Grounding questions

Take your amp to a friend and try it there.

Yes a very good electrician told me it’s not grounded. There is a TV but no cable box. I stream. 

@mschott

You’re fortunate to have @jea48 on your thread. I have one question, an electrician ran a dedicated line for you but left the service panel without a ground?

There is no equipment ground. That is because I tried grounds and it made no difference.

The Furman does not have this indicator.

I don’t have an answer about the ground. I assume when they ran the new lines they just tapped into the existing fuse box. Aging a ground to that was not part of the contract. That is why I am now considering having a ground added.

yes I have a basic multimeter. 

Your electrical system should be grounded, irrespective of audio issues.

I second the suggestion to take your amp elsewhere to see if the hum is still present. I'm inclined to think it will be, and that it's transformer noise. I have the same thing with mine.

+1 on yes, it should be grounded. Will prevent shocks and improve surge protection. May not fix your hum.

At 63 years old, it is time to bite the bullet and come up to code my friend. In panel surge protectors, arc fault breakers and better distribution of your power circuits for the future, not to mention god only knows how many of those fuses are the wrong size.

I have a quote for a new Siemens box. It’s way out of my budget and comfort zone. I’ve been in the home for 24 years with no electrical issues. There is a new supplemental box installed when I had a bathroom reno in 2014. It runs the sump pump in addition to the bathroom circuits. 

Just as a test drop the ground on the amp. Then do the same to the pre-amp. 

Hum independent of volume can be a sign of old/dry power supply caps. I would, per maxwave advise, take it to a friend and try it there.

Also, since you have balanced connection between pre and amp, check where shield is connected on both ends. It should be connected to shell/chassis and not to pin 1 (that would cause noise currents induced in shield to flow thru analog grounds causing constant hum). This is very common problem (1994 AES paper, Neil Muncy).

Answer your own question with an $8 receptacle tester. Then make sure that the green wire is attached on both ends.

FYI the hum existed before the electrician installed the dedicated line. Im

not home to look at the receptical at this time. 

First things first: Power on the amplifier without the preamp. If the hum goes away then connect the preamp. If still no hum connect the source components one at a time to the preamp until there's humming. Then we can narrow it down.

Thank you. I don’t remember if I used a cheater prior to the dedicated outlets which by the way are not GFCI. I isolated the power amp and there is hum from both speakers. When I plug it directly into the wall, there is hum from both speakers but the frequency seems a little different. 

Then I did use a cheater. Yes the outlet is same as the Amazon link in your last post. 

Aging a ground to that was not part of the contract. That is why I am now considering having a ground added.

@mschott FWIW dept.: in order to add a circuit of any kind, whatever it is connected to has to be up to code. So either the electrician did something illegal or else found a way to provide a legal ground.

The suggestions to try the amp elsewhere or with nothing connected to its inputs are good ones! It may simply be that the amp has a hum problem; one potential source of a hum in an amplifier is filter capacitors failing in the power supply of the amp. That can lead to power transformer failure which can be really expensive and disheartening. So its worth it to sort out what is going on.