Re: Hi Z Buffer Distortion

"Chris Hornbeck" <chrishornbeckremovethis@xxxxxxx> wrote in message
news:a82au4hpillpbmbvv9icacrgmvlalrrshq@xxxxxxxxxx

Good bottles of both these types are really, really good. My
favorites are the old Sylvania's with cylindrical cathodes, but
these days the hot tip is to use the 12 volt heater versions
(for availability!) or other un-hip voltages. And plain vanilla
Russians are surprisingly good - not much to go wrong with
these types really.

Not all of them; the Sovtek 6SN7s are godawful, both in tested performance
and reliability. The ElectroHarmonix 6SN7s, also Russian in origin, are a
lot better.

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.

Peace,
Paul


.

Relevant Pages

  • Re: Hi Z Buffer Distortion
    ... 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). ... BTW, for those terminally unhip about matters Audio, Paul is, AFAIK, ...
    (rec.audio.pro)
  • 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. ...
    (rec.audio.pro)
  • Re: what "REALLY" is derivative?
    ... Derivatives are ... > which case they're something to do with linear algebra, ... > and tangent planes to surfaces, and all that stuff, which ... > I like to think has something to do with geometry. ...
    (sci.math)
Loading