50W Transformers

[ChrisM]

I know there is a lot of topics on this subject. I am unclear on a few things though.

As I understand for a 50W ODS you want Bassman transformers, ok.

So I am looking at these transformers at Hoffman. For the PT the HT tap is rated 700V AC at 140mA. Now I think 700V is a bit high. Wouldn't that give me a B+ of just under 500V (490V)? I am building a 50W #124 and it had 440V on its plates.

Also the OT. I am looking at a transformer with a 4000R primary impedance and 2R, 4R and 8R taps. That sounds about right doesn't it?

Thanks...

[Structo]

Chris I have a D'Lite (2 x 6L6) that has a PT with 325v-0-325v @ 300ma.

The 6.3v tap @ 6 amps.
The 5v tap @ 3 amps.

For power tube plate voltage I get around 434v with a full wave rectifier.
That's with 470R screen resistors and a 330 ohm choke resistor.

For the OT I bought a Fender Prosonic OT from Angela made for 2 x 6L6 operation.
Upright end bell construction.

It's rated 50 watts and has 4K primaries with 4,8,16 ohm secondaries.

It seems like a very good OT on this amp.

I also like the impedance switch that Hoffman sells.
Heavy duty with three positions.

[ToneMerc]

Chris, I built a 50W "tweaked" D'lite using some custom Heyboer trannies. The PT is 700V@300mA and depending upon which brand of 6L6's, it varies from about 465-475 volts on the plates with 500 ohm screen and 300 ohm choke resistor. I did have to adjust the string to bring the preamp voltages down a tad. Right now it has TS STR's with 465 on the plates.

The OT tranny is an 4 split M6 lamination, 4.4k, 4-8-16. Lot's of variables I guess, a usable window can be anywhere from 3.4-5K, with 3800-4200k more common and 4k puts you in the middle.

Mike

[ToneMerc]

Chris, I built a 50W "tweaked" D'lite using some custom Heyboer trannies. The PT is 700V@300mA and depending upon which brand of 6L6's, it varies from about 465-475 volts on the plates with 500 ohm screen and 300 ohm choke resistor. I did have to adjust the string to bring the preamp voltages down a tad. Right now it has TS STR's with 465 on the plates.

The OT tranny is an 4 split M6 lamination, 4.4k, 4-8-16. Lot's of variables I guess, a usable window can be anywhere from 3.4-5K, with 3800-4200k more common and 4k puts you in the middle.

Mike