Low level Hum in Phono Signal Path

Try grounding preamp to center screw in AC outlet, that sometimes works. You can also try lifting the ground by using a cheater plug. If you try the latter a further step having nothing to do with hum is to ground down or file off the bigger prong so it can be inserted either way. One way usually sounds better than the other.

If you are using a tube power amp, there may be hum originating from the amp or the tubes. Also, as mentioned above, definitely check the polarity of each component, and interconnects. Cable quality and placement are also important. There may be a ground loop. I was able to get rid of one source of hum with using a battery phono preamp. Good luck!

Sounds like a potential grounding problem. If your tonearm interconnect has a ground wire, connect it to the ground screw (or a chassis screw if the pre doesn't have a dedicated ground screw). Then, get a ground lift plug and put it on the AC cable of your Power amp. Leave the ground on your preamp AC plug intact. Try that and see what effect it has. I've found more than once that leaving the Preamp grounded and lifting the ground on your power amp will resolve most grounding and hum problems.

Acoustat6-Yeah, nice. The guy's trying to explain, in detail, his issue, and he's mocked for his efforts.

I'll assume you're a Community College graduate, so I'll explain this like I'm talking to a six year old: believe it or not, there are 'hum' issues that are steady-state, with no volume differential dependent on gain. Hence, the OP's clarification.

Hope that helps...

I've had this problem a lot on various vinyl rigs I've tried, and I think this is a pretty common issue. I've had varying success in eliminating it and am hardly an authority, but here are some things I'd suggest:
- check the ground from your table to the preamp - make sure it's good and solid.
- check whether the position of your table with respect to your preamp makes a difference and relocated it accordingly.
- get some Craig DeOxit contact cleaner and apply it to every contact in the signal chain - headshell connections, interconects and ground.
- make sure the TT ground connection goes to your tonearm as well as the TT subchassis.

If you can't hear it from your listening position at normal listening levels that's good, and if you can get it cleaned up so you can't hear it at above normal volume levels (ie from your seat, with nothing playing, volume setting higher than normal), you may have to be satisfied with that. This is because you may reach diminishing returns, and IMHO this is just the fact of life with certain arms, cartridges, preamps, and the combination of them. You're likely to have more of this hum on vinyl than with CD or other inputs, even under ideal conditions. The alternative is swap components.

PS - johnbrown - good on you for calling out acoustat6.