sure go for it and when finished lets see the end product.
23 responses Add your response
Well I will probably start with a plinth and the guts out of my fisher direct driver first to be honest... Then I will move onward and upward... This being my first attempt... I suppose I will teach myself some design 101 on the cheap using what I got first... Once I can get that good sounding I will progress.. I have alot to learn and this ought to be fun at the very least.
You may find some of the resources at The Analog Dept useful here: http://www.theanalogdept.com/index.html
This page from the above website is focused on building various plinths that may be useful as well since that is where you are starting out: http://www.theanalogdept.com/plinth_builders_gallery.htm
Hope this helps.
There are essentially 2 schools of thought on TT design. Low mass-high rigidity, and high mass. High mass is probably easier for a DIY'er to handle since there's little additional "tuning" that is required for a low mass design, and therefore is less trial and error prone.
Designing a TT is mostly about resonance control and tight tolerances on some key parts. After that it is about speed stability. I would stongly suggest keeping things as simple as possible to avoid pitfalls that you may not be able to anticipate in your first attempt, such as using a manufactured arm rather than a DIY (unless it is an exceedingly simple design).
Good luck whichever way you go and remember there is more than one way to skin a cat as the variables add up pretty quickly.
Agree with Vernneal. It only make sense if you enjoy the process of designing and building by itself. I do, so I'm having lot of fun along with enjoying the music on the long run; I also have learned great deal about audio. Otherwise, it is not justified economically; lots of excellent second hand TT on the web market.
Through experience, I strongly suggest the following:
* purchase off the shelf platter (many offerings, "Scheu" is one of those) and well -- or tyou can design & machine he latter yourself (a mechanical engineer will help tremendously).
* work on a (electromagnetic) elevation system for the platter -- i.e. a magnetic bearing; get rid of the bearings friction.
I realize it's involved; and that it may not make sense financially... Well that is unless you plan on selling your creation (which we do). This is the start and I realize the wheel could be being reinvented a little bit; But construction has began on the first plinth and I am excited. The first order of business is for me to take the guts of a VERY inferior table and make it sound very much so better. Then they will slowly but surely be swapped out with more custom pieces. This is a learning process... but I learn quickly... hopefully in a few months I will have some results to share.
Nowdays it is easy to find strong magnets for cheap on web. But,be warned that isolation from strong magnet field is extremely difficult. I have abandoned this idea after messimg around with multiply mu-metal sheet screens; my best attempt reduced the magnet field by 30% - still way to mutch to live with it. Buy at least good magnetometer for check if you wanna take the plunge.
How about using a thing sheet magnet under the platter and then shield it with aluminum... much like magnetically shielding a transducer? my idea is to use some sort of less powerful magnetic field underneath the platter to levitate it against another magnet point downward... so pole differential... in theory the repelling action should float it... then there would be a layer of shielding and the opposing forces of the magnets with their backs to the vinyl should not create any undue fields... i would just have to fashion a skirt for the bottom of the platter out of aluminum as well... ooh i have an idea... have to go sketch this out in autocad right quick... bbl
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 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