I wouldn't call it "potting." That is the process of applying an electrically inert compound (like epoxy) to the innards of a cartridge. There are a number of manufacturers who have created bodies out of ebony, but I haven't seen any of them claim it is for damping. The use and understanding of terminology is important. In all cases (of which I am aware, from Clearaudio to Shun Mook) the manufacturer actually claims that the use of ebony is a form of tuning. Shun Mook should be served cold with a grain of salt.
I would also caution against considering "anisotropic" to be a negative. The difference in the physical properties of a material depending on axis of measurement can be an extremely desirable characteristic when dealing with the types of vectors we're looking at in plinth design. Your favorite Panzerholz is extremely anisotropic.
But as you state ebony has very little intrinsic damping capability. However, if you measured higher than the numbers provided, then I would suggest you check your methods. The higher number quoted is almost an outlier in the range of numbers that have been the result of much testing (I just wanted to provide the range, not the average or the mean). Unlike plinth materials, there are decades of testing of various materials for use in the manufacture of instruments, and one should give some degree of deference to them. When numbers corroborate, it's a good thing. When one has a number outside the usual dataset, then one needs to take a good look at the testing itself.
It's clear that you have a strong commitment to Panzerholz, yet you denigrate the family of glulams regularly. Panzerholz is a remarkable material, yet Panzerholz is a glulam, comprised of layers of hardwood and phenolic resin placed under extraordinary pressure. Given how well it tests for you, I would recommend trying one of Delignit's other products, such as carbonwood, which is layers of beech and carbon fiber, or Festholz, which is basically a higher-quality (hard to imagine!) version of Panzerholz, and which has factory-acknowledged acoustical properties. I think you'll find that it is a combination of factors that needs to be considered in plinth design, including stiffness and (lord forbid!) mass. Mass moves the resonance peak, and understanding that can help achieve performance goals in what is a very complicated set of interrelated material behaviors.
In the end, your research has certainly inspired many quality builds. I would, however, caution against considering that research to be "done." Never allow yourself to be swayed by your own biases. There's a reason why there are so many completely different solutions to great turntable design and performance, from American Sound's stainless steel to Win Tinnon's slate Saskia to the TechDAS family: they all are amazing state-of-the-art products, and take different philosophical routes to get there. If Panzerholz was truly the "end," then we would have missed solutions that at their very essence contradict your essential premises and that have pushed the boundaries of what is achievable in turntable design.
thanks for your extended reply, certainly food for thought.
As far as potting is concerned, I would say that the ebony is used as a shell, not a body (which comes, with the stylus assembly, as part of the pickup). I have bought many cartridge bodies, that is carts without stylus assemblies, but only one shell, made of aluminium. That was potted using my own formulation of damping compound (an electrically inert potting compound) and an AT 92ECD cartridge body. The sound was likened to a roller coaster, exciting at first, but much relief when it stopped! The only material I would buy for shell duties is, wait for it, Panzerholz. As regards the term 'potting', we have a delicacy in the UK called 'potted shrimp', that's made with Morecombe Bay shrimp (that's real shrimp, not prawns that are also called shrimp in the US) which are cooked and potted with butter. Lovely on toast for breakfast! We even have a special place for our potting, it's called 'the potting shed'.
Would agree that Panzerholz is 'slightly' anisotropic, but not enough to make any difference in measurements, but I understand how useful it can be with making musical instruments. However, I would emphasize that in hifi, we are reproducing music, not making it, although the edges can get very fuzzy with some kit.
I don't have a strong commitment to Panzerholz, it's just that it happens to be a very suitable material, even if expensive and unobtainable in the US. There are other materials, some natural woods, some definitely man-made, which would do just as well. And lets not forget other Panzerholz-like products. But the problem with real wood is variability and scarcity. For example, Gaboon Ebony is listed in the CITES Appendix III, and is on the IUCN Red List. And ebony covers many different species, so expecting each one to provide exactly the same properties is maybe expecting too much.
The 'super' Panzerholz materials are probably made for strength, rather than damping properties, but thanks for the heads-up on Festholz, I have ordered a sample from Germany.
I 'denigrate' (your words) glulams made of unsuitable materials, because they are unsuitable for plinth duty, and because audiophiles will call them cld! Let's face it, ply and mdf are used because they are cheap, easy to obtain and work with, and fulfill the belief that mass is king. Mass can move the resonance frequencies up or down, depending on which dimensions are changed. However, my goal has always been to damp, rather than tune, so that I can enjoy all the music, not just the ones in a certain key.
I have never stated the 'research' is done. All I have done (and continue to do) is measure damping factors of materials which may be useful in my quest for neutrality. In the end, even if I were to show exact designs, people would still do their own thing, it happens all the time.
One of the biggest problems with natural wood is variability, even wood form the same tree trunk can have different properties, so getting different results is very likely. Then there is the problem of anisotrophy, (one reason why the BBC went to ply for its loudspeaker designs) and not least, identification of species, if not genus. Just because the label says 'ebony'....
As far as potting is concerned, I would say that the ebony is used as a shell, not a body (which comes, with the stylus assembly, as part of the pickup). I have bought many cartridge bodies, that is carts without stylus assemblies, but only one shell, made of aluminium. That was potted using my own formulation of damping compound (an electrically inert potting compound) and an AT 92ECD cartridge body. The sound was likened to a roller coaster, exciting at first, but much relief when it stopped! The only material I would buy for shell duties is, wait for it, Panzerholz. As regards the term 'potting', we have a delicacy in the UK called 'potted shrimp', that's made with Morecombe Bay shrimp (that's real shrimp, not prawns that are also called shrimp in the US) which are cooked and potted with butter. Lovely on toast for breakfast! We even have a special place for our potting, it's called 'the potting shed'.
Would agree that Panzerholz is 'slightly' anisotropic, but not enough to make any difference in measurements, but I understand how useful it can be with making musical instruments. However, I would emphasize that in hifi, we are reproducing music, not making it, although the edges can get very fuzzy with some kit.
I don't have a strong commitment to Panzerholz, it's just that it happens to be a very suitable material, even if expensive and unobtainable in the US. There are other materials, some natural woods, some definitely man-made, which would do just as well. And lets not forget other Panzerholz-like products. But the problem with real wood is variability and scarcity. For example, Gaboon Ebony is listed in the CITES Appendix III, and is on the IUCN Red List. And ebony covers many different species, so expecting each one to provide exactly the same properties is maybe expecting too much.
The 'super' Panzerholz materials are probably made for strength, rather than damping properties, but thanks for the heads-up on Festholz, I have ordered a sample from Germany.
I 'denigrate' (your words) glulams made of unsuitable materials, because they are unsuitable for plinth duty, and because audiophiles will call them cld! Let's face it, ply and mdf are used because they are cheap, easy to obtain and work with, and fulfill the belief that mass is king. Mass can move the resonance frequencies up or down, depending on which dimensions are changed. However, my goal has always been to damp, rather than tune, so that I can enjoy all the music, not just the ones in a certain key.
I have never stated the 'research' is done. All I have done (and continue to do) is measure damping factors of materials which may be useful in my quest for neutrality. In the end, even if I were to show exact designs, people would still do their own thing, it happens all the time.
One of the biggest problems with natural wood is variability, even wood form the same tree trunk can have different properties, so getting different results is very likely. Then there is the problem of anisotrophy, (one reason why the BBC went to ply for its loudspeaker designs) and not least, identification of species, if not genus. Just because the label says 'ebony'....
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Hi Cats,
There are unfortunately a number of severe misconceptions in your reply, but we can leave those to another day.
What I am very curious about is why you refer to "anisotrophy" as a "problem." In the materials that one is discussing (ply, Panzerholz, etc) anistrophy is fundamental to its concept.
There are unfortunately a number of severe misconceptions in your reply, but we can leave those to another day.
What I am very curious about is why you refer to "anisotrophy" as a "problem." In the materials that one is discussing (ply, Panzerholz, etc) anistrophy is fundamental to its concept.
the problem with anisotrophy (different properties in different directions) is that the different properties will influence how the material reacts.
So that density, surface mass, Young's Modulus, Poisson ratio and damping factor differences can affect some or all of the following: Fr and harmonics, Fc, bending stiffness, modal density and radiation efficiency.
Too much anisotrophy can give rise to many different properties, producing a plethora of the above, causing chaos. Of course, with musical instruments, chaos may be what is needed, but not with hifi kit. Plain and simple is what is required.
So that density, surface mass, Young's Modulus, Poisson ratio and damping factor differences can affect some or all of the following: Fr and harmonics, Fc, bending stiffness, modal density and radiation efficiency.
Too much anisotrophy can give rise to many different properties, producing a plethora of the above, causing chaos. Of course, with musical instruments, chaos may be what is needed, but not with hifi kit. Plain and simple is what is required.
just what i thought...i think you might want to spend a bit more time with this. Panzerholz is extraordinarily anisotropic.
"So that density, surface mass, Young's Modulus, Poisson ratio and damping factor differences can affect some or all of the following: Fr and harmonics, Fc, bending stiffness, modal density and radiation efficiency.
Too much anisotrophy can give rise to many different properties, producing a plethora of the above, causing chaos. "
Try that thought again. Your phrase "producing a plethora of above" makes zero sense in the context of your post. A plethora of poisson ratio? Of Young's modulus?
i'd like to get somewhere with this and not waste my time with word-salads.
"So that density, surface mass, Young's Modulus, Poisson ratio and damping factor differences can affect some or all of the following: Fr and harmonics, Fc, bending stiffness, modal density and radiation efficiency.
Too much anisotrophy can give rise to many different properties, producing a plethora of the above, causing chaos. "
Try that thought again. Your phrase "producing a plethora of above" makes zero sense in the context of your post. A plethora of poisson ratio? Of Young's modulus?
i'd like to get somewhere with this and not waste my time with word-salads.
What thickness would they be ?
( am I presumptuous in thinking that these will be available to buy from you ? )
This is my present plinth.
It is just Panzerholz veneered with a very thing piece of carbon fibre which is added for cosmetic reasons only.
I chose to go with the single piece of Panzerholz after reading endless amounts on CLD and the damping factor of nearly every material under the sun.
Lots of other peoples choices seemed to ere towards aesthetic and not scientific in the end .
I suppose it also depends upon whether one is just re-housing an existing TT or building your own from scratch ....I built mine from scratch and only had my own materials constraints to deal with.
It is just Panzerholz veneered with a very thing piece of carbon fibre which is added for cosmetic reasons only.
I chose to go with the single piece of Panzerholz after reading endless amounts on CLD and the damping factor of nearly every material under the sun.
Lots of other peoples choices seemed to ere towards aesthetic and not scientific in the end .
I suppose it also depends upon whether one is just re-housing an existing TT or building your own from scratch ....I built mine from scratch and only had my own materials constraints to deal with.
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Well they will be made out of a piece that is 8mm thick. I’m guessing that they will end after machining at 5 or 6 mm thick.
Yes if it proves feasible to do this and the cost is not prohibitive then I will have some made for sale.
Wondering is anyone has tried a sand filled plinth?
My SP10 is currently in a resin bentonite plinth and I'm in the process of building a tonearm for another SP10 and am thinking of building a plinth from MDF and filling with sand or more specifically garnet as used for sand blasting.
Forget Panzerholtz it's not available in Aus and Permalli is way over my budget at $2000 a sheet.
My SP10 is currently in a resin bentonite plinth and I'm in the process of building a tonearm for another SP10 and am thinking of building a plinth from MDF and filling with sand or more specifically garnet as used for sand blasting.
Forget Panzerholtz it's not available in Aus and Permalli is way over my budget at $2000 a sheet.
If you don’t mind paying shipping from the UK I can sell you a plinth size piece of Panzerholz.
Thank you for the offer but a single sheet will not do the job I need.
A little background. The SP10 is highly modified, the motor is removed from the chassis and mounted directly in the plinth. In order to stiffen up the bearing/motor housing and have the platter recessed the plinth needs to be 80mm thick.
The second pic shows the collar and bearing recess. As the motor is bolted down the collar locks the bearing rigidly to the plinth. The bearing housing in this plinth is less than 10mm above the bottom of the 80mm plinth. There are other modifications inside the motor but they are not in the scope of this post.
I have built a couple of resin/bento plinths now and both of them warped requiring milling the top, bottom and mounting surfaces flat.
My thought was to build a plinth with acrylic/mdf/acrylic top and bottom plates. Machine an aluminium housing to hold the motor and arm pod fixed to the top plate then fill the entire plinth with sand. The theory is the aluminium housings with little to no damping would pass vibration to the sand to be damped.
I have searched for information on the damping properties of sand in TT plinths but can only find anecdotal evidence on it's usefulness.
A little background. The SP10 is highly modified, the motor is removed from the chassis and mounted directly in the plinth. In order to stiffen up the bearing/motor housing and have the platter recessed the plinth needs to be 80mm thick.
The second pic shows the collar and bearing recess. As the motor is bolted down the collar locks the bearing rigidly to the plinth. The bearing housing in this plinth is less than 10mm above the bottom of the 80mm plinth. There are other modifications inside the motor but they are not in the scope of this post.
I have built a couple of resin/bento plinths now and both of them warped requiring milling the top, bottom and mounting surfaces flat.
My thought was to build a plinth with acrylic/mdf/acrylic top and bottom plates. Machine an aluminium housing to hold the motor and arm pod fixed to the top plate then fill the entire plinth with sand. The theory is the aluminium housings with little to no damping would pass vibration to the sand to be damped.
I have searched for information on the damping properties of sand in TT plinths but can only find anecdotal evidence on it's usefulness.
Attachments
The sand pit structure usually relies on particle damping for its usefulness. Scientific consensus suggests it's the collision of the particles with the structure's walls that dissipates most of the energy, compared with particle-particle collisions. However, significant movement of the particles is necessary to dissipate the energy, and I can't see any plinth-type structure moving that much!
keeping on with the alternative design approach.
A Method that might produce a desirable damping is one where a Cavity is created inbetween Two Sheets (Acrylic Base Plate and Top Plate ? ).
The Outer Side Walls can be of a Material of Choice (MDF ?)
The Inner Walls will be the Perimeter Face of the Machined Aluminium.
The Cavity could be infilled with Newplast and the Top Sheet is then fastened into place.
The Top Sheet could apply a compression to the Newplast if desired.
A Method that might produce a desirable damping is one where a Cavity is created inbetween Two Sheets (Acrylic Base Plate and Top Plate ? ).
The Outer Side Walls can be of a Material of Choice (MDF ?)
The Inner Walls will be the Perimeter Face of the Machined Aluminium.
The Cavity could be infilled with Newplast and the Top Sheet is then fastened into place.
The Top Sheet could apply a compression to the Newplast if desired.
Walk before you run
Cats Squirrel,
Good idea!
I found that one of the headaches is coping with all the harmonics and modulation. One of the screen grabs is a piece of 5 inch square steel. I also tried a round one (not shown here) and found it was much easier to interpret.
I've also attached a test on a stiff piece of Vinyl flooring 100 mm in diameter. Practically textbook waveform. Do you agree with the DF of 0.1 ?
The last shot is a 100mm Diameter x 16mm thick piece of Panzerholz. Is this the waveform I should be looking for? If so, does DF of 0.5 look right?
Thanks,
Hugh
I reiterate, I am here to help you!
Those scans do not look good. I would expect something like this:
https://flic.kr/p/2kYEGPWdamping ©wiki
I expect something like it, but maybe not quite so perfect.
Maybe we should check that all is working by looking at something which has little damping, like a thin metal sheet or low damping wood or plastic. Here is one of ebony (much loved by audiophiles as it 'has damping qualities'). Really? Here's one I prepared earlier.
https://flic.kr/p/2kYHEjWEbony © cats squirrel
Note the exponential decay. Experiment with low damping materials until you are getting something like the ebony trace.
I'll say again, it is much easier to look at low damping factor materials than high ones!
Cats Squirrel,
Good idea!
I found that one of the headaches is coping with all the harmonics and modulation. One of the screen grabs is a piece of 5 inch square steel. I also tried a round one (not shown here) and found it was much easier to interpret.
I've also attached a test on a stiff piece of Vinyl flooring 100 mm in diameter. Practically textbook waveform. Do you agree with the DF of 0.1 ?
The last shot is a 100mm Diameter x 16mm thick piece of Panzerholz. Is this the waveform I should be looking for? If so, does DF of 0.5 look right?
Thanks,
Hugh
Attachments
Acrylic
JohnnoG,
By coincidence, I was mucking around with multilayered Acrylic and the Accelerometer. I stuck a few 1/4" layers together with Ductseal. I thought it had a nice effect at the time.
If you'd like to see them, I'll dig up the results and post them.
Hugh
JohnnoG,
By coincidence, I was mucking around with multilayered Acrylic and the Accelerometer. I stuck a few 1/4" layers together with Ductseal. I thought it had a nice effect at the time.
If you'd like to see them, I'll dig up the results and post them.
Hugh
Hi Hugh
I through the idea out there as cats squirrel has very good results with this material and with a bit of thought in how it is used can transform a material to a very similar result undertest as P'holz.
I have though about using it on the underside of my MU 25 Plinth, as a very affordable method to improve the damping factor.
I through the idea out there as cats squirrel has very good results with this material and with a bit of thought in how it is used can transform a material to a very similar result undertest as P'holz.
I have though about using it on the underside of my MU 25 Plinth, as a very affordable method to improve the damping factor.