6c33c SE Duplex Schematics

[Ax1]

Can anyone point me in the direction of a good 6c33c SE duplex schematic with fixed bias. I haven't really been able to find any.

I plan on designing my own, but would like to see some example schematics first.

Any idea what current draw I will get from the 2 6c33c's in parallel?
I assume it just about doubles, so depending on supply voltage I can expect a potential maximum of about 700ma, or 1.2A with both heaters. Is that correct?

Anyone know a good rectifier tube that will handle these currents. I am thinking of a parallel pair of 5C8S's, or making a full wave rectifier with some 866A's.
For the heaters, I am going to use some dedicated filament transformers.

[kheper]

viewtopic.php?f=3&t=4325&hilit=6c33c

[azazello]

Two parallel 6S33S need load output transf. about 700-800 ohm with current about 500-550 ma /250-270 ma per tube/.
Better You can use mixed bias /50 ohms in parallel cathodes multiplay to curent = 25-27V... plus fixed bias about 45-50 v/.
You can use this schem with changes for two tubes, like above.
http://sergeev21.narod.ru/6s33s6e5p.GIF

[Ax1]

Thanks, that helps. What power should the output transformer be?

Can it have a primary of 600 ohm instead? - I am interested in finding out how exactly these values are calculated.

[azazello]

Two parallel 6S33S have Ri about 150 ohms. I think it must be multiply to 3-5 to figure OT, that Ra must be 600-800 ohms. /this method I used in a few OT for my several projects and I thing this is right way/.
It core must be about 25-30 sq cm /the same transformer, that I calculated, works in DIY amp of my friend and the sound is really real, without saturation/.
If You have a schematic for 10-15 W in SE, I thing that power of OT must be calculated: 10-15 W multiply to 15-20 = about 200-300 W.... and more iron - better sound.

https://picasaweb.google.com/1095707775 ... 0216493602
You can see the size of my OT for SE one 6S33S.

[Ax1]

Any idea where I can get an output transformer from? The only one I can find is a lundahl LL1693, which has a max quiescent current of 450mA, peak current 900mA