Filament cooking does very little for an 8877 and it almost always has
to be slowly brought up under current protected HV and bias. A bigger
than normal glitch resistor will provide additional protection. Ive used
a 100 Ω 200W wirewound in the past.
Spare tubes should be cycled in an amp yearly.
Carl
KM1H
----- Original Message -----
From: "Dennis W0JX" <w0jx@yahoo.com>
To: <klahaie@centricata.com>
Cc: "Amplifiers" <amps@contesting.com>
Sent: Thursday, July 31, 2008 11:51 AM
Subject: Re: [Amps] 8877 tests
If/when you build that amp be sure to put a glitch resistor in series
with the anode supply to the tube. Old 8877's can get gassy. I cooked my
Ebay 8877 for three days with only filament voltage and the blower on.
Also started it up with low voltage. Glad I had a glitch resistor
because I still got an arc over. After that, though, it settled down and
performs nicely.
Good Luck, Dennis W0JX/8
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|