What is the absolute BEST arm board material??
- Thread starter 62sunbeam
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marcmorin
RIP 1953-2020
where do you want the arm energy to go?
ripblade
Super Member
+1. While we discuss the nature of what we call an ideal mode of energy transfer, we must not forget to ask if the receptacle we wish to dump the energy into is worthy. I don't know what's best for the Thorens, but I can say confidently that the ideal receptacle doesn't exist, so there's no ideal material to transfer the energy.
And this completely ignores the user's bias for one material over the other for purely subjective reasons, some of which might have nothing to do with the sound.
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marcmorin
RIP 1953-2020
the springs might reduce the energy.......some.......not their job though. the run of the grain will show the path of least resistance. "generally" the harder the wood, the faster the velocity. however spruce and cedar are "fast". The higher the velocity the energy can travel, the lower the amplitude. This being a sprung suspension, I'm assuming, mass becomes an issue. Bass wood has low velocity, high amplitude. when a high velocity material abuts a low velocity material energy is somewhat consumed as it tries to pass through, some is returned but 180deg out of phase.
I recently read an article about new traits that they are discovering regarding cork, and its ability as a insulator to unwanted resonate frequencies. I would think it might be worth while instead of using rubber as a gasket between the arm board and the plinth maybe a layer of cork?
Thunderbox
Super Member
Lead is the absolute best arm board material. Absorbs any sound frequency. Downside is it's maybe just a little soft. Actually a plinth made from lead would be awsum but maybe too heavy.
Gibsonian
Super Member
What is the reason you have chosen graphite? Do you have a source for this material?
So are you suggesting a board made of two materials, one bass/one treble? Low/high velocity?
marcmorin
RIP 1953-2020
the arm base is a very high velocity material. running into a high velocity and the energy (1/2) will pass into it. the energy that does pass into in should then go into a slower velocity material, the energy is then halved again. email me, and I can send you a "paper" written on "wave reflection from mixed boundary". it has animations to give you a visual of what happens to vibrational modes. Actually the site has all kinds of nifty stuff to read and watch.
VinylRob
Vinylphile
Fascinating subject. As it where, I'm in the process of choosing a material for a Reed P3/12 tonearm. The wand is made of Brazilwood (Pernambuco) and obviously imposes a tonal flavor to the final outcome and is often used for cello/violin bows. It is being mounted to a Brinkmann Balance TT that is mostly machined aluminum. The maker of the TT employs aluminum tonearm boards, though I could design and cnc basically anything... a thought was to start experimenting with an acoustic (tone) instrument wood.
Any thoughts on a completely different direction of say... B-15/25 Panzerholz???
Any thoughts on a completely different direction of say... B-15/25 Panzerholz???
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I'm thinking of making up a new arm board from my TD 125 and wondering what route to follow. The one that came with it was MDF, but I made up one from hard ample that seemed to work well, though I didn't have anything to compare to with the same arm. What would you go with for a 125, given the way the arm board is mounted on the tabs off the end of the top plate?
marcmorin
RIP 1953-2020
do you have a size?
You mean dimensions for the arm board? Yes, I do. 11 1/2" (292mm) x 4 1/8 (105mm) x 1/2 (7mm). It mounts on three cast tabs that extend from the main top plate with three screws, the heads of which recess into the board and the underside is beveled on the side closest to the top plate. The arm I am planning on mounting is a Fidelity Research Fr-24 MkII which has a spindle to pivot distance of 230mm.
This is a pic of the original MDF board that came with the 125, drilled for Linn.
I have made arm boards for my TD-125 out of solid maple, solid walnut and out of birch ply that I purchase from Michaels craft supply. They sell it in small pre cut sheets. I like the birch ply the best. It seems to be more ridged than the other two solid woods. Also, it doesn't warp like solid woods do from my experience....
I do a lot of wood working . PLywood is inheritly more stable than solid wood. The different layers of the wood grain are layered 90 degrees opposite of the one next to it ( 1st layer runs N to S,2nd Layer runs E to W, 3rd layer N to S and so on ) The best you can use is cabinet Grade 7 to 9 layers for 3/4 inch. all modern ply uses exterior glue more stable to moisture and temp. All ply interior is pine with a veneer of approx 1/16 to 1/8 thick of what ever wood you want. Hope this helps
GuyK
Addicted Member
[QUOTE="steven94, post: 10624212, member: 204934"... The best you can use is cabinet Grade 7 to 9 layers for 3/4 inch...[/QUOTE]
Nope. The highest grade I've encountered is aircraft grade plywood, and I know for certain that 5 ply 3/16" is available. How 'bout 12 ply 1/4", or 3 ply 1/64"? Cabinet grade got nothing on this stuff.
Nope. The highest grade I've encountered is aircraft grade plywood, and I know for certain that 5 ply 3/16" is available. How 'bout 12 ply 1/4", or 3 ply 1/64"? Cabinet grade got nothing on this stuff.
marcmorin
RIP 1953-2020
damm, I don't have stock wide enough. I have Bass fret board blanks in cocobolo. But it's only 3" wide x 5/16 (8mm) 1/2" is 12.7mm
