304tl-304th guestion.....

[kc2ifr]

Being a little dim witted....I have a dumb question about these 2 toobs. The question is about toobs in general I guess.
Now for the guestion........
The 304tl is a low gain toob...
The 304th is a high gain toob...
Both toobs look the same on the outside but I cant see the inside construction. The way this triode is constructed determins how it works and I know that.......but.....now for the question...
What determins the gain of the toob.......all other thing being equal....I think it has to do with the control grid construction.....the closer the grid mesh, the more gain....but thats just a guess
Soooooo.........what do ya think.....
Bill

[k4kyv]

....I think it has to do with the control grid construction.....the closer the grid mesh, the more gain....but thats just a guess
Soooooo.........what do ya think.....
Bill

That's pretty much it.

[Vortex Joe - N3IBX]

....I think it has to do with the control grid construction.....the closer the grid mesh, the more gain....but thats just a guess
Soooooo.........what do ya think.....
Bill

That's pretty much it.

Don,Bill - I second that.

[W2PFY]

I never blew that

[Vortex Joe - N3IBX]

Bill,
    The 304TH/TL is a very unique tube. It's actually 4 ea. 75T triodes in one glass envelope. If one plate/grid becomes defective, you can actually use the remaining ones, or hook it up so that you only run one,two,three,or four for whatever output you'd like to see.

We spoke over the air about what you paid for it, and you certainly can't go wrong with your investment in it. The filament structures tend to be a little weak and it wouldn't be a bad idea to "ramp" the primary of your filament transformer on a variac until you reach the required filament voltage.

The difference in the "mu" or gain factor between the TL and TH variant will determine what you need to drive it with.Just for reference, a TL has a lower mu, a TH has a higher mu, and a standard "T" variant is a medium mu triode. Eimac produced all three variants with their earlier triodes so one could design his driver around the gain factor of the tube.

I have a few 304TL's I've "lit off" just to see them glow and they make a very pretty sight. As a matter of fact, I've taken a few pictures of them with just their filaments lit, and could send them to you offline if your interested. The "icing on the cake" is a 304TL with it's filaments glowing and plates glowing a nice orange-reddish hue. The early Eimac triodes used "tantalum" plates and were designed to emit an orange-reddish hue when in proper resonance. This was done to give a getter effect to burn off any occluded gases that might develop within the glass envelope.

Very Best Regards,
                         Joe Cro N3IBX

[kc2ifr]

Joe,
The seller had another brand new 304tl he put on ebay and I got that one also. A little more money but still a good deal I think.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=ADME:B:EOIBSAA:US:11&Item=5837772216

[Vortex Joe - N3IBX]

Joe,
The seller had another brand new 304tl he put on ebay and I got that one also. A little more money but still a good deal I think.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=ADME:B:EOIBSAA:US:11&Item=5837772216

Bill - That 304TL looks new and schweet!