power hum

[Charles]

Can anyone point me to a circuit for eliminating a 60 cycle power hum.
I have a small transmitter connected to the audio output of my satellite
decoder and want to connect a receiver to the aux input on my Hi-Fi. It
works fine using a 3v battery supply but when connected to a commercial
battery eliminator, there is an unacceptable background hum. I think a need
a filter of sorts.

Thanks
Charles

 

[John Popelish]

Charles wrote:

Can anyone point me to a circuit for eliminating a 60 cycle power hum.
I have a small transmitter connected to the audio output of my satellite
decoder and want to connect a receiver to the aux input on my Hi-Fi. It
works fine using a 3v battery supply but when connected to a commercial
battery eliminator, there is an unacceptable background hum. I think a need
a filter of sorts.

Thanks
Charles

The first thing to try is to connect a large value capacitor across
the eliminator output to smooth the ripple the rectifiers produce. A
capacitor of at least 1000 uF rated for at least 6.3 volts should
help. Make sure you connect the positive end of the capacitor to the
more positive side of the supply.

--
John Popelish