The only difference in tuning an amp is if it is grid driven or GG. With a
grounded grid amp you tune for max output and don't exceed max grid current
or max plate current. Tuning the plate tune by watching for a peak in grid
current is often a more sensitive indication than watching for a peak in
output power.
Tuning a grid driven amp is done much the same by tuning for max output and
keeping grid, screen and plate currents so they don't exceed maximum
allowed. The most sensitive tuning indicator with a grid driven tetrode or
pentode is the screen current. Tune the plate tune for a peak in screen
current as it is much more sensitive than output power peak. Adjust the load
control (heavier) to reduce screen current. Screen current is the most
important with a grid driven amp.
They both must be done at full power that the tube is to be operated at.
With the exception of a tune indictor meter. Later..
73
Gary K4FMX
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
> On Behalf Of Ron Youvan
> Sent: Saturday, January 30, 2010 3:00 PM
> To: amps
> Subject: [Amps] Tuning amplifiers
>
> Anyone:
>
> I am confused by some of the things I am reading here about tuning,
> but I have long heard triodes and tetrodes are tuned differently,
> I have never figured out why or what, could someone enlighten us and I
> assume pentodes are tuned like tetrodes, right?
> (I have been tuning tube amplifiers for over 40 years now, normally
> with a swept test signal, frequently with -20 dB of drive.)
> --
> Ron KA4INM - He who attacks the fundamentals of the American
> broadcasting industry
> attacks democracy itself. -- William S. Paley,
> chairman of CBS
>
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