New Solid Aluminium Platter for the SL1200

[Marco]

Yup - I expect so

Marco.

P.S Not long until your 1000th post!

[MartinT]

P.S Not long until your 1000th post!

I'm still waiting for my strikingly designed AoS award to put on the mantlepiece.

[Marco]

Oh don't worry, it's extremely cunningly crafted... I'll bring it down when I visit in a couple of months

Marco.

[pure sound]

Larry will be Larry Denham who has an engineering company based in Canada called TTWeights. They make a variety of mats & clamps in various materials for different turntables.

http://shop.ebay.com/ldenham123/m.ht...&_trksid=p4340

While there is some scope for changing the weight of a DD turntable's platter by adding a heavy mat, there will be a limit above which it'd be necessary to adjust the control electronics slightly to allow the motor to remain in control of the platter. The SP10 Mk3 has a significantly heavier platter than the Mk2 but will be set up quite differently to allow for it.

The other issue is that increasing the load on a turntable's bearing will increase the noise that bearing produces. I don't think there's anyway round that short of supporting all or some of the mass on a magnetic field.

[Citation16]

Larry is the owner of the company that makes the copper mat. His web site is at : www.ttweights.com He is located in Ontario, Canada.
At first he made TT legs and then copper mats - he now makes 2 turntables models ( a third model on the way).

My very basic understanding of how DD works is that you don't want a flywheel effect ? or do you

I also have a basic understanding of mass. However, the flywheel effect would be the momentum caused by a high mass platter turning. So this momemtum is greater, as the platter is heavier.
This creates a more stable speed, as often some high mass platters are turned by a very small motor because it can bring the mass up to speed and maintain the speed with very little torque.
Insofar as a DD turntable does not want a flywheel effect, I would refer readers/members to the Brinkman turntable web site about their DD turntable with a 10 kg platter :http://www.brinkmann-audio.de/main.p...=oasis&lang=en

Also look at their Balance turntable with the high mass platter and small motor; the flywheel effect of the platter is most prominent also.

Yves
will update my signature soon.

[Marco]

Cool - cheers.

So what's your first name, mate? We like to be on first name terms here

Marco.

[Marco]

Thanks Yves! A new thread in the Welcome area, introducing yourself to our members (outlining taste in music, etc) also wouldn't go amiss

Marco.

[Marco]

Hi Guy,

While there is some scope for changing the weight of a DD turntable's platter by adding a heavy mat, there will be a limit above which it'd be necessary to adjust the control electronics slightly to allow the motor to remain in control of the platter. The SP10 Mk3 has a significantly heavier platter than the Mk2 but will be set up quite differently to allow for it.

The other issue is that increasing the load on a turntable's bearing will increase the noise that bearing produces. I don't think there's anyway round that short of supporting all or some of the mass on a magnetic field.

Interesting... Do you suspect that the control electronics would need adjusting with the use of Mike's platter, or is the extra weight over the existing platter not significant enough to alter the way the motor behaves?

Feedback from Mike would also be good on this

I'd also like Mike's view here:

The other issue is that increasing the load on a turntable's bearing will increase the noise that bearing produces.

What's your opinion on that, Mike?

I guess it boils down to the old 'choose your compromises' thing. As long as the positives, sonically, significantly outweigh any minor negatives, I'm still very interested in adding the new platter to my SL-1210.

Marco.

[pure sound]

I don't know. I'm sure someone like Dave Cawley would be able to make any necessary adjustment though

[Mike_New]

chris@panteg,
Firstly the Larry that Citation is refering to, is Larry Denham of TTweights in canada.
The flywheel effect that Citation was refering to. In any control system one always has the effect of feedback, the amount to correct any error being proportional to the error in many ways. Instantaneous value, rate of change of error, (de/dt) etc. These corrections are the subject of some pretty involved maths, as indeed they are with audio amplifiers!!
I do not believe that the DD would be any different in this regard, it could be argued that if the platter were of very low mass then any friction or stylus/music effects would occur more quickly and require more frequent corrections. The much heavier mass of the new platter greatly reduces these variables from any instantaneous change, as any heavy platter on any good TT is designed to do.
The flywheel affect would naturally be present as a function of diameter and mass, and is what is required for absolutely smooth control with minimum feedback affects from external influences such as stylus friction. The reason that the DD system is so very excellent for TT application over the elastic band driven machines, is that the correction is immediately felt by the 'system'. In any belt drivem system the belt per se' has to transmit the correction to the platter which can result in all sorts of effects caused by instataneous belt stretch etc. (and this stretch would be proportinal to platter mass) remember in all of these equations we are talking of very small values because that is what recorded sound is all about.