[Alex Pogossov]

"John L Stewart" wrote in message
...

Here is a different kind of test on the PP 6V6 AB2 amp that I posted a
while ago. And an updated schematic. The PS is a Hammond 271X into a FW
CT, 1N4007s into a PI filter of 8 microF, 5H & 100 microF for the +ve
side. There is also a -ve supply using 1N4007s on the same HV winding
into another PI filter of 10 microF, 1.5K & 10 microF. The lid is held
on for the -ve side by VR150 gas regulator. The OPT is a Hammond 125E
Universal.

The 6V6 screen leads go to the +ve supply. You can connect the dots.

From that one might think not to much is possible but they would be
wrong. My objective with this exercise as I had previously stated is to
try some different things. That is, discover what is possible in a
vacuum tube amplifier with low cost parts. It is well known that by
throwing unlimited resources (money & time) at a project that most
anything is possible. That is not my intention here!

There are many tradeoffs in any system. It is the designer's task to
separate what is important from what is not. In the real World market
the end product must be competitive.

The trace shows what happens to the +ve supply under pulsed conditions.
The top marker indicates 10 watts. The red trace is the one KHz test
signal, pulsed. The blue trace is the B+ supply at the 6V6 plates. The
pulse rep rate is about 14 Hz.

How did I do this? I will post that info later.

Cheer to all, John


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Hi John,

What is the purpose of the cathode followers in front of 6V6s? At 320Vdc
they can deliver as much as they are capable safely in AB1. Overdiriving the
amp with Vg2=320V and going into control grid positive zone will either:
a) burn the screen grids if nominal Ra-a load is present;
b) burn the plates if the load happens to short out.