Hi everyone,

If this was covered already, I apologize. I did some searching, but I'm not sure if I covered all the bases I'm my searching.

I just picked up a M97xE for my Technics SL-1700 to replace a Grado Black. Although I adore the Black, it picked up some hum from the motor. I listen almost exclusively via headphones (Senn HD-580 plugged into an Eddie Current Lunchbox amp is my main setup), so it seems like I hear every single thing that happens on the table.

After setting up the Shure cart on the headshell, which is an ancient Technics and probably came with the table, I noticed that as my hand approached the headshell on the tonearm, a very much background hum (only audible with the volume just high enough to hurt) would get louder until it eventually would be very audible at a normal listening level.

Thinking it was a grounding fault, I did all the grounding checks and everything was setup properly. Swaping the Shure for the Grado in the same headshell does not produce a hum (outside of the infamous 'Grado Hum'), so I'm left to think that the problem is with the Shure.

It is possible that the cartridge isn't grounding itself properly? This only without music playing. Once the music starts, I can't hear the hum. I'd like to figure out though, since it's annoying. Is there is a way to force a proper ground in the cartridge?


Thanks

I have the same problem with my new Technics 1210 and Shure V15 III. When I touch the headshell I hear a hum then when I take my hand off it goes away. I also hear an audible click in my speakers when I turn the turntable on. If I take the same headshell and screw it into my SL-1700 (which is hooked into a cheap phono preamp and into my computer) I don't hear the problem at all. My 1210's power cord is plugged into a cheap power strip along with all my other gear, the 1700 is plugged into a UPS that my computer uses.

This weekend I am going to move the 1210 to the computer to see if it still happens. I think there may be a grounding problem in the outlets in my stereo room. At any rate since I don't hear it when it is playing I have never really cared too much, but it's one of those little things that can eat away at you. I have a long list of things for an electrician to do in the near future (my wife forbids me from working with electrical stuff and probably with good reason) so I will add this to the list.

We just worked on this same type of problem in another thread. I cannot find it now. Try connecting a very fine wire from the cartridge blue wire to the tonearm ground (the actual arm). The arm has a large yellow wire on it somewhere that should be grounding it to the chassis. Its possible the cartridge needs this connection to eliminate some type of ground loop you may have. I have a TT that does the same thing with the 97xE but it is barely audible. When the stylus touches down there is nothing but music.

What is the volume level?

Yes, it is probably an open electrical ground on the tonearm itself. There should be a black (or yellow) wire running from some place inside the arm to the the chassis or the ground wire solder point inside the tt. If that wire has become disconnected from the arm or compromised this can result. That's the actual cause, but Old_Tech provided the work around. The idea is to attach a wire from one of the signal ground pins on the cart to the screw attaching the cart to the headshell, but if the headshell is non-conductive, it won't work. Then you'd have to solve the problem inside the tt.

Thanks for the great info everyone.

jlc76, that is interesting that it goes away in the other table. I didn't even think to check that. I have a Marantz 6110 that I can test later.

Old_Tech, I'll try the wire trick tonight and see what that gets me. This combined with what I learn from testing the other table should be interesting.

On this setup, my volume is usually between 9 and 12 o'clock, depending on what's on the table. At 9, the hum is just barely audible if you concentrate, but at 12 the hum is very pronounced, even when I'm standing 10 feet away (the headphones have a very long cord). However, I can never hear it once it hits the record no matter the volume. In the end it's a super trivial thing, but it bugged me.

hakaplan, I will check for these wires tonight. This reminds me of another thing I discovered last night fiddling. It appears that the ground wire coming from the table doesn't really seem to do much. I had the wire hooked to my premap, but removed it while screwing around and there wasn't that typical ground loop drone I was expecting that my other tables make. The ground wire plugged or unplugged really made no difference with the amount of hum I was hearing with the Shure. I suppose the grounding of the table is funky and the Grado never revealed that. I'm a little out of my element with this stuff, but does that make sense?


The metal face on the 1700 needs some attention and I've been wanting to take the table apart to address it, but I can't figure out how to do it. I've never taken one apart before, so I'm not sure where to start. Anybody have some resources for this? I've got the manual from vinyl engine already, but I didn't see too much in there.

If you don't notice a change when the ground wire is removed, I think that may tell you something. I had a hum problem with my HK ST-7. When I got near the tonearm, or moved it there was a hum. If I touched it, it went away. Then after opening up to do some work, I found that the ground wire had broken between the tonearm and lug it is soldered to. Fixed that and all was good. John

G'day all. One more thing to check, ensure that the stylus is fully inserted. This has been known to generate hum. Regards, Felix aka catman.