advertisement


My almost diy project

Some interesting thoughts there Clive. What about a pair of ring magnets under the platter, not to float it but just to take some weight off the ball bearing. Is it the Platine that does that? Fwiw my own turntable uses a Clearaudio bearing with a small diameter shaft and ball bearing something along the lines of the Rega but inverted so I use a dob of grease on the ball bearing. The aluminium/acrylic platter weighs around 8kg and it's showing no signs of wear after four years of constant use.
If I'm properly back on my feet in time I'll come to Scalford and have a look at your deck.
 
Oh my god that is brilliant. Will explore that. Small, thin but powerful Neodymium magnets are easy to get at the moment.
 
I use magnetic support on my turntables bearing but it is fully levitated. I'm not such a fan of thick acrylic platters though - or of multiple motors I'm afraid (three times the noise etc).
 
Yeah. It seems to make things more complicated, I am just riffing about doing... Y'know... "Stuff" one day I thought "three motors" and it happened the other week I thought "phat platter" and lo another day, one arrived. Life is weird, I dream things up and they happen.

I do appreciate why a Basic RP3 is bare minimum, add to it and it gets complicated, as we see here.

But I do like them phat platters. Something unwholesome and american about them.
 
I like "phat" platters and I like acrylic. I also like someone who has the courage of their convictions. It's all good fun at the end of the day and very enjoyable :D
 
So, the platter is with all the subplatter bits on it 10kg, give or take.

so am considering attaching a Neodynium ring magnet with a suitable diameter and thickness under the aluminium top plate above the bearing collar. So far so good.

I would then like to attach a smaller thinner magnet to the underside of the subplatter of say around 2mm Thick so as not to interfere with the normal airhap between top plate/sub-platter underside -- with a 7mm hole for the subplatter's shaft to pass through into the bearing shaft.

What sort of power of magnets ought I be looking at? As I know holding and opposing are different values and the aluminium top plate is 10mm... 20kg hold on the surface seems excessive but maybe not opposing...

http://www.first4magnets.com/circul...-x-5mm-thick-neodymium-magnet-20kg-pull-p3533

For example this is a holding force of 20kg and would fit around the bearing shaft nicely but I seem remember lower repelling force can be achieved by using a physically smaller lower powered oppositional magnet....
 
The magnetic field won't effect the cartridge as it is quite localised.

Clive, you will have to suck it and see with regard to the magnets - as you suspect, repelling force is significantly lower than the same magnets in attraction.

Ah, I see that you considering putting one magnet below the top plate - I would strongly advise against that. You need the magnetic field to be quite compressed and that will only happen if the magnets are close together (closer than the thickness of the top plate) - plus you will need significantly stronger magnets.
 
Clive you could maybe machine a groove in the top plate around the bearing housing for the lower ring magnet to sit it. This will locate it and keep it concentric to the bearing shaft. It can be glued into place. Then you need to do something similar to the underside of the hub to locate the upper ring magnet. You might have to machine a circular adapter plate or something. I'm only guessing as I'm not familiar with your hub and bearing, I only have the standard Rega item to hand.
 
I think I will machine a whole new top plate at some point to accommodate all of these in situ/ad hoc changes with the 3 motor wells equidistant, different depths for the motors and a single arm hole with facility for pillars recessed for rigidity. I also fancy using the curved profile I did on the bottom, but until then I can of course adapt this

I can of course machine out the top to support an neodymium ring but I am loath to do that as it makes the bearing support very thin, some 3mm if I dig deep enough say 5mm magnet into an 8mm sheet... Although the bearing collar my help as it and the nut are wider...

The bearing and shaft are identical to rega's although mine is already recessed to avoid that collar arrangement between the top of the opening of the bearing hole and the rega's body.

Incidentally anyone know the diameter of the bearing hole?
Is it 8mm? I know I know I could always measure it but someone may have it and I am making a PSU at the moment.
 
Yes sorry, my bad - got the words mixed up. I will complete the turntable and not machine anything new until I have this phase completed. A "this is where I am at" stopping moment will be a good place to listen to what it does then decide. The PSU needs finishng and the last pulley needs to arrive so better to complete this and take stock.
 
Ok arm board raised using 4 20mm x 18mm m5 pillars through the top plate and firmly bolted to the underside using Allen bolts, this enables me to drop the collar by 20mm and a further 10mm for the arm base and 16mm for the bearing. It has plenty of thread and passes through top to bottom, a bit like an orbe arm plate...

Arm base raised by c-g., on Flickr

Today's Work by c-g., on Flickr

That's actually pretty unusual having it like this, I expect lots of decks have done this but I have not seen this done to a Rega derived deck...

I also started work on the three motor PSU... Three pins are +18V one is a common ground

Had a nice new shiny backplate machined for this to cover the holes I had made when it was a music controller...

Today's Work by c-g., on Flickr

Plus Heat Shrink. Gotta have your strain relief...

The rear end by c-g., on Flickr

Butt shot...

I'll complete the PSU tonight or tomorrow some work still to do...

PSU by c-g., on Flickr

Not too ungainly looking after all, the oiled frame is really holding the sheen nicely...

PSU by c-g., on Flickr
 
External PSU is now built and working, the deck spins again. All three motors hooked up and powered.

PSU works by c-g., on Flickr

Just need the feet to arrive and its bolted up and rubbed over with oil again... Next up cartridge tags and home stretch. Needle drops soon.
 
You must log in or register to reply here.


advertisement


Back
Top