Love / Hate relationship with vinyl?

Tubes per se don't hum (in the electrical sense of the word, which refers to 60Hz noise created by a ground problem); they just fade away like old soldiers. However, tubes can be microphonic, wherein they will pick up any environmental vibrations and amplify them through the speakers. But it is not clear what you are hearing that irritates; can you amplify on your definition of "hum"? Is it really 60Hz or is it more like a "buzz" composed of mixed frequencies? "Hiss" might (just might) be treatable by changing VTA. Try lowering the tonearm pivot wrt the LP surface. And so far as I can tell, you have not mentioned what phono stage/linestage you are using, except I gather it is tube type.

It's nature of high gain stages to handle LOMC.

A lot of good comments have been made, and, yes, it certainly seems possible that the condition of the tubes in your line stage preamp may be a factor. Especially given the unusually high 30 db gain that the preamp provides. I'll add the following to what has been said:

First, it appears that your system includes an unusual multitude of different power conditioning products. Some such products do unusual things with the power line grounds, which very conceivably could result in some setups in hum, noise, and/or sound quality issues. I would suggest that for experimental purposes you simplify the setup as much as possible, eliminating all of those things, as well as any components that are not necessary for vinyl playback.

Also, when you do that try temporarily using a cheater plug (a 3-prong to 2-prong adapter, with the ground not connected to the wall plate screw) on the AC plugs of each of the remaining components, one at a time. That will break any ground loops that may be contributing to the problem.

Also, it's not clear from your system description photos where the turntable, phono stage, and preamp are located, relative to the components that are shown. If any of them, or their associated cabling, are located near the power amp or the power conditioners, that may be contributing to hum pickup.

Finally, I see that the default settings of your Acoustech PH-1P when in LOMC mode result in an input capacitance of 10,000 pf, which seems wacky to me and could result in excessive sensitivity to RFI pickup. Jonathan Carr, who designed your cartridge, has said in past threads here that in general load capacitance that is applied to LOMC's should be kept as low as possible. 10,000 pf is extremely high. I'm not sure if that value can be readily changed in the Acoustech to the moving magnet default of about 200 pf, by changing the position of an internal jumper. If it can be readily changed, I would suggest that you do that and reassess the sonics it provides in LOMC mode, without the head amp.

Good luck. Regards,
-- Al

I haven't waded through all the replies to your hum problem but do you have the grounding wire from your tonearm to your preamp in use?

I use a Graham Slee Reflex C with my Dynavector 20X2L and it's very quiet. Why don't you try a solid-state preamp that is returnable (Music Direct) and see if that solves the issue? They have very helpful sales staff as well.