Phonoland

If I remember how it looks......there is one small tab from one of the pins on the cartridge connected to the cartridge shell.
The shell is then screwed in to the tonearm.
Is this the the grounding clip that should be removed?


As the new cartridge is more sensitive than the old one, shouldt the leaders be shielded all the way from the pre amp to the cartridge shell then?

I have run into a couple of these "conversions" where the female four pin, socket, mounted behind the tone arm has been shorted to ground. I just replaced it with a loose hanging socket, to solve this problem.

That is common when converting a formerly Cobra equipped version. The RCA socket on the arch does touch the chassis and creates a ground loop with resultant hum.

http://s1192.photobucket.com/user/Rob-N ... c.jpg.html

In those cases I added a free floating cable as you did and just tied it off to the vertical support right there.

Rob

Gbak wrote:If I remember how it looks......there is one small tab from one of the pins on the cartridge connected to the cartridge shell.
The shell is then screwed in to the tonearm.
Is this the the grounding clip that should be removed?


As the new cartridge is more sensitive than the old one, shouldt the leaders be shielded all the way from the pre amp to the cartridge shell then?

When mounted in a metal tonearm that is grounded to the system, the brass grounding strap should be removed from the cartridge.

Brass clip removed< Almost all 50Hz hum is gone
Thanks for the help!

What is left now is the rumble/hum that comes from the turntable motor.
It would be nice if I could get rid of it!

The turntable motor creates a low frequent sound, maby it's the 50Hz I can hear?

Here is my theory:
When this low frequence sound is mixed with the records tracks own frequence, the cartridge/needle starts to oscillate, and the sound is getting higher and higher.......and suddenly its stops when music changes.
This only happens on a few records in my magazine.

This must come from the more sensitive cartridge setup, as I havn't heard this with my original setup.

Have you seen this behaviour before?

Did you change the motor mounts ?? Did you change the drive belt ? Did you purchase them from a"legitimate" source, that supplies the correctly rated scones # rubber ?? Did you oil the turntable enough with 20 wt. oil ( nothing lighter !!) ?? If so, that's probably the best one can do---- remember this is a commercial machine, built to go into a "noisy environment" and MAKE money, NOT, a hi end home unit !
Ron Rich

As Ron stated, a jukebox is not capable of "high fidelity" operation, because if that's what you want, go purchase a nice stereo component system.
These juke turntables are meant as workhorses as he said in noisy bars & such.
I respectfully conclude that doing "magnetic cartridge mods" to certain models is not going to produce "enhanced" results.
It was "designed" with a ceramic cartridge in mind, and that's what it works best with.

All rubber parts comes from Jukeboxparts in Holland but are (in my opinion) to hard!
But the rubber might be ok as I dont have anything to compare with.
I oiled the parts with ordenary motor oil!
But I didnt open up the turntable asm as I didnt have any tool for the locking rings!
I judged it to be ok by the time, maby it was a misstake!
This is acuually the only part I didnt compleatly disassembled in to small pieces!

The turn table assembly will not be the cause of much rumble. It is mostly the motor and gears.

The best approach is, as i mentioned before, to wire it mono. That is easiest done right at the plug on the arch. Strap only the inner (signal) leads -not the shields.

I don't know what the output of that preamp is when coupled with that cart, but on those machines designed for the old Sontone cart there is a good chance it is overloading the input at times. I place a standard volume-type control between the preamp and the phono input (a dual ganged 50k to 100K is fine). The preamp output goes to the high side and the arm goes to the phono input. Adjust level so that even a "loud' record fades up a little at the beginning.

Rob