[mark@marktwain]

Hey guys I almost have all the parts gathered up for my diy turntable rig. I'm using a Clearaudio champion II bearing and a Clearaudio champion II 3" thick acyrlic platter. A Maxon 110191 DC motor and the Mark Kelly DC motor controller from the diyaudio.com group buy. I'm gonna start out with a systemdek profile II arm (Jelco) I picked up from Sturg, thanks Sturg and a Shure M97XE cartridge. I just need to make the plinth. Here's a pic of my first concept watcha think? http://www.audiocircle.com/index.php?action=gallery;area=browse;album=838&pos=0 As for plinth material I'm thinkin corian, I've read that it is probably the best material to use although I would prefer an exotic hardwood maybe cocabola. It's about as dense a wood as you can get. Has anybody been able to apply wood veneer to corian? I'm planning on machining the three adjustable cones and pillars from aluminum or brass. The motor pod will be made from aluminum and filled with lead shot. The motor pulley is being provided from a group buy on diyaudio and is made from brass and will accept either a flat belt or a thread belt. Any other suggestions on this project?

Mark

[Scott F.]

Cool concept 

Rather than a single layer of Corain, you may was to consider 3 to 4 layers of HDF. Laminate the layers together and then you can use what ever veneer you want.

I can also get my hands on some 1" think high density phenolics (free I think). You could also laminate several layers together then scratch up the surface with some sandpaper and apply a veneer to it. As you know, phenolics are super dense and the resonant frequency should be well out of the audible range based on the size and thickness we are talking. They should do well for a plinth I would think.

When it comes to your arm mounting, you may want to take a look at my Opera. They approached it pretty logically. The armboard is adjustable and removable so it can be replaced with a new armboard that is drilled to accept diffrent arms.

[steve k]

How about laminated bamboo? Bamboo is extremely strong, dense and very dimensionally stable. Ask Paul Hilgeman of Nomad Audio about that. He'll give you the Zen of Bamboo, grasshopper.
steve k

[mark@marktwain]

Hey Scott see if you can get some of the phenolic material that sounds like the ticket! around 18" square or better would be keen and enough to make the plinth 3" thick or so.

Yeah, if I was to use corian I was planning on hitting the local countertop shop and see if I could score some sink cutouts and laminate them up to around 3" thick.

Bamboo, Hmmmm.

Yep, I was fiqurin on making the arm mount removable so I could devise different mounts for various arms. The Jelco wants an 8.25" mounting distance from the spindle I believe. Do you guys know what other distances I would want to provide for? I would like to at least plan for a rega, grace, formula 4 and a sme.

Mark

[BobM]

You can find lots of specs on many different arms here:

http://www.vinylengine.com/phpBB2/index.php

If I was making a new TT I would probably look for a 12" arm, rather than go the shorter route again.

Enjoy,
Bob

[Scott F.]

Hey Scott see if you can get some of the phenolic material that sounds like the ticket! around 18" square or better would be keen and enough to make the plinth 3" thick or so.

Mark,

I made the phone call today. I should know something tomorrow or Friday.

I'm almost positive they have some but there's one catch. You'll have to come down and pick it up from their shop. This stuff is damned heavy and you'll need your pickup to haul it in. Chances are it will be a panel that is about 30" wide by about 60" tall. It will take two guys to lift it (I'll help) but you'll need somebody strong at your place to help offload it. I'm not quite sure how to cut it but I'll ask that question too.

[mark@marktwain]

Awesome Scott, you rock! No problem on coming down to get the stuff. Maybe I'll bring down the wolverine subs with me when I come down and we can goof around with em. Do you know what composition this stuff is? It seems like they make this from lots of different materials, paper, cotton, glass. Not being picky, just curious.

Just wondering Bob why the 12" arm preference?  Does a 12" arm sound better than an 8" or 9"? I'm planning on making my arm mount adjustable for any arm or at least removable so I can install different mounts for different arm lengths.

Mark

[Scott F.]

I hate to say this but I just got word back that they don't have any left over stock in the phenolic. Best I could do is 1" thick solid plastic.

[mark@marktwain]

Thanks fer tryin buddy.

[BobM]

Just wondering Bob why the 12" arm preference?  Does a 12" arm sound better than an 8" or 9"? I'm planning on making my arm mount adjustable for any arm or at least removable so I can install different mounts for different arm lengths.

The 12" arms have less of a probelm with the cartridge geometry over the range of the arc. Basically providing a smoother arc (less "arcy", flatter plane) closer to a straight line. This should theoretically give you better sound over the width of the record than a shorter arm. You still use the Baerwald alignment, matching 2 points, but it deviates from those points less than a short arm does.

If you're making the arm mount moveable then this is optimal, since you could go either way.

Enjoy,
Bob

[Wayner]

I'm moding an AR-XA and the plinth is going to be made from Black African Granite. It will kill all vibrations and is easy to cut with a waterjet. I will sandwich 2 layers of granite with the suspension on one half and the motor on the other half, bringing the plinth weight to around 50 lbs. This could be a suggestion for yours but you must have the resources. If you go the MDF route, seperate the layers with sorbothane like the Music Hall MMF-9. It will be way cool! Good Luck!