Topband: 8877 Tube

[Paul Christensen]

Bob,

A non-issue.  Many of us have been running 8877s with Ep of 4KV.  For 
example, the typical no-load Ep of an Alpha 77Dx/Sx amp is right at the 
specified limit of 4KV.

Some owners have been converting their 8877 amps over to the 3CPX1500A7 
which has a much higher rated Ep since it was designed for pulsed service. 
Unless someone has access to a supply of pulse-rated tubes, I think it's 
waste of time unless the plate supply voltage is also increased.

Paul, W9AC


----- Original Message ----- 
From: "Chortek, Robert L" <Robert.Chortek at berliner.com>
To: <topband at contesting.com>
Sent: Wednesday, November 14, 2012 6:56 PM
Subject: Topband: 8877 Tube


> Wonder if someone can help with a technical question with the amp I use on 
> 160 meters.
>
> The Spec Sheet for the 8877 tube lists the "Absolute Maximum Plate Voltage 
> of 4000 Volts" for the tube, and also says in "typical operation" the 
> plate voltage is between 2700 and 3500 volts. In my amp (Ameritron 
> AL-1500), the plate voltage is 3750.  My question is - should I be 
> concerned (it's clearly below the maximum" but above the range that is 
> considered "typical"?   I just want to be sure I'm not adversely affecting 
> the useful life of the tube.
>
> Any help would be appreciated.
>
> 73,
>
> Bob/AA6VB
>
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