Linn to Rega bearing conversion.

this is actually part of another project but may be of interest to anyone who wondered if the crap plastic injection moulded Rega subplatter was just that, crap.

As part of a Mag-lev main bearing project i've fashioned a Linnlp12 subplatter and bearingto fit the standard Rega dimensions, ie 100mm diameter.

It requires a fair bit of jigging to fit from a height perspective, it needs a press fit flange for the top section of the bearing housing so it will sit level and flush with the top of my plinth.

But it's a damn sight more concentric than the stock Rega part and it spins much more freely.

According to various reviews it should be quieter even before the mag-lev, Rega -73db, Linn -81db for bearing rumble. After maglev they are even quieter still.

It's actually quite concerning how out of round the Rega part is, no wonder their speed is all over the place, even with the TT-psu fitted..

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Hi, I've often looked at those plastic Rega sub-platters and wondered if they were a weak point.

How far out of true are they? I guess it would be fairly simple to turn up an aluminium one, or even in Delrin if there really is a reason for the original being non-metallic.

i have a P2 sitting on the floor looking unloved right now - I wonder if it's worth a try?
 
sq225917 said:
this is actually part of another project but may be of interest to anyone who wondered if the crap plastic injection moulded Rega subplatter was just that, crap.

As part of a Mag-lev main bearing project i've fashioned a Linnlp12 subplatter and bearingto fit the standard Rega dimensions, ie 100mm diameter.

It requires a fair bit of jigging to fit from a height perspective, it needs a press fit flange for the top section of the bearing housing so it will sit level and flush with the top of my plinth.

But it's a damn sight more concentric than the stock Rega part and it spins much more freely.

According to various reviews it should be quieter even before the mag-lev, Rega -73db, Linn -81db for bearing rumble. After maglev they are even quieter still.

It's actually quite concerning how out of round the Rega part is, no wonder their speed is all over the place, even with the TT-psu fitted..

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Regarding the accuracy of the stock Rega subplatter: Did you use measuring equipment to check runout.? If so, what deviation did you measure?
 
the runout was all over the place, but two main high spots, one at +.12mm and the other at+.08mm

I guess they do spit them out of the injection tool way too fast.

the modded Linn version is good to 1/100th, past the limits of my borrowed probe.

jeff if you are willing to knock the top cap off the rega subplatter you can skim them on a lathe with a decent spinning centre. I did this to my previous Project subplatter and it made a huge difference to pitch accuracy.
 
of course, you never who might read it and be inspired, just because they don't reply doesn't mean it hasn't been of some benefit to someone.

I wasn't expecting it to start a rash of small scale production of improved Rega parts from Linn parts, most people would have to acquire the linn parts first.

If just one person skims their rega platter to better tolerances then its worthwhile.
 

YNWOAN

Member
2007-01-12 6:01 pm
I don't think that was sq225917's intention with this thread was to put people off buying a Rega. I actually know sq225917 quite well and it is a version of the magnetic bearing that I designed for my deck that he is building for his (he got it working today so may post a bit more). The Rega (in my opinion) has proved to be a good 'donor' deck - although not much of it remains now. The Rega inner platter has pretty good dimensional accuracy for an injection moulding - the Linn item sq225917 is referring to was custom machined to the correct size and is inherently more concentric.
 

Panicos K

Member
2006-10-01 10:47 am
Just joking YNWOAN....... I know rega well,and I agree with you to the point that it is a good "donor" deck for many,myself including.I will soon replace the plastic hub with a one piece corian platter and cut a corian plinth too for a P3.I will keep the arm, drive system and feet.I hope it works ok!!!!!!!!!!!
 
jeff spall said:
Hi, I've often looked at those plastic Rega sub-platters and wondered if they were a weak point.

How far out of true are they? I guess it would be fairly simple to turn up an aluminium one, or even in Delrin if there really is a reason for the original being non-metallic.

i have a P2 sitting on the floor looking unloved right now - I wonder if it's worth a try?

Plastic damps the very dense glass platters. Very little else will.
 
KBK said:


Plastic damps the very dense glass platters. Very little else will.

Hi, yes you're quite right. When I posted the original I was really thinking that the improvement would come from having a really accurate sub-platter, but aluminium has an acoustic impedance surprisingly close to glass, so sound will travel very easily between the two. Just what you don't want for bearing noise and it would probably make the turntable much worse.

Duh! Delrin could still be good though, and nice to machine.

I think a surprising amount of thought has gone into the Rega products, getting good performance from very simple construction, Rather reminds me of Colin Chapman's early Lotus cars.