Need TT Advice From AA Brain Trust
 

Been noticing my TT has picked up a bit of a hum. It's only noticeable starting around 47% power on my MA8000. Above 52% it's very noticeable. Not when the music is playing, but in between tracks and on the dead wax. This is a problem for me because I like to record my good vinyl jazz music to tape and I don't want the background hum on the recording.

Now, I am well aware of ground loops and how to track them down. In this case, I'm focusing on the power supply. Please take a look at the picture and tell me your thoughts on an aftermarket PS that I might be able to replace the existing PS with.

As always, thanks in advance. Hoping for some good news here.

If this system didn't previously suffer from a hum problem, I'd look for potential simple causes first, such as bad or dirty connections at the phono cartridge pins and cabling. It could also be an aging cartridge. Do you have a spare you could use to test that?

My Soundsmith Paua MK II has less than 20 hours on it. It's only just breaking in. Anyway the tonearm wiring comes through the top of the unipivot where it has a screw in plug. When I remove it, the hum is still there, so it's not in the cartridge or tonearm wiring.

It's somewhere downstream and I'm suspicious of the little external power supply.

Have you tried a different set of interconnects between the tt and MA8000? Something with a nice coaxial shield - just to see.

Lose the switch mode power supply.

Fixed!

I moved/relocated the interconnects and ground wire. Seems very sensitive to EMI/RFI. Just to be thorough, I also removed the tonearm to check the connecting pins and found the green wire loose. Tightened everybody back up, checked alignment and VTF.

All is right again. Now my jazz reissues sound superb like they used to.
:banana:

Great news! It always pays to check the simplest causes first. I've learned that the hard way.