if you value fidelity than consider OTL for the output stage is as linear as you can ever achieve, you can still xformer couple that ( the zero comes to mind), or if you're paranoid, you can even capcouple the output to the speaker... it will most likely still sound superior.
What Julius Futterman was aware of IMO is that to maintain this linearity he had to regulate the ouput as well, now that part is going to be as expensive as the entire basic amp.
If any of you ever had the chance to listen to Gizmos' OTL 1 amps I think you'll all too much aware of the importance of proper regulation.
No free lunch there,
Frank: My first OTL was a pair of early (real, not Rosenberg) Futterman monoblocks with 12B4s. Great with my LS3/5As. He didn't use active regulation, but the way the transformers were spec'd and the overall design of the supply (biggish caps for the time) resulted in the regulation being pretty good anyway- no more than 3 or 4 volts sag under hard drive, and pretty low modulation of the rails by the input signal.
I wish I had thought about using a Circlotron when I did my first iteration of the 6528 OTL...
I wish I had thought about using a Circlotron when I did my first iteration of the 6528 OTL...
CIRCLOTRON...
Hi,
Unless you choose to opt for the balanced road all the way, I'd not opt for the Circlotron.
It looks good on paper but it still has to convince me of its virtues, at any rate we're probably doing better than the studio gear already.
Anyways, I feel we're threadjacking...well, that's how most people would see it I presume.
My mistake...
P.S. I pushed the Sovtek 2A3 to above 40W and they accepted it graciously...
Before anyone asks I'm running them at 35W now and I'm very happy with the results....Hey, that's my bedroom amp I'm talking about...
I always prefered the 2A3s over the 300Bs and I'm starting to learn why.
Cheers,
Hi,
Unless you choose to opt for the balanced road all the way, I'd not opt for the Circlotron.
It looks good on paper but it still has to convince me of its virtues, at any rate we're probably doing better than the studio gear already.
Anyways, I feel we're threadjacking...well, that's how most people would see it I presume.
My mistake...
P.S. I pushed the Sovtek 2A3 to above 40W and they accepted it graciously...
Before anyone asks I'm running them at 35W now and I'm very happy with the results....Hey, that's my bedroom amp I'm talking about...
I always prefered the 2A3s over the 300Bs and I'm starting to learn why.
Cheers,
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