Re: Question about Plate voltage to 6V6GT



Geoff C schrieb:

I am converting an old amp chassis to a guitar amp. It has 6V6 pair output
and I have a 5Y3 rectifier from a 350 VAC winding. Without the 6V6's
plugged in, I am getting 450 V DC at the OP tranny centre tap. On a Fender
deluxe AB763 schematic, for example, there is a plate voltage printed on
the schematic of 410 V. The data for the tubes state a maximum of 315-350
V range, depending on manufacturer. The Fender design appears to be at
odds with the datasheets, does it not?

The original rectifier with the chassis I am rebuilding was a 80S, but the
one with it was gassy so it got chucked. I don't want to wreck my tubes so
I am being cautious. I need to resolve this so I can move on to getting the
second stage and output stages working, as the first pentode stage is
running nicely.

Hi Geoff

with 450V DC idle without tubes, I´d expect 380V DC at the plates of
the 6V6s. Assuming an idle current of ca 30mA per tube and the use
of the 5Y3

At these Voltages even the "old" black russian 6V6 or the chinese "RUBY"
can survive. There should be no problem with the voltages. IMHO You
might
even go cathode bias.

Which kind of 6V6 will you use?

I´d take OS or the JJ6V6S. They should be capable to handle up to 450V
DC.


regards

Jochen
.

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