[Amps] SB-220 update and gettering

[John Lyles]

It is my understanding that the 3-500Z has a filament heated getter that 
is always active when the tube is on. Also, if it has a special coated 
anode with gettering ability, then that is active. If the anode is one 
of the reactive metals like tantalum, then it will also getter the tube. 
 From what I am hearing, the new graphite anodes have coatings that will 
help, but I am not familiar with those.

So the answer is yes, there is always getter action on power tubes, not 
just the flash getter that works during manufacture.

John
K5PRO


n 11/26/16 10:29 PM, amps-request at contesting.com wrote:
> Message: 3
> Date: Sat, 26 Nov 2016 18:15:48 -0600
> From: Lee <L at w0vt.us>
> To: amps at contesting.com
> Subject: Re: [Amps] SB-220 update and gettering
> Message-ID: <f91c59b0-5a82-ee12-94aa-ea4842cdecf9 at w0vt.us>
> Content-Type: text/plain; charset=windows-1252; format=flowed
>
> John,
>
> OK I understand what you are saying.  But, how does a graphite 3-500Z
> tube get gettered after sitting around?  You say heating the anode to
> glow does not getter the tube.  I realize the graphite tube was gettered
> when manufactured.  Since glass seals leak, can a graphite 3-500Z be
> gettered again down the road or was it a one time deal at the factory?
>
> Lee, w0vt