[Puma Cat]

Originally Posted by prepress

Problem solved.

While the power supply was the initial culprit, and re-positioning it got rid of the worst hum, it didn't get rid of all the hum. Re-positioning the tonearm cable did; that last, low-level hum I was experiencing is gone.

I re-positioned the tonearm cable so it has no contact with any PC except a 90° crossing of the preamp's PC. I turned on the TT, preamp, and my amps, again using the MM input. NO HUM, even with the volume up to 81; just the usual noise one might expect, barely audible at the listening position, and inaudible at normal listening level (mid-40s). I didn't try a record, as I didn't think it necessary based upon my previous test results. I did move the power supply backward a few inches but doubt that had anything to do with my latest results.

We'll see what occurs when I actually play a record, but based on these new results I don't expect an issue.

Great news, congrats. When I've had similar issues, it was almost always the tonearm cable and/or the position of my SUT.

If you want to take things a bit further in noise reduction, get a box of those little DF-SS Minis (Ivan can help you out), and place one between the tonearm cable and where it crosses the PC. It'll get even quieter. Even moving things a little bit can make a big difference. Again, the inverse-square law is your friend, here.

I use the little Minis all over the place, as shown; separating ICs from PCs...


Getting ground cables off the floor...


As cable elevators for ICs...