Hum from new Jolida 502B-Help

Just set up a new Jolida 502B and have a bad case of hum all of a sudden. Are they that sensitive? I've heard the humbuster from PS Audio may help. Any ideas, comments? The hum is now audible in my powered sub hooked up via pre outs on the amp.
In another thread I explained how my small hum problem with my 302B when I moved the system upstairs was completely solved by the PS Audio Humbuster.

You likely have a DC voltage (aka ground loop) in your AC line that is making the 502's power transformer hum.
Is yours a stock unit? I didn't think the 502b had pre-outs. Does the hum come from both speakers or just one side?
I'm looking into the Humbuster, thanks for that tidbit. The amp is stovk, Jolida will provide pre-outs for a nominal fee. Hum is from both speakers, also the powered sub has it. Never noticed this till I installed the Jolida. Will the Humbuster help with a ground loop issue as you described?
Thanks Guys
used a cheater plug-no more hum !!