Question for Rega Planar 10 owners

[Timcat]

Rega has resolved the issue!

I collected my P10 from the dealer yesterday, after its return from Rega, and I noticed couple of things when re-installing it. Firstly, a small black pen or pencil mark had been placed on the sub-platter and also on the adjacent part of the main platter. Secondly, as opposed to a few grey marks under the main platter where it contacts the sub-platter, there was a fairly unbroken grey ring (as all P10 owners will know, each time you remove and replace the main platter, the sub-platter leaves a mark on it - this is normal). I figured that the pencil marks were intended to be lined up when the main platter is installed, so I did this and .... no more rattle or rocking, the main platter sits rock solid in place!

Clearly, the people at the Rega service department know how to fix this issue. My guess is that they firstly find the spot where any rattle is minimised and then they gently rotate the main platter back and forth a little (maybe just once or twice?) so as to rub off a very small amount of the aluminium from those of the the sub-platter ridges that were a little higher to start with (as removal of a small amount of material happens normally each time the main platter is re-installed, if this is what Rega did, it would simply have been a targeted version of what happens when the player is installed).

I have no idea why the dealer told me otherwise, but it is clear that Rega took the time to fix the rattle, rather than do nothing. I couldn't have asked for a better service!

If I am right, it might be a good idea if dealers learned this fix and checked all P10s before they went out.

And finally, the TT sounds great!

 

[barryb]

That's great that you got resolution. I would have thought the tolerances on the machined sub-platter were quite tight, and that maybe the ceramic platter was the issue. Nevertheless, great that it's sorted.

 

[dave charlton]

My guess is that they firstly find the spot where any rattle is minimised and then they gently rotate the main platter back and forth a little (maybe just once or twice?) so as to rub off a very small amount of the aluminium from those of the the sub-platter ridges that were a little higher to start with (as removal of a small amount of material happens normally each time the main platter is re-installed, if this is what Rega did, it would simply have been a targeted version of what happens when the player is installed).

I find your lapping theory quite alarming but am also pleased you have a resolution.

 

[Timcat]

I find your lapping theory quite alarming but am also pleased you have a resolution.

My idea may well be wrong, but it is a fact that whenever you remove and replace the main platter a small amount of material from the sub-platter (It's probably aluminium oxide) is removed and left on the inside of the main platter. So a degree of lapping is inevitable. Choosing an arrangement and mating surfaces (hard ceramic on soft aluminium) that make this inevitable, obviously with full knowledge of its "bedding in" effect, in my opinion, must have been a deliberate (and effective) design choice. I see no reason for alarm, as the components of an engine undergo a similar bedding in process during the running in period.

Anyway, whatever the Rega guys did it was effective and I'm very happy with the result!

 

[Radiance]

Hi,
the subplatter is manufactured from an aluminium alloy, might be 7075-T6 or similar.
It‘s not aluminium oxide! The main platter is made from aluminium oxide, a material chosen due to its extreme hardness and high density. If there will be anything of some kind of material removal then it will only be on the “softer” aluminium subplatter…
Just my 2…
Regards,
Rad

 

[Timcat]

Hi,
the subplatter is manufactured from an aluminium alloy, might be 7075-T6 or similar.
It‘s not aluminium oxide! The main platter is made from aluminium oxide, a material chosen due to its extreme hardness and high density. If there will be anything of some kind of material removal then it will only be on the “softer” aluminium subplatter…
Just my 2…
Regards,
Rad

Agreed regarding the sub-platter being made from an aluminium alloy, but on exposure to air, a very thin layer of aluminium oxide forms on the surface of anything made from aluminium, which prevents it from undergoing further oxidation through reacting with oxygen in the air. That is why I surmised that the deposit on the ceramic was oxide. See:

https://www.sserc.org.uk/subject-areas/chemistry/chemistry-resources/real-reactivity-of-aluminium/

I don't know what ceramic material is used to produce the main platter; Rega don't say on their website.

 

[dave charlton]

I don't know what ceramic material is used to produce the main platter; Rega don't say on their website.

More recently, starting with the P9 model, Rega fulfilled a longstanding ambition to produce a ceramic platter in ultra-hard aluminium oxide, which approximates ruby in hardness and is significantly stiffer than glass.Those initial platters were made alongside missile nosecones, by compressing a blank of Aluminium Oxide powder under 600 tons of pressure. The blank must be 20 per cent larger than ultimately required to allow for shrinkage when it is fired (for a long period and at very high temperature). The partly finished compressed blank is similar to chalk and may be easily roughly machined. Once fired, the material is so hard that it can only be finished by diamond grinding or lapping. This process can again take many hours (or even days).

Taken from the Rega book 'A Vibration Measuring Machine".

 

[Timcat]

More recently, starting with the P9 model, Rega fulfilled a longstanding ambition to produce a ceramic platter in ultra-hard aluminium oxide, which approximates ruby in hardness and is significantly stiffer than glass.Those initial platters were made alongside missile nosecones, by compressing a blank of Aluminium Oxide powder under 600 tons of pressure. The blank must be 20 per cent larger than ultimately required to allow for shrinkage when it is fired (for a long period and at very high temperature). The partly finished compressed blank is similar to chalk and may be easily roughly machined. Once fired, the material is so hard that it can only be finished by diamond grinding or lapping. This process can again take many hours (or even days).

Taken from the Rega book 'A Vibration Measuring Machine".

Thanks! Maybe I should buy the book!

 

[Craig B]

Yeah, it's a coffee table book about turntables that use wee coffee table tops as plinths.*

* And boomerangs, some of them are made from boomerangs, because they are light and stiff and really fly!