Drrsutliff.
now I have regained some composure you are likely correct.
I believe it is the cable that came with the 401 as once that was on the Rega is when the hum was very noticeable.
Even back on the 401 it is louder than I would really like.
The slightly to short cable that came with the Rega is very quiet back on the Rega.
Solution?
Open up the 5 pin din end of the offending tonearm cable?