Re: 4 Grids

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Steve Ward" <steve.ward-at-gmail-dot-com> 

I have run across many partially dead 304TLs.  I did in fact run 1/2
of the tube in a VTTC circuit.  I think the most i got was about a 12"
spark and the plate was very cherry red.   I didnt care about the tube
so i didnt mind how hot the plate was getting.

Anyway, im not sure if you can actually run just 3 of the filaments,
unless somehow the 4th was shorted out?  From what i remember, they
wired the filaments in strings of 2, and there is no center tap
between each single filament, but there is between all 4.  So you
could either series all 4 filaments at 10V, or you could parallel 2
strings of 2 at 5V.  Anyway, it may be worth your time to just play
around with half the tube, its probably not good for anything else.

Steve


On Sun, 03 Oct 2004 14:46:43 -0600, Tesla list <tesla-at-pupman-dot-com> wrote:
 > Original poster: "Rich" <rdjmgmt-at-socket-dot-net>
 >
 > I was bringing a 304tl up to operating voltage on the filaments.  Well I
 > guess they call the 304 for a reason, 3 for triode and 4 for the 4
 > filaments. One tube has one bad filament. I have the tube set up on a
 > series circuit because my main filament transformer is 10v. I found out
 > quickly I can't run it that way. One filament will pull to much
 > voltage.  Before I junk the tube, I could wind another 5v trans, has any
 > one ever run one with just three of the filaments.
 >
 > Rich
 >
 >