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Old 12th December 2011, 04:34 PM   #21
kevinkr is offline kevinkr  United States
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Quote:
Originally Posted by artosalo View Post
I looked carelessly at the schematic and did not notice the added capacitor from the grid to anode.
But I could not find that there would be 4 tube halves ( 2 x 6N30P) in parallel.
Is it really so ?
Dual triode and the schematic seems to indicate two tubes, each pin has two pin numbers associated - presumably this means there are 4 sections in parallel. I'm not sure, language and drawing issues confuse the matter.
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Old 13th December 2011, 01:42 AM   #22
Charm is offline Charm  Russian Federation
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http://klausmobile.narod.ru/td/data/_6n6p.GIF
Tube Tester Files - 6N6P - 6H9?
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Old 13th December 2011, 11:04 AM   #23
Charm is offline Charm  Russian Federation
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Sorry Tube Tester Files - 6N30P - 6H30Ï
http://www.etd.su/djvu/209/1/6n30p-dr.djvu
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Old 13th December 2011, 11:44 AM   #24
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Originally Posted by Yvesm View Post
Almost !

You've just forgoten the "magical" deliberatly added 10pF that makes this preamp "the best"

Here is "The Better Preamplifier Of The Whole Know And Unknow Universe" :

Click the image to open in full size.



Yves.
Faux ... La réponse est perturbée par l'inductance, la capacité et la résistance du câble coaxial utilisé entre l'entrée et la sortie ... Sans parler de l'absence d'adaptation d'impédance et de gain qui sont les raisons d'être d'un préamplificateur !

Alain.

P.S. I like very much your tubes curves tracer design using the powerline sinewave and the sound card inputs for the voltage and current simultaneous reading ... You are a "pro" !
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Old 13th December 2011, 02:09 PM   #25
DF96 is offline DF96  England
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Quote:
Originally Posted by artosalo
But I could not find that there would be 4 tube halves ( 2 x 6N30P) in parallel.
Sorry, my mistake. I must have counted grid connections instead of grids!

Quote:
Originally Posted by Yvesm
Here is "The Better Preamplifier Of The Whole Know And Unknow Universe" :
Your preamplifier will sound harsh and clinical, even though it will measure almost perfectly.

Last edited by DF96; 13th December 2011 at 02:14 PM. Reason: add preamp comment
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Old 13th December 2011, 04:05 PM   #26
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Ah ah Alain,

You were quicker than me

Cheers,
greg
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Old 13th December 2011, 04:39 PM   #27
kevinkr is offline kevinkr  United States
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Quote:
Originally Posted by DF96 View Post
Sorry, my mistake. I must have counted grid connections instead of grids!


Your preamplifier will sound harsh and clinical, even though it will measure almost perfectly.
It's not really clear to me whether it uses 1 x 6N30 or 2 x 6N30, the tube is a dual and the schematic implies to me based on the pin# shown that there are in fact 4 triode sections in parallel.

Yves, I love the last line in your copyright statement..
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Old 14th December 2011, 02:11 AM   #28
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Quote:
Originally Posted by DF96 View Post
Sorry, my mistake. I must have counted grid connections instead of grids!


Your preamplifier will sound harsh and clinical, even though it will measure almost perfectly.
I like your say: *Your preamplifier will sound harsh and clinical, even though it will measure almost perfectly*

thanks
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Old 14th December 2011, 03:08 AM   #29
AJT is offline AJT  Philippines
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hi quangho, mind sharing your rationale for paralleled tube sections? have you tried the 6080 at such levels of voltage and currents?
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Old 14th December 2011, 04:40 AM   #30
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Ok!

that is circuit of my PRE
Attached Images
File Type: jpg PRE818--2011.jpg (86.5 KB, 859 views)
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