Re: Tube amp project - continued

On Sun, 16 Nov 2008 03:38:03 -0600, <morris.slutsky@xxxxxxxxx> wrote:

The EL84 power tubes are almost wired
up like those of a classic AC30, but I've got separate cathode
resistors and bypass caps for each pair. This makes it so you can pull
1 pair of tubes without the other pair drawing excessive current and
melting.


Not following you here.

What do you mean by "a pair" ?


If you pull both tubes on the push side,
or both tubes on the pull side, then yes, the power equation for
the remaining tubes won't be altered.

But the tone equation certainly will with only half of a cycle
being driven !


If however you mean to pull 1 tube from the push side and also
1 tube from the pull side, then the power equation will be
altered considerably for the remaining.

If the latter scenario is what you have in mind, then you'll
have to give each output tube its own cathode resistor and
bypass cap in order to be able to yank a push tube and a pull
tube without throwing off the bias for the remaining two
tubes.
.

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