I've started this as a spin off from this thread. http://www.diyaudio.com/forums/anal...hesis-why-some-prefer-vinyl-douglas-self.html as a number of interesting ideas were surfacing that were not the key focus of that thread, but I think that they are worth another spin through. I say another spin, partly because there is nothing new under the sun, but also because a lot of 'received wisdom' has not actually been revisited in 40 years and tested. Which means some of it might be wrong.
When I get time will copy some links in from the other thread as there is a lot of useful stuff there, but the area I want to kick off is resonances. There is a lot discussion on damping platters and turntables, but actually dealing with the most troublesome issues seems to be ignored, namely the arm/cartridge interactions and resonances. What would be interesting is a chance to both openly discuss these and also share information on how to measure and analyse them. The average laptop line input is accurate enough and powerful tools are available for free, so let's use them and see where it takes us.
I expect this thread to meander about a bit, which is fine but I would appreciate if we could focus on vinyl imperfections, their measurements and trying to reduce them that would be great.
And I do understand that for some the 'bloom' is what makes it enjoyable. If that floats your boat no argument from me, but please say 'i prefer' than 'it's better'.
Just to kick the discussion off I'd like to throw out silicone damping. Many tonearms have had damping at the pivot end, but to me that seems the wrong place. To date I'm only aware of Max Townsend putting the damping at the cartrige end (ignoring the moustaches of Shure V15s and Stanton 681s). Whilst he may have a patent on it, no reason we shouldn't be able to DIY something and have a play. Polypropylene chopping boards start at £3 and should be easy to hack around at home so there should be no reason not to able to experiment with this at home for less than the cost of a few beers.
When I get time will copy some links in from the other thread as there is a lot of useful stuff there, but the area I want to kick off is resonances. There is a lot discussion on damping platters and turntables, but actually dealing with the most troublesome issues seems to be ignored, namely the arm/cartridge interactions and resonances. What would be interesting is a chance to both openly discuss these and also share information on how to measure and analyse them. The average laptop line input is accurate enough and powerful tools are available for free, so let's use them and see where it takes us.
I expect this thread to meander about a bit, which is fine but I would appreciate if we could focus on vinyl imperfections, their measurements and trying to reduce them that would be great.
And I do understand that for some the 'bloom' is what makes it enjoyable. If that floats your boat no argument from me, but please say 'i prefer' than 'it's better'.
Just to kick the discussion off I'd like to throw out silicone damping. Many tonearms have had damping at the pivot end, but to me that seems the wrong place. To date I'm only aware of Max Townsend putting the damping at the cartrige end (ignoring the moustaches of Shure V15s and Stanton 681s). Whilst he may have a patent on it, no reason we shouldn't be able to DIY something and have a play. Polypropylene chopping boards start at £3 and should be easy to hack around at home so there should be no reason not to able to experiment with this at home for less than the cost of a few beers.
http://www.theanalogdept.com/images/spp6_pics/TT_Design/MechanicalResonances.pdf
Very good reading to give you an idea not only of the scale of the problem, but also the fact that this was known about in 1977. If you look particularly at page 9 you can see the FM sidebands that low frequency resonances cause.
This should all be measurable without needing to spend €250 on the Fieckert test software.
Very good reading to give you an idea not only of the scale of the problem, but also the fact that this was known about in 1977. If you look particularly at page 9 you can see the FM sidebands that low frequency resonances cause.
This should all be measurable without needing to spend €250 on the Fieckert test software.
Now we have to worry about BIM as well as TIM and PIM. This stuff is all measurable by anyone with a sound card and a little savvy.
We had Pioneer Three in one which probably had Pioneer PL15d turntable. The headshell had gooey approximately 15mm rubber square which stuck to the headshell without any glue. Cartridge was fitted on to that. I guess it was for damping. Townsend tonearm is good but I have few queries. The resistance at the far end of the pivot would affect bias. Where as damping at the pivot end would have less resistance to horizontal movement, so we have more advantageous option of having more viscous damping fluid. Isn't it ? Also this has confused me often. When vibrations travel they travel in all available places. why would a fluid damping (weather at cartridge end or pivot end) damp it. Vibrations can still go further at bearing. So complete removal of it is not possible. Right ?
Regards
Regards
Put a ruler on a table sticking off the edge. hold down the edge on the table and hit the other end. You get a nice decaying sound. Same is happening in a tonearm, but more g over a shorter distance. If you damp at the pivot end then the cartridge tail can still wag the arm dog even though the resonances will die down more quickly with damping.
Damping at the cartridge end should damp things out more quickly. The question is how much difference can that make. Which requires a setup that can be damped at either end. Mine could be but the rear trough for an SME309 is not cheap.
You are right that you can never remove it all. You may not even be able to get to critically damped ,but at the moment the system is effectively undamped. The only damping (cartridge compliance) is at a resonant point.
Think back to the ruler. if you damp at the desk, the far end still vibrates.
Damping at the cartridge end should damp things out more quickly. The question is how much difference can that make. Which requires a setup that can be damped at either end. Mine could be but the rear trough for an SME309 is not cheap.
You are right that you can never remove it all. You may not even be able to get to critically damped ,but at the moment the system is effectively undamped. The only damping (cartridge compliance) is at a resonant point.
Think back to the ruler. if you damp at the desk, the far end still vibrates.
As luckythedog said if you create a time axis the two signals are a complex spiral around the origin. Maybe looking at the analytic signal would make more sense? I meant to quote your second question.
I have recently made a significant improvement in sound by putting a small pieces of self adhesive rubber foam on both sides of my Benz Micro Gold cartridge . It is a cartridge which puts much vibration into records during tracking which gives thick sound which some find as a genuine analogue quality. With damping it is much crisper.
One neglected thing in analogue reproduction are contacts in cartridge signal path. The best solution is to eliminate them all except cartridge tags if we like ultimate sound . Five pin tonearm connectors can be eliminated without much loss in comfort. If you must use RCA plugs in my opinion only WBT nextgen connectors approach direct soldering. Cartridge signal is so low and low level details and clarity is reduced on every connector. IC sockets should be eliminated too. I had IC sockets at the input of my phono stage for J-fets matching directly. When I soldered j-fets directly to PCB, I got huge improvement in sound quality. Contact cleaners or enhancers are not substitute of direct soldering.
One neglected thing in analogue reproduction are contacts in cartridge signal path. The best solution is to eliminate them all except cartridge tags if we like ultimate sound . Five pin tonearm connectors can be eliminated without much loss in comfort. If you must use RCA plugs in my opinion only WBT nextgen connectors approach direct soldering. Cartridge signal is so low and low level details and clarity is reduced on every connector. IC sockets should be eliminated too. I had IC sockets at the input of my phono stage for J-fets matching directly. When I soldered j-fets directly to PCB, I got huge improvement in sound quality. Contact cleaners or enhancers are not substitute of direct soldering.
SY I believe filled one of his MM carts with magic goop. Sadly not sure he is able to give us a formula we can replicate without access to his lab, but certainly gooping cartridges is an interesting avenue. Anyone tried putting a tape accelerometer on to measure one?
You can google it, complex maths that can make analysis of modulated signals easier. I admit I would not undertake a full on onslaught to this problem.
Every cartridge or tonearm tube should be as much damped as possible. Vandenhul has a similar damping in his Condor cartridge. We need no instruments to hear the difference.
Attachments
To your original post, damping at pivot vs. damping at cartridge has been scientifically researched in great detail with the results published over 35 years ago. A paper published in the Journal of the Audio Engineering Society in 1978 analyzed the topic of putting the damping either at the pivot or at the cartridge and found that neither approach was right or wrong. Either way, each was a compromise with different tradeoffs, and neither one was a magic silver bullet. Shortly after that was published, Shure introduced their damping brush on their then TOL Type 4. The way that Shure’s brush operated totally changed the mechanics of mass/compliance resonance behavior, so much so that the authors of the paper revised the calculation model to include the mechanics of the brush damping at the cartridge end. The study results were updated and subsequently published in a later issue of the JAES in an extensive entry in the “letters to the editor” section of that issue. In the follow-up they found that, while there is no clear-cut winner to the ‘at the pivot’ vs. ‘at the cartridge’ debate, using a brush damper at the cartridge does yield a mathematically optimum solution of 25% of the system damping applied at the pivot and 75% of the system damping applied at the cartridge end. I have read both papers, and found the information to be well worth the copyright/download fee.
A link to the first paper is here:
AES E-Library Impulse Response of the Pickup Arm-Cartridge System
AES E-Library
Impulse Response of the Pickup Arm-Cartridge System
A model of the pickup arm-cartridge system is considered which includes both stylus assembly and arm pivot damping. The impulse response of this system is considered when the stylus is subjected to a sine-squared displacement. This enables the evaluation of the behavior of the system when excited by both infrasonic (that is, warp) and audio impulses. It is shown that no signal choice of parameters can provide ideal behavior at all frequencies of interest, but that the best compromise involves both arm and stylus damping. This shows up a clear deficiency in most current high-quality record-playing systems, in which no arm damping is used. Equations are furnished to enable further analysis in any specific case.
Author: Lipshitz, Stanley P.
Affiliation: Department of Applied Mathematics, University of Waterloo, Waterloo, Ont., Canada N2L 3GI
JAES Volume 26 Issue 1/2 pp. 20-35; February 1978
Publication Date:February 1, 1978
Permalink: AES E-Library Impulse Response of the Pickup Arm-Cartridge System
A link to the follow-up paper is here:
Permalink
AES E-Library
Comments on -Impulse Response of the Pickup Arm-Cartridge System- and Author's Reply
Authors: Rabinow, Jacob; Lipshitz, Stanley P.
JAES Volume 26 Issue 10 pp. 772, 774, 776, 778; October 1978 Permalink
Publication Date:October 1, 1978
I am not pushing the Shure brand name, but around that time I did buy a Shure Type 4 and also designed and built my own silicone damped unipivot arm geared toward achieving the 25%/75% ratio of damping and found the results of that combination were, and continue to be, astounding. It is important to understand that the brush damper is not as simple as an extra shot of resistive damping into the system. It helps with the damping function all right, but a major concurrent benefit of the brush damper is that it takes ½ gram’s worth of workload off the stylus suspension’s shoulders in having to do its job of shoving the cartridge up over record warps, and the added ½ gram that you dialed into the VTF helps shove the cartridge back down on the tail side of the warp.
Back to the OP, I think viewing the damping location as an ‘either/or’ debate is an over-simplification of the problem. I have found that it needs to be done at BOTH ends in order to get maximum benefit. The Townsend approach with the oil bath includes damping at the cartridge end, but doesn’t shunt/bypass the warp induced dynamic forces around the stylus suspension. The DiskTraker outrigger air-piston approach helps unload some of the dynamic forces off the stylus suspension, but air would not seem to be as effective a damping medium as silicone or an oil bath. I’ve thought about adding a glob of silicone to the hinge of a Stanton/Pickering sylus/brush assembly, but I’ve been putting that off as a retirement project [stay tuned, later this year!]. It would be really great if, say, Jico would offer the brush damper that they include with their several Shure replacement styli as an aftermarket outrigger attachment that could be retrofit to any standard ½” mount cartridge.
A link to the first paper is here:
AES E-Library Impulse Response of the Pickup Arm-Cartridge System
AES E-Library
Impulse Response of the Pickup Arm-Cartridge System
A model of the pickup arm-cartridge system is considered which includes both stylus assembly and arm pivot damping. The impulse response of this system is considered when the stylus is subjected to a sine-squared displacement. This enables the evaluation of the behavior of the system when excited by both infrasonic (that is, warp) and audio impulses. It is shown that no signal choice of parameters can provide ideal behavior at all frequencies of interest, but that the best compromise involves both arm and stylus damping. This shows up a clear deficiency in most current high-quality record-playing systems, in which no arm damping is used. Equations are furnished to enable further analysis in any specific case.
Author: Lipshitz, Stanley P.
Affiliation: Department of Applied Mathematics, University of Waterloo, Waterloo, Ont., Canada N2L 3GI
JAES Volume 26 Issue 1/2 pp. 20-35; February 1978
Publication Date:February 1, 1978
Permalink: AES E-Library Impulse Response of the Pickup Arm-Cartridge System
A link to the follow-up paper is here:
Permalink
AES E-Library
Comments on -Impulse Response of the Pickup Arm-Cartridge System- and Author's Reply
Authors: Rabinow, Jacob; Lipshitz, Stanley P.
JAES Volume 26 Issue 10 pp. 772, 774, 776, 778; October 1978 Permalink
Publication Date:October 1, 1978
I am not pushing the Shure brand name, but around that time I did buy a Shure Type 4 and also designed and built my own silicone damped unipivot arm geared toward achieving the 25%/75% ratio of damping and found the results of that combination were, and continue to be, astounding. It is important to understand that the brush damper is not as simple as an extra shot of resistive damping into the system. It helps with the damping function all right, but a major concurrent benefit of the brush damper is that it takes ½ gram’s worth of workload off the stylus suspension’s shoulders in having to do its job of shoving the cartridge up over record warps, and the added ½ gram that you dialed into the VTF helps shove the cartridge back down on the tail side of the warp.
Back to the OP, I think viewing the damping location as an ‘either/or’ debate is an over-simplification of the problem. I have found that it needs to be done at BOTH ends in order to get maximum benefit. The Townsend approach with the oil bath includes damping at the cartridge end, but doesn’t shunt/bypass the warp induced dynamic forces around the stylus suspension. The DiskTraker outrigger air-piston approach helps unload some of the dynamic forces off the stylus suspension, but air would not seem to be as effective a damping medium as silicone or an oil bath. I’ve thought about adding a glob of silicone to the hinge of a Stanton/Pickering sylus/brush assembly, but I’ve been putting that off as a retirement project [stay tuned, later this year!]. It would be really great if, say, Jico would offer the brush damper that they include with their several Shure replacement styli as an aftermarket outrigger attachment that could be retrofit to any standard ½” mount cartridge.
The effects of stylus scrubbing along the groove are essentially the same as flutter in a tape deck, and would be predominantly FM.
Thanks billshurv. We can have damping at both the ends. Cartridge can be damped by simple method and we can have puddle etc. at pivot end. Another thing I would like to know is for a given cartridge rest being the same which cartridge have more resonance and vibration ? The high compliance or low compliance ? High compliance stylus would have little upperside resonance and vibrations in frequency range. Right ? A light weight high damping property compound would be great for cartridge. We can design a composite layer damping which serve as headshell too.
Regards
Regards
The Cartridgeman Isolator is another clever idea:The Cartridge Man Isolator
And it's not hard to DIY a clone.
And it's not hard to DIY a clone.
That looks like nice headshell Joshua. Can not comment without listening but I guess at cartridge point too much damping may not be good. A little less than moderate level damping would be good so as it does not affect main audio band. Cantilever suspension is also good at damping. Thats why I guess high compliance cartridge may be good with regard to damping at LF levels.
Regards.
Regards.
@diyrayk: Thank you for the links, that is some superb reference material for us to work with on this. I will have a read and digest of that. I hadn't seen that 25/75 reference before and the only mention of front and rear damping I had seen was in some subjective review that claimed it robbed the music of life. Since then I have interpreted descriptions of 'sterile' or 'clinical' to mean accurate!
@jls001: I threw all my old HFN/RR away when I no longer had anywhere to keep them, but there was an article in one of those where a certain Jean-pierre Farkas suggested that you should isolate the cartridge from the headshell with bubble wrap. I was never brave enough to try it
@jls001: I threw all my old HFN/RR away when I no longer had anywhere to keep them, but there was an article in one of those where a certain Jean-pierre Farkas suggested that you should isolate the cartridge from the headshell with bubble wrap. I was never brave enough to try it
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