• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Harman Kardon A-30K (A-300) power supply

It's only very recently that I considered the fact that it might be the EMI from the transformer that is causing the noise because the problem is very similar to the one I have in the Quad preamp after changing the power transformer. What exactly do you mean by "if the hum is not the entire transformer humming" ? Mechanically it's not making any noise.
 
Perhaps, humm is not exactly correct terminology. I have run across transformers that are defective which will have a low frequency buzz. Where the entire transformer is vibrating and emitting a humming or buzzing noise. This noise can increase in frequency when the voltage is increased for example when the equipment is on a variac. This noise can be like humming if one were not familiar with the two types of noise. But one can definitely feel the transformer vibrating when it is bad but it also can be a very subtle vibration too.
 
The transformer is brand new, and just very slightly vibrating, the sound is really only coming out of the speakers. There is a 50hz hum and a higher frequency buzz riding on top.
 
You must log in or register to reply here.
Back
Top Bottom