center tapped choke inverter

[alexg]

I am thinking of using a center tapped choke inverter for my 832A PP amp with a 6dj8 driver.

There is transformer company here in the Philippines that winds my OPTs and PTX and my chokes with great results. However, he has not wound any center tapped choke for phase inversion.

I have searched for any specs of this kind of phase inversion and the only specs I got are those posted by Shoog using toroidal power tranny as phase inverters.

Any advise on how to wind these?

[kevinkr]

I think a bi-filar winding and any techniques possible to minimize stray capacitance are a couple of things I would be inclined to try. Leakage inductance is important too for high frequency balance, hence the recommendation for a bi-filar winding with the problems that brings. The insulation on the magnet wire must withstand full B+ (if present) and more than 2X the maximum plate swing of the driving stage, some margin say 50% would be a good idea.

It goes without saying that 1/2 the winding must have sufficient inductance by itself to permit flat response down to the lowest frequency of interest.

[dave slagle]

Tell your winder to wind the best inverting 1:1 transformer he can and pretend it is a CT choke.

Since the 1:1 needs to be inverting bifilar will not work.

dave

[alexg]

Do I need these airgapped?

Am planning to use it like the SETH 2A3.

[alexg]

Got all the information i need now:

Center tapped choke, bi-filar winding, no gap. very similar to a plate choke winding except for the center tap, the end of the first wind and the beginning of the second wind, together will form the center tap, the end of the second wind will have a 180 degree signal compared to the beginning of the first wind.

I will just ask my winder to make sure it has the same bandwidth as all the plate chokes he did for me.

Thanks for all your help.

[dave slagle]

forget bifilar, it will not give you any bandwidth in this situation.

dave

[Tony]

this is a concept i had in mind....

[Bandersnatch]

hey-Hey!!!,
This is a fairly simple wind. With a dual bobbin, wind 1/4 of the turns in each bay, one reverse direction compared to the other. Continue winding the next 1/2 of each bay's turns in the opposite bay( but in the same direction they were started in ). Finist the last 1/4 of each bay in the same one it started in.

In each bay you'll have half of each half, and half of the other side( wound in opposite direction ). Each of the turns near the CT will be nest to the core, and the signal ends will be at the outside of the bobbin.
Best Regards,
Douglas

[Tony]

HI,

i still want to do it bi-billiar but with 4sections vertical on bobbin, read in RHD4 that capacitance effects are minimised this way...

[Bandersnatch]

Originally posted by Tony
HI,

i still want to do it bi-billiar but with 4sections vertical on bobbin, read in RHD4 that capacitance effects are minimised this way...

what do you propose to do about the bifilar capacitance?

Douglas