Thats far from pushing it, if anything the tube is soft, the circuitry is
inefficient or its not loaded all the way. At 4KV 1500W is easy and there
are many still getting full power on a BC band pull 20-30 years later.
First thing Id do is measure the filament voltage at the socket with the
tube lit; no HV necessary. It should be 7.5VAC RMS +0/-5 % for long life.
If its really soft you can increase it a bit at a time untill its ready to
retire. Some have gone as far as 9V over several years!
Carl
KM1H
----- Original Message -----
From: "Ed Heimbach" <supermechanic18360@yahoo.com>
To: <amps@contesting.com>
Sent: Tuesday, August 30, 2011 8:02 PM
Subject: [Amps] 4-1000a GG conversion
A few ideas to share.
I have a triode connected amp, built this 25 years ago, makes 1100-1300
watts out, with 100w drive,& 4kv on the plate.
I am considering building bias and screen supplies, and reconnecting as
conventional grid driven tetrode.
Reason for this, I only have two of these tubes,I have read that the GG
"triode" connection can be tough on these tubes, I don't intend to buy any
more tubes, this has to last me till my kids sell my stuff.
Till now, I have used this casually, however, I am getting into contesting,
and using this amp quite a bit harder.
questions I have.
Any changes needed to the output tank?
Will input impedance change, requiring a new tuned input?
Should I use a resistor swamped input?
Will neutralization need to be done when changing bands?
73,AB3HT
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