Preamp Deal of the Century

Bopo,
I'm not sure if this is similar to your situation but I had a problem with transformer hum coming from both my SS amp and Chardonnay power supply. The hum/buzz came from the power supply and not from the speakers and was audible from several feet away. Through some experimentation.. unpluging various AC sources, I discovered that when my plasma TV was on the same AC circuit the hum/buzz appeared. Now with the plasma TV is on a separate circuit and a PS-Audio Hum Buster in line, everything is nice and quiet. Apparently rogue DC current on your AC line can 'rattle' transformers.

Dave

Dave,

Thanks for the info. I will try unpluging my other components and see what happens. I am running my audio on a dedicated circuit but it's worth a try. I also didn't notice it when I first recieved it. If I need to I will get some sort of line conditioner. Thanks again.

Bryan

Bopo,

I had a similar issue, try moving the umbilical cord around as it is not shielded.

Mgv,

Thanks I will try that. I did try turning off all breakers except audio and still had the hum so what you are saying seems logical.

Bryan

If it was me having a hum issue, I will find out first if it is electrical or mechanical. Electrical, well, try simple process of elimination. Mechanical, make sure the bolt that hold the toroid in the PSU is tight (can easily seen from the top of hte PSU).

Pardon me but I have a question to ask to those who understand the subject matter well than I can. Bear with me and I dont intend to insult anyone. How can the umbilical cord produce a hum? I thought it carries DC voltages only. Hum if electrical, is AC isn't it? Its an oscillation ain't it? On this regard, another question if you guys do not mind. Why would an umbilical cord make a difference with regards to shielding if it only carries DC? Not to mention that the first stage that the power after rectification (PSU unit) will encouner is the regulator (there is an specific tolerance range where the regulator if working properly will regulate the voltage +/- a certain criterion)on the main preamp box itself so that the length of the cord, if not excessively long, will not degrade/decrease the DC voltages to a significant amount for the application as it encounters environmental interferrence when travelling from the PSU to the main preamp box.

Using a decent power cord from wall to the PSU, I understand that there can be improvements because I am experiencing it. Vibration points, I understand as well and agree that it makes a difference. But a shielded umbilical cord that carries DC improves the preamp performance? In what way and how?

Please, forgive me, but I am not looking for an argument but an explanation only. I want to learn what I am not familiar with (no sarcasm whatsoever!).