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    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Edcor Transformer Problems

Astera

Member
2005-12-31 10:09 am
CA
I'm not trying to be obnoxious toward Edcor, more of a heads-up in case someone runs into this in the future!

To be brief, the output transformers I ordered from Edcor are wired or wound incorrectly.

I had ordered four output transformers from them a few months ago and they were excellent — no problems. I have them running in a pair of PCB-based Darlings. Edcor make an excellent transformer at a good price for the hobbyists like us.

I ordered another four recently however and they're going to have to go back. The first clue was when I wired up my third Darling and the volume coming out of the speakers was exceptionally low. After much tube and PCB swapping I finally isolated the problem to the transformers. Somehow they're not to the same spec as the ones I ordered earlier.

I'm unaware of a test to determine how the transformers are incorrect. A simple resistance check across the input windings showed only a 1% difference between the good and the bad transformers.

Anyway, just a heads up to check the transformers in circuit if you can before you cut the leads or paint the bells (as I did).