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

[John]

The investment in money and time to try the In Soles is not large so I would recommend anyone who is capable of fitting them to try. And, I believe, you can return them if not satisfied.

I actually feel fortunate to have a elastomeric isolator custom made for use in a LP12 on its way to the US.

Here’s a bit from ChatGBT:


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

 

[Chris]

That´s exactly what I wanted to say in Post#1 but I couldn´t spell ELASTOMERIC.

 

[Dowser]

A question for @John R - are the prototype set I still have the same as current production? Maybe I need to try them again

 

[John R]

A long time has passed Richard and much has happened in my life since then, I would have to check the Durometer, possibly yours are slightly harder, I'm not sure?

 

[James]

In anticipation of the arrival of my set of insoles, @John R, can you tell me if there is anything inserted between the top plate and the sub-chassis to take up the slack when the deck is flipped upside down? Ordinarily, the Linn springs will push an unloaded into the top plate, but I imagine the insoles won't be compressed that much by the weight of fully laden sub-chassis. I wonder if inserting a small piece of soft foam centred on each of the three bolts is advisable?

 

[MartinC]

Amazingly despite the post office estimate of a month the insoles arrived today! Hopefully will have some time this weekend to try them out. I haven't really looked into how they fit but imagine it's pretty self explanatory.

 

[John]

Amazingly despite the post office estimate of a month the insoles arrived today! Hopefully will have some time this weekend to try them out. I haven't really looked into how they fit but imagine it's pretty self explanatory.

So did mine. Might be awhile before I get the spacers from LinnArts.

 

[James]

So did mine. Might be awhile before I get the spacers from LinnArts.

Have you tried installing the insoles without the spacers and found that the unthreaded bit of the Khan bolts gets in the way?

 

[13th Duke of Wymbourne]

You don't need to turn upside down to fit them. You will need the deck the right way up to level the subchassis and fitting them is as easy as levelling them. Just remove a spring and replace with the In Sole then move on to the next.

 

[chiily]

You don't need to turn upside down to fit them. You will need the deck the right way up to level the subchassis and fitting them is as easy as levelling them. Just remove a spring and replace with the In Sole then move on to the next.

That's what I did, two piles of books to support the sides and reached underneath, really simple. Just a case of adjusting by screwing each InSole in and out to get the platter level.

 

[John]

Have you tried installing the insoles without the spacers and found that the unthreaded bit of the Khan bolts gets in the way?

You will need the spacers. The In-Sole is no larger than the top grommet that supports the spring.

 

[Chris]

C´mon guys, if I was able to do it with no instructions you lot will laugh your heads off when you do it. Imagine opening an umbrella with a nut on a thread up the main mast instead of just pushing til it clicks. The trouble with the fancier top plates is that the thread stops half way up the main mast instead of carrying on right up to the top, hence the need for a spacer for the nut to push against. Clear as mud !

 

[John]

You don't need to turn upside down to fit them. You will need the deck the right way up to level the subchassis and fitting them is as easy as levelling them. Just remove a spring and replace with the In Sole then move on to the next.

I would remove the outer platter, belt, counterweight, tonearm and replace one spring at a time while the LP12 is right-side up in the jig.

 

[John R]

In anticipation of the arrival of my set of insoles, @John R, can you tell me if there is anything inserted between the top plate and the sub-chassis to take up the slack when the deck is flipped upside down? Ordinarily, the Linn springs will push an unloaded into the top plate, but I imagine the insoles won't be compressed that much by the weight of fully laden sub-chassis. I wonder if inserting a small piece of soft foam centred on each of the three bolts is advisable?

No need James. Just snug it all up then turn the plinth right way up, insert sub platter, outer platter etc and level arm-board to plinth top edge or use a level if you prefer.

 

[per-Sony-fied]

The solution for fitting mushroom’s or In-Soles to a Khan or Karmen top plate if you want to retain the supplied studs is to use spacers sold by LinnArts that sells the mushrooms.

Wondering what subchassis that is. Not seen that one. Looks quite cool.

 

[John]

Wondering what subchassis that is. Not seen that one. Looks quite cool.

Tangerine Audio Phoenix

 

[John]

The spacer kit arrived yesterday from Linn Arts so I took the plunge and installed the Analogue Innovation In-Soles in my LP12 yesterday. Before doing so I made three recordings with the springs in place and recorded the same songs once the deck was all setup with the In-Soles and spacer kit. It was a great day to do this project because the weather had turned mild and there was no noise from having the air conditioner or dehumidifier running to interrupt the proceedings. I also had a few hours to enjoy some album sides I was curious to explore.

David Sanborn - Straight to the Heart
Santana - Moonflower
Jackson Browne - Running on Empty
Jamie Saft - Solo a Genova
Annie Lennox - Nostalgia
Bonnie Raitt - Just Like That
Ella Fitzgerald- The Jerome Kern Songbook

I’m really looking forward to doing more listening as this change has exposed insights into the music that I’m noticing on everything I’ve listened to so far. I’m imagining this is going to be one of those “I need to revisit my entire collection type upgrades”. I’m glad I held off on the Karousel bearing as I’m pretty certain what the suspension change brings is more fundamental to the “tune”.

BTW, those several records were listened to in my living room which is upstairs to where my LP12 and main system is located in the basement.

Here’s what they look like in place with the Tiger Paw Khan top plate studs and Greenstreet sub-chassis.

Analogue Innovation In Sole Elastomer Isolators plus Spacers
https://youtube.com/shorts/H97wrvfHDOg?feature=share

 

[John]

I fitted a set last week and I am very, very happy with the result. John supplied them a couple of months ago but I waited until I had sometime off in order to make before & after needle drops and do some isolation experiments. With hindsight I wished I'd just fitted them straight away and enjoyed them over the last two months. I would say the improvement of going from Karousel+springs to Karousel+In soles is as much as going from Cirkus+springs to Karousel+springs, maybe more.
I found that the isolation from acoustic feedback is about the same between In soles and Springs, so if it is not down to isolation then, perhaps, the In Soles are better at preventing the subchassis rotating due to the motor (a la Roksan Xerxes).

I posted my findings on acoustic feedback on the WAM LP12 forum but it seems PFM doesn't like me linking to it. There I included some needledrops of my LP12 playing a silent groove while the speakers were playing - if you want to listen it is the thread about 'metal plinth makers?' post #53 but I would say there is hardly any difference in that test.

I had been reading that thread from it’s onset and it’s a very interesting read. I’m beginning to believe that the springs themselves are the Achilles heal of the LP12. The springs are so sensitive and easy to set in motion and because of that make the turntable more vulnerable to vibrations coming from all manner of sources. Vibrations that cause the plinth to move will also move the feet, top plate/pulley/belt and transfer to the closed loop of the turntable. Eliminating the vulnerability that the springs amplify with the In-Soles has made a very positive improvement in what I’m experiencing as I get a chance to listen to records I’m very familiar with.

I’ve been able to hear the improvement of the suspension in all three of my systems that are attached to the same LP12 which is located in my basement. Two of the systems are located on a different floor of the house making the turntable unaffected by acoustic energy from the loudspeakers.

I’m looking forward to reading impressions from the three others who purchased In-Soles recently.

 

[per-Sony-fied]

Tangerine Audio Phoenix

Yea, forgot to say thanks when posted

Next question, what does that "weight" do on the underside, is it some kind of balancing weight to even out the spring tension for the arm?

 

[John]

Yea, forgot to say thanks when posted

Next question, what does that "weight" do on the underside, is it some kind of balancing weight to even out the spring tension for the arm?

I believe it is a counter weight supplied by Linn Arts for that purpose but is being used for the mushroom suspension. Perhaps it’s necessary for leveling that particular sub chassis when a heavy tonearm is used in that application.