Ground Hum with Rega RP6, Exact and TT PSU.


Greetings.

Just purchased a Rega RP6, Exact, TTPSU and I am getting a HELL of a hum. I am using an Aragon 47K Phone pre amp. I unplugged the wall wart and the cable which goes from the table and it is still there. I seems to get worse when I turn it on and the tonearm gets close to the center of the arm spindle and it picks up a lot of motor noise. Just sold a 28 year old Linn Axis with a Signet Cartridge and never had this issue with just the normal hiss associated as you turn up the volume. It's not noticeable a lower volumes but it is there during quiet passages and it is extremely annoying. The table sounds way better but the noise is very intrusive and honestly I am disappointed after dropping almost $2000. Thanks in advance
pivetta

Showing 2 responses by toddverrone

I only have an old P3 without the PSU it separate phono pre, but I do have a hum that increases as the cart approaches the spindle. I did two things to reduce it to the point that, if the volume is high enough to hear the hum from the listening position, I'd blow my speakers if I played anything:
: Moved the turntable as far away from the transformer on my preamp as possible. When it sat directly over the pre, the hum was bad

: Removed the motor and control board from the TT and mounted them on a block of wood attached to a block of granite. This is placed on an isolation platform and then the TT is placed over it. I had to install some quick connects to keep the switch functionality. While I DIYed mine, Michael Linn sells nicely manufactured kits to decouple the motor from the base.

With yours being a brand new TT, I don't think you'd want to try the second part. My P3 is 17 years old, so I didn't mind messing about. Plus, I can return it to stock in approximately half an hour. With the motor removed, though, there is such an outrageously low noise floor, it was well worth it. I think removing the power circuit board from the plinth helped a lot with the hum, and physically decoupling the motor dropped background noise. 

That being said, maybe creating a grounded aluminum shield using HVAC tape is worth a shot, since it seems to be that moving the motor PCB away from the tonearm helped. Though you have the PSU, which introduces a difference that I've not had experience with.