[morzh]

From what I understood the original phonograph had an electromagneic pickup, as the transformer is 0.2 Ohm to 5,500 Ohms.
The transformer was omitted, probably due to the V-M phonograph having the piezo pickup.

I re-did the wires with proper grounding, both the motor and the phonograph chassis (via the Phono cable). Also installed new RCA cables, both males with the F-F RCA slug in between them.


The grounding scheme is as follows:
The RCA pigtail from the radio has the shield as the GND and the centrai wire as the signal; the turntable has twin shielded wire; Both shield and one wire are connected at the shell; then the signal and the wire go to teh cartridge while the shield only connects to the turntable's chassis, therefor avoiding GND loop.

46-1213_Phono_Grounding.pdf Size: 16.83 KB  Downloads: 424

The phonograph plays fine, and this with  the old needle.

But. At a decent volume the hum is pronounced.
I did an experiment: disconnected the turntable with no reduction in hum, shorted the Radio's pigtale RCA, also with no reduction and then shorting the Phono input right at the tube socket - same result.

Significant reduction to very acceptable level occurs with me touching the chassis or simply connecting it to Earth GND.

I intend to use a 3-prong Earthed plug for this reason only.