Vibration Control for Lightweight Tube Components

I have one word for you, mass on spring.  Almost all effective vibration isolation solutions employ this simple technique.  

Al wrote,

"Lowrider, I’d suggest trying Mapleshade Isoblock 1’s, or the lower priced generic equivalent that I think may be findable at Home Depot or elsewhere. Assuming that their 1.75 inch height can be accommodated. I say this even though the description recommends that they be used only in conjunction with isolation platforms."

Ah, the age old conundrum, should I isolate or should I couple?

;-)

"The cheapest way to get great isolation: two Baltic Birch plywood shelves with a barely inflated bicycle tire between them, with a trio of roller bearings between the pre-amp and the top BB shelf (this design courtesy of Barry Diament). If you have the dough, a Minus K platform ($2500 or so). Alternative: a trio of the Townshend Audio Seismic Pods (about $750, I believe)"

i can do it better and cheaper. The issue with the bicycle inner tube approach is that the surface area of the air bladder/spring is too large relative to the volume. To maximize isolation effectiveness the surface area of the air spring or bladder must be minimized. Besides, a barely inflated inner tube doesn’t provide sufficient pressure/spring rate to actually do anything. That’s kind of the whole point of mass on a spring isolation.

@geoffkait , what do you mean by mass on spring?

Any any isolation device that employs airsprings, mechanical springs, tennis balls, bungee cords, etc. operates as a low pass mechanical filter for vibrations, where the component represents the mass.  The springs are selected in terms of how springy they need to be according to how much mass is to be isolated. So for very heavy components the springs would have to be very stiff, otherwise they would compress too much under load.

Lowrider,

according to the blurb for the IsoNodes they are vibration control devices as opposed to real (mass on spring) isolation devices. They are not springs nor do they act like springs, in other words. They are apparently some sort of viscoelastic damper. No offense intended to IsoNodes.

"IsoNode Large Isolation Feet are 1.25" wide and .75" tall and are great for integrated amps, preamps, DVD players, CD players, and more. Use them by themselves or with other isolation accessories such as platforms. Adhesive backing is included for easy attachment and positioning on your components."

Spencer wrote,

@geoffkait
Every post you write should be signed like this:
"Geoff Kait
machinadynamica.com"

Anything less is a lack of disclosure and doing a disservice to this community. You've been around long enough and involved in enough controversy to know better.

It's a shame this has to be brought up again.
Cheers,
Spencer

It's actually never been brought up before.  I thought everyone knew me.  Thanks for being Johnny on the spot, Spence.

"Geoff---When you say "I can do it cheaper and better" and "My springs are the lightest in the business", may I take that to mean you market such a product? Can you direct me to a site, or provide contact/product info?"

I've been in the business of isolation and vibration control for 20 years as well as many other things.  Currently I offer small steel springs of different spring rates for isolating anything from one pound to 250 pounds. These springs are very low profile so can even be used on submarines.  ;-)

Geoff Kait
machinadynamica.com

Lowrider57 wrote,

"@geoffkait, I thought they might be "spongy" like the 1/2 tennis ball concept."

-- tennis balls or 1/2 tennis balls don’t have the right spring action to act like a real spring either. You actually need to match the spring rate of the springs to the mass of the component. I’m not saying tennis balls or bicycle inner tubes or gooey type devices won’t do anything, I’m just saying they’re just not as effective as real isolation devices, like my springs. While gooey or rubbery type materials like these or say Sorbothane might seem like good materials, even perfect materials for audio applications, they seem like such a good idea, right? But they are a pig in a poke. You will do much better with mass on spring plus very hard materials to support the iso device and to support the component on the iso stand, generally speaking. It has been 20 years since the Vibraplane iso stand blew into town. That changed everything.

"The ad goes on to state...
IsoNode feet are specially engineered from a unique polymer that rejects a wide range of vibration trying to enter from underneath the component. The highly compliant IsoNode acts as both a liquid and a solid for superior vibration control. Vibration and resonance that could interfere with the performance of sensitive electronic circuitry are converted instead to extremely minute amounts of heat and harmlessly released."

-- They are apparently viscoelastic in nature and act together with the load as constrained layer dampers. I’m not saying they won’t work to some degree but to deal with very low frequency vibration you need real isolation, as opposed to "vibration control." You can have both, which is why they suggest they can be used UNDER a real iso stand. At least that’s what they say. How you should support a real (mass on spring) iso stand is another issue unto itself as well as how you should mount the component on the iso stand.

"BTW, I googled "mass on spring" and I see that the spring has a non-negligible mass."

-- A spring (steel spring, air bladder or bicycle inner tube or air spring) would usually be what, 1/100 the mass of the component being isolated? Where I come from that’s negligible. My springs are the lightest in the business, coming in at around 1/200 the mass of the load.

Lowrider asked,

"@geoffkait , interesting.
"OUR NEW PRODUCT!! - Super compressible MINI ISOLATORS - VERY LOW RATE SPRINGS FOR ISOLATING REALLY LIGHT THINGS."

Are these springs heavy enough to stand on their own? Will a board placed on top with a component be stable?"

I have several types of springs.  They should be used in sets of four or more.  They are very stable when used with the proper weight.  They are especially stable being low profile compared to larger springs I used to sell. As I said earlier the springs will isolate any component - with or without a board - weighing from 1 lb to 250 lb, depending on which spring is selected.  Obviously the heavier the component the stiffer the spring has to be since you obviously want to avoid compressing the springs to the point where the coils start to touch. If you use a board you need to add the weight of the board to the weight of the component to get total weight so I know which springs to send. For example, a preamp weighs 8 lb and the board weighs 4 lb, the total weight is 12 lb. Thus 3 or 4 of the medium stiffness springs will be appropriate for that load.

Good point about the power cord or ICs tending to pull the component down on one side, ruining the isolation effectiveness or, in the case of CD players, putting the CD transport out of absolute level, unless the power cord and ICs are suspended or otherwise dealt with. I also want to point out that my new Super Stiff Springs are the ticket for very heavy objects such as VPI turntables, Verdier turntables, really big amplifiers such as the Classe flagship. Four Super Stiff Springs will support and isolate objects up to around 150 lb. Use five Super Stiff Springs for a 200 lb object and so forth. Give me the right spring and I’ll isolate the world.

Since there are six count ’em directions of motion for which isolation would need to be applied and since springs isolate quite well in the vertical direction and isolate somewhat less well in two of the rotational directions and, practically speaking, not at all in the twist rotational direction or in the horizontal plane, a comprehensive solution would be mechanical springs plus roller bearings, which are rather good at isolating in the twist direction and the other two rotational directions as well as the horizontal plane, but hardly at all in the vertical direction. Voila!

Gee, funny no one mentioned Herbies tube dampers for all tubes, rectifiers, 6SN7s, 12AX7s, you name it. Would you believe two dampers per output tube and rectifier often sounds better than one? One on the glass, the other on the base. Yeah, I know, that's more than the cost of your tubes just for the dampers.  And of course the transformer needs to be wrapped with mu metal (and physically damped).  The tubes are sitting right in from of that big honking magnetic field.  Hel-looo! And now sis the time for the cork, isolating the circuit boards. 

Lowrider57 wrote,

@geoffkait, I’m using Herbies tube dampers. In the past, I found that 2 dampers would deaden the sound. But I never tried a damper on the base."

obviously one can over-damp the tube or anything for that matter. As I’m sure you know the sound is quite sensitive to exactly where on the glass the damper is placed. The ideal location appears to be wherever the getter is located. So on a bottom getter tube the damper would be placed around the glass down near the base of the tube, assuming it has a base. The Sylvania Badboys have bases and so does the Tung Sol rectifier, for example.

Mesch wrote,

Geoffkait, My preamp has those metal cylinders over the tubes. Can tube dampers be used in this case? Also, I have some of the red and what I will call “o-ring’ dampers. What do you think of those?

Don't know if the tube dampers can be used on metal type tubes, but maybe.  Check with Herbies Lab to see what he says.  Might be worth a shot. I don't actually like those elastomer o rings, actually I never found anything other than Herbies dampers to do anything except hurt the sound. 

Please note for most applications small springs don't require a board of any type so that eliminates that variable.  Also, if one wishes to use a board or granite whatever, due to the nature of mass of spring operation/function the physical characteristics of the board or slab are minimized since the board or slab itself is isolated from structural vibration hence can't get too excited.

moryoga wrote,

"I have it on pretty good authority that Vibraplanes are the only truly legitimate isolation platform. I think that this is confirmed by the fact that an air based isolating platform is what is used in all real deal labs and research facilities. For light weight gear you can "mass load" meaning adding a steel plate or other level, stable weight to fulfill the platforms weight requirements. I have three, one exclusively for my tt, a Basis 2800. I’ve added a 110lb steel plate and it sounds truly awesome, much better then before I added it."

Actually while Vibraplane is one of the first audiophile vibration isolation stands it is certainly not the only air type platform nor are air type platforms the only "real" isolation devices. Actually Vibraplane used to be a microscope stand that was marketed to the audiophile market. Prior to Vibraplane there was the Townshend Seismic sink, another air spring (I.e., mass-on-spring) device. I introduced Nimbus almost twenty years ago, another air spring device. Bright Star also had an air spring device. And there were a bunch of others, like Relaxa magnetic levitation, Vibrapods, etc. The Minus K device employs "negative stiffness" which is not an air design to achieve super isolation performance. Vibraplane and my Nimbus employed heavy mass mounted below the air springs to preload the platform but more importantly - in the case of Nimbus - to provide much needed lateral support since my Nimbus used only ONE air spring. Obviously preloading reduces resonant frequency of the device. Mechanical steel springs and, say, bungee cords work the same way as the Vibraplane, as a low mechanical pass filter.

geoff kait
machina dynamica

r_f_sayles wrote,

"This is why it may be "ultimate" but people have to skin-the-cat for far less. And I would bet you we are getting most of what the Vp isolates (80-90%) for a fraction of the cost."

Hope springs eternal in the heart of the frugal audiophile. Springs. Get it? ;-) The article Bad Vibes! by Shannon Dickson appeared in Stereophile about the time Vibraplane came out, about 20 years ago.

http://www.stereophile.com/reference/52/#x5wTtreK38fkz2gg.97

G. K.
M. D.