I think I am going to attempt to make turntatbles


First off let me say I am not new to the audio realm. I am a computer engineer and yes I realize that deals in ones and zeros. However, I have made a few custom guitars. I know a master woodworker and a talented machinist. I have been searching for that perfect table for years whilst living in mediocrity. Well, I have the resources; why not make one from scratch. More than likely I am going to attempt a belt drive unit at first using an off the shelf arm... More than likely an SME. I am working on the power supply circuitry right now as my piece. Any one have any tips... I am thinking solid, large mdf plinth with an attached copper mat and either a heavy plinth with an acoustically decoupled motor or completely detached. Thoughts?
bc5k
I would look for something other than MDF for the plinth. Maybe the ikind of wood musical instruents are made of?
Another catch in repelling magnets idea is a strong side force applied on the magnets and hence on the journal bearing, if any slightest non-concenricity of the two magnet fields exists. Magnet levitation is inherently unstable. Try to bring opposite poles together and you will feel a whole magnitude of this force. One more lesson I've learned about magnetic field isolation: the shield must be of closed contour around magnets with minimum gaps, otherwise isolation is greatly reduced.
Good for you... I applaud your interest. I would caution you to keep this effort as a hobby, and not expect to make boatloads of dollars from it. I talk from experience. If indeed it turns to gold that others are willing to pay for...so much the better. Good luck
Bc5k,

Good for you! I wish you the best of luck, and I hope that you have a little fun in the process.

My $.02 worth: designing a shielded MagLev bearing is not for the faint of heart, pocketbook or math skills. If you are seriously looking for an alternative to M2M or jewel bearings I would suggest that you look at air bearings. They are readily available in a variety of configurations and sizes, and are (relatively) low cost from eBay and other sources.
Well I love a challenge and as an engineer I am really proficient in both calculus and physics... I drew out my plans today while I should have been working (ha ha ha). So its going to work something like a speaker does when it moves the voicecoil within the magnet and will have a regulated power supply to the electomagnet... lots of trial and error I presume... Also going to attempt to make this a direct drive idea... (I know I know lots of magnetic fields fighting each other... most have a good shielding plan)... BUT.. This is the kicker... VTA can theoretically be adjusted one of two ways... Raise and lower the arm or the platter... See where I'm going... Electronically adjustable VTA. On the fly!!! Also when the turntable powers of the platter will rest in a groove in the plinth. I'm running with this idea and there are going to be lots of pitfalls; curse words; and hopefully a supreme result... A turntable with 0 resonance except that made by the stylus and what little the direct drive motor makes. Good thing I used to build and play with tesla coils as a kid :D