DIY Turntable - revisited

[squeegy200]

I've attempted this little experiment many times before with miserable results. Mainly because I didn't take the time to acquire decent quality parts and materials and my limited engineering and craftsmanship skills.

Since then I've scavenged several garage sale turntables and have made some progress.

One amusing discovery is that although I possessed several different TTs, ultimately, they all used the very same platter bearing. This part seems to be the most difficult to improve upon. And Teres, DIYAudio, and others once offered after-market bearing kits, they no longer do. (I'd love to use an oversized acrylic platter and bearing)

I have an upgraded MG-1 Air Bearing Tonearm which is driving many of the design requirements. My reference Turntable is a suspended SystemDek IIx which does not play well with the long cantilever design of the MG-1.So that will remain in my current system as is --for comparison.

I've experimented with several plinth shapes and materials to accommodate the MG-1 but find that I keep returning to the traditional square plinth. Acrylic material in this size and shape are extremely expensive--money I would rather expend on an upgraded cartridge or cables. But Ill reserve that for future consideration.

With this latest redition, I have successfully established an isolated rotating mass that is constant and consistent.furthermore, it seems to be completely quiet of any exterior noise.

My present challenge is belt tension and motor height adjustment in relation to the platter.

I've read that some use Dental Floss for a belt. Any other suggestions?

Feedback would be appreciated from my fellow Analog enthusiasts.
http://lh3.ggpht.com/_ymqtEqbJfmo/S50QKEhtJDI/AAAAAAAAIrA/16iXneelTcQ/s912/Experimental%20Turntable%20%281%29.JPG
http://lh5.ggpht.com/_ymqtEqbJfmo/S50QJldtq7I/AAAAAAAAIq8/z0iFCsf2AAo/s912/Experimental%20Turntable%20%282%29.JPG

[hifitommy]

hi les,

first suggestion is to use a piece of heavyweight marine plywood for the base. its likely to be deader than the pine you have there.

next, you asked about a belt-howbout an O-ring ? available locally anywhere and affordable. the floss ting just seems dicey to do effectively and there is a knot to deal with sonically. and which flavor to use-? spearmint ? ;^)

what will you you be using for a pump? one day i might get a compressor with a big tank and the particulate and moisture handling filters and put it in the garage for my maplenoll athena (idle at present).

[squeegy200]

You have an Athena? That's awesome. In essence, that is what I am trying to mimic.

I selected this type pine for the plinth after noticing several Teres models made from this same material. They just finish it to an extraordinary lustre. The shapes would have been very easy to fabricate however I wasn't too keen on the minimalist shape as it does not lend itself well to the cantilevered design of the MG-1 which would protrude too far out into open space. It would be far too easy to tip over unless I could add substantial mass to the platter.

I will have to see if I can acquire some Marine Plywood in this size. I've found it for ~$60 per sheet online.

I've not considered O-rings. Will they be compliant enough?

Regarding the air pump, I am using the Alita. It's sufficient but it is noisy. I just set it up in the next room and run the tubing through the wall. Ada has mechanical drawings of a surge configuration with two tanks and a pressure filter/regulator which I assume would simply be the same items used in airbrush compressors. I think at a minimum, the pump should be filtered air and a moisture trap should be inline somewhere in the air path. Ada's drawing looks similar to the pictures I saw of the Walker setup only they put it in a fancy case. I did read a discussion in the Audio Asylum where a guy used Medical grade air pumps from hospital supplies. Although expensive, he indicated they do show up on eBay. Although I've never tried to acquire one, it was an interesting angle--he acquired it for $60, normally around $250 from a medical supply.