push-pull transformer in single ended amp

[phsyconoodler]

I saw Weber using push-pull transformers in their single ended amps a while back.Does anyone remember how to hook them up?
  There was some method of combining the primaries to make it work single ended but I can't remeber how it was done.
 Any help is appreciated!

[JayB]

Their W022913 OT they use for a SE El84.

You could do it. If you had 2k PP OT, from one end to the other, it would be total of 4k. From center tap to either side, would be 2k for each side. Use one side of the OT winding that you would normally use for a plate as the B+. The center tap would be 2k and the next tap would be for 4k. Pick which one you need.

In parallel they would be 1k for the same 2k PP OT. So I don't think you would want to do that. I'm not positive how the secondaries would work. I think it would be the same if you used half of the winding.

[Tiny_Daddy]

A few years ago I rigged up a Hot Rod Deluxe with both output tubes in parallel, cathode bias, same output transformer. Works fine and is great for small clubs.

[zendragon63]

JayB is right on.The ADA EL84 Rocket does this. Regards

dennis

http://www.schematicheaven.com/newamps/ada_rocket_ra10_ra20.pdf

[jeff]

In parallel they would be 1k for the same 2k PP OT. So I don't think you would want to do that. I'm not positive how the secondaries would work. I think it would be the same if you used half of the winding.

Don't run them parallel they'd be out of phase. From CT to one end is out of phase from CT to the other.

[JayB]

In parallel they would be 1k for the same 2k PP OT. So I don't think you would want to do that. I'm not positive how the secondaries would work. I think it would be the same if you used half of the winding.

Don't run them parallel they'd be out of phase. From CT to one end is out of phase from CT to the other.

I didn't think of that.   

[PRR]

> method of combining the primaries to make it work single ended

Just hook it up. It will "work".

Bass power and distortion may suck.

Remember the teacher's pointer stick? (Before laser-pointers.) Tie a string to a spring on the stick, and try to point. You can, but it's very different. That's how iron feels in SE mode.

> The ADA EL84 Rocket does this.

Note this has a 50 Watt Bassman P-P OT for a 4 Watt SE amp.

Yes, with E-I iron (not toroid), 10:1 over-size iron will tolerate SE operation.

There's no magic connection. There are a dozen patents which attempt to cure magnetic unbalance on SE amps. All are at least as much trouble/cost as going P-P, and most lack P-P's distortion cancellation.

[phsyconoodler]

Yeah,every time I have tried PP iron in a single ended application it lacks tone.
  I ended up just getting the proper SE iron from Hammond.The reward was great tone.