Turntable platter-LP impedance match

ack

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Lots of manufacturers, dealers and audiophiles talk about the perfect platter-LP impedance match. In the cases I cared to research - like AMG, Basis, SOTA et al - some seem to be converging on a vinyl-to-vinyl solution of one kind or another, or PVC-to-vinyl, or some other form of plastic, resin or other. The new Basis super platter, for example, touts its some-sort-of-vinyl-based layer on top of the platter.

I am building my own impedance matching solution, which so far partly depends on a thin layer of Isodamp - another highly damped vinyl, possibly coupled with Spec's AP-UD1 (still in evaluation phase) - and it appears to have hit the nail on the head, with excellent damping, evidenced by the tightening of the bass with exceptional reduction in overhang, increase in leading edge attack and clarity, smoothness of choral works, and obviously, a reduction in mechanical noise... among many other improvements (I may post the final solution under my system thread one day).

So I was curious what others know about this subject, and how do you approach this type of mechanical impedance matching.

-ack
 
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PeterA

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Lots of manufacturers, dealers and audiophiles talk about the perfect platter-LP impedance match. In the cases I cared to research - like AMG, Basis, SOTA et al - some seem to be converging on a vinyl-to-vinyl solution of one kind or another, or PVC-to-vinyl, or some other form of plastic, resin or other. The new Basis super platter, for example, touts its some-sort-of-vinyl-based layer on top of the platter.

I am building my own impedance matching solution, which so far partly depends on a thin layer of Isodamp - another highly damped vinyl, possibly coupled with Spec's AP-UD1 (still in evaluation phase) - and it appears to have hit the nail on the head, with excellent damping, evidenced by the tightening of the bass with exceptional reduction in overhang, increase in leading edge attack and clarity, smoothness of choral works, and obviously, a reduction in mechanical noise... among many other improvements (I may post the final solution under my system thread one day).

So I was curious what others know about this subject, and how do you approach this type of mechanical impedance matching.

-ack

Nice topic Ack, and good luck with your experiments. I think you are addressing something that other manufacturers have pursued for a while, wether it is leather, rubber, some hard plastic or metal. I would think that metal would ring or reflect energy and transmit internal vibrations to the surface of the vinyl record, but those who like metal may consider it a type of tuning. I don't really know. SME, for instance, uses a layer of Isodamp-like material on all of their platters. It is semi-soft and machined with a fine scroll to improve the interface/contact with the vinyl record. Together with the clamp and washer, there is excellent contact and damping of internally generated energy and I suspect that energy transferred from the stylus into the vinyl is also damped a bit with this platter surface.

Does Isodamp leave any residue? If so, I would be cautious about direct contact with the vinyl. Your description of the initial listening impressions is what I would expect with a lowering of resonance which might otherwise lead to distortion.
 

Mike Lavigne

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when the Wave Kinetics team (Stanford PHd's doing robotics for NASA) was deciding on platter materials for what became the NVS tt, the direction was a composite material sympathetic to the vinyl used to press Lps. when I first had the NVS in my room, I also had a number of other tt's sitting there including the Rockport Sirius III with a stainless platter with a textured surface and vacuum hold down, a copper topped platter with the Kodo 'The Beat' and a copper topped Dobbins Garrard 301.

I felt that the NVS was onto something with it's platter material. later I played around with mats and weights and found no mat as best and the Durand weight as best.

which proves nothing at all, just that this issue was a significant design consideration. and when the fur flies in my system I feel that the platter material plays a part of system coherence.
 

mountainjoe

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Timely and great topic!

Timely as I just finished some experimentation with mats and weights on my new Artisan Fidelity Technics SP10MK3 NGS turntable which uses a copper mat.

IMG_0379.jpg

I tried a carbon fiber mat (TTW) that is no longer made and also one of these Dereneville mats http://www.dereneville.de/#xl_xr_page_magic_mat and found while each incrementally improved some aspects of playback (primarily bass response) they took away more than they contributed, sonically speaking. Both mats reduced the dynamic performance evidenced by a slowing or rounding of leading edge transients and also reduced the high frequency extension of my setup.

Next I experimented with three weights - one is the Stillpoints LPI, another is a simple brass weight (Mapleshade), and lastly a (modified) periphery weight (Wayne's audio) - all with similar effect as the mats. Some improvements in one area while degrading transients and highs (to one degree or another).

This was by no means a scientific nor exhaustive study (I used what I happened to have on hand) but the consistent trend seems to indicate that it is easy to dull the transient performance and high frequency response of this particular TT implementation. I am hesitant to apply this conclusion to any other TT design as the impact of these devices may well be a function of the specific design (e.g. idler, DD, or belt drive, the bearing structure & design, and lastly the platter and plinth design & weight).

If this latter part is true, then that may lead us to wonder if a single mat or weight design can have a net positive effect across all TTs or if designs will need to be specific to particular TT architectures or implementations?

In my instance it's pretty clear to me that it's very easy to negatively affect the transient performance in particular, with any damping material or device added to the base design...

Cheers, Joe
 

bonzo75

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when the Wave Kinetics team (Stanford PHd's doing robotics for NASA) was deciding on platter materials for what became the NVS tt, the direction was a composite material sympathetic to the vinyl used to press Lps. when I first had the NVS in my room, I also had a number of other tt's sitting there including the Rockport Sirius III with a stainless platter with a textured surface and vacuum hold down, a copper topped platter with the Kodo 'The Beat' and a copper topped Dobbins Garrard 301.

I felt that the NVS was onto something with it's platter material. later I played around with mats and weights and found no mat as best and the Durand weight as best.

which proves nothing at all, just that this issue was a significant design consideration. and when the fur flies in my system I feel that the platter material plays a part of system coherence.

Mike, as you changed LPs, and played different record labels on these, were changes in recordings, especially labels, equally transparent? Possibly the Garrard was more colored, what about the others?
 

Mike Lavigne

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Mike, as you changed LPs, and played different record labels on these, were changes in recordings, especially labels, equally transparent? Possibly the Garrard was more colored, what about the others?

I assume your question would be related to the record weight, which potentially might cause the weight to vary in it's interface effectiveness with different labels. I can say I've seen no noticeable difference regarding that, but have not looked for any difference either. so one could exist.

the Durand record weight uses three small Sapphire balls imbedded in the bottom of the weight that interface with the labels. I know Joel Durand experimented with various interfaces and found this one best. those little balls 'dig into' the paper on the label a slight amount......as opposed to a flat surface of other weights that can move and slide. I would guess those little balls might mitigate label material differences.

and there was so much different on the Garrard it's hard to isolate one factor. less so on 'The Beat'......i'll just say I preferred the NVS as a bit more refined and spacious. but this was now 7 years ago so hard to get too granular with my perceptions from that long ago.
 

bonzo75

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I assume your question would be related to the record weight, which potentially might cause the weight to vary in it's interface effectiveness with different labels. I can say I've seen not noticeable difference regarding that, but have not looked for any difference either. so one could exist.

the Durand record weight uses three small Sapphire balls imbedded in the bottom of the weight that interface with the labels. I know Joel Durand experimented with various interfaces and found this one best. those little balls 'dig into' the paper on the label a slight amount......as opposed to a flat surface of other weights that can move and slide.

No, I meant due to the TTs. Did some platters or motors color the sound in anyway, showing less difference in various records
 

ack

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Thanks for the responses so far. One thing is clear to me so far, vinyl sitting bare on a plain platter - of any material - is not cutting it. This impedance is critical, and moreover, I just don't think simple and soft materials like leather are sophisticated enough, and neither is carbon fiber for that matter.

Peter, there is a thin layer of clear film between the LP and Isodamp; I may well end up with Isodamp/Spec/Isodamp, but time will tell.

PS: I am intentionally not calling this interface a 'mat'
 
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Mike Lavigne

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No, I meant due to the TTs. Did some platters or motors color the sound in anyway, showing less difference in various records

you can't isolate platters, plinths, arm boards and motors.....unless you get a chance to compare versions of those items.

I'd say the Garrard was obviously colored and therefore synergized and excelled with certain types of music where beat and flow were prominent, and was just 'meh' on other types where refinement and textures were significant to the musical message.

beyond that I would not call the Rockport or Kodo colored at all, they did have their 'sound'......the NVS less so. it got out of the way better. was the platter material part of that that? I don't know. likely everything was part of that.
 

jeff1225

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I've expiremented with after market mats on my last two turntables: Transrotor Fat Bob S and Acoustic Signature Ascona.
I've tried cork, carbon, paper composit and copper. Both times I ended up preferring the mat that came with the turntable. A plastic composit that came with the Fat Bob and a leather mat that come with the Ascona.

I was surprised with both results.
 

PeterA

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Thanks for the responses so far. One thing is clear to me so far, vinyl sitting bare on a plain platter - of any material - is not cutting it. This impedance is critical, and moreover, I just don't think simple and soft materials like leather are sophisticated enough, and neither is carbon fiber for that matter.

Peter, there is a thin layer of clear film between the LP and Isodamp; I may well end up with Isodamp/Spec/Isodamp, but time will tell.

PS: I am intentionally not calling this interface a 'mat'

Ack, two questions:

1. Why not call this interface a "mat"?

2. Does not the Isodamp material require a great deal of load (compression) to function properly? With such a large area (platter surface) and such a light load (vinyl record) this requirement will not be met unless the material is paper thin and a great deal of pressure is applied with a center clamp and periphery ring. Perhaps in this application, the material does not need to be compressed, as I noticed a dampening effect by simply placing some Isodamp scraps on the top of my amplifier casework.
 

ack

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Ack, two questions:

1. Why not call this interface a "mat"?

Well, what exactly is a 'mat' - is this like a carpet? It's an interface, and it needs to be treated as such

2. Does not the Isodamp material require a great deal of load (compression) to function properly? With such a large area (platter surface) and such a light load (vinyl record) this requirement will not be met unless the material is paper thin and a great deal of pressure is applied with a center clamp and periphery ring. Perhaps in this application, the material does not need to be compressed, as I noticed a dampening effect by simply placing some Isodamp scraps on the top of my amplifier casework.

I am using 1/16" thickness, which probably doesn't need to be compressed, but one of the reasons I am experimenting with the Spec is the additional, though small weight it adds (about 400g).
 

DaveyF

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The Linn table has used the same simple mat for ever...a felt mat. There are numerous mats out there that have been developed over the years for this table. None of them have ever sounded better on the table than the felt mat. Many Linnie’s go so far as to ‘clock’ the outter platter to the inner platter, as even this makes a difference. Now there is talk that one side of the felt mat sounds better than the other! Having tried this experiment, I couldn’t hear a difference, but without doubt, no mat or a different mat material definitely sounds worse, to my ears.

On a friends Basis, we experimented with different mats...and he even tried a different platter material ( a platter that he had custom made at a machine shop from stainless) The stock acrylic was the best.
 

BruceD

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I think this Platter Mat interface question lies with what flavour you require/pleases--bit like Yoghurt some want Natural,some Berries, Honey,Mango etc/etc

I've tried Felt, Non-Slip Rubberised Cloth, Leather, Super stick gooey ones( Anyone remember the Spectra from France!) Auditorium23, none( Feickert BB2) Shindo,

All seemed to work one way or another--the only one that delivered to my way was the Graphite plate on my Simon Yorke.

One picks the Flavour

Horses for Courses:D

BruceD
 

morricab

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Lots of manufacturers, dealers and audiophiles talk about the perfect platter-LP impedance match. In the cases I cared to research - like AMG, Basis, SOTA et al - some seem to be converging on a vinyl-to-vinyl solution of one kind or another, or PVC-to-vinyl, or some other form of plastic, resin or other. The new Basis super platter, for example, touts its some-sort-of-vinyl-based layer on top of the platter.

I am building my own impedance matching solution, which so far partly depends on a thin layer of Isodamp - another highly damped vinyl, possibly coupled with Spec's AP-UD1 (still in evaluation phase) - and it appears to have hit the nail on the head, with excellent damping, evidenced by the tightening of the bass with exceptional reduction in overhang, increase in leading edge attack and clarity, smoothness of choral works, and obviously, a reduction in mechanical noise... among many other improvements (I may post the final solution under my system thread one day).

So I was curious what others know about this subject, and how do you approach this type of mechanical impedance matching.

-ack

What about the Funk Firm Achromat, which is a special type of structurally rigid foam?
 

ack

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What about the Funk Firm Achromat, which is a special type of structurally rigid foam?

I just don't think it provides the right impedance match, nor does felt, leather or similar.
 

PeterA

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Ack, Have you tried placing a blank (no grooves) vinyl record under your LPs? I have some clear audio disks that are only cut on one side. That would be an impedance match, assuming their thicknesses are similar. Sounds silly I know, but this seems an obvious impedance match. I wonder if vinyl is too hard a surface and might reflect back some energy.

Is this about tuning or finding the right resonance that sounds pleasing, or is it about draining energy and damping vibrations? This is just theory. I guess you have to keep trying until you hear a sound you like.
 

XV-1

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On my two DD's, I really like the copper gunmetal Micro Seiki cu-180's. they are the bomb.
 

morricab

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I just don't think it provides the right impedance match, nor does felt, leather or similar.

My understanding is that is precisely what it provides. If I didn't have vacuum hold down on my TT it is the one I would try.
 

ack

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Ack, Have you tried placing a blank (no grooves) vinyl record under your LPs? I have some clear audio disks that are only cut on one side. That would be an impedance match, assuming their thicknesses are similar. Sounds silly I know, but this seems an obvious impedance match. I wonder if vinyl is too hard a surface and might reflect back some energy.

I tried that, not to good effect. If anything, it would have to be vinyl flat on both sides... well, Isodamp is just that, and built to absorb.
 

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