Constrained Layer Damping, anyone?

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TheChairGuy

Constrained Layer Damping, anyone?
« on: 11 Feb 2008, 08:18 pm »
A couple folks have told me how beneficial the Marigo 'magic' dots are for treating tonearm resonances.....but at $50 for what amounts to several different thickness constrained layer dots (likely made from EAR Isodamp) I've always passed on the option.

The last two tonearms were fluid damped (homebrew for one, and internally oil damped both vertically and horizontally in the other).  Fluid damping, among other matters, damps resonances before they reach your amplification gear - providing a cleaner presentation.  Providing it is not overdamped, it improves TT sonics substantially.  Any of you with a Technics SL-1200 and bought a KAB damper trough know this well enough  :thumb:

While built to very high standards, the Origin Live Illustrious tonearm I have is not fluid damped.  The sound has been on par with or slightly worse (overall) than the JVC QL-F6 with internally damped arm  :o  It's been better in some ways, but it's not as exacting - most notably in the midrange and treble for me. 

Having an extra piece of constrained layer damping sheet around (from Parts Express) yesterday I cut out 5 of my own magic dots (using a hole puncher) and delicately placed them on the Origin Live armboard and pillar assembly (I can't bring myself to apply these gooey gobs to the tonearm itself).  The idea is to 'wick' away the excess energy/vibrations/resonance before it travels down into my pre/amp/speakers. 

WOW - does it ever work well in this regard.  It's much cleaner now with tighter (and still substantial - telling me it's not overdamped) bass.

I think TheCartridgeMan's Isolator is rediculously overpriced at $150 for what amounts to a 3M damping square and some mounting bolts/nuts and I could probably DIY one real nice (they are 15 mils thick), but it'll take time to do right (aligning the mounting holes perfectly is critical). So, I may buy one and see what all the fuss is about.

I use a thin wedge of Plast-i-Clay and paper (business card stock) between my cartridge and headshell now...but this might be adding too much weight to my medium mass arm now...it seemed to work better with the slightly lighter JVC arm). 

The idea of the Isolator is to damp any resonances well before it even enters the tonearm assembly (and damps the cartridge body itself).  As one who has experienced the wonder of the Townshend Rock turntable, and it's oddball fluid damping trough at the end of the tonearm, I think it might make for sonic bliss  :violin:

As much as I dislike enriching that robber-baron Len Gregory...I think he might've come up with a doozy neat idea there  :thumb:

Brad

Re: Constrained Layer Damping, anyone?
« Reply #1 on: 11 Feb 2008, 08:32 pm »
Nice post,

I just remembered I had a sheet of Dynamat left from my car stereo install. :duh:
You've convinced me to give some small pieces a try on various places on the Empire, probably starting on the armboard.  8)

BobM

Re: Constrained Layer Damping, anyone?
« Reply #2 on: 11 Feb 2008, 08:56 pm »
Try cutting out a small rectangle of the EAR Isodamp (the thin version) and put that between cartridge and headshell. Just like below:

Enjoy,
Bob


TheChairGuy

Re: Constrained Layer Damping, anyone?
« Reply #3 on: 11 Feb 2008, 08:58 pm »
Nice post,

I just remembered I had a sheet of Dynamat left from my car stereo install. :duh:
You've convinced me to give some small pieces a try on various places on the Empire, probably starting on the armboard.  8)

Yeah Brad - do the armboard first then work up the nerve to treat the tonearm  :thumb:  That's how it is with me.  It's a very nice sonic treat this stuff.

I don't think you can overdamp the armboard....but probably can quite easily the tonearm itself if you are not judicious in the use of the constrained layer sheets or dots.  The dots look purdier then squares or rectangles.

John

bacobits1

Re: Constrained Layer Damping, anyone?
« Reply #4 on: 12 Feb 2008, 02:11 am »
How's about a bit of Herbie's "grung buster" material?
It's thin enough, I'll have to try it.

Den

TheChairGuy

Re: Constrained Layer Damping, anyone?
« Reply #5 on: 12 Feb 2008, 05:18 am »
How's about a bit of Herbie's "grung buster" material?
It's thin enough, I'll have to try it.

Den

Tried that one, Den - on my ADC TRX-1....didn't find any material difference using it.  It's also so thin that unless the cartridge has a perfectly flat top and your headshell is not perforated.....it won't be sticking/damping to much of either.

Anyhow, try it and see for yourself.....I'm no expert.

Not sure if I'm gonna' buy that $150 CartridgeMan Isolator.  I don't doubt it works.....I would just doubt my (remaining bit of) sanity for shelling out $150.00 for $3 in materials and 20 minutes of someone's time to drill holes and install set screws  :roll:

John

Zero One

  • Jr. Member
  • Posts: 50
Re: Constrained Layer Damping, anyone?
« Reply #6 on: 13 Feb 2008, 04:20 am »
Well I am 100% sure the isolator works, but you can diy one simply enough, ranging from just some double sided foam tape and carfully aligning the cart with no screws at all. This works a treat and I have one cart set up like this.  The alternative is to actually make a pair of thin alloy plates with the foam in the middle and screw attached to the top plate.  This is what I have done here on my home made/modded waveclone cart.   http://homepage.mac.com/braddles/PhotoAlbum9.html    see pics towards the bottom. 

Overall clarity is improved but the best benefit is the far lower surface noise.

It works beautifully, but a bit of a fiddle.  The thought of paying $150 for an isolator.........way too much.

Cheers
Zero One

TheChairGuy

Re: Constrained Layer Damping, anyone?
« Reply #7 on: 13 Feb 2008, 04:39 am »
Hey ZO - long time, friend!  :thumb:

Not sure about using foam - doesn't seem like it would damp enough.  It may only be the slight de-coupling that is of benefit to your modded cartridges.

Technical paper from E.A.R. people (the folks that bring you Isodamp constrained layer damping):

http://www.earsc.com/HOME/engineering/TechnicalWhitePapers/Vibration/index.asp?SID=61

The thought of spending $150 for a 1" square does tend to me me wretch/lurch...but CartridgeMan may have come up with a doozy this time.

John

Scott F.

Re: Constrained Layer Damping, anyone?
« Reply #8 on: 13 Feb 2008, 05:14 am »
I hate to jump in here but John, you should know as well as anybody the $150 bucks you keep ripping on is really 85 euro (the price on his website). That fact that the dollar has tanked against European currencies only exacerbated the matter. Now, when you look at that 85 euro, that is about 1 hour of labor (lets say at 50 euro/hr) plus material (even though a very minor amount, granted) and some mark up. Now, take into account that the Cartridge man has to invest in having the die made to stamp the Isolator out. Unlike your hand carts that are manufactured by the thousands per week, the Cartridge man likely hand makes these by the tens at his facility since the demand is low.

Regarding your comments about the double sided foam tape, don't forget that if you DIY as you suggest, you are reusing the mounting screws and nuts. In doing so, you have just created a path for the vibrations transmitted by your cartridge to migrate back into the tonearm rendering the tweak far less effective. The only way to truly isolate the cart is the double sided foam tape (maybe in several layers) or the Cartridge mans isolator.

Regarding the foam tape, it might work. I doubt seriously you would ever get the cartridge aligned properly. Forget the fact that there is the possibility of the cart sitting cockeyed in the vertical axis because the cheap foam compresses and permanently deforms when you cut it (all foam is not created equal). When you consider the Isolator at least allows simple alignment of the cartridge (you have mounting screws on top for this adjustment), Len may not be quite the 'robber baron' you paint him to be.

Just because you are a cheap sod doesn't make him a thief, especially after you factor the cost of money.

TheChairGuy

Re: Constrained Layer Damping, anyone?
« Reply #9 on: 13 Feb 2008, 06:25 am »
Yo Scott  8)

Re-read my (first) post again...or I'll outline the pertinent lines here (I underlined key points of it):

Quote from: TheChairGuy
I think TheCartridgeMan's Isolator is rediculously overpriced at $150 for what amounts to a 3M damping square and some mounting bolts/nuts and I could probably DIY one real nice (they are 15 mils thick), but it'll take time to do right (aligning the mounting holes perfectly is critical). So, I may buy one and see what all the fuss is about.

I use a thin wedge of Plast-i-Clay and paper (business card stock) between my cartridge and headshell now...but this might be adding too much weight to my medium mass arm now...it seemed to work better with the slightly lighter JVC arm).

The idea of the Isolator is to damp any resonances well before it even enters the tonearm assembly (and damps the cartridge body itself).  As one who has experienced the wonder of the Townshend Rock turntable, and it's oddball fluid damping trough at the end of the tonearm, I think it might make for sonic bliss.

As much as I dislike enriching that robber-baron Len Gregory...I think he might've come up with a doozy neat idea there   :thumb:

It is hideously expensive, the cost is 85 British Pounds (actually more like 76 when you remove VAT) and that equals $150-$170 to us in the US and that it's a small market overall for this kinda' thing.  It is still hideously expensive for what it is.

Nonetheless, as mentioned above, I think it's ingenious and not easily duplicated.  I even called Bill Feil (Audiofeil, the CartridgeMan's distributor in the US) to discuss the product today and might even purchase one soon.

I think the idea of a modded Grado is great too...the Music Maker III is also outrageously expensive, but it probably nonetheless wonderful to hear.  I give the guy major props for resourcefulness - as I would any successful businessperson.

The foam tape was brought up be Zero One, not I  :)

Len Gregory is a robber baron....but one that has chosen his products very carefully and thoughtfully. I don't believe the many reports that he winds 100's of feet of coils by hand to reach a 4mv output either....a machine must do it and that machine is 99% likely located in Brooklyn, New York and not the UK  :icon_lol:

I'm a cheap sot...ummm, maybe/could be, but I know when it's time to pay up for performance I cannot achieve on my own feeble DIY knowledge 8)

Ciao, John


Zero One

  • Jr. Member
  • Posts: 50
Re: Constrained Layer Damping, anyone?
« Reply #10 on: 14 Feb 2008, 11:06 am »
Greetings Chair Guy

Since my last posts I have done many things in terms of mods to TTs and other bits, I really must get around to updating a bit on these, for now though just a couple of comments on the foam.

When I looked at the issue I examined several different types of materials, for example the mounting tape used for car trim, neoprene with tape on both sides etc. The thing that worried me about many was they had too much movement in the horizontal plane and I felt they would degrade bass performance, I feel the isolator works by damping vertical movement, which to my mind is why it cuts down surface noise. Looking at the cartridge man isolator I just can't help but feel it is too thick, and it must cause some VTA issues as well for most carts.

The foam I felt was a good compromise and I tried it on a few carts, in all cases the change was quite profound, with no damage to bass at all.  In the end it would cost almost nothing to try and it might just prove to be a winner for you, not much too lose except a bit of time and perhaps 2 cents.

In the cart on the linked page I have no problem with location as the foam is between two plates with normal bolts on the top plate so I just adjust as per normal, note that the top plate and bolts are completely isolated from the bottom plate.  Its times like these I wish I had taken more construction pics.

The foams damping can be softened (as I did) by pricking the foam all over with a pin, this breaks the closed cell construction up a bit.

Locating the cart on foam without plates etc is tricky but not impossible, it will locate level in both horizontal planes, so long as the cart and headshell are flat surfaced.  It is surprising just how well it holds, I have one that mounted this way for about 9 months on a turntable I cart all over the countryside for my LP to Digital classes with not even the slightest movement. From memory I think I did this by mounting trimming the foam to exactly match the cart, I stuck it to the cart first.  Next I left the protective tape on the other side and spread a very thin layer of blutac on the top of the foam.  I then stuck the foam to the headshell and moved it around until all was lined up. Next using a scriber I marked an outline around the cart (this is hard as the cart could be moved if I bumped it).  Finally I removed the cart, peeled of the backing tape and lightly positioned it, then nudged it into place and pressed down firmly....job done.  This is worth a try just to see if it helps. Ultimately it is probably not a perfect alignment method but it is not bad either.

It should be possible  to make a type of damper that is constructed from layers of different materials, this may in fact work better as each material would likely damp a different freqs and act more as a barrier in each direction, I image you could use say, very thin neoprene, cork and foam. Overall I feel this whole isolation, cart mounting and longhorn tweaks area could be one of the most fruitful of all analogue modding areas as we are dealing with the source not something down the chain.

TheChairGuy

Re: Constrained Layer Damping, anyone?
« Reply #11 on: 1 Mar 2008, 01:20 am »
Holy crap  :o - I just received the EAR constrained layer damping pads from Michael Percy.

I had already cut my own magic dots from damping pads purchased long ago from Parts Express and noted some benefit when places on my armboard.  Slight, but helpful. About 12 total on there.

I cut only 5 of the EAR SD40 stuff up (it's their thinnest and lightest pad).

It is an amazing difference.

I listened with three added to the twelve and there was betterment.  Feedback rejection was a lot better - I could wrap on the top of the Technics before and heard a dull thud thru the speakers.  Now, almost nothing.

Adding the two more dots and wrapping the top of the deck yields almost no notable thump at the speakers now...until it is turned up far louder than I typically play it.  However, it's sullen now...it's overdamped.

12 dots from Parts Express did little, the first 3 EAR dots were helpful...and now it's overdamped.  It's amazing stuff this EAR stuff.

Critical damping may be critically important to phono playback...getting is juuuuuust right is a bugger  :roll:

More experiments to come.....

John

TheChairGuy

Re: Constrained Layer Damping, anyone?
« Reply #12 on: 1 Mar 2008, 02:26 am »
2nd Experiment

This stuff so easy to work with, that in 15 minutes I was able to cut a rectangular wad...and affix between the cartridge body and headshell.  I used the top of the line stuff from EAR, the ISODAMP SD125 (which is 1/8" thick, or 5-6mm, or about the same depth as the CartridgeMan's Isolator  aa).

Momma Mia and gadzooks - this stuff really works. 

It replaced a wad of Plast-i-Clay I've used to good measure in the past, so it is a bit lighter overall....I think I had too much weight on the arm for the Grado (it's a medium mass arm to begin with).  So, that might be part of the benefit - lighter weight more suited to the Grado.

I doubt it is the total benefit, however.

On my Fleetwood Mac 'Future Games' album, an early 70's recording before they became boffo popular, it sounds fantastic overall.  The recording is okay - it's a bit of a muddy analog recording / not exactly live sounding and not quite good enough to accurately portray anything in the studio during the taping, it sounds altogether better now using the EAR pad in there.

It now almost sounds as it it morphed into a 200gram, pristine copy recorded from the original analog master instead of what it likely is, a poor copy of a 3rd generation master  :o

Ambience is enhanced now, bass is notably tighter, lower volumes sound fuller, treble and midrange sound a bit more pure, perhaps I hear a little less noise overall, and feedback rejection is even more enhanced.  I'm not sure how much better CartridgeMan's Isolator may be or may not be, but it may well be worth $150 if it's better than this.

I suspect my sliver of EAR ISODAMP SD125 costs maybe $0.30 + my time (2 minutes) is more cost effective way to improve vinyl performance  :thumb:

Allright Scott F - yes, I can be a cheap sot  :wink:
« Last Edit: 1 Mar 2008, 10:36 am by TheChairGuy »

Scott F.

Re: Constrained Layer Damping, anyone?
« Reply #13 on: 1 Mar 2008, 04:35 pm »
Allright Scott F - yes, I can be a cheap sot  :wink:

 :lol:

John,

I've no doubt at all that your and Zero's tweaks are pretty effective. What Zero is doing comes quite a bit closer to the intent of The Cartridge Mans design since he isn't using the mounting screws for the headshell (he's using double sided tape to hold the cart in place). As he mentioned, his alignment is close but probably not dialed in like it could be like it is on the Isolator.

Zero seems to be getting the full benefit of decoupling the headshell from the arm. I can imagine that it makes one heck of an improvement. Same goes with yours. You are getting some reasonable benefits as you heard but that last step of total decoupling (eliminating the cartridge mounting screws and ability to properly align the cart) will allude you until you figure out a way to replicate the bottom (cartridge) side of your DIY isolator in a similar fashion to the Isolator.

I've got not doubt that you are seeing 50% or better of the benefits of the Isolator going the DIY route. It's seems to be that last 5 or 10 percent that gets in the way. Machining tolerances, proper tools of manufacture, availability of non-commercial materials to test and play with, those types of things will be the ultimate differences between yours and TCM's commercial version. Then the question becomes, is it worth the money TCM charges not to have to mess with a DIY solution. Don't forget, the devaluation of the dollar inflates the cost of his product for those of us on this side of the pond.


TheChairGuy

Re: Constrained Layer Damping, anyone?
« Reply #14 on: 3 Mar 2008, 06:41 am »
So, I kept playing with the other EAR stuff I bought today.

I have been using a Herbie's Way Excellent Mat as a top mat, and an old Audioquest sorbothane mat under that to damp the record platter - a critically important thing in any set-up, but vastly more important in DD decks.  Their motor is coupled directly to that platter - all the better for speed control - and all the worse for energy transfer, noise and degraded sonics.

I know from previously studying it that sorbothane is effective damping agent....but mostly works in a narrow range of frequencies only.  The proprietary EAR Isodamp stuff works in a far wider frequency range.

Shit - howdy it works.  Using the AQ mat as my template, I cut a round piece of the 0.625" thick Isodamp and laid it on the platter. Before the first cut, riding in the outer groove only, I knew there was less nise from the record.  3 seconds later - the music bloomed from the inky blackness with a little finer resolution throughout the audio band.

Feedback rejection was enhanced, as well.  A good doink on the top deck during high level playback was better damped than ever.

So, try some Isodamp (0.125") wedge between your cartridge body and headshell and make a 12 x 12" round submat for your deck with the 0.625" thick Isodamp (or you can use thicker for even more benefit if you have adjustable VTA...I do not on my JVC that I'm using right now)...the whole thing will set you back less than $35 with shipping from Michael Percy (and you'll have lots left) and experience a significant betterment for your playback.

Some serious stuff from EAR  :thumb:

John