[Amps] Alpha a77s-1 transformer hum

Rich Hallman - N7TR rich at n7tr.com
Thu Jan 31 10:11:06 EST 2013

I just received two new Peter Dahl A77s-1 transformers and installed them last night.  Both of the transformers have a loud audible hum while transmitting. Low and high power.  I felt the transformer while transmitting and there is a bad physical vibration as well creating the hum.  The amps worked fine with the stock transformer before changing them out for the Peter Dahl. 

Anyone else running this transformer and are they seeing the same problem?   I can't think of any other wiring I need to do since the stock transformer worked ok.  Should be just a drop in replacement.

Thanks.....Rich. N7TR

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