My new cj friend

Originally Posted by Puma Cat

Yeah, yeah, yeah, I know....sounds at first like voodoo or snake oil, but it's not; it's pneumatic isolation in a simple embodiment. I was skeptical at first, but putting an inner tube under a component DOES work and it works well.

Try it for yourself; it'll cost you $2 for a plywood board cut to 18 X 16" and $4 for a 14-16" bicycle inner tube. It provides subsonic seismic isolation and is very effective at this.

To add some street cred, there some fancy isolation bases that utilizing pneumatic isolation for many different applications, including isolating balances in the lab (FWIW, I work as professional molecular biologist at one of the world's largest biotech companies):

Vibration Isolation Platform & Table Systems | Isolators, Platforms & Tables

Compact Pneumatic Vibration Isolation Platform with Self-Leveling BenchTop

ELpF Lightweight Benchtop Vibration Isolation Platform

These are much more sophisticated embodiments, but functionally (from a physics perspective), they function exactly the same as a board resting on an inner tube.

Smart setup. I have used a marble slab as well as solid maple butcher block sitting on top of 4 raqcuet balls placed in plastic furniture foot cups -- excellent for under at turntable or any component. Vibrapods I believe are built on similar notion and work well.

[jimtranr]

Originally Posted by Puma Cat

Me, too.

Regarding isolation, I've found placing a component on a light plywood board resting on an inner tube works wonders. And way, way, less expensive than an SRA isobase.

Stephen, how thick a plywood board would you consider ideal?

In the past, I've used slightly underinflated doughnut seat cushions with reasonable success under CD players and preamps. A bit more expensive than bike inner tubes, though.

[bgiliberti]

Originally Posted by Puma Cat

Yeah, yeah, yeah, I know....sounds at first like voodoo or snake oil....

Oooops, sorry PC, I was just trying to get in on what I thought was a little joke you were making, but I guess the "yolk" was on me, to quote the 3 Stooges. No offense intended, and I trust none taken!

[turntable]

Originally Posted by Coppy

Hmm... Not to speak for him but my guess is that Peter at Symposium would beg to differ with your statement that the Ultra platform does not isolate.

Bob

Bob, It DOES NOT ISOLATE. I have discussed this with Peter and he has even changed his website as it was factually incorrect - see quote below. Please see link below on our overall discussion.

NOT designed or intended for isolation of extremely low frequency footfall problems

The Ultra platform is a so called drainage device only and IMO only changes the frequency resonance of what is sitting on it, not isolate it. Just like any other like device like cones.
$4 Vibrapods isolate more than the Symposium Ultra.

AudiogoN Forums: Simple TT isolation.....nice sounding result

[Puma Cat]

Originally Posted by bgiliberti

Oooops, sorry PC, I was just trying to get in on what I thought was a little joke you were making, but I guess the "yolk" was on me, to quote the 3 Stooges. No offense intended, and I trust none taken!

Nope, none taken.

To be honest with you, I found out about using inner tubes from one of my local high-end dealers. He gave me one and told me to take it home and put under my Rega Planar 3 TT or Arcam AVR280 AVR...I thought he was smokin' crack! LOL! I thought, "Yeah, riiiiggghhhttt!!! This is some high-end audiophile dealer hoo-ha!"

Boy was I wrong.

When I actually put it under my Rega or my Arcam, it actually made each one sound notably better! Really opened up the spaciousness and made the system sound more natural and less constricted.

Cheap, easy, and very effective!

[Puma Cat]

Jérôme,

Here is one of my best photos showing my CT-5 resting on a light birch plywood board on top of an inner tube. The key is to inflate the inner tube just enough so that the inflation pressure keeps the weight of the component keeps the board off the valve stem so that it does not "couple" to the board. You also need to put a straw (yes, a drinking straw) under the tube between it and the shelf so that the board and inner tube do not create a seal (which in fact, it does if you don't use the straw). This would raise the resonant frequency, which you want to avoid. The idea with lowest possible inflation pressure is to keep the resonant frequency as low as possible.



The CT-5 is also resting on home-made "roller blocks", which are Shepherd plastic furniture cups sandwiching a large stainless steel ball bearing. Again, cheap is the order of the day here. These provide horizontal and rotational subsonic seismic isolation, in the same way Rollerblocks do.

So, the idea is the inner tube provides subsonic seismic isolation in the vertical dimensionm, and the roller blocks in the horizontal and rotational dimension.

My P5 Rega also rests on a light plywood board on top of an inner tube.

[ronenash]

Stephen, what your experience with good old sorbothene feet? I have used them very effectively under my preamps and disk spinners. They will not work under heavy equipment such as my LP125 power amps or VPI Classic 1 table.

[Puma Cat]

Originally Posted by ronenash

Stephen, what your experience with good old sorbothene feet? I have used them very effectively under my preamps and disk spinners. They will not work under heavy equipment such as my LP125 power amps or VPI Classic 1 table.

Ron, I've never tried them, to be honest. The dealer that first gave me the inner tube to try out (Stereo Unlimited in Walnut Creek, CA) carries the sorbothane feet but says the inner tube works better. I just set up the Premier 17LS just now back on it's inner tube, and it's sounding great. Better I think, that the Herbie's silicone Iso-Cups and carbon black balls under the plywood board I've had been using. The inner tube makes components sound more open, spacious and more liquid; more like real music. Just like a GrooveTracer Reference subplatter in a Rega, come to think of it!

I am thinking of trying a set of extra-firm Herbie's Tenderfeet under the power amp, though, because as you say, these lighter isolation materials don't work under big heavy tube power amps...the transformers just crush 'em down.

[Puma Cat]

Originally Posted by jimtranr

Stephen, how thick a plywood board would you consider ideal?

In the past, I've used slightly underinflated doughnut seat cushions with reasonable success under CD players and preamps. A bit more expensive than bike inner tubes, though.

Jim, I'm using what looks like 3/4" inch? Maybe 5/8"? Just birch plywood from the hardware store. I bought a sheet and had them cut it up in to 14" X 16" boards for me. The idea is to use something that is as stiff as possible but as light as possible, just like the piinth in a Rega. I've been thinking the tops of those Ikea Lack corner/occasional tables would be ideal, but at 20X20, they are a bit too big. But they are stiff and very light. If you could still get those Neuance platforms, those would be ideal.

I have one plywoord board under the Rega P5, and one under the Premier 17.

Try it, you'll like it, my fellow Premier 17 owner!

[Removed]

Originally Posted by Puma Cat

Ron, I've never tried them, to be honest. The dealer that first gave me the inner tube to try out (Stereo Unlimited in Walnut Creek, CA) carries the sorbothane feet but says the inner tube works better. I just set up the Premier 17LS just now back on it's inner tube, and it's sounding great. Better I think, that the Herbie's silicone Iso-Cups and carbon black balls under the plywood board I've had been using. The inner tube makes components sound more open, spacious and more liquid; more like real music. Just like a GrooveTracer Reference subplatter in a Rega, come to think of it!

I am thinking of trying a set of extra-firm Herbie's Tenderfeet under the power amp, though, because as you say, these lighter isolation materials don't work under big heavy tube power amps...the transformers just crush 'em down.

Is Dave still calling his inner tubes "Audio Bladders" and signing them with a silver color Sharpie pen and getting $50 a pop