Sick and tired of hum-please read

JBL 4345's
Canary 500 monoblocks using emission lab 300B tubes
PS Audio MK ll Dac
Dish Network VIP 612 DVR
Dedicated 120 line from panel

You name it, I've tried it. I have a low level 60hz hum that I for some crazy reason am unable to get rid of.

Lifting the ground, power re-generators, cable changes, equipment to equipment grounding, Satellite new cable and grounding and turning off the whole house except my music room has not resolved. The only explanation I can conclude is that 300B tube amps and very high efficiency speakers will always produce hum. Drives me crazy. This subject has been beaten to death but if any of you guys has any out of the box ideas other than the obvious, I would be interested to hear. Thank you in advance
Have you tried other amps including SS?

Try completely removing the DVR and substitute a CD player or transport.

I had a hum from the cable before, that might be your culprit.

Sounds like you have tried most things. Might there be any non audio electrical items in room such as Fluorescent lighting. And outside of repositioning your gear, which you may have done already, play it louder. Alas...the price of a system you love.
You have efficient speakers so there may be some residual hum from your Canary Amps ( I have a set of REF2) that you cannot eliminate. Start from the very end ie. connect speakers to amps, short the inputs with shorting plugs and turn them on, the level of hum you have at this point is your base level. Then work your way forward, connect the DAC to the amps if hum increases or appears you have to look at how equipment is grounded. You mention that you have dedicated circuit (s) to you system - if two circuits one from each leg of the feed to your house, this is a certain way to introduce hum in your system.

Best of luck

Have you tried one of these on the cable to your Dish Network DVR?

From what I understand Jensen makes a better and more expensive one as well. I have the Viewsonic and it works well enough.

All the best, hope it helps,
I had a similar problem with the audio output from my Dish Network reciver. I solved the problem by replacing the digital SPDIF coax cable from the Dish reciever to my processor with a Toslink cable. No more copper connection between the two units, no more hum!
Know anyone else nearby with efficient speakers? If so, try the amp out there to see if you have the same problem.
Fluorescent lighting will cause hum to a phono cartridge for sure. If that's the case, those lights could cause hum to a lesser degree in other sources.
I agree the amps sound like the culprit, perhaps residual transformer hum coming through the speakers?
Had a ground loop hum also. Got rid of it when I went from rca's to xlr's. Whiskey helped in the interim.
I got my hum to go away when I ran a new ground from the cable tv coaxial connector to a 6 ft copper coated rod I drove into the ground.
Invstbiker, if I were you I would start by disconnecting the preamp from the amp and see if the amp hums on its own.

300bs don't make a lot of power, so they have to be on efficient speakers. For this reason, they have to be hum-free. If, not, I would return it to the manufacturer for repair, unless there is a hum balanced control that simply needs adjustment.

OTOH if the system is quiet after this test, the next step is to disconnect all the inputs to the preamp and see if the preamp is quiet with amp and speakers.

Let us know what your progress is.