Good evening, guys…
A few days ago I decided to buy, after many, many years, a new turntable, so the Pro-Ject Primary E Phono was my choice.
The hi-fi setup in my living room is as follows:
Naim Muso Qb (first generation);
Schiit Magni (headphone amplifier).
Once all the connections were completed, I realised that the turntable was suffering from a very annoying humming (or grounding) issue, this because nor the Muso or the Schiit Magni have a screw to hang the earth cable on to.
As I don’t want to return the item, that is working well, I was thinking to disable the phono stage on the Pro-Ject turntable, connect it to this phono stage and then connect the Edwards Apprentice to the Schiit Magni headphone amplifier.
This should be the scheme:
Pro-Ject Primary E Phono, from Line Output (2 RCA) to Edwards Apprentice Input (2 RCA);
Edwards Apprentice, from Output (2 RCA) to Schiit Magni Input (2 RCA).
In case I wanted to use the Muso speaker:
From Edwards Output (2 RCA) to Muso Qb (3.5 mm. jacket).
Also had a similar experience helping a friend connect his new Rega P1 Plus, with built-in phono stage to his 1st gen Muso QB. When we connected the table directly to the Muso QB, there was an unbearable humming noise if the volume was past 50%. We tried different cables, same results. We also inserted a ground loop isolator between, which improved things but humming was still present. We then added some ferrite cable cores around the Muso’s power/AC cable and on the 2 RCA cables from the table to the ground loop isolator; This proved to be a winning formula. He can now raise the volume on the QB almost to 100% without the annoying humming noise. We purchases a pack of 10 snap on ferrite cores of various sizes online for very little. Might be worth trying this to see if it helps.
Thank you very much, Ants!
Are you talking about something like this?
I think, of course, I’d need to use a core for each power plug and RCA cable, is that true?
Secondly, is the ground loop isolator necessary?
Just in case, should it be this one?
Yes, the clip-on ferrite cores is what we used. We had a box containing multiples of various sizes so made it easier to find the right ferrite for cables of different widths. We introduced the ground loop isolator before adding the ferrite cores. You could try the reverse and see only using the ferrite cores improves things before spending on an additional piece of gear. As for an isolator, we are using a XtremPro ground loop noise isolator.
We used one ferrite for the Muso power cord, closer to the lead going into the Muso Qb and two closer to the RCA cable leading out of the Rega’s RCA outputs.
If you get hum you could try unplugging and turning the 2-pin mains input to the Qb 180 degrees. This may change the phase of the leakage current to cancel out the current from the other device connected to the line input.
