New Solid Aluminium Platter for the SL1200

[DSJR]

The NAS Mentor bearing was something to behold and the main platter was around 35 - 40Kg as I remember. Mine did many hundreds of hours and was second-hand when I bought it from Tom Fletcher. I can assure you that there was absolutely NO wear on the bearing, not even a running mark or dimple on the inverted spindle. Tom changed the bearing after mine as I remember, to enable the oil to be better retained where it mattered, but even so, 10Kg is nothing to a bearing such as Mike makes.

[Mike_New]

Re percieved increase in bearing 'noise'

I do not believe that there would be any measureable increase in noise from my bearing comensurate with an increase in weight. The actual 'bearing' consists of an 8mm diameter Precisiuon ground Silicone Nitride ball, resting on a precision ground Carbide Pad. These Nitride balls are use in very high tech bearings which run at in excess of 100,000 rpm. Additionally the cavity of my bearing is filled with Synthetic Oil added to which is a very Extreme Pressure additive.

The statement that more load equals more friction and therefore more noise might be theoretically valid, but one has to consider the design parameters of the componenent under reveiw.

The problem is, that we can all sometimes get carried away by perceived problems before exhaustively examining the relavent parameters and requirements dictated by the application in question. (recently in another place I had to field an observation that the position of the lifting holes in my new platter were incorrectly spaced according to the theory of levers. Unfortunately he was not considering what practical function the holes were to perform)

For instance by the term 'noise' presumedly we mean vibration transmitted through the bearing shaft and into the platter. Now if we consider that the ball/carbide interface represents surfaces that are very smooth to within fractions of a micron, any noise (vertical vibration) will I beleive be unmeasurable. Secondly regarding the 'Physics' of the problem, It is well accepted theoretically that a perfectly sphearical ball pressed against a perfectly flat surface represents a point contact. Now a point contact in free space has no area!!, therefore the pressure at the point, by simple maths must be infinite!!

In fact of course this cannot be, and in fact as hard as the two surfaces are, there exists a very small deformation at the contact point which absorbs the load. (Just like the wheels on rail carriages) The argument of course revolves around 'how flat' and how 'smooth' are the surfaces. The bearing that I have designed and manufacture is made from the best available materials consistent with the 'not low' price, and was done so, cognisant that users would want to use the heavy copper mats and the newly released heavier platter.

For sure, there is an upper limit to the weight that the bearing can withstand, but I do not think we will sensibly reach this.

[Dave Hewitt]

Hi,
I once worked at an engineering firm where they had the capability to machine turntable platters from solid billet with ease.I had at the time a connoisseur bd1 turntable.I got the guys there to machine me a solid platter as opposed to the cast machined one,this along with the new motor pulley looked superb,but the resulting sound was not as good as the original.Perhaps the guys at Sugden and Technics know a thing or two about their products.Also why does every mod made to existing designs 'improve' on the original? Regarding the ability of the new bearing to be capable ,it seems easily up to the job of supporting the new platter,its only a record player after all.
Regards Dave.

[Mike_New]

I was interested to read over the weekend, the "White Paper" describing the philosophy of Brinkman GmbH concerning direct drive turntables A lot of it make sense!!

However in their description of their new DD motor which they describe as a soft drive, they say that it takes aprox 12 seconds to run up to speed! I initially considered that this must be a misprint, however the specs on the last page restate this and also say that 45rpm takes 16seconds!!!!!!!!!!

So you see the Technics SL1200 DD is still far supeior after all this time. Try counting up to 12 sec after you put the vynal onto the platter before you can lower the aaaarm.

[anthonyTD]

hi all,
i have followed this development with interest and i too have a few concerns about how the extra weight of the new platter may affect the sonics of the 1210. i have played about with turntables from all three designs over the years ie; idler drive, belt, direct drive and know from experience that even subtle changes like oil to grease bearings, as found on the garrard 301 makes a sonic diffrence, so i would like to ask mike first of all what it is he thinks was fundamentaly wrong with the original platter that warranted the design of this new heavier model, also, how in his opinion he thinks it may affect the speed stability ie; the motor's ability to make the very subtle but essential changes to speed that are needed for maintaining platter speed accuracy.
A...

[DSJR]

I think the "soft drive" is a carry-over of thinking with regard to belt drives, which take ages to reach speed (or the platters have to be spun up in the deliberate case of NAS decks) Linn's own Lingo supply gives full power to enable the quickest start possible and then scales back to minimise vibration once running. I'm sure the brinkman could do the same - increasing power on startup for a few seconds and then scaling right back once running. perhaps the buyers of such a deck would leave it running for hours on end, in which case 12 - 16 seconds is neither here or there if the record is changed while the deck is running. I think my SL-150 takes 4 to 5 seconds to bring the platter up to speed, as does the Dual and that's quite long enough for me..

[Marco]

hi all,
i have followed this development with interest and i too have a few concerns about how the extra weight of the new platter may affect the sonics of the 1210. i have played about with turntables from all three designs over the years ie; idler drive, belt, direct drive and know from experience that even subtle changes like oil to grease bearings, as found on the garrard 301 makes a sonic diffrence, so i would like to ask mike first of all what it is he thinks was fundamentaly wrong with the original platter that warranted the design of this new heavier model, also, how in his opinion he thinks it may affect the speed stability ie; the motor's ability to make the very subtle but essential changes to speed that are needed for maintaining platter speed accuracy.

Good one, Anthony. I would also like to know this, as the answer will have a fundamental influence on whether I'll be buying a new platter or not.

Mike, over to you....

It would also be useful if Dave C chipped in on this. Come on, Dave, your expertise here is needed

Marco.

[The Vinyl Adventure]

i was chatting with Dave about the platter the other day, he has been doing some quite in depth measurements and he sounded very confident that the motor was up to the job.
he spoke of adding even greater mass and that not causing any issue - and was telling me about all the little bits of wire hanging out the bottom of the turntable from the various ic's to do these measurements.
i asked him how it sounded, he said... "yes better, really how you would expect.... more like an sp10 i suppose"(or something along those lines... you know what he is like, he likes people to make up thier own minds on what sounds better) the impression i got from what he was saying is, yes it does sound different, better if its what you are after, and no there is no issue with it causing any problems to the turntable!... i doubt he would release it as a product if it was going to cause any problems with the turntable as he would no doubt end up with loads of unhappy people with damaged tt's... or at very least not as good sounding ones... i would have thought he is likely to be pretty thorough in his testing to avoid those situations ... so why not just sit back wait until he has them available and try it yum selves.
i think the answer to the question of what is wrong with the original platter is probably "not much.... but why not try and make a better one if a better one can be made".
the whole philosophy of modding the techie is trying to get every inch of performance out of this motor ... creating something that reduces the performance of the motor would be bloody stupid ... im not sure dave or mike come under the category of bloody stupid really! i for one will be giving them both the benefit of the doubt until the highly unlikely event of me hearing my turntable tell me otherwise

[Marco]

Nice one, Hamish

That's all well and good, though, but I'd still like Mike and Dave C themselves to comment specifically on the question Anthony asked (especially the bit I highlighted), supported of course with appropriate rationale.

No offence, dude, but rather than you having cosy chats with Dave in private about this, I'd like such discussions to occur out in the public domain here, where the information is in full view and of benefit to everyone, and of course where it can be challenged if necessary.

We scrutinise subjects in detail on AOS; we don't just simply 'accept' things, as the in-depth, probing, nature of discussions is an intrinsic part of our ethos.

Anyway, for some reason, Dave appears to have gone a little 'shy' on the matter.......

Marco.

[leo]

Good one, Anthony. I would also like to know this, as the answer will have a fundamental influence on whether I'll be buying a new platter or not.

Mike, over to you....

It would also be useful if Dave C chipped in on this. Come on, Dave, your expertise here is needed

Marco.

Indeed, especially this for us fiddlers

how in his opinion he thinks it may affect the speed stability ie; the motor's ability to make the very subtle but essential changes to speed that are needed for maintaining platter speed accuracy.