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Old 9th July 2014, 08:50 PM   #1
YashN is offline YashN  Canada
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Default Edcor CXSE CFB wiring.

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.
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Old 10th July 2014, 11:51 AM   #2
bobrown14 is offline bobrown14  United States
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Try it both ways and report back .....

Cheers,
Bob
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Old 10th July 2014, 05:59 PM   #3
YashN is offline YashN  Canada
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Tried it the inverted way, but can only report a blown fuse on power up for now...
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Old 10th July 2014, 06:00 PM   #4
YashN is offline YashN  Canada
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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.
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Old 10th July 2014, 07:15 PM   #5
bobrown14 is offline bobrown14  United States
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Quote:
Originally Posted by YashN View Post
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
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Old 10th July 2014, 10:18 PM   #6
YashN is offline YashN  Canada
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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...
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Old 11th July 2014, 09:56 PM   #7
YashN is offline YashN  Canada
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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.
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