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[AMPS] 3-500Z filament voltage

To: <amps@contesting.com>
Subject: [AMPS] 3-500Z filament voltage
From: rakefet@rakefet.com (Vic Rosenthal)
Date: Sun, 31 Jan 1999 11:47:00 -0800
Monty Taylor wrote:
> 
> I have just reduced my filament voltage on the 3-500Z's in my Linear from
> 5.75 volts to 5.00 volts, added 40 ohms in the primary of the transformer,
> with no load or drive.  

<snip>

What I did was bring out the filament pins directly from the tube socket to  pin
jacks on the back of my amp.  I put 10K resistors in series with each line, and
bypassed them at the pin jacks.  Since the input impedance of the DVM is high,
the 10K resistors don't affect the reading much, and they isolate the DVM from
RF.  This allows me to measure the filament voltage under key-down conditions.

73,
Vic, K2VCO
Fresno CA

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