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Tubes Asylum Questions about tubes and gear that glows. FAQ |
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Tubes Asylum Questions about tubes and gear that glows. FAQ |
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In Reply to: Eric, that is not fair posted by Victor Khomenko on September 23, 1999 at 06:24:33:
Well, you will have to ask Steve Bench about his
test procedure.
He and I have both found that 6DJ8/6922 types are
all over the place with regard to noise AND to
microphony. There are good ones, and there are
terrible ones! Low Rp and high Gm
is not always a guarantee of low noise.You will agree, Victor, that 6N1Ps tend
to be low in microphony. On the other hand,
6DJ8 types can be VERY microphonic sometimes.
And when they are, the harsh metallic ringing
sound of a microphonic frame grid is intolerable.I have a bunch of NOS Siemens CV2492s--these
are alleged to be "premium" mil-spec ECC88
types from the 1970s. New in box. Cost about
$80 apiece today, if you can find them. They
are the most microphonic preamp tubes I have
ever tried! You could use them as microphone
elements. (Very, very bad-sounding ones.)
I hope this was just one bad production run...A little industry anecdote:
Svetlana was recently approached by a major OEM
of tubed condenser microphones for studio use.
They were interested in the 6N1P and EF86,
because they had been buying Sovtek 6922s,
and said that recent production of
the Sovteks was so noisy and microphonic that
they were "unusable".Their engineer chose that 6922 because of its Rp
rating (for low noise), and for its continued
manufacture. He was SHOCKED to find that the Sovtek
tube didn't meet the specifications in his 1960s
Telefunken tube manual!.......I know some high-end OEMs who have had similar experiences.
The problem is not the tubes, the problem is the quality
of current design engineers.......
(this doesn't include you, Victor--you're a very
capable designer, and BAT products do give excellent sound.)But too many tube audio OEMs today
hire complete FOOLS to design all their products!
Especially guitar amps.It's getting really depressing.
No, I won't name any names.......
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Follow Ups
- Re: Eric, that is not fair - Eric B 11:32:23 09/23/99 (0)
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