2. analog
  3. 138237-4374

Home grown turntable platform/base?

I picked up a used Pro-Ject Debut Carbon turntable for the family room. We are not big into vinyl, mostly listen to digital, but my 16yo daughter has shown an interest in getting some records. I’m getting excited about her interest in vinyl and audio. What is a good platform material to use? Wood? Granite? Should I add sorbothane and/or spikes underneath? I’m not looking to spend a lot but feel I should have some decent isolation for it. The turntable currently sits on a hollow shelf. It’s where it has to be so I need to make this work.

Thanks for any input.
asahitoro

Showing 5 responses by bdp24

bdp24's avatar
bdp24
10,109 posts
 
A sheet of 3/4"/19mm 13-ply Baltic Birch plywood (it is available in both 4’ x 6’ and 5’ x 5’ sheets) will cost you only $50 or so. Cut two pieces to size and glue them together. MUCH stiffer that the twice-as-thick 3" thick piece of maple, and more non-resonant. While some people like the sonic signature of Maple, remember, it is stiffness and a lack of a sonic signature we want in a support platform, not a pleasing coloration. IMO, of course.
bdp24's avatar
bdp24
10,109 posts
 
asahitoro, even if you go with maple or butcher block, consider getting two pieces and placing a thin sheet of constrained layer damping of your choice between them. That will mitigate the resonance found in all materials, including wood. Actually, especially wood---that's why they make drums and guitars out of it! Another thing to do is put the grain of the wood in the two pieces 90 degrees opposed to each other; one with the grain front-to-back, the other side-to-side. That will increase the stiffness of the assembled shelf.
bdp24's avatar
bdp24
10,109 posts
 
Good point had2be, one that had not occurred to me. I have Solid Steel racks, which unfortunately have 3/4" MDF shelves (yuck!). I bought extra top shelves to double the thickness (for my fairly heavy turntables), as well as ASC Wall Damp cut to the size of the shelves, but haven't added them yet. I'll eventually replace them with BB ply. But no screws! ;-)
bdp24's avatar
bdp24
10,109 posts
 

Regarding has2be's statement that screwing the two pieces of birch ply together will defeat the isolation provided by the constrained layer damping placed between them, that layer of damping material is put there not to provide isolation for the turntable, but to absorb and dissipate the resonances of the plywood itself. Green Glue, ASC Wall Damp, and EAR Isodamp is too thin to provide any isolation. It is the springs, roller bearings, Herbies feet, or Seismic Pods (or even slightly inflated inner tube) placed under the shelf that provides isolation, not the constrained layer damping.

No harm in trying the two pieces of ply both screwed together and not, though. However, Green Glue doesn't completely harden, which would allow the two pieces of ply to slide around in relation to each other a little. ASC Wall Damp is tacky enough to keep the pieces of ply from sliding against each other, but EAR Isodamp isn't; if using it, the two pieces of ply will have to be attached to each other in some fashion, ergo my suggestion of screws. Since the ply/constrained layer/ply construction should function as a single unit, you actually WANT the two pieces of ply to act as one. The reason for using two is to increase the stiffness of the shelf, and to allow the installation of the constrained layer damping, to make the shelf less resonant.

If you want a layer of isolation-proving material between two outer layers of stiff material, the Symposium shelves are the way to go. They have outer layers of stainless steel, with a thick layer of foam between them, to provide isolation. Symposium makes a version of their shelf with springs attached to the bottom, specifically for turntables. That model is relatively modestly-priced, around $350-$400 I believe. 

bdp24's avatar
bdp24
10,109 posts
 
Buy a sheet of 3/4" Baltic Birch plywood (about fifty bucks), and cut (or have cut at a cabinet building shop) two pieces to size. Put Green Glue, EAR Isodamp, ASC Wall Damp, or other constrained layer damping between the two pieces, and screw the pieces together. Put a set of springs, roller bearings, or other effective form of isolation under the platform (Townshend Seismic Pods are great, but not cheap). Enjoy.
More to discover