Re: Hi Z Buffer Distortion

On Wed, 15 Apr 2009 07:06:55 GMT, "Paul Stamler" <pstamler@xxxxxxxxx>
wrote:

A good 12AX7/ECC83 is in this same ballpark, and IME more reliably
linear (into very high Z optimised loading, yada yada). "Good" here
means Telefunken's and large geometry Amperex's. Also the old
large geometry TungSol's and RCA's if sorted for noise are great.

There are lots of crappy, inexcusable 12AX7 type devices these
days - they are *not* 12AX7's - anything that looks Chinese is
probably a 12AT7 geometry (and worthless for linear audio).

True. But I was thinking of tests I ran on real 12AX7s -- Telefunkens and
Amperexes, back when those were available new off the shelf.

Never seen a really linear 5751, but then I've sure not seen
everything! And they have an excellent rep.

A real 5751 (as opposed to a 12AX7 with new labels reprinted on it, which is
what most of the 5751s out there these days are) is close in behavior to a
6SL7, although it requires different bias points. I ran tests on some from
GE that were very nice.

Very cool; thanks.

BTW, for those terminally unhip about matters Audio, Paul is, AFAIK,
the only person to ever be a cover model on the deeply missed Audio
Amateur magazine from the last Golden Age of homebrew (It'll Come
Back!), accompany-ing *the* definitive three-part article about
mixer design considerations, still completely relevant! and very
accessable at all technical levels.

Must be available somehow through Peterson and an absolute Must Read
for anybody interested in Audio recording. Gain staging? Here's why.
Like that.


Much thanks, as always,
Chris Hornbeck
.

Relevant Pages

  • Re: Hi Z Buffer Distortion
    ... Russians are surprisingly good - not much to go wrong with ... linear (into very high Z optimised loading, yada yada). ... large geometry TungSol's and RCA's if sorted for noise are great. ... probably a 12AT7 geometry (and worthless for linear audio). ...
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  • Re: Hi Z Buffer Distortion
    ... probably the most linear device (into a suitably high ... the 12AX7 isn't anything like the most linear tube out there. ... linear (into very high Z optimised loading, yada yada). ... large geometry TungSol's and RCA's if sorted for noise are great. ...
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