what suspension?

I have finally got around to planning a turntable build that has been lurking in the back of my mind for years. The mechanicals are basically Rega and the arm is Audio technica. The plan is to build these into a plinth formed from a solid block of oak that I have had sitting around for years. The plan is to fabricate an aluminium/MDF laminated sub chassis to take the arm and sub platter/bearing assembly. This will then sit on some form of three point suspension in a recess cut into the top of the plinth. The motor will be mounted off the sub chassis. The plan is that the majority of the sub chassis is hidden by the platter with just a small extension for the arm visible. This is to maximise the wood showing on the top. The main platter will be a newly made deep section affair, the idea being to give a similar look to that of some early japanese turntables. Now to my question, what are my options for the suspension. I'm sure there are people out there have done much experimentation with various materials over the years and have some recommendations. I do not need any levelling system for the sub chassis as the whole plinth will sit on Microsorber adjustable feet and I will shim the suspension to bring the sub chassis flush with the surrounding plinth material.
 
I have just realised that my terminology is a bit awry in my post above. It won't be a suspended sub chassis but one sitting on a three point resilient mounting system. It is the absorber material on which the subchassis will sit that I am asking for advice on.


No easy answer.
The only way,is to pick several samples of various materials,not only absorbing.Try them 'til you find the one that suits you.Just for the record,try some rubber,felt,acrylic,metal cones,glass balls,pumice stone,samples of wood.
Each one has certain qualities,good and bad for the situation.But stay away from another springy absorber.

B.L
 
Thanks for that, I guess experimentation is the way to go. Is the wise thinking that a cone is probably the best shape to use? These would be very easy to employ in my design

Yes and no. It depends on the synergy of the individual materials to each other.No hard and fast rules apply.Spend some time,enjoy the ride,and you'll be there

btw a stethoscope, like the ones used for measuring blood pressure,works wonders here.
B.L.
 

Xoc1

Member
2008-11-08 8:25 pm
Devon UK
Sorbothane rubber feet are one solution.
It forms a self dampening suspension when used in compression.
A quick google search produces a lot of relevant links.
Various sizes & grades available on ebay.
I think that my Townsend Rock turntable uses 3 of these as feet.
(The prototype if I remember correctly used super slow squash balls, cut in half?)
 
Thanks for the replies. The idea with this TT is that the supporting medium for the lightweight subchassis can be very easily changed allowing easy comparison between materials. I hope to initially compare the two ends of the scale with wooden or steel spikes at one end and perhaps foam or sponge etc at the other. Hopefully I should hear some differences and thus judge where between these I am likely to get the best balance. Sounds great in theory......
I have made a couple of design changes since my original post. I have moved away from solid oak for the main plinth and will use a more stable laminated construction. I have also moved away from a bespoke platter as I have sourced a heavy metal affair that will do the job nicely.
 

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Member
2008-12-18 2:29 am
UK
Has anyone ever experimented with silicone sealant for any form of suspension?

Too much direct damping is not good for me. What you want for the best performance is a good "spring" tuned at the lowest possible frequency with minimum damping.
A rolling suspension.... because this gives you the best transmission curve, i.e. the best attenuation in the working (audio) band. The best suspension I know is an air spring. There are for industrial use and also other specifically designed for HiFi use. The drawbacks are the cost (about 600 £ for a set of 3 supporting up to 5Kg each, including everything from the air reservoir to spare parts) and the fact that you have to check them once every 10-15 days which is an easy and quick operation anyway....

As an alternative to suspension I would consider an highly absorbing seismic base. A rigid and heavy base with some highly absorbing material inside.

45