I'm having a (what I think is a Grounding) issue with my Audiophonics MPA-S250NC XLR amp, connecting to my active sub's speaker level inputs (RSL Speedwoofer 10s).
Setup: Source = PC > Duok U2 PRO XMOS XU208 Digital Interface > Schiit Modi DAC > Schiit Loki preamp > Schiit Vali2+ headphone/preamp >
Audiophonics MPA-S250NX XLR Amp > Speakers (RCA/Banana Plug from Amp's Output)
> RSL Sub, Speaker Level In (Spade Connectors also coming from the Amp's same Output)
- When I make the connection to any of the Sub's Speaker Level Inputs I get a significant, constant humming from the subwoofer. I am reasonably sure this is a grounding issue.
- It occurs even when the amplifier is Audiophonics amp is powered off
- Both the sub and amp are connected to the same outlet (power strip)
- I tried connecting the sub to an entirely different outlet, issue remained
- I was using a different amp recently that has a dedicated sub out (RSL ia255.1) without any hum, I just tried upgrading to the Audiophonics and from my research this spade connection to sub speaker level in seemed like the simplest way to connect my sub. I don't have any other available connections on my preamps in this setup.
Since discovering the issue and doing some research, I'm reading that some Class D amp's black speaker terminals are not actually grounded, rather both terminals of each output are active. Is this the case with my Audiophonics amp? If so this means I have a grounding issue, is there an easier/cleaner solution than buying a Line Out Converter?
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Thanks in advance!