• 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

electrical engineer needed

Thanks so much Empirelvr. I appreciate your help and patience. The copper ground on the cart was the culprit. Got it off and put headshell back and same hum but then I realized i hadn't moved ground back to Marantz and when I did I did a dance. Connected everything else back and crossed my fingers and all was fine
 
empirelvr said:
Okay, so you have hum when there's nothing but the TT and Marantz plugged into the power strip. That would rule out a ground loop sourced from the grounded components. Our next is to try removing the ground strap from the cartridge. Since the cartridge body, clip, and headshell are metal, that might be what's giving you hum. Even if you are using the plastic spacers and nylon screws, that's no assurance there still isn't metal to metal contact somewhere. It's best to remove the strap with a pin or toothpick, as you want to remove it, but keep it so you can replace it if it doesn't work.

So, now do this. Disconnect the DAC and CDP's power cords from the power strip. Keep the 698's output and ground cable connected to the Marantz. Remove the headshell from the 698 and pry off the ground strap from the 2000E/III and put the headshell back on the 698. Turn on Marantz and listen for hum. If there is no hum, try plugging in the CDP and DAC's power cords one by one in the power strip. If there is still no hum, congrats, you did it. If hum comes back, there are more steps to try.
Click to expand...

check the tread
 
That's what I was getting at. If the cartridge ground strap is in place and any metal part of the cartridge is touching the metal headshell, it creates a ground loop and...hum. Some part of your metal cartridge body must be in contact with the metal headshell and removing the ground strap does the same thing as isolating the cartridge body.

The idea is that you only want one ground path. Otherwise, a ground loop acts as an antenna for airborne 60 or 120 Hz currents.

Doug
 
Doug G. said:
That's what I was getting at. If the cartridge ground strap is in place and any metal part of the cartridge is touching the metal headshell, it creates a ground loop and...hum. Some part of your metal cartridge body must be in contact with the metal headshell and removing the ground strap does the same thing as isolating the cartridge body.

The idea is that you only want one ground path. Otherwise, a ground loop acts as an antenna for airborne 60 or 120 Hz currents.

Doug
Click to expand...
Thanks for the help and explanation Doug, it is good to understand WHY it was happening.
 
You must log in or register to reply here.
Back
Top Bottom