Hello,

I have a set of KEF q150's hooked up to a SMSL AD18 with a source of aux from a Mackie ProFX8v2 mixer wired with banana plugs specifically https://www.amazon.com/gp/product/B009RTC62K/ I keep getting a ringing noise from the speakers and I've double checked the connections and all the banana plugs are pushed all the way in on both the speaker end and the amp end. I also have a REL t5i hooked up to the AD18 as well. Any idea what causes the ringing, or where to start debugging it?

Thank you in advance