[stevecuss]

Hello,

I know this is a bit off topic, but I wasn't sure who else to ask.

I have an interesting dilemma. I have a Yaqin tube amp and it doesn't have subwoofer output, so I 'biwire' one et of speaker terminals on the Yaqin and just run speaker wire into the Sub. All good there. The Yaqin plays through my GR N2x monitors and the sub brings low end.

Sounds glorious.

I only use the Yaqin for music. Everything else (TV, Roku etc) goes through a Vizio soundbar that has a RCA style sub out. When I run a single, shielded RCA cable from soundbar to Sub, I get a hum.

The Yaqin, Vizio, Cable box etc plugged into one output. The Sub is plugged into different outlet across the room. Cable box has a coaxial isolation transformer.

I did some research - sounds like a common ground loop issue solvable with an isolation transformer. No problem. I can buy one if that is the fix.

But before I order a blue jean iso transformer, I thought I'd check: is the fact that I am running speaker wire from one source and an RCA from another potentially causing the hum?  Or is it causing any longer term issues?

any help or thoughts appreciated.

[aldcoll]

You might add some make model of the Sub woofer and how it is powered, i.e. plate amp and inputs.

And when any type of him issue I would start with isolation tests.  Unplug one item at a a time and check.  Also swapping cables etc.

Having the two different sources for the sub would make be my first guess.

Alan

[stevecuss]

Thanks - its a Dayton 12" with plate amp and speaker inputs as well as RCA inputs. I have an isolation transformer coming and I am assuming that will do the ticket.

[avahifi]

Hum could be coming from bad earth ground on your incoming TV signal connection.  Disconnect that at TV set and see if hum goes away.

In line small isolation transformers are available to fix that issue.’

Stay healthy

Frank

[stevecuss]

thanks Frank, I ordered a sub isolation transformer and see if that does it. It will come in a few days and if it doesn't work, I'll do some deeper troubleshooting.