[Amps] Tetrodes working as triodes

[Peter Frenning, OZ1PIF]

Guillermo, if you need the added gain the answer is yes, otherwise no...

My QB4/1100 in GG, with both grids tied to ground, and 2900V on the plate, 
gives 700W out for 100W in, which is some 7dB of gain, and just right for my 
usage (read power supply capacity). Two ways to increase gain: either raise 
plate voltage (in my case 3800V ups the gain to 10dB) or - raise the screen, 
some 80-100V will do the same trick.

Vy 73 de OZ1PIF, Peter

**********  OZ1PIF **************
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Peter Frenning
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Denmark
***********************************
----- Original Message ----- 
From: "GGLL" <nagato at arnet.com.ar>
To: "Amplificadores Lineales" <amps at contesting.com>
Sent: Friday, October 29, 2004 9:30 PM
Subject: [Amps] Tetrodes working as triodes


> I was intrigued with the QB3-300 amplifier thread, but regarding other 
> tubes. Despite difference in plate dissipation,  what kind of performance 
> can I expect in G.G. mode from a 4-400 tube (for an example of tetrode) 
> with  screen and control grids tied together to ground, respect the same 
> circuit with a 3-400 or 3-500 triodes?. With the first tube, should I 
> expect a higher "grid" current (that is, control and screen currents 
> added)?. Could be useful to add some volts to screen in case of the 4-400 
> to increase gain, or not worth the added work?.
>
> As usual, many thanks in advance.
>
> Best regards
> Guillermo - LU8EYW.
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