phono hum source found, need cartridge recommendations

Archived from groups: rec.audio.pro (More info?)

"antonlamont45"

>
> My question is--does anybody have suggestions for cartridges that do
> not pick up EMI as much as the one I am using (Goldring 1012gx, came
> stock with the TT)? does anyone have similar experience with this kind
> of problem?
>

** Most phono cartridges are fairly well shielded from mag fields by the
use of mu-metal housings.

Maybe yours is not.


> does anyone have suggestions for how to go about shielding the
> cartridge from the motor?


** Why not shield the motor from the cartridge ???

A strip of transformer lamination material ( as used in toroidal cores)
wrapped all around it and tied in place may be all that is needed.





............. Phil

Archived from groups: rec.audio.pro (More info?)

antonlamont45 <antonlamont45@yahoo.com> wrote:
>
>This morning I finally found the source--the cartridge is picking up
>electromagnetic intereference from the motor. I took the glass platter
>off and moved the tonearm around and this became very obvious as the
>hum increased as I moved the cartridge towards the motor.

This is a very common problem and it is especially worse with the
Grados.

>My question is--does anybody have suggestions for cartridges that do
>not pick up EMI as much as the one I am using (Goldring 1012gx, came
>stock with the TT)? does anyone have similar experience with this kind
>of problem?

Is it magnetic pickup, or electrostatic pickup? If it's magnetic,
there is nothing you can do about it. If it's electrostatic, you can
easily shield it with thin brass foil (shim stock works well), or
purchase a shielded version from the manufacturer as an option.

If you have an electronically-controlled motor, this could also be
an issue with the motor drive electronics producing more trash than
they should.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."