MiniDSP 2x4HD Hum issue

[jjkessler]

I know others in the forum know far more than I and might some ideas. I finally got around to installing my MiniDSP 2x4HD to help sum / align 2 subs prior to Dirac.

I am going from my RMC-1L mono sub output to an XLR to RCA adapter then into input 1 on the MiniDSP 2x4 HD. On the output side of the MiniDSP I am using channel 1 and 2 into separate Emotiva wireless sub extenders and then into two SVS PB12 plus subs

The issue I am having is a terrible low level hum in the subs. If I take the MiniDSP out of the loop the hum goes away. Seems to be something at the MiniDSP level. Did some reading and see this isn’t unusual with lots of ideas throw around and wanted to ask if others have come across this and if so, how did you solve it as I it’s not useable as is today ?

[marcl]

Apr 24, 2024 19:14:45 GMT -5 jjkessler said:

I know others in the forum know far more than I and might some ideas. I finally got around to installing my MiniDSP 2x4HD to help sum / align 2 subs prior to Dirac.

I am going from my RMC-1L mono sub output to an XLR to RCA adapter then into input 1 on the MiniDSP 2x4 HD. On the output side of the MiniDSP I am using channel 1 and 2 into separate Emotiva wireless sub extenders and then into two SVS PB12 plus subs

The issue I am having is a terrible low level hum in the subs. If I take the MiniDSP out of the loop the hum goes away. Seems to be something at the MiniDSP level. Did some reading and see this isn’t unusual with lots of ideas throw around and wanted to ask if others have come across this and if so, how did you solve it as I it’s not useable as is today ?

Seems like a ground loop issue where the subs are plugged into a separate circuit from the processor and miniDSP.  But honestly having a wireless adapter in the mix makes me not so sure,  I have a hum issue using an XLR to RCA adapter to an amp for my rear channels, and I solved it with an isolation transformer.  It might work to put such a transformer on the sub end, between the wireless adapters and the subs.  Maybe ... or between the processor and the wireless transmitters.  

www.amazon.com/gp/product/B0009GUOQA/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

[jjkessler]

I guess writing about it helped. Upon further investigation I found the hum happens when I’m connected the MiniDSP to the computer via USB to connect to the software. When I break that connection, noise went away. That’s manageage at least and one the ground loop is while connected to the computer / software and temporary

[ttocs]

Ground loop hum can happen when multiple devices are plugged into multiple electrical outlets. The outlets might be on the same circuit, but some distance from each other, or, they can be on separate circuits. The issue often arises when the distance to a common grounding point travels various distances from the outlets while electronic devices are also connected to each other.

The idea for avoiding ground loop hum is to connect as many interconnected components as is practical to the same electrical source, along with as many of those components relying on as few paths to ground as is practical.