Best surface, Marble, slate, cutting board???

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Mr Pig
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Re: Best surface, Marble, slate, cutting board???

Post by Mr Pig » 01 Dec 2019 10:18

kalaur wrote:
01 Dec 2019 02:35
Plinths are not there to just damp vibrations. If they don't vibrate in the first place from external forces, that's step one.
Mana is the best support I've ever heard, yet the whole thing rings like a bell!

This is a complicated situation. There is a lot going on, some if it I don't think anyone fully understands, which is why my only advice is to try different things and see what works in your system and what you like the sound of. There is no one size fits all answer.

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Re: Best surface, Marble, slate, cutting board???

Post by Woodbrains » 01 Dec 2019 13:37

Mr Pig wrote:
01 Dec 2019 10:18
kalaur wrote:
01 Dec 2019 02:35
Plinths are not there to just damp vibrations. If they don't vibrate in the first place from external forces, that's step one.
Mana is the best support I've ever heard, yet the whole thing rings like a bell!

This is a complicated situation. There is a lot going on, some if it I don't think anyone fully understands, which is why my only advice is to try different things and see what works in your system and what you like the sound of. There is no one size fits all answer.
Hello,

What is Mana? I assume it isn't food from heaven!

Mike.

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Re: Best surface, Marble, slate, cutting board???

Post by Mr Pig » 01 Dec 2019 15:19

Woodbrains wrote:
01 Dec 2019 13:37
What is Mana? I assume it isn't food from heaven!
That's manna ;0)

Mana was a hi-fi support built and sold from the eighties up until about ten or so years ago. It was sold direct rather than through dealers so despite getting amazing reviews across all of the Hi-fi press it was always a niche product. That fact that it was ugly and expensive probably didn't help

Sonically, it makes you rethink everything you thought you understood about how Hi-Fi works.

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Re: Best surface, Marble, slate, cutting board???

Post by cats squirrel » 01 Dec 2019 16:27

AsOriginallyRecorded wrote:
30 Nov 2019 05:04
well, with all due respect, I suggest that you are incorrect, regarding travel and vibration, as any simple googling of "do vibrations travel" will yield a long list of articles on the topic. Particle alignment....each material has a consistent typical arrangement of the atoms, molecules and building block units of it's elements. This alignment determines much of the physical characteristics of the material under specified conditions. Vibration traveling....repeat, traveling through various substances is alternately attenuated by the alignment of particles and molecular shapes in the material. This is why alternating materials will reduce the vibration from one material to the other, such as when using an isolating pad between a turntable, for instance, and a dense solid like a concrete slab or wood fibre cutting board. Assuming a reasonably sprung TT, various material selections will produce varying effective results. The principles are easily understood and comprehended, the methods to attenuate are less clear. Hence, YMMV. For what it is worth, I have had good success with using thick slabs of fine grain cedar, a relatively light and fine grain (high density) wood for speaker risers, with a carpet isolator between block and speaker. Likewise, the close cell foam mats have proved very successful. We are not all blessed with extensive degrees in physical sciences, but using relatively simple models does help clarify what we are dealing with, and some alternative methods of dealing with it. :)
well, with all due respect, I suggest that you are incorrect. Googling "do vibrations travel" brings up umpteen opinions on wave propagation in air. Your suggestions about traveling through various materials is not correct, however.

If a slab of material (a plinth or support) is excited, it will vibrate according to very well defined ways, depending on various parameters and edge effects. A single board (lets say of wood, but it applies to virtually any material) will vibrate at its fundamental frequency, the lowest (usually) and behave in exactly the same way with any material and any size (down to nanometer dimensions). Then there will be harmonic vibration, depending on the foregoing. The shape of the deflection is a sine wave, viewed from any edge. The size and shape of the board help determine the wavelength at which the board vibrates. Other variations are determined by how the edges are configured, be it clamped, free, simply suspended or guided. All this has been well known for decades, and various mathematical models have been developed to validate it (or visa verse). This is all in the scientific press, written by scientists and verified by scientists, not audiophile opinion.

The science of different materials put together is well understood by scientists, although not by audiophiles, it would seem. If slabs of materials (scientists call them plates) are just placed one on top of the other, then mechanical impedance comes into play. If the various materials are glued together, then a new (glued laminate or glulam) is formed, and all layers vibrate together, in the same direction, at the same time, at the same frequencies. There is no reason why gluing several disparate materials together would get you what you need, and prayers won't help.

I would suggest the principles are not easily understood, evidenced by your misunderstanding, but methods of damping are. Mileages will not vary! If you have had 'success' by your methods, then if you believe that there has been an improvement, so be it, I am happy for you. But don't suggest an untrue description of what you think is happening, that is how urban myths are started, and there are more urban myths in hifi than truths.

The problem with not understanding the physics is that one comes up with alternative ideas, which are not the facts.

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Re: Best surface, Marble, slate, cutting board???

Post by cats squirrel » 01 Dec 2019 16:32

kalaur wrote:
01 Dec 2019 02:35
cats squirrel wrote:
20 Nov 2019 13:19
A 'heavy' plinth isn't recommended in any material.
I suspect every mass loaded turntable manufacturer would argue this.

cats squirrel wrote:
20 Nov 2019 13:19
A heavy plinth becomes the immovable object, so no damping can take place, so any turntable connected to it must damp the vibrations itself. How many can?
Go rap your knuckle on a cinder block while touching it with your other hand. Now rap your knuckle on a cardboard box while touching it with your other hand. Cinder block is certainly heavier than the cardboard, yet it transmitted no vibrations to your hand. Plinths are not there to just damp vibrations. If they don't vibrate in the first place from external forces (footfalls, trucks driving by, bass, etc), that's step one.
Yes, you set up a good straw man argument. Breeze block (in the UK) or cardboard. I don't think that any sane person would use either of those. But the breeze block will have more mass, will be thicker and have a much greater mechanical impedance. If you placed a TT on top of one of those, very little vibration would be transfer to it. So that the TT would have to deal with all the vibrations from all the inputs by itself. How many do?

And I suspect every knowledgeable turntable manufacturer would argue for it. More and more TT's are being sold with thin plinths, for good reason, not because it looks better!

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Re: Best surface, Marble, slate, cutting board???

Post by Woodbrains » 01 Dec 2019 18:22

Hello,

There are good reasons for making thin plinths. They are cheap!

Rega are using very low density material for their higher end tables. The reason being, if there is less material for vibrations to propagate through, there will be less energy to transfer etc. I agree, it is a fine application of physics and it apparently works well if the reviews of these products are reliable.

However, mass loading also works from the other point of view. The energy of the vibrations that we are talking about are tiny. If they haven't enough oomph to get a massive body vibrating they won't give too much trouble. Plus a lot of mass has many particles to lose energy as heat.

It is all very well talking about 'plates' having fundamental frequencies that with vibrate in harmony with external sources of vibration. Well that is true, but, and even counting all the harmonics as well, we are talking of a very narrow band of frequencies that will cause trouble. Multi layering of dissimilar materials does have an effect on reducing vibrations transferring at the fundamental of one through a junction to a fundamental of another. Just the same as sound moving from air to a wall back to air. If it didn't lose energy at each junction, playing your music in one room would sound just as loud in the next. It clearly does not.

There are many ways to skin a cat. But making massy plinths with lovely wood veneer finishes is 10 times more expensive than a polyurethane sandwich with a rather dreadful appearance, as per Rega. Cost has more to do with it than physics.

By the way. I have just made a massy plinthed table from a Rega Planar 2. I'm using the original AC motor, and it is the most eerily quiet table I have (not) heard. I'm willing to bet my humble Rega is at least as quiet at any higher end Rega with the new motors and neo PS. And it looks 10 times more beautiful, belying its humble origins. It would cost a lot to produce my table, though and not production line semi skilled operative produceable.

Mike.

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Re: Best surface, Marble, slate, cutting board???

Post by Mr Pig » 01 Dec 2019 20:22

Woodbrains wrote:
01 Dec 2019 18:22
I'm willing to bet my humble Rega is at least as quiet at any higher end Rega with the new motors and neo PS.
I doubt it. The RP10 is the quietest deck I've ever heard. Not just in terms of motor noise but bearing and groove noise too. It's ridiculously quiet. If a heavier plinth would be better I'm sure Rega would use one. The super light one on the RP10/RP8 causes all sorts of manufacturing difficulties. How do you bolt things to foam?!

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Re: Best surface, Marble, slate, cutting board???

Post by Woodbrains » 01 Dec 2019 20:35

Mr Pig wrote:
01 Dec 2019 20:22
Woodbrains wrote:
01 Dec 2019 18:22
I'm willing to bet my humble Rega is at least as quiet at any higher end Rega with the new motors and neo PS.
I doubt it. The RP10 is the quietest deck I've ever heard. Not just in terms of motor noise but bearing and groove noise too. It's ridiculously quiet. If a heavier plinth would be better I'm sure Rega would use one. The super light one on the RP10/RP8 causes all sorts of manufacturing difficulties. How do you bolt things to foam?!
Hello.

Like I said, it is cheaper! To make something like I have is not possible in a production environment, not at all. Just as making things from injection moulded foam is not (easily) doable as a one off product by a lone craftsman. It is horses for courses and the choice is made according to the production methods available. My Peruvian olive veneered, double plinthed, sorbothane footed, gluelam, sand filled, stainless steel, plywood, aluminium sandwiched concoction is something Rega could not touch with a barge pole. It makes the Premotec AC motor utterly silent, though. Oh and the Delrin main bearing makes it silent there, too. It isn't costing me as much as a Planar 3 to do, but if I had to make it to sell for a living, it would be cost prohibitive.

Mike.

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Re: Best surface, Marble, slate, cutting board???

Post by Mr Pig » 01 Dec 2019 22:45

Woodbrains wrote:
01 Dec 2019 20:35
To make something like I have is not possible in a production environment, not at all. Just as making things from injection moulded foam is not (easily) doable as a one off product by a lone craftsman.
I'm not sure I can agree with either of those suppositions. There are many hi-end manufacturers who build turntables using broadly comparable construction methods to the ones you've employed. They might not be cheap, but they exist. Similarly, you could build a turntable using the same or similar materials and methods as Rega if you wanted to. Virtually all of the parts on the RP10 are outsourced and only assembled by Rega. The platter, doubt you could replicate that without deep pockets though.

I have to say though that using the Planar 2 as the basis for a very labour intensive turntable isn't a very good idea as neither the bearing or motor, the bits you've kept, are particularly good. Even the main champions of that motor, Linn and Rega, have abandoned it in favour of DC ones. The problem with the Premotec motor is that there is a limit to the speed stability you can get out of it, no matter what sort of power supply you use. Rega sell a DC motor kit you should be able to slot right into the deck you've built, I'd look at that if I were you.

The original Planar bearing isn't terrible but again, even Rega don't use it for their better decks. If you're going to put a lot of time, effort and money into building a turntable I think it deserves better.

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Re: Best surface, Marble, slate, cutting board???

Post by Woodbrains » 01 Dec 2019 23:33

Hello,

You sort of are agreeing with me. Rega outsource the parts to production specialists because these are the experts with the set up to do these things cheaply and efficiently. The investment in tooling and space simply is not worth Rega bothering. Making a beautifully laminated veneered plinth, either takes the meticulous skill of an (expensive) craftsman, or outsourcing again to specialist panel manufacturers with 10 ton heated presses, veneer stitchers, spray booths etc etc. They are unlikely to be bothered with putsing around with this sort of nonsense. I have made high end furniture for years, and trust me when I say, it is unviably expensive.

But this is besides the point; my argument is that making heavy plinths are one way of solving a problem. For a custom TT build, with a high end look, it certainly can yield spectacular results.

I started with a planar 2, simply because it was what I had. Designing a plinth to overcome the disadvantages of the Premotec motor was part of the fun. Rega's original solution to using this motor was to soft mount it to the plinth, which reduced the vibration problem a little, but caused a speed instability issue. My rigid mount, in a sand filled module, coupled to a heavy sub plinth, makes the motor utterly silent and has no speed instability.

Incidentally, Rega still use AC motors, just 24 volt ones with electronics designed to smooth out vibrations, so they can rigidly mount them to overcome speed stability issues. I have used mass loading to smooth out vibrations and rigidly mount the motor. Different paths to the same end, and trust me, it is utterly silent. I have changed the platter bearing for a delrin one, made a new platter, (plywood, aluminium and acrylic sandwich); plywood and Stainless steel arm board; aluminium tube, foam filled legs with sorbothane feet.....

I have also modded the arm. Drilled tube, silicon rubber internal damping, SS counterweight stub, and I modified the standard counterweight to have a slightly lower axis mass with neoprene foam plug damping. I'm just rewiring it so pics will come soon. I will have to get a new belt, too. Overall I have spent not a great deal and don't believe I could get a better table for the outlay even a used one.

Mike.

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Re: Best surface, Marble, slate, cutting board???

Post by Mr Pig » 01 Dec 2019 23:51

Woodbrains wrote:
01 Dec 2019 23:33
My rigid mount, in a sand filled module, coupled to a heavy sub plinth, makes the motor utterly silent and has no speed instability.
I've heard and used that motor in various turntables powered by some of the most highly regarded power supplies and trust me, it does have speed instability. If it didn't Rega and Linn would put it in their best decks. But they don't and when you hear the RP10 it takes seconds to understand why.
Incidentally, Rega still use AC motors...
No, they don't. I'm guessing they did use one in their budget decks until relatively recently but even the P1 has a DC motor now. I've got one here.

I'm assuming you modded the RB250 that came off the Planar 2? Again, while easy to work on and cheap, there are limits to what that arm can do. Even the RB300 has a much better bearing arrangement and comes with a stainless counterweight stub as standard. The hole drilling and tube damping I really question. Rega could do that stuff if they wanted to be they don't and never have. If you want to do something that will work, take the paint off.

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Re: Best surface, Marble, slate, cutting board???

Post by Woodbrains » 01 Dec 2019 23:56

Hello,

http://www.rega.co.uk/planar-1.html

24v synchronous AC motor.

Mike.

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Re: Best surface, Marble, slate, cutting board???

Post by Mr Pig » 02 Dec 2019 08:05

Woodbrains wrote:
01 Dec 2019 23:56
Hello,

http://www.rega.co.uk/planar-1.html

24v synchronous AC motor.

Mike.
Amazing how they get that to work with a DC power supply! Don't see the word AC in that blurb.

And it's not relevant anyway. You've tried to make a silk purse out of a sow's ear.

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Re: Best surface, Marble, slate, cutting board???

Post by Woodbrains » 02 Dec 2019 10:30

Hello,

Really I shouldn't dignify this with a response.

However....https://en.m.wikipedia.org/wiki/Synchronous_motor

Mike.

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Re: Best surface, Marble, slate, cutting board???

Post by Mr Pig » 02 Dec 2019 14:00

You could be right. I've got a Rega P1 power supply here which says 'DC' on it but maybe I'm wrong. As I said, it doesn't really matter does it?