[HomeBrew] 4-65A amplifier info?

[Brian Burns]

Hello Ian,

 

I first noticed the 4-65A in an ARRL Handbook project, and later in the
"West

Coast" Handbook. 

 

I'll have a look through my handbooks, as I have several from "back in the
day"

 

A significant number of the 4-65A's that I've acquired over the past few
years

have had a problem with gas. Some of these I was able to rejuvenate by

running the filaments for several hours followed by running the tubes in an
RF
power oscillator on steadily increasing B+ until any trace of blue glow
disappeared.

I don't know whether there was a problem with the seals or something else.

 

I don't have any idea what the condition of these tubes will be, but it
should be easy enough to light up the filaments for a goodly while.

 

Although I started one 40m TX using the 4-65A I didn't complete it, don't

recall the reason now. I have had more luck with the 4-125A (none have been

duds and it seems easier to control somehow).

 

Well these tubes are coming to me at "the right price" so that's why I'm
thinking of using them. I took the vows of poverty when I decided to be a
Spanish guitar maker for a living!

 

The 4-65A has that classic Eimac look and is very appealing with the
filament

lit up. Perhaps I should revisit my project list....

 

Yes, I'm a glowbugger all right, and part of the appeal is visual.

 

Thanks very much for the quick response and the information!

 

Cheers,

 

Brian

 

 

 

 



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