Isolation tweaks

[saildoctor]

Has anyone tried washing their sorbothane feet first before using?  Is it possible the marks are being made by the mold release left after manufacturing?

[johnsonad]

My trick for those sticky Sorbothane balls is a cutting board.

Whatever those super thin, white cutting boards are made out of is actually a pretty decent dampening material (at least the ones they sell at the Japanese dollar store). And if you have a hole saw around the size of the Sorbothane ball you can make a nice little coaster out of it to protect your stuff.

Funny, I was about to throw one of those away!  Nothing like the 100 Yen store for all your daily needs.  I miss that store!  My wife hates the cheapy cutting board and now it will have a new use

[Grainger49]

Kerry,

After you wash sorbothane it becomes tacky after you dry it.  I have some HUGE AudioQuest sorbothane pucks that have been on squares of polypropylene plastic since a week after I bought them.  I also still have some shiny rings they left on my oak equipment cabinet from 15 years ago.

[4krow]

Yah, I had some of those big Audioquest feet too. I wonder what ever happened to them? Now they would cost a lot!

[ssssly]

My trick for those sticky Sorbothane balls is a cutting board.

Whatever those super thin, white cutting boards are made out of is actually a pretty decent dampening material (at least the ones they sell at the Japanese dollar store). And if you have a hole saw around the size of the Sorbothane ball you can make a nice little coaster out of it to protect your stuff.

Funny, I was about to throw one of those away!  Nothing like the 100 Yen store for all your daily needs.  I miss that store!  My wife hates the cheapy cutting board and now it will have a new use

Where in Japan are you located?

Has anyone tried washing their sorbothane feet first before using?  Is it possible the marks are being made by the mold release left after manufacturing?

I'm pretty sure sorbothane actually bonds to petrochemicals. Will literally strip paint, finishes, and permanently bond to plastic.

[johnsonad]

I was in Yokosuka up until mid December of last year. I've since moved to San Diego.

[mp9]

I'm pretty sure sorbothane actually bonds to petrochemicals. Will literally strip paint, finishes, and permanently bond to plastic.

..how about Sorbothane HEMISPHERE with Urethane Coating? part#0510124-30-10, 1.25"/30A rated load 2-4lbs.

(i'm thinking the 1.5"/30A @ rated load of 4-7lbs could be better in the long run # 0510134-30-10)

I haven't looked into pricing and min quantities, if high, we could do a group buy?

http://www.sorbothane.com/faq.php

http://www.sorbothane.com/blog/wp-content/uploads/2012/12/11-26-12-Sorbothane_SPG_11.2012_v4.pdf

[Doc B.]

Note that the PDF says "underloading will result in poor isolation". The preamp weighs about 12.4 lbs (now 13.4 with my new tube dampers), well within the spec for four 1-1/4" hemispheres, but too light for the 1-1/2" ones.

[caffeinator]

Whoever mentioned the washing before use may be onto something for the sticking/marking problem - from the sorbothane site on "adhesive recommendations":

"Sorbothane, Inc. uses silicone-based mold release agents for most components. The surface silicone must be removed prior to attempting a bond. Parts can be washed with mild detergents, rinsed with clean water and air-dried. Alternately, rubbing the surface lightly with alcohol or Methyl Ethyl Ketone (MEK) will clean off the silicone and "activate" the Sorbothane skin. Do not soak parts in water, alcohol, or MEK prior to assembly."

Note that this doesn't necessarily mean the cleaned surface wouldn't be sticky.  It sounds like it might actually have some tack to it.  However, it might also be easier to bond some kind of non-marring layer to it after cleaning.

It sounds like adding a non-stick layer might reduce damping a bit.  If the 'furniture-side' surface were allowed to slide, say, wouldn't the dampers just slide, and not have any displacement relative to the supported piece of equipment (say, a BeePre), and thus not get into the damping act?  So I'm thinking maybe a non-marring, flexible layer that still has 'traction' on the 'furniture-side' would be better.

Or maybe it's just the coffee talking...

[ssssly]

Depends on how much of the vibration dampening is from mechanical isolation and how much is from dissipation of the vibration as heat.

The loading recommendations are an attempt to find some equilibrium between the two that is more effective than either alone for the product.

Surface decoupling could be bad or good depending on the mass of the object and the level of the decoupling. In this case it shouldn't matter too much.  Under the suggested load, regardless of how clean you get it, you shouldn't be changing the coupling of Sorbothane by any appreciable amount.

Now, placing another surface in between (such as the cutting board I suggested) could. Would be interesting to try out different combinations to see if they made a noticeable difference.

My guess, would be that to make a large enough difference, the second surface would have to drastically decouple. Such as placing the Sorbothane on a small glass disk and then placing the glass disc on another smooth surface.

Anyone conduct any similar experiments?

[4krow]

I like these ideas. It is true that about anything that you do can have an(unwanted) effect. I have toyed with the idea that the cutting board could be used, allowing the Sorbothane to stick to it. Then, place the cutting board into a box(no edges touching) mostly filled with sand. I know that this may seem extreme for an amp, but there would be little doubt that mechanical transfer would be reduced. Put Sorbothane on the bottom of the box, and here we go again...

[Doc B.]

I didn't have much luck trying to locate a wholesale price for the damper rings, so I am going to share the retail source and folks can buy them for themselves. Just remember that when someone tells you about "the ultimate 300B tube damper" everyone is using, that good old Doc is the one who dug it up:

http://www.belart.com/shop/183070005-vikemreg-vinyl-coated-lead-ring-p-183070005.html

[mp9]

Re: vinyl coated lead ring, "cushioned surface is chemically resistant", no specs on temp range. 300B's get hot, will 4 - 8 hour listening sessions/prolonged use cause them stick to the tube and or with vinyl pulling off of the ring being permanently bonded to the vacuum tube?

[Doc B.]

I might not be the brightest bulb on the Xmas tree, but yeah, even I thought to check if they would melt before I recommended them. The rings don't even get that hot, easily cool enough to lift off the hot tube tube to demonstrate the effect on microphony. And I often run our system 10-12 hours at a time.

Am I vindicated? 

[mp9]

- just to be clear, your link is to the 1/2lb ring, is that the recommended