14 Mar
2013
14 Mar
'13
4:50 p.m.
On Mar 14, 2013, at 6:16 PM, ard at p850ug1.demon.co.uk (Tony Duell) wrote:
For guitar effects pedals, certainly. I've seen quite a few
schematics online that claim to be tube distortion schematics which
run a 12AU7 (ECC82) at 12V. Guitar amplifiers are quite different
in design from hi-fi amps; among other things, they're often run
open-loop, which gives you a hell of a lot more power from your
output tubes and far fewer stability concerns (until you get to
the microphonics issue, which is significant for an amplifier that
sits atop a >=100W speaker output). Distortion is, of course, not
generally viewed as undesirable for guitar amps, at least not most
of them.
- Dave
Then I spoke
with a guitar tech about using 12AX7s, I think it was, in
guitar effects, and was wondering where they got the high voltage. He
told me B+ in such circuits is, IIRC, 12V. It makes sense - power
delivered is not really a consideration in such things - but it was a
bit of a surprise to me....
A low anode volatage is likely to cause distortion at quire moderate
signal nlevels, which might be an advantage for that application.