noise through speakers

[louie3]

My Musicmaster .5 idler table (Japanese 301) has developed a rhythmic "thruming" noise which is actually picked up by pickup and comes through speakers.

Don't think the noise is coming from the drive system as it stays same when i put in old worn idler wheel.

I assume the noise is caused by either a worn main bearing (Although re-lubing the bearing did not change the noise at all. Changed to heavier lube, and would have expected at least a difference in the noise.)

Or: a worn bearing or bushing in the motor.

Noise has to be something in direct contact with the platter and record to get noise to pickup and speakers, right?

Any guesses welcome....reduced to VPI belt drive (sigh):steam:

[DSJR]

All I can suggest is that you check all the motor wiring to make sure this isn't fouling any decoupling the motor has, since you've replaced the idler with no effect. The motor must make full use of its suspension, whether it's rubber bushings or springs as the 301 and 401 use. If the motor "features" an eddy-current brake to regulate speed, make sure the disc hasn't been dislodged so it oscillates when running..

Good luck.

P.S. if any of the deck and arm fixings have worked loose, this plays havoc with signal to general noise, whether this is a humble Rega deck, a Linn LP12, a garrard and even my Mentor had a "hum transmission" problem which i eventually traced to the loosened off arm platform fixing bolt underneath.

[louie3]

whatever it is it has to be getting to the platter and record, so I will check the motor suspension and so forth,

Thanks

[YNWaN]

the tie-wire on your cartridge hasn't failed has it, and the cartridge is bottoming out?

[sq225917]

turn the power off and have someone spin the platter by hand, then you'll know if it's electrical or mechanical. Yeh the motor will generate EMF from being turned but nothing like it does from being driven.

If there's no noise then you know it's an electrical shielding/earthing issue. if the noise remains then it's most likely mechanical in nature.

[louie3]

Not a cartridge issue...noise there with two carts and even two different tonearms.

Very simple wiring....almost has to be mechanical.

[louie3]

Sorry, thought I had posted the solution to this.

The "noise" was, apparently, a bad tube in the Luxman EQ 88 phono section.

Or at least disappeared with new tubes.

Could be that some resonance or over-driving the EQ 88 caused the demise of the tube, but it could also be that I just needed a re-tube.

In anycase, the noise is gone.