Turntable ground hum??

Rennrig

Happy Thanksgiving everybody,

I hooked up a Music Hall 5.1SE to a Conrad Johnson "Classic" tube preamp with a phono and line stage. I am getting a serious hum on the phono stage when the turntable is hooked up, with or without the ground wire connected. When I have the interconnects off (disconnected) the preamp side, I just get that wooosh sound of stage gain coming through the 250 W monoblock amps.

Any ideas on this? or things to try?? I have switched outlets, put a cheater plug on the preamp to eliminate the ground, no dice!! When I touch the ground plug the buzz dissipates, leading me to believe it might be a turntable ground fault.

I am not that handy at this stuff. It does sound awesome when the LP's are playing, but I know it is too much noise. The CD and Tuner sections are quite as a mouse.

Any help appreciated.

Thanks,

Rennrig

Toolfan66

I am going through the samething myself with my Jolida JD9 phono pre. so I hope this helps me as well.

Good luck on your end,

Larry.

Libertyc

Is the turntable ground wire hooked up?

vc69

Guys that is definitely a grounding problem. If the tt hums no matter if the ground wire is attached or not, perhaps the tt has a loose ground wire internally. Being brand new, it's a possibility. Can you follow the ground wire into the plinth and through the tonearm to be sure it's not disconnected anywhere?

Libertyc

on the back of the turntable between the line outs is a ground lug. You need to run a wire from there to ground.

vc69

Doh... I was assuming he had done that.

Edit: He stated "with or without the ground wire connected".

I'm wondering if there might be a problem within the table, perhaps in the tone arm.

Toolfan66

Libertyc wrote: »

Is the turntable ground wire hooked up?

I disconnected mine and it sounds a thousand times better, but there is still a little hum as I turn up the volume, enough to bug me from the sitting position.

Rennrig

Thanks everyone, these are good suggestions.

FYI, I have run the unit with ground and without ground wire attached. I have also used a cheater plug (3 into 2) to eliminate the preamp ground from the 120V system. Under all conditions I get the noise. The only time I don't here it in the phono stage is when the interconnects are disconnected from the preamp.

I like the idea that there may be an internal ground wire that is funky. It is a brand new table with a rosewood plinth, so I am cautious about going in and yarding around. These wires seem pretty delicate to me.

Cheers,

Libertyc

Seems like a ground problem in the TT. Hey Joe help us out.

Libertyc

BTW - where did you purchase it from?

Rennrig

I bought it from Spearit Sound, Northhampton , MA. They are willing to ship me out another unit if it looks like I can't isolate the problem.

Polkersince85

Double check the wire connections at the cartridge, making sure of correct polairty and not touching each other. Make sure the interconnect is not run close to power wire. Avoid metal or speakers close to the cartridge. Also as said before, there could be an internal ground break.

jimbo1421

I had the same problem with my Akai TT which turned out to be the contacts between the headshell and tone arm. These are spring loaded and compress slightly when the headshell is tightened down. In my case one or more contacts didn't spring back when I removed the headshell and did not make good contact when put it back on. It buzzed like mad. The solution was to poke the spring loaded contacts with the tip of a pencil to free it up.

disneyjoe7

I plugged a TT in the non switched outlet of a CJ PVC-5 pre amp and have no hum at all. Maybe something you could try the TT was such a low draw 9 watts I couldn't see why not use the outlet.