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  3. 161137-245

TONEARM DAMPING : DAMPED OR NOT ? ? USELESS ? ? WELCOMED ? ?

Dear friends: This tonearm critical subject sometimes can be controversial for say the least. Some audiophiles swear for non damped tonearms as the FR designs or SAEC or even the SME 3012 that is not very well damped in stock original status.

Some other audiophiles likes good damped tonearms.


In other thread a gentleman posted:


"  If a cartridge is properly matched to the tonearm damping is not required. " and even explained all what we know about the ideal resonance frequency range between tonearm and cartridge ( 8hz to 12hz. ). He refered to this when said: " properly matched to the tonearm ".


In that same thread that a Triplanar tonearm owner posted:


" This is the one thing about the Triplanar that I don't like. I never use the damping trough...... I imagine someone might have a use for it; I removed the troughs on my Triplanars; its nice to imagine that it sounds better for doing so. "


At the other side here it's a very well damped tonearm:


https://audiotraveler.wordpress.com/tag/townshend/


Now, after the LP is in the spining TT platter ( everything the same, including well matched cartridge/tonearm.  ) the must critical issue is what happens once the cartridge stylus tip hits/track the LP grooves modulations.

The ideal is that those groove modulations can pass to the cartridge motor with out any additional kind of developed resonances/vibrations and that the transducer makes its job mantaining the delicated and sensible signal integrity that comes in those recorded groove modulations.

 That is the ideal and could be utopic because all over the process/trip of the cartridge signal between the stylus tip ride and the output at the tonearm cable the signal suffers degradation (  resonances/vibrations/feedback ) mainly developed through all that " long trip " .


So, DAMPING IS NEED IT AT THE TONEARM/HEADSHELL SIDE OR NOT?


I'm trying to find out the " true " about and not looking if what we like it or not like it is rigth or not but what should be about and why of that " should be ".


I invite all of you analog lovers audiophiles to share your points of view in this critical analog audio subject. WHAT DO YOU THINK ABOUT?


Thank's in advance.



Regards and enjoy the MUSIC NOT DISTORTIONS,
R.






rauliruegas

Showing 6 responses by antinn

antinn
435 posts
 
@rauliruegas,

You and @lewm have it right - every application is different.  Its more than the just the cartridge and its compliance.  There is a decent article on tonearms in this Audio Magazine https://worldradiohistory.com/Archive-All-Audio/Archive-Audio/80s/Audio-1980-06.pdf, and as stated in the magazine - all materials have some damping capacity - https://sites.utexas.edu/taleff/files/2019/10/jmatersci_v28n9y1993p2395.pdf.

The tonearm manufacture is literally between a rock and hard spot trying to design a tonearm for the multitude of table and cartridge designs that all together form a resonant system.  But, as has been stated, if your cartridge has the option for viscous damping then it may be worthwhile trying - but its success aside from table/cartridge could also be music type - maybe good with classical but not with vocals.  All the more reason for multiple arms and/or multiple tables LOL.

Just some thoughts.
antinn
435 posts
 
Here is another cartridge article from from the past (B&O cartridge designer) https://worldradiohistory.com/Archive-All-Audio/Archive-Audio/70s/Audio-1979-03.pdf.

A couple of items to grasp is the amount of pressure (1000's of psi)  that the stylus is developing, the elasticity of the record (its deforming) and the incredible torturous path the stylus is tracking in highly modulated grooves (i.e. the high frequency that gives the air/life to the music).   

Everything matters.  If the 'system' is over-damped, the stylus will not be able to vibrate or change vibration as quickly - for an electrical equivalent consider it slew-rate (uv/sec) - and the sound will be dead and lifeless.  Under-damp and stylus can go out of control and you get distortion and record damage.  Critically-damped (system dependent) and it sounds great.  Of course this is no easy task and @rauliruegas dissertation above and this very post and so many others like this are clear evidence.

I have recently been playing with record mats; a thin leather mat was doing OK, but the suede-side collected lint (visible with UV light) and eventually gave it back to the record. The thin (3mm) Technics rubber mat did not attract lint (must be nitrile rubber - near neutral triboelectric-scale), but was relatively soft (estimate about durometer-50) and sucked the life out of the music (VPI 2" AL platter). I am now testing a 3-layer material as a platter mat (not marketed as a platter mat) that is much stiffer (durometer 85) and the sound is great (and the material may solve static issues - will know more this winter).   So the platter mat can have a profound influence because it couples to the record which is not infinitely stiff.

So, everything matters - but unfortunately the devil is in the details; and in many ways that 'can' be the appeal of playing records.  There are an near infinite number of ways to achieve success (and of course an equivalent near infinite paths to frustration).  


antinn
435 posts
 
Dear @rauliruegas,

Thank-you for the forum references.  My choice of the word lifeless was more in haste then any proper assessment.  I found the softer rubber Technics mat to put a soft-focus on the music; the small intricate details were missing; essentially the system was now over-damped.  

Of the audio magazines - as you state, for sure Audio has/had the most technically founded (justified) papers.  

Otherwise - one more good paper http://www.laudioexperience.fr/wp-content/uploads/2017/04/Bruel-Kjaer-Audible-Effects-of-Mechanical-..., and this one is specific to measured  Audible Effects of Mechanical Resonances in Turntables and it is an interesting read.

Stay well
antinn
435 posts
 
Dear @rauliruegas,

FWIW - when I tried the Technics 3mm rubber plater mat, I stayed with it for a few months - I know it can take that long before I get over the newness factor and declare it good or otherwise. But, here is what happened - after a while I found myself listening to my digital sources more than my analog. Houston We have Problem. My analog source by design is suppose to be ’better’ than my digital source (I gave-up on investing any $$$ in digital). That’s how profound but subtle was the change. The new change in mat material (now ~4 weeks ago) has changed it back - analog is once again preferred. Like it not, the sub-conscious does have a vote. Who was it - Harry Pearson of the Absolute Sound - who said to the question - What is good sound? You will know it when you hear it.

Stay well,
antinn
435 posts
 
@rauliruegas,

I have both the VPI 10.5i/AL-tube (EL = 266mm) and the 12-3D /printed-tube (EL-313mm). By just a simple balance analysis, the 12-3D tonearm fwd of the pivot is 3X the weight (not effective mass) of the 10.5i tonearm fwd of its pivot. The 12-3D is over-damped and it plays fine and is generally well regarded, but the counterweight I have is a total of about 215-gms. So, at least by observation - I have to agree that you cannot over-damp the tonearm. I would venture to guess that so long as you can balance the tonearm, and the requisite bearing design will not impede motion, that over-damping similar to the 12-3D printed arm pretty much eliminates any sharply defined resonant frequency.

But, the fO.q tape is a piezo-electric damping tape that converts vibration into electricity - and the vendor states not to use on sensitive electrical components. I would think the very minute electrical signal carried by the tonearm wires would make use of the fO.q tape inappropriate for a tonearm.  Also, from military application experience,  there is a science to damping a tube with externally applied damping material. 

Otherwise, for tracking a lot has to be associated with the tonearm length/bearing design - single-pivot, gimble, knife edge, magnetic and all variations thereof. Add to this the cartridge stylus-shape, and cantilever/suspension ’system’ and the benefit of silicone damping has to be variable. There are just too many variables.

Neil
antinn
435 posts
 
@rauliruegas, et.al, 

Per your request from PM, attached is the link to the Audio March 1981 magazine with the article on VTA/SRA and the effects of both.  https://worldradiohistory.com/Archive-All-Audio/Archive-Audio/80s/Audio-1981-03.pdf.  While the results are now widely accepted that Shibata and similar contact line shapes are very sensitive to SRA, this other article pivot vs tangential in Audio magazine June 1982 https://worldradiohistory.com/Archive-All-Audio/Archive-Audio/80s/Audio-1982-06.pdf highlights an associated problem.  The tonearm resonance can cause large changes in VTF which then alters SRA. The Audio 1982 article addresses  "There are two practical ways to stabilize the cantilever deflection'  One is tonearm damping, the other is to reduce the effective mass of the tonearm/cartridge system to change the resonant frequency.  We are now some 40 yrs past when these articles were written, and better materials and manufacturing processes offer a wider range of solutions, but the root of the problem(s) are the same (thankfully, it does not appear that we have created any new one; at least not yet).  Also note that static on the record can also change/increase the VTF, and could cause similar distortion.  
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