Phono cable not caps to le with preamp?

bicycle, "knowledge is never useless"????

It's true; I have too many posts here. But I think that is over a 15-20 year period and includes the duration of the pandemic when I was going out of my mind with boredom and the confinement.

On the other hand, can you name your phono stage? And by the way, you don't necessarily HAVE TO ground your turntable.  It's something to try if you have hum. I've got 5 turntables up and running, and none of them is separately grounded to the phono stage(s).  Yet I have no issues with hum.

Bicycle, am I correct in the belief that the blurb you quoted is from your owners manual and that your phono stage is not identical to the OP’s? If so, the bit about playing with internal ground switches is useless to the OP, because the vast majority of phono stages provide no such options. However the verbal points to consider do apply to most situations. I think his new phono most likely has an internal short owing to a cold solder joint or to a broken one.

A VERY loud hum is possibly due to a more major ground fault than the hum that typically results from failure to ground the TT or tonearm, in my experience. If the usual suspects don't work at all, I would look at either the cables (maybe the solder joint between the cable itself and the grounded barrel on one of the RCA connectors came loose) or the new phono stage itself.  Crack open the chassis and have a look at the solder joints to the outputs.  But one huge question: Is the hum in both channels or in one channel?  If in both channels, then my hypothesis loses some credibility.

Definitely.