Base Plate.jpg

Hi Folks,

I have not been to proactive of recent weeks on this forum, mainly because I have been flat out producing bearings and platters. Interestingly, a larger percentage of users are from the US, but I guess this reflects the very large uptake of SL1200s in that country. However I guess it’s time for me to come out from under my rock and let you all into the secret. I sincerely hope this does not cut across the edicts of the commercial rules, the problem is, anything to do with the SL1200 is really a bit special and dare I say, boutique.

I have for some time been pondering the problem of the SL1200 chassis mechanics and had come to the conclusion some many months ago, that using my new 6Kg Alluminium platter was one thing; however, does the existing chassis do optimal justice to it?? A study of the ‘mechanical system’ using CAD analysis showed me otherwise. With the added weight, the SL1200 chassis will tend to act like a diaphragm, since it is cast from very thin metal and has little ‘real’ positive mechanical support. Studying the situation prompted me to evaluate the idea of stiffening the chassis with a steel plate of suitable size.

At this time I would like to acknowledge the contribution that Yves, Pete, Mark, Martin and a number of others who have contributed their thoughts on the subject, to bring this upgrade to a point where the average Audio/DIY person can implement the upgrade successfully. It is not rocket science (although others would have you believe it is) and rather quite exciting, when you complete the project and listen to the results of your efforts.

I guess what I am trying to say, is that anyone who is contemplating using a heavier platter, from whoever, is really not going to get the real maximum benefit from it, in terms of the money they may be asked to spend, unless they do something about enhancing the platform on which the much heavier load has to be supported!!!

Accordingly, I have manufactured a “Bearing Base Plate” which has been specifically designed to accommodate my High Precision Bearing so as to provide the optimum rigidity to the Chassis, under the much heavier load of a 6Kg. Platter.

Additionally, the added height of 6mm, allows much more flexibility for those people who have Jelco, SME, Dynavector, Rega, or other arms which require more height for effective VTA adjustment, than is allowed by the restricted envelope of the standard SL1200 configuration.

I have included a few Pics, so as to show what I am trying to achieve.

I have accordingly, offered all users of my new Alluminium Platter the ‘Bearing Base Plate’ upgrade, for a nominal cost. All future users will receive the Bearing Base Plate as part of the Platter upgrade. They do not have to implement the upgrade, if they do not desire to do so. Others can of course, use it independently of my Platter if they are using the standard Technics platter with my High Precision Bearing.

Specification:--

a) Lazer cut from 6mm Milled-Flat-Plate, (not un-coiled sheet)

b) Holes threaded for 1/8” Whit, Tensile Allen Head bolts to more effectively clamp the bearing/coil/motor assembly to the Bearing Base Plate. (The bolts are threaded into 6mm of steel, not self- tapped into soft die-cast-alluminium!!!

c) Five, 5mm holes for clamping to the chassis (bolts & nuts supplied)

d) Three 4mm holes provided to additionally positively clamp my Bearing to the Base Plate, for those people who require the optimum engineering rigidity and sonic integrity.
Note: For those people who opt to obtain the Bearing/Platter upgrade at the one time, then the Bearing will be supplied already secured and locked to the Bearing Base Plate.

e) The ‘Bearing Base Plate’ affords an increase of VTA adjustment of 6mm and allows for a much more substantial arm board than is commonly available from suppliers.




e) This ‘Bearing Base Plate’ upgrade will be compatible with my shortly-to-be-released Bottom Plate. Which is designed to far more effectively clamp the three SL1200 components together as an integral assembly.

f) The diameter of the Base Plate, 125mm ( 5”) is maximized to fit within the floor of the SL1200 chassis, so as to provide the maximum support to the much heavier weight of the Platter, and commensurate with ease of installation.

In summary, it is my considered judgment that the use of a substantially heavier platter, (than was envisaged by the designers of the SL1200); is to an extent, an invalid option unless one considers the engineering /sonic constraints represented by the chassis, and accepts that the chassis must be upgraded to accommodate the extra loading.
I have recently added the upgrades to my own personal SL1200
(I couldn’t use my development unit, as it has more holes that a Swiss cheese!!) It would be rasical of me to make esoteric claims for radical improvements across the sonic spectrum, however I am always impressed with the perceived improvements, which I believe I have achieved.

I am now using a SME-V and have ordered a Benz Micro Wood MC to hopefully improve the sound!!! and have just received a SME cable set from John Miller in the UK.

I posted my production version of the ‘Bearing Base Plate’ to Martin last Monday, so hopefully he will be able to comment on it’s validity in the next few days.

I have updated the design of my Platter to accomodate the new 'Bearing Base Plate' so that cosmetically there is no discernable gap between the Chassis and the new Platter.