Humming problem in turntable is not uncommon. Darel Jenkins of USA has encountered this problem with his Rega Planar 3 turntable recently :

Hi Michael,

Yes I did receive the upgrade, and the installation was quite easy. I love the sound, however, when the needle gets close to the center, I still hear the low hum from the motor when the volume is high. My speakers are full range, and hide nothing. I will consider getting the 24v motor upgrade next, but for now, I'm content. You can only hear the hum at very high volume levels, and I don't generally list to music at those levels. I don't hear the hum at the outer periphery. ....


Very often this humming is caused by the electro-magnetic field. That's why expensive TT's (like Rega P9 TT) often come with magnetic shield(Mu-metal) for the motor. Other than Mu-metal, Ultraperm 80 is another good alternative for the same purpose. 

Rega P9 with magnetic shield

"Some kind of electro-magnetic shielding may help ...." I suggested to him.

Darel immediately got hold of some electro-magnetic shielding foil and promised to come back with the results! 

Yes, humming problem is solved with the "shield"! Let's take a look at how he has done it :

Can you spot the  electro-magnetic shield?

Darel explains the details here:

Hi Michael, 

The shielding is effective, however it did not work very well wrapping the motor itself. I ended up putting the foil between the plinth and the pulley. The foil diameter was about the same as the platter diameter. If you can figure out a way to incorporate it into your base, let me know. 

The rumble reduction was incredible. From what I understand the 24v motors have more emf magnetism than the 110v motors. It appears that shielding the 110v motors is the way to go with your base. 


Thank you, 


Darels's systems :

Rega planar 3 with upgrades :
(Aluminum sub-platter, Motor base, dual pulley, silicone belts, thrust bearing)

Audio System:  
Amplifier: Zeus by Rogue audio, Speakers: Philharmonic 3 by Philharmonicaudio, 
Phono Stage: GCPH mod. by PS Audio, TT: Rega P3, DAC: Wyred4sound, 
DAC2, Server: Macmini

Home Theater: 
AV Receiver: Denon 3311ci, Speakers: Reference 3A, 
M3: TV:Panasonic 58vt plasma.  
Subs and surround speakers: Definitive Technology

Thanks Darel for sharing these beautiful pictures and info with us!


Detlef said...

Humming problem in turntable is not uncommon. Darel Jenkins of USA ...

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