Phase splitting using directly heated tubes?

[Legacy]

I have been hunting high and low trying to use a battery tube (pentode) as a Phase splitter. The tube has a directly heated Cathode, is there a way to do it?

[TheGimp]

Could you strap them in triode mode and make a LTP out of them?

I'm not very familiar with DH tubes so this may not be practical.

[TheGimp]

I think to do this you would need to run seperate heater transformer windings (batteries) for isolation between the cathodes. What filament voltage and current demand?

[Eli Duttman]

Pentodes can be used in LTPs, no problem there. However, a floating filament supply will be needed. Triode wiring and "concertina" topology presents the same problem

Legacy, what are you trying to get done? Are you looking into a battery powered PP amp, with something like 3S4s as the "finals"?

[kevinkr]

Use as a unity gain inverter, drive one tube directly with the voltage amp, the other with the inverter. Scott used this technique in some of their early 299 series amps. Not the most elegant approach, but it should be pretty simple to implement.

[Eli Duttman]

The Scott 299A illustrates Kevin's point. I think separate filament batteries would be needed here too, given the different bias needs of the 2 devices. Also, finding a suitable triode will be difficult, if (as I suspect) the OP is looking at tubes found in battery powered AM radios, like the 1U4 and 1S5.

A circuit along the lines Dyna used (pentode voltage amplifier and DC coupled "concertina" phase splitter) could be executed using either of the pentodes mentioned above and a FET. B+ for the portable radio types tops out at 90 V.

[Legacy]

I am trying to make a nifty little distortion setup using 8124 Tubes, 12 volts plate. I only need very low output level. I did try using battery on the Heater/cathode but I just could not get it to work, I was getting 2 in phase signals.. Got me beat so far.