[Top] [All Lists]

Re: [Amps] NOS 8874 (3cx400)

To: <>, <>
Subject: Re: [Amps] NOS 8874 (3cx400)
From: gudguyham--- via Amps <>
Reply-to: "" <>
Date: Sun, 2 Jan 2022 11:06:37 +0000 (UTC)
List-post: <>
Those tubes getter with just filament voltage so to degas them run them with 
normal filament voltage and cooling.  Those tubes are very unlikely to get 
gassy but anything is possible so why not be safe and getter them for 24-48 
hours.  Running lower plate voltage isn’t very helpful unless it’s a thoriated 
filament which it’s not so once you run it with filament voltage only for some 
time, that’s the best you could do.  Getting the anode hot doesn’t degas those 
tubes.  It’s very possible you can use them right off but no harm done waiting. 
 Being the tubes are rare and expensive being cautious is wise.  Good luck and 

Sent from the all new AOL app for iOS

On Sunday, January 2, 2022, 4:22 AM, <> wrote:

Hi to the group,

I have been offered a  pair of new old stock 8874 tubes. These would be very 
nice to have for a rebuild project, BUT with  date codes in the 1980's, what 
would be the normal practice to get them back to normal expected output (I ask 
in the hope that this would be possible)

Should I run them up just on heaters & blower a few days, then try HV on them. 
Or slowly bring HV on over a period of time??

What's would be my best options??

Any advice would be much appreciated.



Amps mailing list

Amps mailing list
<Prev in Thread] Current Thread [Next in Thread>