Bottlehead Forum
Other Gear => Phono => Topic started by: Thoburn on December 23, 2011, 12:29:27 PM
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I am building a sandbox platform for my VPI Scout II turn table. It will consist of a 3/4 inch thick mahogany box with a 3/4 inch plywood base that is 1/2 inch up from the bottom of the sides. I have a 3/8 inch thick piece of polycarbonate that will sit on top of the sand. Under the box I am either going to use small tire inner tubes or Vibrapods. I have read good and bad things about sand boxes. Have any of you Bottleheads used a sand box platform or know somebody that does. I would appreciate some feedback on any type of turntable platform experiences.
Thanks!
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If you have cats in the house, I wouldn't go the sandbox route.
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Have a look at this on Wardsweb's site:
http://www.wardsweb.org/audio/isolation_table.html
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Hey guys.
We have a cat, but unless he can do his business in a 1/4 inch slot while balancing on a 1 inch ledge I think I'm safe. Actually, I plan to put very soft 1/4 inch tubing between the edge of the polycarbonate and the sides of the box. Mostly to keep any sand dust from escaping and fouling up my records and table.
Thanks for the link. I have read that one and a bunch of others. The only negative I saw (and I can't remember where) was a guy that dished sand boxes and advocated inner tube(s) under a piece of MDF with roller blocks supporting the turn table. It has very bad WAF, but probably works well.
I will try to post info and results on my sand box experiment.
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. . . inner tube(s) under a piece of MDF with roller blocks supporting the turn table.
I can't imagine this staying level two hours in a row, much less two days in a row.
I do want to try Wardsweb's idea with the glass bead media. The drawback is you have to buy a whole bag of it and use about 1/4 of it.
My cat sleeps closed up in the listening room every night. I keep the turntables covered so she doesn't jump on them. She has her own box in the room too.
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Hi Granger,
I like the glass bead idea to. IIRC you live in Colorado. I'm in Washington state. If we were closer I would happily split the purchase price with you.
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At Berkeley in the 70's we used a giant sand box on inner tubes to stabilize a holography setup that had to keep the vibration of the mirrors down to just a few wavelengths of the HeNe laser's output frequency for something like 13 seconds at a time in order to get a good exposure. The added challenge was that the laser setup was on the third floor of the building. One would set up a Michelson interferometer on the table and project the interference pattern on the wall, and then count how long the average period was before someone on the third floor would walk down the hall, close a door, or sit down at their desk and disturb the pattern. I thought it was pretty amazing that the thing worked so well. IIRC the recipe was a 4'x8' sand filled table with inner tubes on top, with another sand filled 4'x8' box on top of that. I don't recall the top of the top box floating on the sand, I think it was attached to the sides of the box. Might have been a piece of slate from a pool table, or my old brain may just be embellishing...
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I have the box up and running. It took all 50 pounds of play sand to fill it. And I can say that it is definately worth the effort. Imaging is improved. The instruments are more focused and there is more 'air' between them. The sound is more detailed. I would say that just about everything is a bit better. Will try to take some pictures when the light is better.
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Hi Granger,
I like the glass bead idea to. IIRC you live in Colorado. I'm in Washington state. If we were closer I would happily split the purchase price with you.
I'm in Knoxville, TN. I expect the cheapest shipping would cost the price of a whole bag of beads. But thanks for the thought.
Won't the sand settle after a little while? I suspect the glass beads do too.
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Merry Christmas Granger,
Here is a design where settling is discussed.
<<http://cognitivevent.com/sandbox.html>>
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That is pRC's site. He was an old hand here when I arrived. He is a materials specialist. He knows a lot about vibrations and materials.
I'll consume it soon. Thanks for the link!
Merry Christmas to you and yours!
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Here is the new rig.
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Sandbox in relation to other gear.
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Grainger,
This may be a project we can share. I've got the woodworking down, you can work on the design. We could share a bag of beads. I've also been wanting one for my Wadia iPod transport.
It's something we can discuss in Jan.
Joel
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Sounds good!
Thoburn, your sand box looks better than my old VPI base.
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Hi Granger,
I like the glass bead idea to. IIRC you live in Colorado. I'm in Washington state. If we were closer I would happily split the purchase price with you.
I'm in Knoxville, TN. I expect the cheapest shipping would cost the price of a whole bag of beads. But thanks for the thought.
Won't the sand settle after a little while? I suspect the glass beads do too.
I forgot to mention that as I added layers of sand I tapped around the frame with a rubber mallet to get the settling started. It has been a couple days now and I don't see any uneven settling. The bubble level show the same on the platter as it did in the beginning.
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What feet did you end up using?
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What feet did you end up using?
I picked up 2 canisters of racket balls at Target for about $8. I cut them along the seem with a one sided razor. It was surprising how tough they are. There are 12 half-balls under the sand table. You can see their turquoise bottoms between the shelf and the sand box. The bottom of the sand box is 1/2 inch up from the bottom of the sides. I think I mentioned that I used 3/8 poly instead of the 1/4 mentioned in the design. I went with the 3/8 because my Scout II table is about 40 pounds and I wanted to spread the weight around as much as I could.
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Thanks, that's a pretty good idea.
Some people also use small super balls sitting in rubber washers or o rings to keep them from rolling and just sit the base on them.
Sounds like some experimenting coming up!
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It has been about a month now and I have been checking the level of the turn table. No change so far. I think the tapping with must have helped a lot. Very pleased with the results.
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I'm thinking of building some for my speakers. Would you still use the Raquet Balls as feet? I don't have carpet.
Thanks
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Bainjs and I are considering build a couple of these for our turntables.
Thanks for the update.
It has been about a month now and I have been checking the level of the turn table. No change so far. I think the tapping with must have helped a lot. Very pleased with the results.
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I'm thinking of building some for my speakers. Would you still use the Raquet Balls as feet? I don't have carpet.
Thanks
Hi,
I think for the price it is worth a try. I kind of like the superball in washer idea as well. I wonder if 'floating' speakers is the right thing to do. It seems to me that most speakers use spikes to 'anchor' them solidly to the floor. I think that keeping the driver frame from moving lets the cone transfer as much sound energy as possible. Just a guess on my part.
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Joel sent the box, beautiful work! I bought a bag of glass beads from Harbor Freight. I have ordered a piece of glass and I have veneer to finish the box front and sides. Then it all gets loaded into my shelf below my VPI table.
Thanks to Joel (bainjs), and all the posters. Here is hoping!
Edit: I thought this link was in here but I didn't find it this morning. This is another vintage Bottlehead pRC:
http://www.cognitivevent.com/sandbox.html
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I used 3/8 inch poly carbonate instead of glass as that is what the design called for. I have no idea if it makes much difference. Still no sign of uneven settling. I'd like to hear about other folks results. How is it sounding?
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I think you were looking at the pRC site and I was looking at the Wardsweb site. They call for slightly different setups.
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I went with the real cheap and made mine from 1/2" MDF. No settling here either.
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After reading this thread I built up a sandbox for my Rega Planar 3. I built it to match the dimensions of my TT to hide things away and tried to make it look like it was part of the TT. Now the base will match my Crack and soon to ship Seduction. I used 3/8" poly as well. For feet i used soft foam hockey pucks, works well. I also use them under my weighted speaker stands (my springy floor creaks and shakes when my speakers are directly on the floor).
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Andrew,
That didn't look like a sandbox till I read the text. I clicked on the thumbnail first. It looks like a turntable with a "normal" base. Nice job!
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For those of you interested in using washers for super balls to sit in, I have been using Sorbothane rings for some of my projects. I found them on ebay for a really cheap price. They are 30D, which means they are soft. Each one is rated for 5#, so, a series of them would be very effective. I think I paid $9 postage paid, and shipped really fast.
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I forgot to mention that for $9, you get a set of four. Sorry
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Well, I am nearing completion. Joel Bain, bainjs, built the box. I bought a bag of glass beads and a piece of glass for the "raft" in the swimming pool. The veneer looks much better in this picture than in person. We won't talk about my first veneering attempt.
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi244.photobucket.com%2Falbums%2Fgg7%2FGrainger49%2FFor%2520Posts%2520Private%2FSwimmingPool.jpg%3Ft%3D1331663685&hash=b6bded5e3dabddaa1e14089d7e16a3a8552926d5)
The plastic jug is full of glass beads, the rubber mallet is for hitting the box to make the beads settle.
I screed, and screed, I don't think I can scree any more! Now to bring it upstairs and float the raft.
The box and beads weighs about 30#, the turntable another 30#. I have four Audio Quest sorbothane pucks under it. I think they will go flat!
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Grainger, It is projects like this that keep me inspired. Simple in some ways, but labor/time intensive. Most importantly, effective in the end. Think of what some company would charge for such a product, and it probably wouldn't be EXACTLY what you want. That is the very reason that I make as much of my own things as I do, I have certain expectations. Don't ever stop experimenting.