Hum from both speakers...This is New Please read.

Is it the negative speaker post on the amp?
Is it the negative speaker post on the speaker?
Is it the cable?

This should not be too hard to figure out. You have several components that can be the problem. If you isolate each component to verify it is OK, you will narrow things down until you are left with the problem.

Start with the speakers. Switch them from right to left. If the problem doesn't move with them, the speakers are OK.

Now, do the same exact thing with the speaker cables. Again, if the problem stays the same, you have now eliminated both the speaker and speaker cables.

**I just noticed something in your post. You don't say if the problem occurs with just one or both your sources. Unless you say otherwise, I will assume both and that will rule out all source components and cables. ****

Now go to the amp. I know you have tried new tubes. Try this anyway: Turn the amp off and move the tubes from the right channel to the left and from the left to the right---do all of them, not just the power tubes. If the problem follows the tubes, you have the problem.

Unplug your subwoofer and remove the IC. If the noise is still there, I would have to say that there is some type of internal issue in your amp. But first..

Completely disconnect 1 of your sources (TT, phono pre, interconnects and powercords or Transport, Dac, interconnects and power cords). If after completely disconnecting one of your sources the noise is still there, hook it all back up and unhook the other source.

If the noise is still there after checking both sources, my best guess would be something in your amp or your AC. If you can, try the amp in a different location. If the problem follows one of your sources, you should be good enough at this by now to keep going and isolate the problem.

Also, I'm not a repair person of any kind and could have very well overlooked something. Check all the other posts as they may have thought of something I missed.

Blk25, Thanks! I have gone through the above steps and I'm leaning towards the AMP. Nothing else changes the hum. The right negative changes on the speaker are the only way I can make it stop. ( On both speakers ) and switching the speakers lends the same results. So, the question I have now before me is.. Do I open up the AMP and have a look at the wiring (Grounds to the speaker Posts ) or Pack it up and live without an AMP for ~two weeks, I would think. Really a drag. With the new tubes in, it sounds awesome, but I can not live with the hum ( Knowing it is there kills me! )

Thanks for all the help!

When you solve this one let me know. I have an identical problem with one of my amps. And it is the amp! And it has something to do with the amps grounding scheme. This came up a few years ago when I was trying to use it and I researched it. I believe there is a devise which can be inserted between the preamp and amp input/output to remove this hum. I was first alerted to this possibility by an amp designer. I did the research on Google but unfortunately did not keep the references and the specifics nor do I remember them, but it is there. I never pursued this but from what I read it sounded as if it would/could work. I just started using a different amp.

Good luck

Yeah, if you find an answer please post it. I've had the same problem with a Cary
v12r for a couple of months now. Sent it in to Cary for what wound up being a very expensive service (cap upgrade) and they could not duplicate the hum AND it was still there when I got the amp back. Switching to the 4ohm taps helped some. Curious to hear if you can fix yours.

Sometimes it's a ground loop involving the subwoofer. Have you tried unpluging the subwoofer from the wall?? Sometimes the audio isolator works at the rca inputs to the sub if you're running it passively.