guitar-amp triode conn.

[Eric]

>The triode pair has lower output, less power
supply rejection (more
>backgrond hum) and clips at a lower level, but it
is a soft "spongy"
>clipping.
>The Pentode pair has higher output (maybe
25-20%), much less hum, and stays
>clean until clipping (which is "harder" or more
fuzzy then the triode).

I know guitar-amp experts who have tried both
triode connection
of beam tubes and pentodes; and real triodes. They
never seem
to like the triode sound--they always return to
screen-grid tubes.
(Terry Buddingh of Guitar Player, for one.)

>Why the poor hum rejection for the triodes ???


Probably because triodes are more prone to noise
in the B+ supply--pentodes don't need such a
stiffly
regulated and clean supply to get good PSRR.
I'd have to look into it further.

PS--did you folks see the tube "log converter" on
my website?
http://www.metasonix.com/oldcircs.htm
It finagles the grid-plate curves....sort of
approximate, and
depends on the precise tube type you use.

Yes, I admit, a log function is definitely one
thing that
semiconductors do better.......

--Eric