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When is a spring not a spring ? When it’s a polymer Insole

Option 2 will exhibit lower compliance and probably more effective at isolation.

From another thread ...

seyles said:
I’ve been looking into the silicone mushrooms with a view to trying them out, I think rather than being a specific part ‘made in Japan’ for the Thorens 124, they are a generic isolation product for PCBs with the brass collar removed:
B1.jpg

These can be purchased for £10.72 from RS components, the manufacturer is Taica corporation of Japan

https://taica.co.jp/gel/en/product/vibration_damping/gelbush.html

The 14mm size is more suited to the LP12 sub-chassis, the Thorens are normally 16mm and a different shape.
Click to expand...
 
James said:
Spring rate?

Should be relatively easy with suitably sized weights and a rule ...
Click to expand...
LP12 springs are quite diverse in their free lengths, I think the rates are much more consistent.

But it wouldn't be hard to make a jig where you push the spring to a datum with it all on a kitchen scale, zero the scale, and then push a further centimetre, where the jig defines that end point. Could be pushed by hand no problem. You need the initial datum to cater for the variations in free length.

I've been tinkering with an arrangement using squash balls, requires the 'springs' to be offset from the bolts, so the ball can remain intact. But there's nothing magic about the spring arrangement in relation to the CoG. So who knows where that goes.
 
Thanks for that, option 2 it is then.
The top will go 1.5mm into the sub-chassis, not all the way through, but enough to locate them.
I shall order the Taica B1 model from RS and give them a go, it may be a while before I fit them though.
 
The feedback I’ve read on fitting mushrooms to the LP12 has been positive so I wouldn’t hesitate giving them a go. Now someone needs to find the engineer supply company that supplied the In-Soles.
 
Sorry to hijack this thread but I have a set of insoles I bought from John shortly before he passed. I was going to have a play with a Linn but have decided not to now. PM me if you would like to buy them, I only ask what I paid and postage. Having said that I need to find what I did actually pay, does anyone remember what they cost?
 
Here’s a bit I posted elsewhere:


Elastomeric isolators are commonly used for mechanical isolation in various applications. Elastomeric isolators are typically made from rubber or elastomer materials that exhibit high elasticity and damping properties. They are designed to provide effective isolation and attenuation of vibrations and shocks across a wide range of frequencies, including low-frequency vibrations. Here are some key features and benefits of elastomeric isolators:

  1. Vibration Isolation: Elastomeric isolators are specifically engineered to isolate and dampen vibrations. They can effectively reduce the transmission of vibrations from one component or structure to another, thereby minimizing the negative effects of vibrations on sensitive equipment or structures.

  2. Load-Bearing Capability: Elastomeric isolators can support varying load capacities while maintaining their isolation performance. They are available in different designs and configurations to accommodate different load requirements.

  3. Broad Frequency Range: Elastomeric isolators offer isolation capabilities across a wide frequency spectrum, including low, mid, and high frequencies. They are particularly effective in attenuating low-frequency vibrations that may be challenging to isolate using other methods.

  4. Resilience and Durability: Elastomeric isolators are resilient and durable, allowing them to withstand repeated loads, shocks, and environmental conditions without significant degradation in performance. They can provide long-lasting and reliable mechanical isolation.

  5. Versatility and Customizability: Elastomeric isolators come in various shapes, sizes, and configurations, allowing for flexibility in design and integration into different applications. They can be tailored to specific load requirements, vibration profiles, and environmental conditions.

  6. Easy Installation: Elastomeric isolators are typically designed for easy installation, making them convenient to use in various settings. They can be easily integrated into machinery, equipment, structures, or mounting systems.
Common applications of elastomeric isolators include:

  • Industrial machinery and equipment
  • HVAC systems and machinery
  • Construction and building structures
  • Automotive and transportation systems
  • Aerospace and defense equipment
  • Power generation and distribution systems
It's important to select the appropriate elastomeric isolator based on the specific requirements of the application, including load capacity, frequency range, environmental conditions, and desired level of isolation. Consulting with experts or engineers specializing in vibration isolation can help determine the most suitable elastomeric isolator solution for your specific needs
 
Interesting. I wonder why NAIM uses mass damping on the boards of their 500 series components (heavy brass ingots) instead of compliance damping using these silicone mushrooms (presumably to mitigate microphonic distortion)?
 
The Taica 'Mushrooms' arrived, they fit the (cirkus) sub-chassis perfectly:
IMG-7375.jpg


IMG-7377.jpg


The brass collar pushes out easily.
 
Yes type 1, they have a lower optimum load rating 3 - 11.25kg for 3 load points, the B-2 is optimised for 11.25 - 24kg.
I'm assuming the mass of the platter, sub-platter, bearing, sub-chassis, arm board, arm and cartridge would fall into the first range.
 
Cheers for confirming that and of course for you having done your homework. By a stroke of luck I ordered Insoles from JohnR last year. Not so much in search of improved sound but at my age I was looking to remove the lingering doubt that In 40 years my deck had never been set up by anyone other than myself - gurus are a bit scarce over here - and at last I would be able to “relax” when listening to a more “constant” source, for better or worse, that didn’t depend on my imagination, self doubt, the phases of the moon etc. to attain pistonic spring nirvana. In spite of Peter’s efforts, there must be a fair few of us frustrated saddoes dotted around the globe who can now rest in peace. I shall buy a spare et of mushrooms, just in case.
 
sktn77a said:
Interesting. I wonder why NAIM uses mass damping on the boards of their 500 series components (heavy brass ingots) instead of compliance damping using these silicone mushrooms (presumably to mitigate microphonic distortion)?
Click to expand...

Perhaps because the reviewer says "wow that is heavy, quality engineering that"? It might be that simple. I am not saying it may not have other engineering advantages, just saying a weighty product helps justify a weighty price. If both solutions were as good as each other and one helped justify the price ...

Somewhere on the diy forum there was a thread with folk trying out silicone model engine fuel tubing to mount Naim PCBs in e.g. pre-amps if I recall correctly ...
 
Has anyone compared the silicone mushroom filter measurements with Linn springs? Do they cover the same range?
 
I finally got around to ordering some mushrooms from RS and got them fitted to my 'B' deck. This has a Supatrac Blackbird arm with Stack Audio Soprano sub-chassis, Cirkus bearing and an Evolution power supply. Cartridge is an Audio Technica VM-740ML. Previous to adding the mushrooms I liked this deck a lot, it's not crazy expensive but it sounds wonderful (due largely, I think, to Richard's amazing tonearm). Instinctively I'd thought it would sound somehow more sterile (less 'boogy' factor?) after changing the regular springs for the mushrooms but that's just not the case. It still retains the character of an LP12. That said I think modern LP12s have a lot less character (a good thing) than older models since a lot of the frequency imbalances have been ironed out. What it still has is that inherent musicality, an organic quality that digital still seems to lack in all but perhaps some of the highest-end DACS and streamers.

So, what's different? Well pitch stability is drastically better - this is starkly revealed on solo piano music which always sounded a little laughable on LP12s of any specification. With the mushrooms in place piano has the stability I've really only heard previously with digital sources. As far as detail / resolution goes I'm not really perceiving this as any better or worse but it's probably too early to give a view on that. Am I hearing a slight lightness in the bass end? I haven't reached a conclusion on this as it may be that it's actually just better resolved and lacking 'bloom' that the sprung suspension perhaps adds.

One huge benefit is that footfalls no longer disturb the deck. Before I had to creep around near the deck to avoid it jumping, now I can literally jump around with no effect!

Initial overall conclusion is that the deck is at least as enjoyable as before and now I can listen piano music as well. And pogo around to my heart's content....

I bought two sets of mushrooms, shall I commit sacrilege and bastardise the Klimax deck?
 
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