304TL Tubes

Nigel Holmes 03 9626 1914 fax 03 9626 1899 holmes.nigel at ABC.NET.AU
Mon Apr 28 22:27:00 EDT 2003

304TL's were commonly found in industrial & commercial devices, a bit
like 6Y6 and 6B4G's (but obviously in bigger applications!) sort of next
step up from 810 or 8000.

I recall a 3000 volt regulated power supply for the magnet of a small
cyclotron at Monash University that used nine (!) 304TL in parallel.

They show up at Australian ham fests. Much less common is the socket,
but at this scale a  friendly turner & fitter can knock up something in
brass in a jiffy.

I wouldn't expect audiophiles to start squeaking excitedly over a 304TL
- they tend to fancy the singled-ended bottles so they can display the
naked spectacle of a 212E or a 845. A couple of kV on a top cap tends to
dampen even an audiophool's ardour after first contact... hence the
single-ended modern versions of "low mu 811's" Suitable output iron
would be a bit rare too. Though I s'pose you could put nine of them in
parallel for the mother of all cathode followers...

73 Nigel VK3ZNQ

-----Original Message-----
From: Boat Anchor Owners and Collectors L
Sent: Friday, 18 April 2003 14:21
Subject: Re: For Sale: For Sale: 304TL Vintage Transmitting Tubes

Wow! Such a DEAL! ;-)  I can remember when 304TLs could be had from many
surplus peddlers for one buck a pop. Of course, that was 35 or more
years ago...that was then, this is now. I never could figure out why
there seemed to be so many of them available surplus; the only military
equipment I ever ran across that used them was the SCR-584/784
auto-track radar sets that I used to work on. The tubes were used as the
magnetron keyer, one per set, and I can't remember ever having to change

Just be careful you aren't trampled in the rush of audio-phools if they
find out about your tubes...they seem to LOVE triodes, and the bigger
the better!

Dave Hollander wrote:
> These all came from an estate. All appear to be in excellent
> I am only able to test filament continuity and all test good. The
> haze is a reflection off of the cloth I used as a backdrop for
> photographs.
> Click on the links for pictures.
> Eimac 304TL Transmitting Tube - $65
> http://members.cox.net/radiostuff9/304tl2.jpg
> Eimac 304TL Transmitting Tube - $65
> http://members.cox.net/radiostuff9/304tl.jpg

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