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Old 17th September 2012, 02:14 PM   #51
palmas is offline palmas  Portugal
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Originally Posted by Tubes4e4 View Post
Hi Tweeker,



Interesting half-sentence in front. Two weeks ago I was given some boutique 300B (considered to be somehow "improved" 300B) to trace, and after sending the plots back to the distributor, he very angrily called me by phone, forbade me to publish those and mention the brand by threatening for lawsuits because it would harm the business. "With your plots you have done enough harm on business already anyway", he shouted. Oh well, some folks just canīt stand the truth, especially when it will have impact on their wallet.

But usually a good real (non-boutique) 300B, WE or not, is considerable more linear than a triode strapped plain EL34, hands down, indeed. Usually.

For those who donīt believe, they should stop repeating legends and pointing at stone-age plots, but should apply my tag-line and see for themselves.

Regards,

Tom

EDIT: A similar effect can be found with modern KT88/6550. Patrick Turner (Australia) did some interesting measurements with these, showing how off modern copies are compared to old original datasheet plots. Funny enough, everbody makes SPICE models after those old plots and draws load lines on those old plots and then, using current production tubes, wonders what is wrong .....
Need to replace my EH 300B drivers in my SET amp, because I find them too microphonic. Can you suggest a maker that produces good solid linear 300B?
Thanks
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Old 17th September 2012, 10:55 PM   #52
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On the original thread topic, here is a DHT pentode wired as a triode:
You can throw out your 300B's, these cost $3. (not quite the same Watts though)
Attached Images
File Type: jpg 1E7G.jpg (6.6 KB, 506 views)
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Last edited by smoking-amp; 17th September 2012 at 10:58 PM.
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Old 18th September 2012, 08:50 AM   #53
Yvesm is offline Yvesm  France
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Originally Posted by palmas View Post
Need to replace my EH 300B drivers in my SET amp, because I find them too microphonic. Can you suggest a maker that produces good solid linear 300B?
Thanks
My faith is that microphony iS largely responsible for the "famous" 300B sound.

. . . just MY faith.

Yves.
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Old 18th September 2012, 08:51 AM   #54
palmas is offline palmas  Portugal
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My faith is that microphony iS largely responsible for the "famous" 300B sound.

. . . just MY faith.

Yves.
Well I have a few and prefer the type that has less microphony, just my taste
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Old 18th September 2012, 08:52 AM   #55
palmas is offline palmas  Portugal
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Originally Posted by smoking-amp View Post
On the original thread topic, here is a DHT pentode wired as a triode:
You can throw out your 300B's, these cost $3. (not quite the same Watts though)
Wich one is that?
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Old 18th September 2012, 03:43 PM   #56
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4P1L?
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Old 19th September 2012, 12:06 AM   #57
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1E7G

1.5 Watt Dual Pentode (common cathode)

Looks like the price went up to $4 already.
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Last edited by smoking-amp; 19th September 2012 at 12:09 AM.
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Old 19th September 2012, 12:20 AM   #58
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where for $4?
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Old 20th September 2012, 09:08 AM   #59
palmas is offline palmas  Portugal
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Originally Posted by smoking-amp View Post
1E7G

1.5 Watt Dual Pentode (common cathode)

Looks like the price went up to $4 already.
That's a low voltage dual pentode that in fact is like a dual triode (can u really use it as pontode?).

The lines are perfect, but how does it sound? And is it noisy?
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Old 31st December 2012, 11:53 PM   #60
cotdt is offline cotdt  United States
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The EL34 is the only pentode that can be run as a true triode. You can run it either as a pentode-strapped triode or a true triode. One would think it would sound the same, right? But NO! I have tried this. The EL34 sounds better as a true triode than as a strapped triode. More clear and dynamic sound. Try it for yourself and listen. I bet the EL34 would sound even better with the screen grids completely removed. And even better if it used parallel plate construction, which would require direct filaments.

Since my posts years back, I've changed my mind regarding IDHTs vs DHTs and now believe that DHTs are better (more dynamic and detailed sound). It may just be due to the parallel plate construction, though. Those biplate 2A3's sound mushy, but monoplate version sounds awesome.

Last edited by cotdt; 31st December 2012 at 11:56 PM.
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