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Tone Arm board material

My VPI Ares3 turntable which is made with a laminated acrylic/aluminum/acrylic plinth, about 2.5 inches thick in total, has a 5/8 inch circular cut through the top layer of acrylic which exposes the center laminate of aluminum.  Set into this circular cut out is the 'puck' arm board mounting disc which is about 7/8 inches thick acrylic.  This bolts to the aluminum via three machine bolts.  My SME Series IV magnesium tone arm is bolted to the acrylic tone arm puck.

Magnesium is known for its superior vibration and sound deadening qualities, so I was wondering if anyone has any thoughts on making the tone arm board 'puck' out of solid magnesium vs. the factory supplied acrylic??  I can see why they probably don't use magnesium as it's super expensive.  I just got a quote on a small piece of magnesium to machine a new tone arm board and its $125.  But if it were to make an improvement in performance, its cheap money.

Does anyone out there have any thoughts on this?

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Showing 3 responses by bdp24

bdp24's avatar
bdp24
9,393 posts
 
@travbrow, is the damping material bright blue in color? If so, it may be EAR C-1002 Isodamp, considered the constrained layer damping standard in the industry (though Geoff Kait disapproves of it). Michael Percy Audio sells C-1002 in varying thicknesses. Another good cld material is Wall Damp by ASC (Acoustic Sciences Corp., makers of Tube Traps), sold in 4" X 4" pieces for a pittance.
bdp24's avatar
bdp24
9,393 posts
 
By the way, the generic name of Delrin is Acetal. There's also a long chemical name for it (abbreviated to POM), but you don't need that.
bdp24's avatar
bdp24
9,393 posts
 

One other material to consider is a close cousin to acrylic---Delrin. That's a brand name I believe, not the material's generic name. Delrin is the material VPI used for the platters of the HW-19 MK.2-4, Aries 1 (top layer), and TNT (pre-Mk.6) tables. It is a little denser and harder than acrylic, and has a matte sheen in contrast to the high gloss of acrylic. I had an acrylic arm board for my Aries 1 made at a good plastics supply house, and the price for a Delrin version was only slightly higher than for the acrylic.

Another option to consider is to have two 1/2" thick boards made, with a thin piece of constrained layer damping placed between them, for damping of any ringing in the material.

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