[lovingdvd]

Wayne,

Its so strange that this thread was just resurrected after all this time - I was just getting ready to post an update to where we last left off based on some testing from last night!

As you may recall a bit earlier in this thread you helped me understand how to create one of these XLR adapters to solve my hum problem.

This worked great for several months, but recently I started getting this VERY slight hum from my subwoofer that was only noticeable when a source (such as my HD DVD player or STB) was outputting a signal AND it wsa in a silent passage. Nonetheless its been driving me crazy.

So in other words if the source was not sending a signal, such as if a HD DVD was stopped and my AVR showed not bitstream or PCM signal, then there was no slight hum. But once I hit play, during silent passages I could hear the hum - and if I hit mute on the AVR the hum would go away. And I know this is not the HD DVD player as the same thing would happen with other sources.

I rechecked all my connections and things looked fine. Eventually I became suspicious over my home made RCA female to XLR plug with the wiring change to isolate the ground loop. And that's indeed what turned out to be causing the slight hum.

I verified this by temporaily putting a cheater plug in and removing my custom adapter, connecting it instead with a standard Radio Shack female RCA to male Phono plug. Violia, no hum whatsoever.

Now I don't think that my custom XLR plug has gone bad (or at least not completely), because if I wire things direct without my XLR plug and without the cheater then it hums badly. And then if I insert my home made XLR plug then the hum stops completely - except for when the AVR is sending an active signal, in which case the hum returns. Again, with the cheater plug in and no custom XLR, I get no hum whatsoever at any time.

What do you think may be going on here? I don't think this is the typical grounding loop hum, because it only happens when there is an active source.

I really hate the idea of sticking with the cheater plug and would like to solve this once and for all.

Any ideas what may be going on here and how it can be definitively solved without the cheater plug? Apparently my custom XLR approach was not the full solution (either that or it has gone bad, at least partially)?

Thanks!