I use 14" child's bike tyres. 2 in a box about 500x500mm, with a central divider. Cheap soft tubes work well, pump up to get required tension (that's where soft tubes score), also mass load the top plate to get the resonance right. Max Townsend used to use tubes, but I think he only used one, in a figure of eight configuration, with a steel top plate. I use mine under my speakers, where the large mass makes it easier to tune.
I have looked into magnets, but there are difficulties; stopping them slipping sideways, magnetic fields near electronics, and neodymium magnets are so strong they can cause injuries if you're not careful!
I had thought of rubber o-ring material and magnets , as you say keeping it stable is a problem . SME 30 uses o-ring material . The magnets I listed above are sensible and cheap . I would love to know if it works . Returning to just o-rings them in extension would be fine . There are many industrial suppliers . Use them as I did to damp platters ( seen on Garrard 501 prototype at Swindon as a machined in groove with rubber set in , 6 were made and belt drive ) . That turntable was said to be the origin of Elite Rock . Mine is the traditional 401 type .
Static magnetic fields are usually not a big problem . The iron platter of a TD124 is ( some were ) . Keep magnets well away from pickups as they might smash into them . With iron TD124 do at least check playing weight as the cartridge may be attracting itself to the platter . Sonically I am not sure . Mostly a good thing I feel .
DuraBelt Oring Belting, Oring Belts, Oring Drive Belt
Note the Loricraft 501 uses 5 squash balls . It is a very heavy turntable ( > 20 Kg ) . They are normal ones which can be bought anywhere . Changed about once a year ( 5 years if you shim them with paper to raise the height ) . Someone said we should paint them gold and say they are special . No way . However we had people who wouldn't buy a Garrard because it uses squash balls . I notice in Germany they coped with that ( item 40 ) !
Static magnetic fields are usually not a big problem . The iron platter of a TD124 is ( some were ) . Keep magnets well away from pickups as they might smash into them . With iron TD124 do at least check playing weight as the cartridge may be attracting itself to the platter . Sonically I am not sure . Mostly a good thing I feel .
DuraBelt Oring Belting, Oring Belts, Oring Drive Belt
Note the Loricraft 501 uses 5 squash balls . It is a very heavy turntable ( > 20 Kg ) . They are normal ones which can be bought anywhere . Changed about once a year ( 5 years if you shim them with paper to raise the height ) . Someone said we should paint them gold and say they are special . No way . However we had people who wouldn't buy a Garrard because it uses squash balls . I notice in Germany they coped with that ( item 40 ) !
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calling nigel pearson...
...please PM me.Thanks
and all others: Without trying to contradict nigel, using 3 squash balls, my old Oracle squashed 3 squash balls (Dunlop yellow 1-dot, Competition, NSR) used underneath the factory feet in less than a week. If nigel is correct (and I have no reason to believe that he is not), 5 are suitable for masses upto 20 kg, then a great solution for isolating (internal vibrations) almost any turntable from the environment. Me and my audio partner (Mike) successfully used squash balls to re-vamp an old Roksan Xerxes to very good effect, replacing the "blobs". So I am not against their use. In fact if suitable I'm all for it. I do know that they (squash balls) have been used successfully in audio for a very long time, as a cheap alternative. Here in Canada something like $3 or $4 ea. (under £2 or £2.5).
Regarding the use of inner tubes, here in Canuckland, Princess Auto sells "ATV" inner tubes for a very low price. These are capable of very low pressures (under 2 psi) and are very flexible. They also have a large enclosed volume. For ATV use, the tires provide the support for the load, the inner tube is used to permit and maintain the use of very low pressures for increased traction. I've used bicycle inner tubes of various sizes over the years as well under lighter source components.
Now concerning the tuning to use when an inner tube is used, Vibraplane suggested (IIRC) a resonant frequency in the 2 Hz range for use with their product. This is easy to do as long as the volume of enclosed air is adequate. Put the tube under the component (whether in a box or not, under some plywood, or the component directly as long as there are no sharp edges) and inflate it until the bottom of the component (or plywood sheet) easily clears the supporting shelf (perhaps an inch or so). Moving the valves to the outside surface of the inner tube(s) is a smart idea, as you can then add air without removing the component. If I were doing this I would buy some inexpensive Presta valve equipped bicycle tubes, as they are locking and a small bicycle air pump can be used for inflation. Push the component down until the plywood or component can almost touch the supporting shelf. Once released the component should stop moving within one or two bounces with minimal air pressure. That's it.
...please PM me.Thanks
and all others: Without trying to contradict nigel, using 3 squash balls, my old Oracle squashed 3 squash balls (Dunlop yellow 1-dot, Competition, NSR) used underneath the factory feet in less than a week. If nigel is correct (and I have no reason to believe that he is not), 5 are suitable for masses upto 20 kg, then a great solution for isolating (internal vibrations) almost any turntable from the environment. Me and my audio partner (Mike) successfully used squash balls to re-vamp an old Roksan Xerxes to very good effect, replacing the "blobs". So I am not against their use. In fact if suitable I'm all for it. I do know that they (squash balls) have been used successfully in audio for a very long time, as a cheap alternative. Here in Canada something like $3 or $4 ea. (under £2 or £2.5).
Regarding the use of inner tubes, here in Canuckland, Princess Auto sells "ATV" inner tubes for a very low price. These are capable of very low pressures (under 2 psi) and are very flexible. They also have a large enclosed volume. For ATV use, the tires provide the support for the load, the inner tube is used to permit and maintain the use of very low pressures for increased traction. I've used bicycle inner tubes of various sizes over the years as well under lighter source components.
Now concerning the tuning to use when an inner tube is used, Vibraplane suggested (IIRC) a resonant frequency in the 2 Hz range for use with their product. This is easy to do as long as the volume of enclosed air is adequate. Put the tube under the component (whether in a box or not, under some plywood, or the component directly as long as there are no sharp edges) and inflate it until the bottom of the component (or plywood sheet) easily clears the supporting shelf (perhaps an inch or so). Moving the valves to the outside surface of the inner tube(s) is a smart idea, as you can then add air without removing the component. If I were doing this I would buy some inexpensive Presta valve equipped bicycle tubes, as they are locking and a small bicycle air pump can be used for inflation. Push the component down until the plywood or component can almost touch the supporting shelf. Once released the component should stop moving within one or two bounces with minimal air pressure. That's it.
I think all these ideas are cheap and easy . Surprisingly in our application they worked well . They looked destroyed quite quickly , however as long as they move a bit they work . Problem is if too many used it starts to defeat the isolation .
We did use Sorbothane and was pleased with that . Thought squash balls better . Bubble wrap was excellent . Not the right shape for what we were doing ( the big stuff )
Hope that helps . Thanks also for being able to show what Garrard might have done . Loricraft have sold a few .
We did use Sorbothane and was pleased with that . Thought squash balls better . Bubble wrap was excellent . Not the right shape for what we were doing ( the big stuff )
Hope that helps . Thanks also for being able to show what Garrard might have done . Loricraft have sold a few .
Presta valve inner tube, con't.
Sorry, I didn't finish my thoughts and include the "recipe" for using a Presta valve on a inner tube with a :
Sorry, I didn't finish my thoughts and include the "recipe" for using a Presta valve on a inner tube with a :
- cut the Presta valve area out (maybe 2" dia. bout the valve) from a Presta equipped bicycle tube
- cut a 1/4" hole in the ATV inner tube in the desired location
- use a good RTV (Room Temperature Vulcanizing) rubber or patching glue and attach the Presta valve
- cut the existing Schrader valve out and patch as necessary (or leave it in).
For those that don't know, the Presta valves have an integral screw down "lock" that provides a better valve with better sealing for the enclosed air. As nigel suggested moving the valve to a convenient location to allow air to be added without removing the component is handy).
They might have changed the design by now . Good news is it is a proven principle . I am assured by people who have taken theirs apart what we describe is similar .
Seismic Sink Platform ? www.townshendaudio.com
Seismic Sink Platform ? www.townshendaudio.com
Turntable is a Denon DP-30L. The plinth is a bit live (taping on it passes through to the speakers).
I use a phenolic laminated 1" fiberboard atop a steel table with leveling feet, then 1/4" silicone pads, then 1"x4" laboratory rubber stoppers, then a 1" piece of granite (granite store dumpster throwaways). This combo seems to do nothing for isolation. At least I’m not out any money.
It might be nice to try a 1/4 silicone sponge two sheets between of granite slabs...
I use a phenolic laminated 1" fiberboard atop a steel table with leveling feet, then 1/4" silicone pads, then 1"x4" laboratory rubber stoppers, then a 1" piece of granite (granite store dumpster throwaways). This combo seems to do nothing for isolation. At least I’m not out any money.
It might be nice to try a 1/4 silicone sponge two sheets between of granite slabs...
Slate
When you say you can't wall mount (fails SAF,) I presume this is dry walling?
I have suspended wooden floors, and ended up mounting AC brackets onto the wall (brick & mortar external.) My equipment racks are spiked onto the brackets.
If you don't have a basement, and the soil layer isn't too far below the floor, you could
drill four holes through the wood slats 1.25" diameter and then knock 1" reinforcing rods (sharpened) into the soil below. The tops can be neatly cut off. You couldn't have a more solid platform. The gap between the wood and rebar you close off with an appropriate sealing strip. Just an idea, WAF allowing the hole drilling.
Kevin
P.S. My plinths are 1" thick slate I managed to scrounge from a sidewalk upgrade in the olde section of our capital city.
Hi Bill,
When you say you can't wall mount (fails SAF,) I presume this is dry walling?
I have suspended wooden floors, and ended up mounting AC brackets onto the wall (brick & mortar external.) My equipment racks are spiked onto the brackets.
If you don't have a basement, and the soil layer isn't too far below the floor, you could
drill four holes through the wood slats 1.25" diameter and then knock 1" reinforcing rods (sharpened) into the soil below. The tops can be neatly cut off. You couldn't have a more solid platform. The gap between the wood and rebar you close off with an appropriate sealing strip. Just an idea, WAF allowing the hole drilling. Kevin
P.S. My plinths are 1" thick slate I managed to scrounge from a sidewalk upgrade in the olde section of our capital city.
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Nigel, the correct spelling is Voyd BTW. Looked it up, because I saw one some years ago at an expo. Very nice looking decks, and beautifully finished. There are a few other current highend turntables that do two or three motors, but way out of most enthusiasts price range. But a little DIY can go a long way.
Regards, Kevin
P.S. Evidently part of Audio Note now!
Regards, Kevin
P.S. Evidently part of Audio Note now!
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We're talking about isolating the turntable from floor bumps, not adding acoustic room treatments to the walls. The slab just has to float in place as the floor moves. Acoustically its underneath the turntable so not doing much, and it will certainly be doing far less than the room and floor itself.
Squash-balls cut in half for feet perhaps?
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