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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
theo's avatar
theo
2,696 posts
 
I had a similar issue years ago with a P25. Since Rega doesn't use a ground wire on the tonearm, I ended up getting the tonearm retired with the Incognito kit. That ended my issue, however I believe that Rega uses the right channel ground of the SE connection for ground. I did try an alligator clip before investing, that revealed the solution before I invested. So you may try that, as a note I have an RP10 with a Kleos and have no ground hum. 
Good luck
pivetta OP
46 posts
 
Thanks Theo. Could you be a little more specific using an alligator clip?? I just unplugged the right channel and nothing changed. I talked with the folks who do the incognito wiring upgrade and they said that it not a cure for the ground issue. I Have read nothing but positive reviews on their work and the guy is about 1 1/2 hours from my house. May consider it however I will talk with my dealer first thing on Tuesday when they open. Thanks again you all.
sfall
346 posts
 
" Sfall mentions to lower the gain which It is already done. "

Its probably still a gain issue. The Exact puts out 7.0mv. Just to give some perspective, a very common high output cart like the DV10x5 puts out 2.5mv. Most likely, nothing is broken, you just have a mismatch. Your dealer probably didn't say anything about it because its a package deal and they didn't want to lose the sale if they told you it would be necessary to buy a phono pre as well.

Call your dealer Monday and tell them the cart they sold you puts out 7mv and is over driving your phono preamp on the lowest gain setting, and see what they say.
theo's avatar
theo
2,696 posts
 
Pivetta, I used the alligator clip clipped on the ground portion of the RCA jack. It was cumbersome and would work its way loose. But it did identify the problem. However if you have disconnected ed the Rt. Channel and the hum is there, this not the solution. 
Hard to say at this point, have you double checked the cart leads or tried another cartridge? There used to be an issue with Grado carts producing a hum as the tonearm approached the spindle. I remember reading that there were "Mu metal" shields to place around the motor, but really don't recall much beyond that.
lenmc2964's avatar
lenmc2964
240 posts
 
I'm using a Rega Fono phono preamp and still have the hum issue. But I think it could be the cartridge. My RP3 came with a Elys and I had the same hum. Thought upgrading to the Exact might take care of it. Only have about 40 hours on the cartridge so hate to change but it my be the solution. 




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