Question Possible ground loop? But inconsistent...

Candan

Honorable
Jul 27, 2014
237
1
10,715
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Hi all,

I have a ground loop noise, coming from my speakers with a new audio connection. But it's inconsistent when I swap out certain components. Hoping someone can help me fix it.

I'm trying to replace a solid state amp (Sony STR-DN860 with optical inputs and HDMI) to a line-in only Tube Amp (Willsenton R8).

It's the kind that sounds like amplified coil whine, and increases pitch based on what's on screen, including mouse pointer noise.

Here's what I've done so far...

- Video card (RTX 2080Ti) to Sony STR-DN-860 with HDMI = No noise at all. (Using second display from video card to audio only)

- Mobo to Sony AVR using toslink, no noise.

- 3.5mm line-out cable to split L/R RCA line-in to tube amp = Lots of noise

I added a DAC (Audioengine D1) toslink from PC to toslink on DAC = Same noise through the speakers. (No noise with headphones plugged into DAC though)

If I use the same cables and same set up as above and connect to Sony AVR line-in, there's no noise at all.

However, if I remove the DAC and use my Bluesound Node 2i streamer's DAC instead (toslink from mobo to toslink on the Bluesound) and line-out to the tube amp, there's also no noise.

I'm not planning on using the Bluesound as a permanent fix, as it lives elsewhere. I want either this D1 to work or, use the mobo sound card straight to the tube amp without noise with RCA cables. Any suggestions please? Here's some grounding info from my set up...

Tube amp and PC (grounded 3 pin power cords)
Audioengine D1 DAC USB powered
Sony AVR and Bluesound Node 2i (ungrounded 2 pin plug)
How I'm plugging anything into the wall remains consistent on all ways of trying and I've tried separate and shared wall outlets.

Thanks!
 

Candan

Honorable
Jul 27, 2014
237
1
10,715
12
Update... I've since found that removing the ground pin from the tube amp power cord solves the issue. But I don't like the solution on a permanent basis. Any suggestions to remove this ground loop while keeping it safe?
 

Ralston18

Titan
Moderator
Consider that the problem is in/via the outlet and circuit serving the tube amp.

Removing a ground connection pin is not (as you posted) at all a likeable and viable permanent solution.

Time for a qualified and knowledgeable electrician to check your outlets and circuits.

Could be that the ground loop is simply a precursor to a potentially more serious problem developing somewhere.
 

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