I FOUND THE HUM ON MY PHILCO 90!! - Printable Version

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+--- Thread: I FOUND THE HUM ON MY PHILCO 90!! (/showthread.php?tid=1515)

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I FOUND THE HUM ON MY PHILCO 90!! - Guest - 11-24-2008

A few posts back I was asking about the electrolytics on my Philco 90 (single 47 tube) and the pesky 60hz hum on the thing. Signal was strong, voltages were all normal (except for a defective 24 tube, which I replaced). I thought something was grounding on the chassis, like a bared wire. Replaced a few suspect wires. Double checked my rebuilt bakelite blocks. All good.
After a week of fiddling around, I thought 'To H**l with it. I'll live with the hum'. I started reattaching the speaker to the radio (while it was on) and accidentally pushed on the paper cone. The hum went AWAY! Closer inspection revealed that the speaker cone was glued off-center onto the frame from the factory. Plus, the cone (either due to heat or moisture or whatever) had a slight warp to it on one side. I stuffed a piece of foam in behind to return the cone to roughly its original contour and VIOLA, hum is gone! I should get it rebuild but oh man, the sound is so rich now (it's the best sounding of my six radios), I don't think I want to be without it for any length of time!

Thanks again guys for taking the time to respond to my post

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Re: I FOUND THE HUM ON MY PHILCO 90!! - Ron Ramirez - 11-25-2008

Congratulations!

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Re: I FOUND THE HUM ON MY PHILCO 90!! - rghines1 - 11-26-2008

My Congrats as well.

This sounds more like a weird case of speaker rattle, excuse the pun.
Hum is normally of electrical origin.
Always new things to learn.

Richard

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Re: I FOUND THE HUM ON MY PHILCO 90!! - Texasrocker - 11-30-2008

another reason Philco added the "hum-bucking" coils in their spkrs?

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