DIY CLD Plinth Design--A measured Approach

[Mike56]

Mike,

Thanks for posting that. Do you notice any difference subjectively from the change?

What's your platter made of? Is the record directly on the platter, or do you use a mat?

Hugh

Yes Hugh, but i am always wary of autosuggestion, before i measured anything, everything i did always sounded better......................
Now with this latest i hear less background noise, more black and a few details, its the odd cymbal or distinction in sound here and there, and instruments like piano sound, well, slightly more piano like, nice dynamics, don't forget all the TT is a cheat (for a diy forum) its an Origin live Aurora, bought before i started making things, so far i did speakers, Troels Gravesen Fusion, and my arm, may do a pre next, or the Lenco project, hence the plinth interest.......i like making things and when they sound good that's a bonus. M

 

[Mike56]

Yes Hugh, but i am always wary of autosuggestion, before i measured anything, everything i did always sounded better......................
Now with this latest i hear less background noise, more black and a few details, its the odd cymbal or distinction in sound here and there, and instruments like piano sound, well, slightly more piano like, nice dynamics, don't forget all the TT is a cheat (for a diy forum) its an Origin live Aurora, bought before i started making things, so far i did speakers, Troels Gravesen Fusion, and my arm, may do a pre next, or the Lenco project, hence the plinth interest.......i like making things and when they sound good that's a bonus. M

Sorry, platter, stock OL with their mat, i will test the Rega one i have and post the differences.......M

 

[JohnnoG]

Hi Mike
I have enjoyed looking at the TT set up, it has come a long way from the Rega looking arm seen further into the image.
The Structures are quite something and dare I say it, brave to produce them from the composite stone materials.
The Tonearm has got me quite intrigued, is this a personal design?

I have used inner tubes and then changed to a very aerated soft foam that is quite thick about 100mm x 50mm and can be stacked to a increased thickness where extra weight bears on it.
There is a difference between the two materials when used, but it is too long in the past to recollect what was the attraction, usually when I perceive a tighter bass note and a improved envelope of a not or vocal, I will stick with the material that best produces this for my own tastes.

I am about to go off on a 'John Moment' to describe my ideas that are of interest.

I am not finished with the idea of an inner tube being used to support equipment, but the changes of use for it, has been to use it as a method to contain other substances other than air.

One method has been identified with a risk attached where a leakage can be an unwanted occurrence, and a little thought will need to be used to utilise the method and protect other equipment, it is quite doable.
I won't elaborate on it too much, but the idea of removing the valve and filling with a low viscosity oil/liquid rubber such as a modellers latex has been a method of interest, the Valve can be reinserted once filled and the Cap can be replaced with a PTFE Tape to improve the seal.
The risk of a puncture will always prevail, if the seepage from the Valve/Cap is not a cause for a concern, and a tray to lay the Tube on might be the best way to contain a leakage of oil if a puncture occurred.
This would create a different tier of suspension in place of air in the support structure.

The other is to use a Oil Saturated Sand contained within a Inner Tube Sausage, I have done this before on Long Telephoto Lens using a Kiln Dried Sand only contained within a Inner Tube Sausage. This worked exceptionally well at taming the vibrations occurring in the housing of Manual Focus Nikon Long Focal Length lenses, no inbuilt vibration control in these older generation lenses.

Others including myself have used Kiln Dried Sand for its more known off methods of usage, adopting it for their support needs within the HiFi system, either using the sand for a filling of a internal hollow of a support frame, or making a Support Platform/Plinth with a Sandwich Layer of Kiln Dried Sand.

A Saturated Sand Sausage will work similar, but will be slightly different to use, as it will be a less flexible material, as the mixture works at its best when compressed.
It can be used as a Sandwich Layer on a Support Platform/Plinth in the same way Kiln Dried is contained in place.

There is a lot of white paper research carried out from industries that are all quite supportive of the use of Saturated Sand, there are calculations available for the mixture ratio's and whether additional sizes of aggregate particulate used within the mixture creates a improved mixture.
It is very affordable and is proven that when correctly mixed will yield wanted results.

My Plan was too cut the Valve out of the Inner Tube and then seal of one of the tubes open ends, then fill the tube with a saturated sand mixture.
When filled a bung can be inserted into the tube to keep the mixture compressed and the tube end can be sealed to the bung.

Either of the alternative uses for the Inner Tube are nothing ventured nothing gained exercises.

 

[Mike56]

Sorry, platter, stock OL with their mat, i will test the Rega one i have and post the differences.......M

Hugh, lots of subjects in there!
The PTA is an Origin Live arm as well, i believe they make excellent kit.

The RTA is my own concept, it was all Carlos fault really, he had done LC and it seemed obvious to me that the vertical motion should be taken on the carriage not by moving the whole set of rails, Carlo thought it unlikely, i didn't know it was difficult so i had a go, i did dozens of experiments, i used to record them methodically but no more, if it seems better it becomes the current arm.
Carlo has now done an excellent version, far better built than mine where he keeps the paralelogram almost flat, its all on the LTA thread.
Then several people encouraged me to measure things, i resisted for a while but when i started it was a great benefit and i had often fooled myself by thinking if i thought it was a good idea and worked hard at it, it must be an improvement and often listened and believed it when measurements showed otherwise.
I am now at a point where the consistency of the apparatus is a limiting factor, i can measure the same thing twice and not get the same answer....
I did test rega and ol mats earlier, no mat was poor but the other two varied, one better sometimes the other at other times.
With measurements done my way you only see the dominant result, so one artefact can hide another, so you have to remove the first to reveal the other..
Anyway, other subjects, under my plinth is a sand box, this is in my view the separation level, vibration coming up is supposed to die in the sand box and any going down is supposed to be absorbed there as well. so my construction is to try and get vibrations caused by the sylus out through light stiff parts to the arm base and into the sand box.
Oh, and the rails are polished stainless tubes, also 95% sand filled, i tried foam rubber, blu tack and sand to get to there.
M

 

[hjam]

Mike,

I think it's mostly John's comments that you're responding to, but interesting stuff just the same.

The reason I had asked whether you noticed anything subjectively was a recent test with my LTA on a suspended Heybrook turntable. I placed the cartridge on a stationary LP, then tapped the arm, platter, plinth, etc and recorded the phono output. A few nasty resonances from all.

Then, I played and recorded a pink noise track as well as a sweep from a couple of test LPs. The resonances from the platter and sub platter seemed to show up, but at a very low amplitude. The ones from the LTA were not obvious at all. It may have been masked by other influences.

For my new TT, I'm doing quite a bit of work trying to damp the resonance of the Carbide rods - all the while wondering if it's something that's not audible anyway.

Is the OL platter an acrylic one? What's the mat made of?

Hugh

 

[Mike56]

Mike,

I think it's mostly John's comments that you're responding to, but interesting stuff just the same.

The reason I had asked whether you noticed anything subjectively was a recent test with my LTA on a suspended Heybrook turntable. I placed the cartridge on a stationary LP, then tapped the arm, platter, plinth, etc and recorded the phono output. A few nasty resonances from all.

Then, I played and recorded a pink noise track as well as a sweep from a couple of test LPs. The resonances from the platter and sub platter seemed to show up, but at a very low amplitude. The ones from the LTA were not obvious at all. It may have been masked by other influences.

For my new TT, I'm doing quite a bit of work trying to damp the resonance of the Carbide rods - all the while wondering if it's something that's not audible anyway.

Is the OL platter an acrylic one? What's the mat made of?

Hugh

The platter is acrylic looking, maybe another similar plastic, as i have said before each area i look at OL have done fine work, if i didn't like making things i would simply buy their kit, easy. the mat is a moderately hard thin felt type material. have a careful read of their site. A puzzling coincidence, Mark Baker studied naval architecture at Southampton just a year or two before me...........an irrelevant fact i know!

 

[hjam]

Mike,

I had a look at the OL site. They describe their present "Platter Mat" mat as a a "flexible composite material". Is it the same one you use, or is yours the earlier " Performance Mat" ? I'm tempted to try their new one - the price is not horrible.

Quite a while back, I did some hammer taps on the Rega P6 with the standard felt mat and a leather one that someone recommended. My recollection is that the leather one did measure better when I tapped the platter.

I see that the top 2 Turntables on the OL site apply some sort of damping technique to the platter. Sounds like good stuff.

Hugh

 

[Mike56]

Mike,

I had a look at the OL site. They describe their present "Platter Mat" mat as a a "flexible composite material". Is it the same one you use, or is yours the earlier " Performance Mat" ? I'm tempted to try their new one - the price is not horrible.

Quite a while back, I did some hammer taps on the Rega P6 with the standard felt mat and a leather one that someone recommended. My recollection is that the leather one did measure better when I tapped the platter.

I see that the top 2 Turntables on the OL site apply some sort of damping technique to the platter. Sounds like good stuff.

Hugh

I asked OL which i have but no reply yet, i will call them soon, meanwhile i took out the inner tube and replaced with foam rubber compressed about 50% of its original height, that showed a measured improvement and i would say sounds a bit tighter in the bass as a result. But i cannot suggest using flexible materials under the TT as this must stay flat, the arm must stay really level. M

 

[JohnnoG]

Hi Mike
I have seen your trying out a compressible Foam rubber material, the one I use is from the Brand EKI and is a acoustic barrier.
The trick I have adopted for foam is to have it used as a separator under a Tier in a Sub Plinth assembly with a Sub Plinth laid onto it as a load spreader.
I then place the TT with middle height set adjustable suspension footers directly onto the the Sub Plinth and see how the compression of the foam affects the level, I then add a extra foam where the most compression occurs. This is usually enough to show the Levels Bubble as being not too far off.
I have a selection of weights I then distribute onto the Sub Plinth to be positioned where the improvement is seen on the level of the Sub Plinth and Bubble, the adjustable footers will creep the TT to its final level position showing a ideal Bubble.

 

[Mike56]

Hi Mike
I have seen your trying out a compressible Foam rubber material, the one I use is from the Brand EKI and is a acoustic barrier.
The trick I have adopted for foam is to have it used as a separator under a Tier in a Sub Plinth assembly with a Sub Plinth laid onto it as a load spreader.
I then place the TT with middle height set adjustable suspension footers directly onto the the Sub Plinth and see how the compression of the foam affects the level, I then add a extra foam where the most compression occurs. This is usually enough to show the Levels Bubble as being not too far off.
I have a selection of weights I then distribute onto the Sub Plinth to be positioned where the improvement is seen on the level of the Sub Plinth and Bubble, the adjustable footers will creep the TT to its final level position showing a ideal Bubble.

Hi John, i just had some upholstery foam, no idea of the spec...................my arm is RTA so needs to stay absolutely level, i cannot put the arm or TT on foam for that reason, but it works well to isolate the motor!
M

 

[misko1989]

Hey guys… less and less time for turntable and my system improvement… anyway, wanted to hear you out about an idea…

I have recently shared my plinth for Elac 50h2 with pics. I am thinking about purchasing some drum dampers (6 pack) and try to stick these to the metal body of my turntable underneath to damp it as much more as possible. One more thing I am thinking is to use these under metal pads of spikes as isolation.
I will proceed with this since it is not an expensive play, but wanted to check if anyone has tried this already or have some experience or comment to share. These are used for damping cymbals so, it makes sense they could be useful for the turntable/plinth damping in some way…

 

[Mike56]

Hey guys… less and less time for turntable and my system improvement… anyway, wanted to hear you out about an idea…

I have recently shared my plinth for Elac 50h2 with pics. I am thinking about purchasing some drum dampers (6 pack) and try to stick these to the metal body of my turntable underneath to damp it as much more as possible. One more thing I am thinking is to use these under metal pads of spikes as isolation.
I will proceed with this since it is not an expensive play, but wanted to check if anyone has tried this already or have some experience or comment to share. These are used for damping cymbals so, it makes sense they could be useful for the turntable/plinth damping in some way…

Morning Misko, i have used what i consider might be equivalent, the self adhesive butyl car body panel dampers, mostly this had little effect when applied to the thicker panels i used in construction, however with your thinner metal assembly it may do better. as you say, try it and see, they remove easily enough. are you set up to measure the effect or just listen?
M

 

[misko1989]

Morning Misko, i have used what i consider might be equivalent, the self adhesive butyl car body panel dampers, mostly this had little effect when applied to the thicker panels i used in construction, however with your thinner metal assembly it may do better. as you say, try it and see, they remove easily enough. are you set up to measure the effect or just listen?
M

No measuring eq sorry… I will share listening impressions at least. I can only garantee I am not someone who falls into hype for every tweak I do… trying to be objective and not lie, myself first.

 

[hjam]

No measuring eq sorry… I will share listening impressions at least. I can only garantee I am not someone who falls into hype for every tweak I do… trying to be objective and not lie, myself first.

Hi misko1989,

Is the plinth of the Elac 50h2 steel? Aluminum? If it's aluminum I have a suggestion.

Hugh

 

[misko1989]

Steel.

 

[hjam]

Ok, I'm not sure how this will go with steel.

I tested some small pieces of Aluminum about 100mm x100mm x 3 mm thick. A sandwich of 2 pieces with ductseal in between damped fairly well. When I made it 4 layers of Aluminum and 3 layers of Ductseal, it was surprisingly good. If I had a TT with an Aluminum chassis, I'd ad 3 more layers of similar thickness with a VE in between.

This may work for a steel chassis but I have NOT tested it.

I'm hopeful that there's a Polyurethane sealant mixture that will work as well as Ductseal. That's what I'm testing now. More in a few weeks if it works out.

Hugh

 

[misko1989]

Thanks for the comments guys... I'm thinking it cant go wrong anyway. It will damp for sure, how much and will it make difference that can be heard, we shall see

 

[MrKlinky]

Ok, I'm not sure how this will go with steel.

Cork and steel are a most effective combination due to their wildly different acoustic impedances. (The combination was used in industry until MLV came along). Cork also has that organic charisma the might appeal to purists!

 

[misko1989]

Noted. But how to attach/glue it to the steel? Should be some thin layer of glue or already mentioned 3m double tape?

 

[MrKlinky]

Noted. But how to attach/glue it to the steel? Should be some thin layer of glue or already mentioned 3m double tape?

Contact adhesive.