I own 3 Crown professional power amplifiers that were purchased new a few years ago. These amplifiers have ONLY balanced XLR input jacks. Each Crown power amp pumps out 500-watts per side into 8 ohms and they can really crank on JBL speakers. All my sources (1) CD player, and (2) Bluetooth radio have standard home RCA outputs which are currently plugged into a Denon home receiver with pre-amp output jacks going to the Crown power amps.

Unfortunately, they all HUM (ground loop) and it drives me nuts.....

I have tried hooking these power amplifiers up to my Denon receiver using many different RCA to XLR cables with no successful elimination of the HUM (ground loop). The connections I'm using include 3-pin adapter jacks that go from XLR to RCA. These XLS-to-RCA conversion jacks have ONLY two wires (+, -), however.

A few weeks ago, I researched "HUM" and "ground loop" on the Internet and found a few interesting threads that discuss ground loop problems. The first suggestion was to insure that all electronic pieces are properly grounded and attached to the same electrical circuit on my circuit box (fuse box) but this exercise did not solve the HUM (ground loop).

The second suggestion was to use an Artcessories Clean Box Pro This unit is advertised to convert unbalanced output to balanced output. This did not work either but I am connecting this unit with the same XLR-to-RCA conversion jacks and the RCA cable wires only have two wires (+, -) which I am thinking defeats the purpose of the Clean Box Pro unit. I'm going to order two XLR cables (Male-to-female) that will have 3 wires to see if that solves the HUM when I connect them to the Clean Box Pro unit.

At this point, if this does not work, I'm thinking that I have only three choices, (1) dump the Crown power amplifiers in favor of some other large home power amplifiers with RCA inputs like the Adcom 555, or (2) use a cable that connects a 1/4" stereo headphone jack to an XLR jack, (3) buy a professional disco (??) pre-amplifier that will accept RCA inputs like a CD player and which will funnel its output into an XLS cable that will match the Crown professional power amplifier input jacks.


Any ideas on this is much appreciated.