Buzz from the left channel of a Rega Brio

I’m getting a distinct buzz from the left channel of my Rega Brio. This is obviously worse when the phono preamp is adding gain. I switched the speaker cables so as to isolate the problem and I’m hearing the buzz in the right speaker (hooked up to the Brio’s left channel). This is the set of binding posts closest to the power cable. Is it possible that a better-shielded after market cable would creat less interference and thus help with this problem or is this an issue with the Brio itself? Although like a lot of other folks, I have upgrade-itis, the Brio is only a few months old and I can’t justify switching at the moment. 

By the way, as a relatively new and low-budget member here, asking these questions sometimes feels a little intimidating (like asking guys that own Gulfstreams questions about my Cessna single-engine). 

Thanks