Edcor CXSE CFB wiring.

[YashN]

Has anyone with Edcor CXSE25-8-5K used CFB (cathode feedback)?

If so, could you please tell me if the Edcor OPT wires must be inverted on to the PCB?

Thanks.

 

[bobrown14]

Try it both ways and report back .....

Cheers,
Bob

 

[YashN]

Tried it the inverted way, but can only report a blown fuse on power up for now...

 

[YashN]

The thing is, I was looking for somebody who already has implemented it with the same Edcor, so that I avoid having to try both ways.

 

[bobrown14]

The thing is, I was looking for somebody who already has implemented it with the same Edcor, so that I avoid having to try both ways.

I never tried the inverted way always used the Edcors as indicated on the schematic with good result, so I never tried it the other way around. I think the transformers with the issue are Hammond but don't quote me on that.

Cheers,
Bob

 

[YashN]

I don't think it's an issue per se, just a question of how the wiring is done in the transformer so that you actually get cathode feedback in the proper phase.

Guess I'll have to try both ways and choose the lowest volume as George recommends if nobody did it before.

But for now, it seems I'm stuck, Pin 2 of the 12AT7 misbehaves, probably C10 or some other thing is fried...

 

[YashN]

Looks like inverted works for me (George's diagram is inverted). I tried using it non inverted, but then a type of high-pitched screech started to build up, probably oscillation as the feedback was positive rather than negative.

With inverted, there's no screech.