I think my Sub is gonna die....

[Beta Man]

Long story short, I have been shopping around new subs (sunfire EQ is being auditioned next week, thanks to the help of others here) But I can't afford a new one quite yet, But in the meantime, my sub has a very apparent "HUM" from the amp, even when it's not connected to my receiver..... I took it appart, checked connections, looked for melted/crossed wires, and it all looks good. Since it does it when it's not connected, I know it's the amp in it that is going bad. I plugged it into it's own dedicated monster-power-source, and it still does it, so it's not EMI interference, and it's 2 prong, so it's not a ground issue.

Anyone know if there is a way to save it, or if it will continue to work, or is it done for?????? I know I'm planning on upgrading, but I'd really like to keep this one working for my Rec-room, and I don't want to have to purchase its replacement this soon, because my wife is still salty about the $9k I've spent on speakers in the past 3 months, and honestly I don't want to tell her I'm getting a new sub before father's day (that was our arrangement!)

If anyone knows of anything that might be causing this, please help!

It's a CV Sub-Model 150 (piece of junk I know) I've had it for 10 years, so nothing would surprise me. When listening to something, I can't hear it, but when the T.V. and Stereo are off, I hear it quite clearly (as if there was a refridgerator running just on the other side of the wall)