[Elecraft] KPA500 Hum

[Ian White GM3SEK]

Ron D'Eau Claire wrote:
>Mike, I certainly concur with Eric's observation. What I thought was 
>very unusual was that you said that the hum would come and go, which I 
>presume happens when you aren't doing anything at the amp.
>

Hum that comes and goes for no apparent reason might be caused by some 
other large electrical appliance distorting the AC supply waveform - for 
example, an electric motor with a chopper-controlled Variable Speed 
Drive.

Although the 60/50Hz hum level from the KPA500 transformer is normally 
very low, a sudden increase in the higher harmonics could be quite 
noticeable.


-- 

73 from Ian GM3SEK
http://www.ifwtech.co.uk/g3sek