Roksan tonearm

[Delboy]

Can anyone help?

I have a Roksan Tabrizi tonearm on my Pink Triangle turntable with a Music Maker cartridge. Everything sounds great except there is a hum present through the speakers at normal listening levels.

I have disconnected the ground wire of the arm and the hum worsens, so this is definitely needed. I have also tried a different phono stage with no change in the outcome and also tried a different cartridge.

Any ideas?

 

[EC8010]

Hum loop?

I suspect that the Music Maker is a MM cartridge with a metal body that contacts the headshell. I think you have a hum loop. Unplug the arm from the pre-amplifier and measure the resistance between each phono plug shell and arm/turntable chassis. Resistance should be infinite.

 

[Havoc]

Some cartridges do have a ground connection between the pins and the body that can be removed. Check for a metal tab making connection a one of your pins.

 

[Delboy]

Re: Hum loop?

I suspect that the Music Maker is a MM cartridge with a metal body that contacts the headshell. I think you have a hum loop. Unplug the arm from the pre-amplifier and measure the resistance between each phono plug shell and arm/turntable chassis. Resistance should be infinite.

Thanks EC8010, I shall check the resistance and let you know what I find, at the moment though my tt motor has packed up and I have to source a replacement.

Some cartridges do have a ground connection between the pins and the body that can be removed. Check for a metal tab making connection a one of your pins.

Thanks Havoc, there is a ground connection, however I do not see how it can be removed, I will have to lok more closely at this one.

 

[Delboy]

Solution

I have found the cause of the problem.

The fault is not with the arm or its wiring. It is the cartidge that is picking up what appears to be mains hum from my amplifier.

Solution: I have moved my amp to the bottom of my hi-fi rack and now no hum.

Thanks to all who contributed 🙂