Turntable speed accuracy

Hiho, The motor was grounded. I am not the only one with a hum problem on their Classic. There is a thread about it on this forum.

(quote)Sarcher, What is the evidence that the hum is (or was) due to the motor/cartridge interaction? (/quote)

The hum occured when the tonearm was swung over the platter in both cases. With the motor off on the Classic there was no hum with the tonearm over the table. The LP12 was likely the power supply because I had to unplug it to make the hum go away with the arm over the platter. I have solved the hum issue on the Classic by using an outboard Teres motor.

Unfortunately bringing the motor closer to the platter also brings it closer to the cartridge as well. Which on the TT's I have had with that arrangement caused hum on most of my cartrides. There may be some TT's that sheild the motor well enough to pull it off.

Good point Ketchup. The belt is more likely to slip on the capsan than the platter. Of course if it uses a sub platter that problem is reduced.

Lewm, The Artemis is an interesting design. I have not heard one yet.

I had hum caused by the motor on a VPI Classic and a LP12. The Classic's motor is on the front left. Maybe if the motor was placed in the rear it would have been better. The LP12 had the motor and power supply under the platter. Could be if I had an outboard PS like a Lingo it would solve the hum. I was not using a Grado. I am sure there are TT designs that have the motor close that don't have hum issues. Just a matter of being well designed.

I have a SP10 mk2a now and experience no hum with the same carts. Sorry if all of this is off the topic of this thread.