Using mains transformer as output transformer

[boiss]

Hi Revintage,
Some food for thought, really not too worried about the driver as it will be constantly running grid current. Driver could even be SS transformer coupled. I want 2 big bottles up there, fantastic visual impact and with 150 watts of filament power at least 10W of impeccable sound.
A bit miffed that it cant be done with 100V HT. Anyone understand why 833 characteristics look like a classic pentode?
Seriously, triode chars are all vertical while these are all horizontal.
Mike.

[boiss]

Maybe I should add that I use 813s where others use a DL96, ie even lower HT like 25V for RF etc.
Mike.

How about a simple desktop regen MW RX (tuner) using an 833 with all of it running on 10V dc inc the filament supply.
Mike.

[boiss]

Just an example, A modulator for 1930s radios on Medium wave
813 screen modulated, HT for both valves 25V, O/P 1mW at 1MHz into 50ohms harmonics <-60dBm.

[revintage]

Will use EL519/6KG6 instead of 6550 as anti-triode in my SEPTORS with parallelled 6B4Gs. Sims so much better, must be the high Gm. Will take some photos tomorrow when I have mounted the magnoval sockets and topcaps.

[hoktuna]

Yesterday i move the 150H choke and hook up the scope.
The sine wave now looking good below 100 hz

[Elias]

Hello,

Time to move this thread forwards!

This idea came to my mind of output toroid current compensation. For the input signal it acts like a SE amp. It works with split supply. Capacitor decouples the signal at the middle. No need for transistor current mirrors No need for current tracking, same current goes through both windings. I think some of those 115V + 115V mains toroids works fine here as in my previous protos as well.

What do you think?


- Elias