Reduce audible hum Pro-ject RM-5

I have just upgraded my system, being on a budget I have the following now.
Turntable Pro-ject RM-5
Phono pre amp Pro-ject tube box SE II
Pro-ject speed box
Goldring 1042 cartridge
Audio quest copperhead cables
Valve Audio exclame' 100 integ amp
VMPI RM2 speakers

Here is the problem. I notice a hum musically at about low A when listening at pretty high volume only occurs when the stylus in on the vinyl. It does not sound like rumble as it is very constant. Interferes with quieter passages of music.
Probably hum caused by your cartridge and or TT motor is not shielded. Quite often it appears as the cartridge approached the motor. In running a Grado on a favorite TT at the begining the hum was not present, but on the last 1/3d of the LP the hum started. There was no problem with some other cartridges. On another TT the Grado was/is very quiet. I think it takes two to tango.

Alternatively, are your TT and IC's isolated from other components, especially those with transformers. This can be a big problem as well.
Well: I do not think it is either of these, when the cartridge is not on the vinyl there is no hum, none. Also the hum is constant in volume and pitch, not louder as it gets toward the motor, still, given the motor position this could be an issue ( shielding ). Any solutions that aren't too expensive? I suppose it could also be tone arm resonance -- though the conical carbon fiber arm should prevent this...