Phono stage hum

My next guess is TT itself is not grounded properly within TT chassis. I would check RCA solder joint and make sure it checks out.

My amp (parasound a21) has a ground lift option and the hum is still there when enabled.  Would testing a cheater plug do anything different?

I will confirm the TT rca solder joint to make sure it is ok - but if there was an issue wouldn’t it be present on the other phono stage (sim audio lp5.3)?

I would think you are right @otherones.
I guess chinook had some issues before according to google search. Might have to give them a call. I would try a cheater plug first tho.

Did you buy it new from a dealer?

Does the Chinook run a  lot higher gain than the simaudio?
Is the gain adjustable on it?
Could account for some of the excess hum
Could be your expensive tt and wires are more sensitive to the gain difference than the cheaper tt ?

My older Teac tn300 never gave me any hum no matter what was in front or behind of it, My Nottingham on the other hand is a LOT more sensitive to things like cables, ac power lines, phono stage gain etc.

Call Manley tech support.  I had a SE version that developed a hum.  After various steps of troubleshooting they had me send it back.  They rotated one board 90 deg and solved the problem.