[Amps] henry hum

[Jim Thomson]

>? ? The 8 Henry filter choke with an oil filled .1mFd in parallel then an oil filled 20mFd cap to 
> ground is a tuned filter, tuned to 120 Hz.? If you truly have 60 Hz hum, you have a diode open in 
> one of the arms of the bridge rectifier.? ? If you truly have 120 Hz hum, you have a "detuned 
> filter" possibly the oil filled 20mFd cap has changed value.? Check the values of both caps first.
>? ? With this, like all power supplies the HUM sounds greater with a higher current draw, from the 
> supply.

##  if the 20 uf filter cap dropped a  bit in value.. that will NOT  de-tune the 8 henry filter choke.

##  The .1 uf in parallel with the 8 h  choke is the tuned choke.   Now if the .1 uf resonating cap
changed value, the choke is now de tuned. 

Jim  VE7RF