On Jul 14, 6:52*pm, Bret L wrote:
*I mean, penishead, that a small signal tube is optimized for audio in
a different way than a power output tube. For example the heater
connections may be changed to reduce hum, important in preamps and
power amp first stages, irrelevant in a power tube.
Therefore the 7025 is the only 12AX7 variant designed with audio in
mind. Any company that uses a standard 12AX7 is "phooey".
Most all 12AX7s were dual numbered from the late LBJ era on.
So what? As tube production wound down many tubes were relabelled with
multiple numbers.
Were they audio tubes to begin with? I think not. They were "phooey".
i.e, whether one is talking about small signal or power tubes, and as
opposed to general purpose tubes or tubes specifically designed for
other purposes. In some cases tubes specifically designed for other
applications work quite well in audio applications and in others not
so well.
That makes no difference, people.
*In the case of power tubes, specifically audio types differ from RF
output, TV horizontal deflection, and voltage regulator tubes in
several areas. Linearity is at a premium, plate caps are undesireable,
Tell that to McIntosh, who used 6BG6 tubes with great success. Yes,
it's similar to 6L6 tubes. However, they used these tubes even though
6L6 tubes were as cheap and (perhaps) more plentiful.
*Only on one, obscure industrial model
Did I say otherwise?
http://mcc.berners.ch/power-amplifiers/A116.pdf
*This tube was identical to the 6L6 except for pin out...http://www..vacuumtubes.com/6BG6.html
So why did they use a horizontal deflection tube? McIntosh is clearly
"phooey".
*The same reason legions of CB linear builders did and even still do.
In a Class B device operating at a high crest factor it was the
cheapest and most easily field obtainable way to get a certain level
of plate dissipation, without going to transmitting tubes and their
higher plate load (and transformer winding ratio) requirements. This
was a Nestorovic/Modafferi design and they were damn good. Julius
Futterman (don't even say it) was also good though a bit obsessed and
his OTL tube designs worked well-if you understood their very
significant limitations.
*But all things being equal, these designs would have benefitted from
more linear tubes.
As I said, 6L6s were cheap and plentiful. You're emitting large
amounts of gas out of your rear end, Bratzi.
*McIntosh approached Varian EIMAC for a purpose built audio tube and
Eimac wanted nowt to do with audio.
*If I had a timeride offer I'd ask Frank McIntosh why he never thought
of the EL156, but since John Titor has not shown back up I guess we
will never know. as Frank and Gordon Gow are both very dead.
And both very "phooey".