2E24 ultralinear

[mach1]

Has anyone used the 2E24 in ultralinear mode ???

I am interested in finding a ball park operating point (The data sheet give a g2 max of only 200V) and the best opt impedance.

thanx, paulm

[PRR]

http://www.webace.com.au/~electron/tubes/ulo.html

[pmillett]

I played with it some. I was running it at B+ of 300V so something like 280V on plate and G2. 3.5k or 5k (better) load. It did not blow up, and measured pretty well. I did not build it into a complete amp, just a breadboard experiment.

In general I think people are paranoid about the G2 ratings on these RF tubes. In general you can get away with higher voltages in audio use, especially in triode mode. UL maybe not quite as much, but you can definitely push it over what they specified.

Also look at the DH variations of the 6146 (like the 8042), they have a lot of potential as well.

Pete

[mach1]

Thanks a lot Pete,

I also have a few D3A and 6AK5 looking rather lonely, so I might try an E-Linear topology similar to your KT88 (very nice BTW).

Looking at that circuit, am i right in thinking that you are running the D3A plate voltage pretty close to the g2 voltage ? (on your pentode driver spreadsheet I think you actually run the D3A plate lower than g2).

If so, I am rather puzzled, as normally I run the driver plate at the voltage swing required for the output tube above the driver g2 voltage (in this case I imagine the required swing to be around (.4 x 280) + 20V).

It would be great if you could shed some light on this.

paulm

[316a]

Originally posted by pmillett
I played with it some. I was running it at B+ of 300V so something like 280V on plate and G2. 3.5k or 5k (better) load. It did not blow up, and measured pretty well. I did not build it into a complete amp, just a breadboard experiment.
Pete

Hello ,
Funny that these are mentioned , I'm about to build a dedicated compression driver amp with 2E24 I had one strapped as a triode sitting at 400V on my tester no problem . I seem to remember as triodes these have mu of 7 Ra 2.5k and the curves I plotted looked very nice (on my old pc which has a blown psu!!!) with very evenly spaced curves . My only concern is the lifespan but the things are cheap enough and easy to light up with a small (ish) LC filament supply

cheers

316a