The 77DX tube is likely getting soft (or will be) as 100 ma is considered
the absolute safe maximum and at that point you are also likely well over
the legal limit.
Reduce the drive and grid current and enjoy it.
Carl
KM1H
----- Original Message -----
From: "Larry P. Greenberg" <wa9mag@ameritech.net>
To: <amps@contesting.com>
Sent: Tuesday, September 18, 2012 9:39 PM
Subject: [Amps] 8877 Grid Current
For a good number of years, I had a Henry 3K Classic export with a single
8877. Peak power (fully tuned) occurred when the grid current was low,
around 10 to 20 MA. I recently picked up an Alpha 77DX with a single
8877. Peak power (fully tuned) occurs when grid current is around 100 MA.
Why is there a difference in operating grid current between the two
amplifiers? What is the maximum grid current an 8877 can operate with
out destroying the tube?
Larry, WA9MAG
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