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Moving magnet hum

I have just installed an AT150 MLX cartridge after years of moving coils (thanks to the long thread). I like the sound a lot, but I have some low level hum which I have never had while using LOMCs. Could it be due to a ground loop caused by the ground strap on the green cartirdge pin? If so, please advise if it is a risk to remove and if it can be reinstalled.
oldears
yogiboy's avatar
yogiboy
5,732 posts
 

You fixed the problem! Is the headshell metal?

Some installations may require the cartridge shield to be elec�trically isolated from the"RG" terminal. This can be achieved by removal of the ground tab.

lewm
13,220 posts
 

To the best of my knowledge, only a very few cartridges have one of the two "ground" pins connected to tonearm ground and hence to earth ground.  Decca and early Grado come to mind.  Certainly there may be others. So, Yogiboy, what "ground tab" are you talking about? I respect your fund of knowledge, but I am confused.  Sounds like the AT150MLX has a ground tab(?)

yogiboy's avatar
yogiboy
5,732 posts
 

@lewm

The OP said his AT has a ground tab. All of the Shures that I have owned had a ground tab. Hence I quoted that from Shure. BTW, I have never seen a ground tab on any older Grados that I have owned!

lewm
13,220 posts
 

By the same token, I have some older AT's that don't have a ground tab.  Back in the dinosaur era, I used to own Shure V15s... Don't recall any of them having a ground tab.  But we didn't have electricity yet back then, either.  So I may not have been able to see the tab by candle light.

mijostyn's avatar
mijostyn
8,570 posts
 

@lewm 

You have electricity?

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