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I have an AR turntable that develops a hum that begins when the tone arm is placed above the outer edge of the record. It is not very loud, but it is very annoying. Does anyone have a guess as to whether this is being caused by the tone arm or the cartridge? Or anything else? Thanks!
Bad tonearm ground wire or you are using a Grado Cartridge.
Heck I am using a Grado Cartridge! Please explain the hum.
Grado's are not shielded real well so they tend to hum in many tables. Not much you can do about that. Lots of people live with it, otherwise you need to swap carts.
Not only is your grado not shielded, which in many applications is of no consequence, but more importantly the AR's motor is not shielded either, and it is making your system hum. I bet it gets worse as the arm moves closer to the center. Audio "lore" has long warned against mixing grados with ARS. That being said, it can be done either by getting your dealer to order a version (which they used to carry) that is less hum prone, or by shielding your table's motor. I have no experience with such shielding, but I have read posts where people used "mu metal" what ever that is. Apparently it is used in rf shielding. Russellc
They make copper tape that works also, but I have always thought that since Grado's are inexpensive; why go to the effort. Half a dozen carts out there sound just as good or better and they don't have the problem. Unless you have a loyalty to that unit, try calling John Grado in Brooklyn and see what he says, he's usually a freindly guy and helpfull.
I had a little lug on my cartridge that grounds the cartridge casing to the left ground lug (blue). sometimes it will stop the noise.