Vibration Control for Lightweight Tube Components

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

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

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.

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

It's not the tubes. It's a new Atma-sphere pre, new tubes, and I have also rolled in some other tubes. IMO, the unit needs to absorb vibration or be decoupled from the shelf.

My previous Rogue preamp, also with exposed tubes, experienced the same problem. (it weighed 30 lbs.). I used Herbies as footers and also mass loaded the top to stop the vibration.
It's similar to a footfall issue.

Thanks everybody for the input so far, but I have a theory...
both preamps have exhibited the same problem; both have an exposed tube design on top of the unit.
The preamp sits on a shelf enclosed in thick wood (pine) open in front and back. If the shelf is tapped on, it may create resonances surrounding the unit thru the sides and shelf above it. These resonances may be picked up by the exposed tubes which are in close proximity. (The shelf is 10" high with enough room for air to circulate).
That would explain why a 30 lb. Rogue preamp picked up noise from tapping on the shelf. Does this theory make sense to anybody?

@geoffkait
 Ok thanks, I understand the concept of "mass on spring" now. In addition to the Mapleshade Isoblock 1, following this concept, there are Bright Star IsoNodes for isolation...

http://www.audioadvisor.com/prodinfo.asp?number=BSISO&variation=L4
IYO, would these be a good size and provide the right amount of spring rate?

@almarg ,
Al, as a test I used a wad of bubble-wrap as a cushion under the IC's and was unsuccessful. 

Thanks for stating your experiences, Al. And as far as my thoughts on "sympathetic vibration" go, you're right about the different tube types and the use of tube dampers. The Rogue used 4 12AU7's which are low noise and rarely microphonic.

In both cases, with the Rogue and the Atma-Sphere, I've removed the stock feet. As mentioned earlier, the only solution to remove the noise with the Rogue was to isolate beneath the unit and mass load on top.

 I wonder if the new lightweight preamp should sit on some MDF with isolation footers between the pine and the MDF.

@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'm now convinced that I should use a suspension system for isolation. I'm going to take adg101's advice and use a bamboo cutting board with either the Moongels or geoffkait's springs beneath it.
Thanks to all for your input.

@r_f_sayles, thanks for the detailed explanation and the preamp is a UV-1.

With a preamp that light, just like a small phonostage, or DAC, what-have-you, you need to be aware of not "loading" the preamp chassis with a heavy mains cable dangling from it, causing an energy path from whatever the cable is also in contact with.

I did think about that and swapped the heavy Audience cable with the stock PC for now. I'm also supporting the ICs so they don't hang on the shelf.

It's your IC's guarantee it.

They are unbalanced ICs, Purist Musaeous and Grover Huffman Empress and I'm not sure if they're shielded.
So, is there a solution to prevent extraneous sound from traveling thru a cable?

Mass loading on top of a component is advised, if possible for its dampening and absorption properties. Something I have found most effective for this, I no longer know where to source. They were paperweights, leather bags filled with lead shot, used to hold down large architectural roll size drawings. Perhaps diving ballast bags would do the trick and be most cost effective.

@r_f_sayles, I plan on mass loading if I can find some weights that are only 2" wide. It made a significant improvement in sonics to my previous preamp. I’ve been looking thru my house and workshop for a DIY solution.
Maybe some calibration weights for a triple-beam scale. Too bad I got rid of my scale years ago, LOL.

@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.

@mesch , great minds think alike. I used 2 1/2 lb. barbell weights with cork on some components as well.

Tube shields can be removed and Herbies dampers used instead for better sonics, less microphonics. Tube shields are used for RF Interference. Are you using a Jolida? 

http://m.wisegeek.com/what-is-a-tube-shield.htm

mesch, if you're using short runs of cables, separate your components from power supplies and avoid coiling power cables, etc., you most likely wouldn't experience a EMF/RFI problem. Do you use any conditioning or a surge protector with filters?

For $15 per tube damper, you could get tighter bass and possibly a more focused image. It's a great tweak.

So, in other news, while I’m waiting for my bamboo board and Moongels to be delivered, I installed Bright Star IsoNode Feet under my preamp.

The sound of my system is more transparent, with much more low-end detail than when using the Vibrapods or Herbie’s Tenderfeet. This softer, more compliant material works better on a lightweight component.

But still picking up resonances from the shelf.

I'm pleased to report that my problem with resonance between my rack unit and the preamp has been resolved. Using the IKEA bamboo cutting board with the Moongels underneath was the solution. So, a big thank you to adg101 for sharing this cheap tweak with me.

I'm using a 17"x11" bamboo board with 4 Moongels at the corners, and 2 in the center. The pine shelf has been completely dampened and this bamboo shelf with the preamp is now isolated.
I have the Bright Star IsoNode's under the preamp chassis and the sonics are really outstanding.

I use Peter Erskine's "Dream Flight" as one of my reference CDs and this jazz quartet sounds so live, that I feel like I'm in the same room with them. The presentation is more forward and I've never heard such inner detail from my system.
However, symphonic music is sounding too lean for my taste; clearly the bamboo is causing a different timbre than the pine shelf. The detail in the orchestra is just right and the layering between instrument sections is very realistic. Strings are smooth, but lack the warmth I am used to hearing.
I guess this is what a transparent, neutral system sounds like.

Thanks to everybody who participated in this thread.

I think the bamboo is causing too much of a "live" sound. The mids are sounding lean from my Gallo's which have previously had a lush presentation.
 Would maple be a better platform, possibly warmer?

Tomorrow I'll play with placement of the Moongels, and I do have various pieces of wood to try.

adg101... what are the dimensions of the Daedalus DiD's, specifically the height?
I have a height issue with the large tubes now that I've added the bamboo board.

Thanks adg101, some good ideas. The bamboo might be too stiff with 6 Moongels.
I'll also try them under the stock feet. They are an amazing invention; when I was playing drums, all we had was duct tape and a wad of paper towel on the skins.

And I have always placed Herbie's tube dampers at the upper third near the top of the plates.

@bpoletti, no I haven't.

@r_f_sayles, the Isonodes are adhered to the bottom of the chassis.
Let me clarify this issue; my system has always had lush, warm sonics using a preamp on the pine shelf. With the new lightweight preamp, it still had the same timbre (due to tube selection), but suffered from resonances thru the shelf.
I tried Herbie's, Vibrapods, and now Isonodes; all kept the warm sonic signature, but the Isonodes provided greater detail.

@bpoletti, I put Vibrapods back under the preamp, and it sounded warmer, but there was a loss of low-end detail. The Isonodes are superior.

@r_f_sayles, I appreciate your advice. Yes, the sound is new to me and I had a long listening session today. I don't mind the neutral timbre the bamboo brings to my system, but there is a characteristic that is a problem. CD's now have an "edge" in the higher frequencies; eg, cymbol crashes do not sound realistic.

 Trying some wood blocks under the chassis is a good idea. I can say for certain that the change in timbre is due to the wood and not the footers, because I previously tried the Isonodes on the pine shelf and they were completely transparent. In other words, the preamp on pine sounded warm and lush as usual, but with more detail than other footers.

I found some scrap wood today in the house and pulled out a board which had been cut in half. It's a soft wood and lightweight.

Using 5 Moogels underneath, I swapped it with the bamboo and take a guess...my system sounds terrific. It's got a warm timbre with realistic sounding instruments. Preamp is using the Isonodes.

As a test, I used the worst DG mastered CD's I own and the music does sound natural. These are the harsh sounding, close-miked orchestra CDs and they sound quite acceptable when using this new suspension shelf. And no resonances from my rack.
So, I think I'll buy some finished wood at Lowes.