Quote:
Originally Posted by radiotvnut
There is one thing that's a little annoying with this Electro power supply. When connected to this Silvertone radio, there is a little 120 cycle hum and I can hear some slight oscillation when I tune off a station.
I have a Perma-Power eliminator and the problem is not there when I use that one.
On the electro unit, I've tried bridging electrolytic caps as well as clipping in a .01 uf cap across the various outputs and nothing helps. The only thing I have not done is remove the .047 uf "across the line" cap. Like I said earlier, the filament supply uses a transformer and is isolated. The B+ supply is rectified directly from the AC line.
On the perma-power unit, both filament and B+ supplies are derived from a power transformer and are isolated from the power line. There is also no AC line cap in this unit.
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I read a period article about the battery eliminators that indicated that hum was common. The article suggested relocating the eliminator. The B+ might be clean but the eliminator itself might be the source of the hum.
Do you have a scope you can check for ac ripple?