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Big Bad Bob Big Bad Bob is offline
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Default The most important tubes ever made.....

On 01/24/19 16:36, wrote:
Unfortunately these days I am running solid state amps. 1100 watts RMS
to be exact. It has good sound, but there is still something missing,
namely the tubes.


yeah, the natural tube distortion is the sound you're looking for,
probably. Modern transistorized amplifiers are "perfect" and add
nothing to the sound. The guitar amplifiers, however, altered the sound
as a part of how they work.

I personally never noticed the difference between solid state and an
older tube stereo system, but that tube system had reasonably low
distortion and physically large output transformers for maximum
fidelity. I think it used 6BQ5's in an ultra-linear config, as I
recall, 12W per channel, good enough for a reasonably sized room. So in
that case, the tubes didn't really add anything to the sound.

On the other hand, your typical Fender guitar amp WOULD add "something"
to the sound, because of how they designed the amplifiers to operate.
Any kind of open gain triode pre-amp will have some amount of 'tube
distortion'. So when you see bypass capacitors on the cathode resistor,
nearly all of the negative feedback for the stage goes byby, and you're
dealing with pure 'mu' gain on that stage. And that changes the sound.

Also guitar amps tend NOT to have a lot of negative feedback in them.
So they'll have more "tube sound" distortion than a stereo system, for
example.

And of course a guitar amp is probably going to be designed to pass a
more limited frequency range. You can see that when you look at
replacement output transformers, typically rated for 100Hz to maybe 4kHz
as opposed to a 20Hz-20kHz range for hifi/stereo amplifiers.

[that, too, is part of "the sound" of a tube guitar amp]

--
(aka 'Bombastic Bob' in case you wondered)

'Feeling with my fingers, and thinking with my brain' - me

'your story is so touching, but it sounds just like a lie'
"Straighten up and fly right"