• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Is connecting 2 amps via their grounds a safe choice?

alex-z

Addicted to Fun and Learning
Joined
Feb 19, 2021
Messages
910
Likes
1,684
Location
Canada
My HT setup is a Onkyo NR555, with the subwoofer RCA output feeding into a miniDSP 2x4HD, which then outputs into a Yamaha R-95 stereo amp powering the subs.

There is also a TV and PC on the same circuit. Only the PC has a 3 pin wall connection, and it is connected to the receiver via HDMI.

Without the miniDSP 2x4HD, everything is great, no ground loop (60Hz hum). With it in place, substantial humming. All 3 devices have 2 pin wall connections.

The NR555 and R-95 both have ground hookups. My initial thought was to connect both ground hookups to each other via a short 16 gauge wire.

I just want to know if I am being stupid, and should instead connect each ground directly to the wall ground. I don't want to cause any potential safety issues.

Edit:

Nevermind. Connecting the grounds had minimal improvement. Turns out the PC hooked up HDMI was the primary issue, and just putting the amps on a different outlet (yet same circuit) helped tremendously. Somehow this problem never cropped up until the miniDSP was added.

Going to purchase some shorter RCA cables and a higher quality computer power supply to try and remove the last bit of hum.
 
Last edited:

rwortman

Addicted to Fun and Learning
Forum Donor
Joined
Jan 29, 2019
Messages
740
Likes
683
If that doesn’t fix hit Jensen makes high quality audio isolation transformers that will kill it completely. They aren’t cheap though.
 
Top Bottom