Nude Turntable Project

Time to pick-up this thread again as I have made a notable improvement to my nude TT-101.

Damping and draining vibrations is one area that all audiophiles are aware of and many try to address in any number of ways.

I have previously worked on the vibration problems of the TT-101 in two ways: I put rubber bands around the sides of the tin-can base (an obvious problem area) as well as putting a support (I tried both a brass cone and squash balls) in the center of the bottom of the can and brass cones as feet to a granite slab base. (See earlier entries). But, I knew that I hadn’t done near enough to optimize this TT. By the way, all of these new improvements will work on turntables that are plinth-mounted as well.

For previous turntables I followed the advice of a poster on another site who recommended using copious amounts of clay to fill-in cavities and cover surfaces and I found it worked but I knew that clay was the wrong material for the tin-can base of the TT-101, so I went looking for a different solution.

I decided on 3M Sound Deadening Pads: http://multimedia.3m.com/mws/mediawebserver?mwsId=66666UuZjcFSLXTtOXMEMXMtEVuQEcuZgVs6EVs6E666666--

One pad costs $7 and was more than large enough to do the entire TT. They are designed to sound proof cars so are available where car parts are sold – I got mine online.

I covered more than 60% of the inside of the tin-can including much of the bottom as well as the sides – necessarily covering a lot of the air-holes. I left enough of the holes open for air circulation (I had monitored the can for heat and after many hours of operation it was still at room temp so I knew it was not a big problem to cover some of the holes). I did leave the top edge of the can uncovered – the area where it mounts to the TT - so that a solid metal-to-metal contact remained and allowed vibrations to drain from the TT. I put a rubber-band back on the outside of that area of the can to damp it.

I also covered 90% of the surface area of the cavity below the platter – to me this is just a resonating chamber left there for manufacturing reasons and in need of damping – see photo: http://s1106.photobucket.com/albums/h373/Garya1/Nude%20Turntable%20and%20DIY%20Arm%20Pod/?action=view¤t=TT-101damping003.jpg

I also covered the bottom surface of the TT where it used to sit on the plinth – why not.

The entire job took me about two hours. The material is very easy to work with and mistakes are easily rectified. I used dinner plates of various sizes as templates and a bowl to hold the TT upside down. A circular mat knife was perfect to cut the material – a scissors did well also.

My first spin after putting it all back together was Brahm’s first piano concerto (Rubinstein and Mehta on London) an album that I know well and love. I was floored by the improvement in image solidity and full-volume orchestra clarity. Of course I asked my wife to come in and give me the true story – without my bias. After listening to the Brahms as well as Christopher Parkening (a rather long listening session for her) she gave me congratulations and confirmed a significant improvement overall.

So, $7 in material and 2 hours of time, I guarantee you will be floored as I was. What are you waiting for.

Gary

I just noticed that the url for the photo doesn't work - this one will take you to the album and the first photo is the one I was highlighting.

http://s1106.photobucket.com/albums/h373/Garya1/Nude%20Turntable%20and%20DIY%20Arm%20Pod/

Victor 101 -
Could you get rid of the flimsy bottom cover completely and mount the nude deck via an inverted tripod ? It doesn't look particularly rigid from the photos.
Potentially could you remove the internal transformer and some of the electronic boards from the main chassis and mount them separately to eliminate as much vibration as possible. Make sure all internal joints are as rigid as possible.
If you check out the Cotter and Kaneda versions of the SP10mk3 you can see what is possible in terms of stripping down to the bare essentials.

Although I would like to have all of the electronics mounted remotely it doesn't seem practical - it sounds to me like many hundreds of dollars and weeks of absence - after I find someone to do it. As far as the rigidity of the base goes it is one piece of pressed steel supporting 7 lbs or so. Not a problem.

Gary

Hi Gary,
Very interesting improvements and co-incidentally.......I have been testing and analysing the 'weakness' with the nude Victor as well.
As you have discovered.....the thin perforated metal circular surround is, I fear, the Achilles heel to supporting the Victors on spikes?
With the Technics SP10 models (as Chris has shown)..... it is possible (and preferable) to fit custom long tube spikes to the underside of the platter surround itself whereas it is exceedingly difficult to do with the Victors?
The problem is structure-borne feedback as is mostly the case with turntables?
Every supporting shelf is under 'stress' to some degree depending on its material, thickness and load, but most importantly.......on the 'span' and 'type' of span.
In my case with the wall-mounted shelf.........the cantilevered nature plus the heavy load and wood core structure sets up a particularly 'nasty' stress pattern.
What I have recently discovered is that 'stress' in any material....... creates a subsonic 'sound-field' within that material which is directly related to the 'level' of stress.
I previously thought.....wrongly I must admit.....that lower frequencies could not 'bridge' the pointy end of a spike support?
It is now known that they can and that spikes in fact 'couple' rather than 'de-couple'.
The 'stress-induced' sound waves in my cantilevered shelf are being transferred to the thin metal surround of the Victor which in turn passes them on the platter surround, motor and spindle support which the stylus then 'reads'?
This can be verified by placing the stylus on a record without turning on the motor......and then turning up the volume of the preamp until one can induce a loud low-frequency feedback loop through the speakers.
You, Gary.....have tackled the problem at the resultant culprit.....the metal surround which can work well.
I am going to attempt to tackle the problem at the 'source' by trying to prevent the transfer of this 'sound field' between shelf and turntable by isolation devices.
I'll keep you posted......:^)