DIY Platter

[Oldpinkman]

So, who has a platter that IS balanced?

The AR XAU's platter was balanced as was the AR 77's.

Nearly 40 years ago I used Bostik Sound Deadening Panels intended for use on cars on a Thorens 160 and AR XAU to good effect.

The Technics SP10 platter was dynamically balanced and had stickers to say so. It is much less of an issue on a belt or idler. If they use an AC motor it is phase locked and has no servo's to confuse with platter imbalance, and even dc motors are operating at much higher speeds, and can make more, smaller corrections to maintain constant speed. Different on a DD - potentially

[sq225917]

My Kuzma platter is balanced,

[dimkasta]

Sorry for the necroposting... I think it fits here...

Has anyone tried Dynapad along with Dynamat? It is supposed to help kill low frequency vibrations. It is quite thick though... Perhaps as a liner in the chassis instead of the platter? Or on top of the platter again replacing the heavy rubber mat?

About balancing, my opinion is that the rotation speed and the size and rigidity of the platter makes dynamic balancing rather not that important. Static balancing should be more than adequate and can easily be done by tilting the turntable ~30degrees allowing the heavier part of the platter to rotate to the bottom, allowing us to treat it either by adding more weight on the light side or drilling (or something) the heavier side to remove some mass.

[6L6]

I think any of the 'Dyna' materials have lots of merit compared to the stock rubber liner.

That said, I'm going to fill mine with a barely flexible marine epoxy if I ever get around to it.

[rubber duck]

Not sure if this has been raised elsewhere before but if we're on the subject of damping and dynamically balanced platters, should not the Technics rubber mat be compulsory in terms of damping and correct mass and hence speed stability?

[6L6]

...should not the Technics rubber mat be compulsory in terms of damping and correct mass and hence speed stability?

I don't see why -- the rubber mat is a big nod to the realities of mass-production. Because the platter was cast to make other portions of the process easier, the rubber was installed to stop it's bell-like ringing mode. It works quite well. And has the advantage of also being molded in a specific shape.

Adding a different damping material will do just that - damp. And quite possibly in a better way than the stock mat.

As for mass, there is no stability issue, the motor has more than enough grunt if you make things heavier, and also plenty of finesse of you make things lighter. Speed stability is a function of the motor sense coils and the drive logic, not the platter mass. That motor is what makes the Techie such a good candidate for modification.

[rubber duck]

I understand that the Techie motor can drive heavier (or lighter) loads but is this ideal? If it was designed with a specific platter mass in mind, then changing this surely would affect what the motor "sees" and how hard it works? Should the motor be made to work harder than is necessary even if it can?

[6L6]

Those who have added mass have not reported any problems. And the general consensus (well, of the handful of people who have done it...) on the epoxy-filled platter is overwhelmingly positive.

[WOStantonCS100]

The Technics SP10 platter was dynamically balanced and had stickers to say so. It is much less of an issue on a belt or idler. If they use an AC motor it is phase locked and has no servo's to confuse with platter imbalance, and even dc motors are operating at much higher speeds, and can make more, smaller corrections to maintain constant speed. Different on a DD - potentially

In addition, the Technics

SL-1300MK2 (1310MK2)
SL-1400MK2 (1410MK2)
SL-1500MK2 (1510MK2)
SL-150MK2
SL-M2
SL-M3
SL-M1A (I suspect but have not actually held in my hand)

all have balanced (drilled) platters, as well, that are heavier than a stock SL-1200MK2 platter.

[dimkasta]

Do you know if they have any holes drilled on both sides of the platter? Or just on the bottom?