PP output transformer used in SE?

[Audio_Works]

Is it possible to use a PP transformer in a SE amp with? The PP primary has a mid tap so if it can be used driven by one tube only how should it be connected? Between the midle tap and one of the ends or the entire winding of the primary?

Im planning on using 6p3s-e tubes in SE. Got everything expect output transformers, looking around found some pp transformers for 6p3s-e, so im wondering if i can save some money using these.

Thx.

 

[dnewma04]

You can use them, but you typically need to have transformers that are rated at a significantly higher power rating than an equivalent SE transformer with the air gap. I believe that i've seen a situation where a designer used 60w rated PP opts for a 10w SE amp.

PP transformers have their primary rated across the entire winding unless specified otherwise. I believe it would be best to use the entire winding.

 

[bricktop]

You can do a parafeed, which will require a plate choke and capacitively coupling the output transformer.

Alternatively, you can use a pentode on one leg of the opt as a constant current sink and the SE tube on the other leg. Both methods eliminate DC current imbalance in the windings.

 

[soundmotor]

Pre-war, UTC transformer applications called out that you could use their 15W PP for 1-2W SE with acceptable frequency response. The loss was at the bottom-end where core saturation has the greatest impact.

I have also heard about people restacking laminations on a PP transformer to create an air gap with some success. I don't know however if this was actually done and isn't anything more than urban tube audio legend.

 

[Audio_Works]

Thanks for your posts. The Opts i want to use are from PP version using the same tubes i want to use in SE: 6p3s-e (soviet) i think they're equivalent of 6v6, im not sure. The PP were rated at 30W. Based on what you said it may not be that good over 1W. As i know the 6p3s-e in SE can deliver about 7-8W.

Here is picture with PP Opt i have, sry for quality:

Mains Transformer:

6p3s-e Tube, ECC83:

Alternatively, you can use a pentode on one leg of the opt as a constant current sink and the SE tube on the other leg. Both methods eliminate DC current imbalance in the windings.

Can you give me more details about this technique? A picture of a schematic might help me understand. Thank you.

 

[dnewma04]

6P3S-E is roughly equivalent to a 6L6, I believe.

I would expect you'd need a physically larger output unless you followed one of Micah's (bricktop) suggestions.

 

[bricktop]

Can you give me more details about this technique? A picture of a schematic might help me understand. Thank you.

Here's a blurb on it at diyaudio: http://www.diyaudio.com/forums/tubes-valves/118725-another-kind-hybrid.html

The solid state MOSFET current source in the first pic can be replaced with a pentode to maintain glassy purity and glowiness.

 

[Audio_Works]

i see, thanks for your help. I belive i will get SE OTs in the end, its the easiest and lets say purest solution even if more costly but time is on my side. Thanks again.