Hum from turntable

[Muse]

I have a lightly used Technics SL-1200MK2 DJ-quality turntable with a Stanton D6800EL cartridge. My AV receiver (Kenwood VR-6070) has a phono button feature and phono inputs. I'm getting an annoying hum when I access the phono input on the receiver and turn the volume up. The volume of the hum is dependent on the volume level set by the receiver. If I remove the cartridge from the tonearm the hum is considerably reduced, but does not come close to disappearing.

I have the ground wire from the turntable attached to the ground terminal of the receiver. I tested the ground and the tonearm is continuity-connected to the chassis of the receiver. The hum is rather loud at ordinary listening levels, making the use of the turntable impossible. What could be at play here and what might I do to eliminate the hum? Thanks for any ideas.

 

[spidey07]

Does sound like a ground loop hum. Check to see if you have a MM or MC cartridge and if your receiver supports what you have.

 

[RupTheKid]

I agree with spidey on this one. Cheapest quick fix I can think of is getting a cheater plug adapter (three prong to two prong) if your Kenwood has a three prong power cord. You can also try this with the Technics, but from memory I believe this is already a two prong power cord. The cheater should be 0.99 at your local hardware store. You can also try plugging in the Technics into different outlets from the Kenwood, or look into purchasing a power condition (Monster, Panamax, BPT, etc), though this is a more pricey proposition.

 

[Gneisenau]

Also make sure they both get their power from the same outlet.

 

[Muse]

Originally posted by: spidey07
Does sound like a ground loop hum. Check to see if you have a MM or MC cartridge and if your receiver supports what you have.

Funny thing is the manual for the receiver doesn't indicate what the phono inputs do support. I bought it hoping (and figuring) it would work OK. I have used it before and IIRC, I didn't have much if any hum problem... nothing like what I'm experiencing today. Except for the hum, the sound seems fine. The hum is the same whether the TT is turned on or off.

 

[Muse]

Originally posted by: Gneisenau
Also make sure they both get their power from the same outlet.

Right now, the TT and receiver are plugged into the same outlet. Both components have two-pronged plugs. I will try plugging the TT into a different outlet. I can actually very easily plug it into an outlet that's on a different circuit breaker altogether. Will try that in a few minutes. If that doesn't work, I'm wondering if I can try making a connection from the receiver chassis directly to ground.

Edit: Plugging the TT into a different circuit didn't stop the hum.

 

[iRONic]

Does your AVR have an unswitched outlet on the back? If so, try it.

 

[Muse]

Originally posted by: iRONic
Does your AVR have an unswitched outlet on the back? If so, try it.

Yeah, it does. I'm going to try it now. The hum (most times) goes away completely the second I remove the cartridge from the tonearm.

Edit: So, I plugged it into what turned out to be a switched outlet on the back of the AVR and the hum mostly disappears! It's practically usable right now. The hum is faint without the tonearm on a record and with the music playing, nothing I'd notice.

Edit2: Both outlets on the AVR are switched. Well, it's pretty much OK this way. Thanks!!

 

[Muse]

Someone suggested there might be a problem with my cabling. Specifically, that I am using unshielded cable. I checked, and in so doing, quickly realized that the cabling is problematic. The receiver is about 4-5 feet from the TT, and the TT's cable doesn't reach, so I am using a coupling system. Evidently the coupling was problematical! What I have is a couple of male-male joins that go between the female connectors on the TT's cable and a joining cable that goes to the AVR. The connections there were faulty and twisting them has totally eliminated the hum, whether the TT is plugged into the receiver or not. :Q

 

[iRONic]

Silence is golden.

Glad you figured it out.

 

[Muse]

Originally posted by: iRONic
Silence is golden.

Glad you figured it out.

Right you are... thank you!