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Hum in my system; its the turntable R and L interconnects. Huh?

Pioneer PL-570 reconditioned turntable

EAR Phono Box

Cambridge Audio Integrated amp

DALI Floorstanders

I have a very pronounced "Hum" in my system, sounds like a 60cycle hum. I tried all the troubleshooting steps; it originates in the EAR, which has just recently been serviced and has new Goldline tubes. But here is the kicker, if I disconnect the R and L TT interconnects the hum cuts out and I get a fine white noise sound of much less volume. The TT produces the hum in the system even if the TT is unplugged from the wall receptacle. Removing the ground wire from the TT to the EAR has no effect. I can place my ear on the EAR case and hear nothing, dead quiet. A fault inside the TT?

jereeb
jeffbij
113 posts
 

@jereeb  -  What cables are you running from the turntable to the phono-pre?  Is it possible that they are picking up the 60Hz hum from one of the power cords, the AC wiring in the wall, close by power suppy, etc.  I had a problem once where I was picking up EM interference from a nearby radio station on the cables from my VPI table and the phono-pre.  I could actually hear the radio program/music.  I switched to a set of shielded cables and it went away.

I've also heard, somewhere a long time ago and I don't remember where, that some Grado cartridges are  susceptible to EMI.  Might be complete bs, but might be possible.

Just a thought.

jereeb OP
5 posts
 

Good tips! I'll try the additional ground wire, dbl check the cartridge clips are tight (pretty sure they are, they were a tight fit going on). The TT cables picking up EM is a suspect as even when the TT is disconnected from power, the hum is there. I am also going to try a different TT later this week.

buellrider97's avatar
buellrider97
453 posts
 

Did this just start one day randomly? You mentioned your repair prior to this happening. As mentioned above cable shielding was an issue for me. I have a modded Thorens with a Grado Prestige cartridge. When I hooked it up I lacked a good pair of cables so I tried a pair of Anti-Cables level 3 non phono that I had in the leftovers box. The TT is close to my plasma TV and the 60hz hum was noticeable as my ZU’s are high sensitivity. Another random thought is a friend just asked me for advice regarding his vintage Pioneer TT. It’s having noise issues only when the arm is moving from the rest over to the record. Once it hits the record it stops. It’s always something, but yours is definitely interesting. I think we’re as eager as you to know the cause. Regards , Mike B. 

jeffbij
113 posts
 

@jereeb   If you are also going to try a different TT, I'd also try a different set of cables, ...any different set of cables.  It could be that one or both of the cables were damaged when you unplugged the EAR out or hooked it back in.  (It happens.)

jereeb OP
5 posts
 

All good suggestions! The cables from the TT are soldered in place, they can't be swapped. I would consider upgrading the cables if when I try my son's TT in the system, the hum goes away,

I did try different cables between the EAR and the amp: no change. And tried a different input on the amp: no change.

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