Isolation tweaks
- Thread starter Doc B
- Start date
..how about Sorbothane HEMISPHERE with Urethane Coating? part#0510124-30-10, 1.25"/30A rated load 2-4lbs.ssssly said:
(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
caffeinator
New member
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...
"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...
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?
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?
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4krow
Guest
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...
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
http://www.belart.com/shop/183070005-vikemreg-vinyl-coated-lead-ring-p-183070005.html
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?
Am I vindicated?
If you look at the published dimensions the 1/2 lb. ring is the one that will fit over the top of the EH 300B we supply with the kits. If you use other brands of shouldered tubes or a globe shaped tube - which I do not necessarily recommend because they can be more microphonic than the shouldered tubes - or you wish to try this on something other than a 300B you may wish to evaluate the published dimensions of the other ring sizes. I suspect the 1/2 lb ring would fit most shouldered and globe style 300Bs but I have not measured any but the EHs and TJ globes.
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4krow
Guest
Whenever I go to the hardware store, the clerks know just to let me be. What I am looking for they have never heard of, and what I am using it for they have never thought of. Such is the case here. But I still wonder if there might be a way to make your own. If it's anything like coffee, I am better to just pay the $3 and let someone else do it. This does seem to be a really good idea. Maybe I can use truck bedliner spray on tubes Heh heh
Grainger49
New member
Dan,
You are going to make me post a picture of my Lava Lamp. That was my Birthday present to me last year. The Eros was the year before. Quite a difference!
Does the same ring go around a 2A3?
Thanks,
You are going to make me post a picture of my Lava Lamp. That was my Birthday present to me last year. The Eros was the year before. Quite a difference!
Does the same ring go around a 2A3?
Thanks,
Here they are on Ken Rad 2A3s in the Stereomour built to demo our awesome new Bottlehead/Orca system. I have not listened to this setup. And I will say that I don't really notice a microphony issue with either 300Bs or 2A3s in amplifiers, with the occasional exception of globe style tubes. I also don't know if the increased dissipation of a 300B in an amp would create a potential heat issue for the vinyl or not. Remember that we are running the 300B very gently in the BeePre, only about 10W of plate dissipation.
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I measured a few ST shape tubes. 1/2Lb i.d. ring fits my RCA and Sylvania 2A3's. Shug 2A3-Z could fit either the 1/2Lb or 1LB. JJ 2A3-40 would require the 1Lb i.d.Grainger49 said:
Only 300B's on hand which i plan to use are Sophia Princess, they can fit either 1/2Lb or 1Lb ring with possibly only one smaller contact point using the heavier 1Lb 2" i.d. vs two points of contact with the 1/2LB 1.7" i.d.
I don't know how or if the ring weight (2X) or surface area contact would affect the intended purpose? Compelled to ask, given i was wrong about upping the sorbothane hemisphere's size:\
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4krow
Guest
Didn't the Coneheads use rings too?
I can't answer to what the effect will be if you change the weight of the ring, other than to say you may need to re-evaluate what sorbothane hemispheres you use since the overall weight of the preamp will change. Sometimes the data comes out in a more timely and useful fashion if more than one person does the experiment.
Doc B. said:
Rated load is 2-4Lbs (1.25"), and 4-7Lbs (1.5"), so 1.25" hemispheres should be good with either size ring.
Unless i read otherwise, i'll get the 1.25" hemi's and hold off on ordering rings 'till i hear the BP without them.
I'm thinking if the .5Lb ring is working for you then why possibly stress the tube with more weight? Conversely, the larger 1Lb ring/one contact point when fitted on the Sophia tube may trap less heat allowing the tube to maintain a more constant temp?? IDK???
Again this is all just thinking out loud, 300B's are expensive tubes for me to be tweaking with.
