Dear Dover, I have no problem at all to admit that I was wrong. Anyway if math. is involved I usualy skip the whole subject matter. And I just started to like you. How about 'Fourier analysis' as a separate-separate thread?
Regards, |
Well then the answer to Lewm's question is yes - shape will affect resonance. You can mathematically model a proposed shape using fourier analysis, but the traditional method of measuring resonance is the use of accelerometers to measure the resonances induced by applying a frequency sweep to the item to be measured at multiple points. The pencil & ear test does not really do much here as I would surmise that it is checking the dampening behaviour at 1 frequency point only for the particular mass, size and shape of both the pencil and the sample material tested. The "sound" of the tap will vary with the positioning of the "tap" on an irregular structure as well. Of course if you add feet - 3 or 4 - then you have built a trampoline and the resonances induced will be quite different to no feet, or varying the location of the feet. The more complex the shape the more nodes there will be that need to be factored into the calculations. A concave plinth will have more nodes and the maths will be more complex than a flat plinth for example.
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Dear Dover,It is an old tradition to try to nail subject matters with categories or classifications. Those however are verbal and belong as such to language. The other part is called 'reference' while the aim is to point to the so called 'reality'. We need both to discovere the truth. Well the reality is that among others our Lew is unbelievable eloquent and even more inquisitive. Why should he split his curiosity in different threads? I enjoy reading his post and prefer the same place or thread to find them. I am sure some other members will agree with me but, of course, not everyone. Those however can chose among many other threads to satisfy their 'categorical needs'.
Regards, |
Hi Don, LOL the one I didn't like came from TTNeedles. The good one came from LpGear. I suspect they were from the same mfg. They looked identical. I doubt if Jico makes them exclusively for others, while they don't sell them themselves. Who knows?
If you check the bottom of the cart of the 120/440 series, against the 3400 (95, CA) series, you'll see that the cantilever angle is a little different. If you have 2 respective plugs with stylus and compare them, it's easy to see. An alum cantilever can be bent down slightly to work in the 95 plug, but beryllium and boron tend to break. Isn't the 152LP beryllium? If so, I hope you have better luck than I had. Maybe I'm just getting too old, but I broke a beryllium and a boron trying to transplant from a 120 series to a 95 plug. One of them was an irreplaceable 152MLP. Such is life. Regards, |
Mainly for Raul, My friend....I propose that you need to do ABA type of evaluation for those fuses or any other audio comparison.... along with putting some time in between like live with it for a month then go back to your original fuses or what have you... and redo your evaluation...also your music selection is bogus thats a studio recording! WTF?!
Raul my friend you seem to want to get to audio nirvana (like live music) but you have done no comparo testing as in ABA
I will say that i am sure i am much younger then you and have a better audio memory and hearing or at least we maybe on the same level but my point is... irrational quick decision making is non productive...maybe if you like to play with your audio components and get yourself off....... but IMO you will never get anywhere.....
my reasons for saying this is depending on the time of year time of day your mood etc....you need to average it out in a much longer evaluation
now i Know there is no absolutes in audio but personally if I am going to spend time and read your postings please write something worth reading...IMO your getting audio goofy on me...
and for Christ sakes get some good non molested live music for your comparisons patrica barber?! Really!!!
Lawrence Musical Arts |
Lewm - you should probably start with another thread on plinth shape. If you are embarking on a new plinth you should really start with a comprehensive project definition listing your requirements. What are you trying to achieve, what are the deliverables. For example the plinth requirement for a vintage idler, which has more shake rattle and roll than Elvis' hips, in my mind would be vastly different than for say a Direct Drive turntable, most of which the motors are mounted in a resonant pudding bowl. The resonances generated by each drive system would be quite different. Do you want a dead plinth ? Do you want a plinth that deals with the vibration & resonance of your particular TT motor drive ? These could yield radically different results depending on your goals. What arm and cartridge are you going to use ? What are their resonant characteristics and grounding requirements ? Does the intended tonearm use dampening or does it require energy to to dealt with by the plinth ? What are you going to place your TT on ? Wall shelf ? Stand ? What type of stand ? What materials ? Even if we assume Richards solution is nigh on perfect, the resultant structure will still have fundamental resonances and at some point at least one will be increased in amplitude relative to the initial impact. But what would your fundamental resonant peak requirement be ? Assuming it is in the musical bandwidth - then where ? What is going to do the least damage to the music ? Most of the plinths built are tone controls, a cacophany of complementary colorations that 'sounds better because I spent so many months & $ building it' it IS better. Did you strip off the wood from the slate to check what had been traded off for the gains you heard ? As I said above start by writing down a list of your requirements, then let's debate that, before we start on materials & shape. You might like to engage your local university or technical college, where with Fourier Analysis software quite commonly available you might find a student interested in taking up your question and doing some modelling for you. Ideally they may have measuring gear that can determine the resonances inherent in the TT drive system to start with.
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Lew, while I can't offer any commentary re how the shape of a material might affect it's sound (resonance characteristics) in a turntable plinth application, I can tell you that the shape of the material is an important consideration for musical instrument makers. I see no reason why some of the same principles would not apply. I am not talking about the shape of, for instance, the bore of wind instruments or the shape of the resonating cavity of string instruments. In those examples we have a case of a vibrating column of air and it is much easier to understand (and is well documented) how altering the shape of the cavity created by same materials of the same mass would affect it's resonance. Take the case of a clarinet barrel. The clarinet barrel is the small piece of tubing that is found between the mouthpiece and the upper of the two main, and larger, parts of the clarinet. It is a kind of interface between the mouthpiece and the main body of the instrument and is most directly affected by the reed's vibrations. There are two design parameters that have the most profound effect on the response/sound of the barrel, the shape of the bore and the shape of the barrel itself. The impact of these two parameters in design choice are at least as significant as the choice of material. You can have a barrel that looks like this: http://backunmusical.com/product/fatboy-barrels/which has the exact bore taper and dimensions, and uses the exact amount of material as one that looks like this: http://backunmusical.com/product/moba-barrels/and they will each have entirely different response characteristics and sound. Barrels are typically constructed of various types of wood such as cocobolo, rosewood or grenadilla, hard rubber, plastic, or metal. It is surprising how small the differences in sound are between the different materials compared to the differences due to the shape used. I think that it is entirely plausible that the shape of a piece of metal or acrylic (homogenous) would have a significant effect on the way that it resonates due to externally (ambient) and internally (motor) caused vibrations in a plinth application. |
Dear Richard, Your research in the area of plinth design and construction dwarfs my own very limited experiences. It seems that I am doomed to be misunderstood here; I meant no slur on acrylic in my previous post. I only meant to say that it is not acrylic per se that I wonder about but merely what is the effect of shape, assuming a plinth made of any homogeneous material. Since acrylic lends itself to shaping perhaps better than most other commonly used materials (wood, slate, lead, granite, etc), and since Clearaudio in fact used acrylic, the discussion happens to center on the use of acrylic.
As to your other experience, I often wonder whether tapping on the plinth tells us anything at all about its goodness as a plinth. But I have very firmly come to think, like you, that combining two or more materials in layers, so as to affect CLD, is the way to go. I was very happy with my all-slate plinths for a long time until I had a carpenter make me a baltic birch and cherry base for my Mk3 slate plinth. I then affixed the wood base firmly to the bottom of the slate, using 5 or 6 large diameter bolts threaded into inserts that I epoxy'd into the bottom of the slate, after drilling holes for the inserts. I then bolted the Mk3 chassis thru both layers, using very long metric screws (the total plinth is now nearly 6 inches thick). The result is a huge improvement vs slate alone, in terms of total "neutrality" (the holy grail). (Using also Albert's idea of the bolt that engages the bottom of the bearing housing so to transmit vibrational energy to a large brass block mounted below the chassis. Albert uses brass bolt/iron block. I use brass with brass.)
As to what materials sound good, I only know that MDF sucks. |
Hi Fleib, Your comments are one of the underlying reasons I bought mine from TurntableNeedles.com. Their add states Jico manufactured. Actually never had a problem with either suppliers but truth in advertising being what it is, well, stated Jico, I went with them. I had taken notes from some of your statements pertaining to this transplant and did have on my list a ATN7V. Now that I have done this opperation, I just might do a 152LP that I have lying around next. Maybe my 440MLa (also not being used). This just might be fun. You are one of the people I must thank for leading the way in this transplant. Thank You! Regards, Don |
Regards Griffithds, I was reading a thread on Karma and someone asked LpGear/tunes if their Vivid line replacement stylus was made by Jico. Their reply was, it is not. These ATN95 styli also do not appear on Jico's site. There was some conjecture about the identity of the maker(s), but no conclusion. Of the available styli suitable for replacement or transplant, the ATN7V is quite good. Cu is nearly identical and nude .2 x .7 elliptical performs well, good detail if not as sweet as the shibata. Quality control on the replacements isn't perfect. Of the 2 examples of shibata I bought, one was better. I suspect you got a good one. Regards,
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Lewm . My two cents worth. I have been building TTs for over 30 years now. Some have been disastrous and some ok and only a few were good Plinth materials have been. Slate, concrete, aluminum, MDF, hardboard and finally acrylic using lead in a CLD laminate. Both acrylic and lead get bad press. This is in my view not justified provided they are applied correctly. If you bond acrylic to lead with a hard exoxy glue the resultant laminate has most interesting properties. One test I conducted during my research into plinth materials was to tap the plinth with a pencil and listen to the plate with a stethoscope. All of the materials were glued to lead and then subject to this test. The concrete slate and aluminum still rang slightly. The MDF and Hardboard gave a slurred sound indicating a smearing effect. The acrylic gave a short, sharp and loud tic. It took me some time to appreciate what this meant. The conclusion is that there is minimal storage of energy " short, sharp" and that it conducts this energy quickly " loud tic" The trick is to glue with a hard epoxy. I adjusted the Hardner ratio to get a material that was the same hardness as acrylic. In this way the acrylic is effectively fused to the lead. Lossy, soft glues were disastrous. Listening tests were conducted in a search for the material that gave the maximum difference between LPs. Since each LP sounds different, by definition, greater audibility of these differences implies less coloration of the TT itself. The second and probably most important test was to listen for a connection to the music. Did I connect with the musicians, how did it make me feel. Again Acrylic lead scored the highest by these two metrics
I have not tried panzerholst but can report that Albert Porter gets excellent results with his highly engineered plinths.
Regarding material shape, I have no scientific input on that interesting question. The triangular shape chosen was to facilitate the three feet whilst almost eliminating any part of the plinth from being cantilevered outside of these feet. This approach seemed to be logical. That said it may be wrong regarding resonance control. I also find it pleasing on the eye. An agreeable byproduct. |
Regards, In_Shore: I've a JVC TT-71 deck on the back burner, have been giving consideration to matching it up with a MS-505(S) TA which gets good ratings from several trustworthy A'goners. Also have a spare EPA-B500 (base) with choice of either the curved 250 or straight 500H wands. Should you have Panzerholst remnants available this spring, please give me a reminder. The Pioneer PL-70L-11 http://audio-database.com/PIONEER-EXCLUSIVE/player/pl-70lii-e.html is in excellent condition. Have both straight & curved pipes, a treat to both eye & ear. Best wishes for the new year & Peace, |
How about we start the New Year off with a horror story with a happy ending! Of the 2 Virtuoso's that I own, the Black with the Sound Smith's cantilever/stylus is the one kept in rotation. The original Red Wood with factory stylus/cantilever has been occupying shelf storage space. I discovered early on that its stylus guard also fits the Signet TK10 MKII cartridge in which I bought guard less. The TK10 also is kept in rotation so I have been storing the Red Wood guard less. Well a couple of months ago, while fumbling around looking for something on the shelf (wearing a sweater), somehow the bare stylus caught on my sweater sleeve and was flung across the room, bouncing off the far wall. After staring in disbelief, the only word that came to mind was S**T. I should of ordered a spare guard. Well, a few weeks ago, when my wife asked me what I wanted for Christmas, my quick reply was a Jico/Shibata stylus. After explaining to her what the hell I was talking about, one got ordered. To make this long story somewhat shorter, it has been received and the necessary trimming of the stylus housing has been accomplished and said stylus/plug installed. Well, upon first listen, I was not impressed. Thin, bass shy presentation. I tore everything down and reinstall/adjusted everything, No change. My first thought was surely Clear Audio didn't voice this cartridge to work only with the cheap ($33 at LPtunes), AT 95e stylus ! Perhaps, letting it run in for a few hours might change things. High hopes I did not have. Well, it didn't take a few hours, but only a few sides of record playing. I've never had a cartridge change so dramatically. Day/Night difference. It will be a few days before I get to compare it to my other Wood (the Sound Smith version). I can say that I am impressed with the added midrange clarity that is now quite noticeable. The Jico was money well spent, but not an operation for the faint of heart. I had considered transplanting the cheap AT95e for practice, but if "smart" was something I practiced, I would have bought a stylus guard many months ago. Thanks to all that brought this stylus/plug transplant to our attention. Fun exercise. Updates to follow. Regards, Don |
Hello Timeltel, i think Kentucky and area got blasted with snow weeks before we did here in Canada, well where I am anyway. Regarding plinth material I helped out on a few projects the most recent were two VPI tables, one a TNT 4 and a Superscoutmaster both belt drive. The factory plinths and feet were discarded and replaced with two layers of 30 mm thick B25 Panzerholz laminated together in combination with Newplast plasticine as damping test done on that stuff on Audioqualia site. This elevated the performance of these tables according to the owners especially notable was the superscout master which may erk me to find a used one to modify, but I have to directly compare to my tables before committing, this winter.
So one alternative material that is high lighted on Audioqualia site. I don't know what type of panzerholz Albert Porter uses for his plinths but he was willing to spend 10 times the amount for this alternative material after experimenting with other material. Timeltel this spring I will have some more b25 panzerholz if your interested in installing your Pioneer dd table and arm in some.
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I would never do a plinth in acrylic. The genesis of my interest in this arcane subject is that Clearaudio once made the claim that their pure acrylic plinth had favorable resonance characteristics (the definition of which could be almost anything any audiophile wants it to be), because of its piano-like shape per se. And, as I noted, they have since abandoned this selling point entirely in that their most recent generation plinths are in essence rectangular and use materials of several different types in order to achieve CLD. I always wondered whether their earlier claim for their pure acrylic plinth had any merit. It does seem to me that a highly irregular 3D shaped object made of a single pure material might (or might not) ameliorate resonant peaks just due to shape, but I know of no theory that treats this subject. |
Regards, Lew: Western Ky. Sometime today I'll clear the 6' drifts from the driveway & re-engage with civilization. Meanwhile music has been good. Have been watching the gauges, beginning to *imagine* an association between humidity & level of (this) listener's involvement. Congratulations to you & Mrs. M on your anniversary. :) The majority of information concerning resonance (that I've found) is largely oriented to the realm of either physics or architecture resulting in analogies rather than conclusions. If considering acrylic, a couple of DIY plinths illustrating application: http://www.audiokarma.org/forums/showthread.php?t=405770: Peace, |
Timel, Where are you located? Indiana? We had snow this morning and then torrential cold rain ever since. Yuk. But my wife and I just went out and had a fabulous French dinner in Georgetown to celebrate our anniversary. Hooray for us.
The pages you cite do not address the issue of shape, except to say that panel thickness of a given material affects resonant frequency, inversely. But the assumption is that the shape is that of a homogeneously flat panel. Shape is what I am interested in. |
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I believe I have the honor of making post #9000. Ad aspera per astra. |
Dear friends: Speaking of our audio/music hobby and now that the 2012 is just at the end and looking for what happened about I can tell that with out doubt this one was and is my best audio year I can remember. Of course because I " walked " throught with the best persons I could that where all and each one of you. I learned a lot and enjoyed any single post in this thread and other threads from you Agoner's.
In the other side I never imagine when this 2012 started that I could ( trhotugh it. ) achieve the quality level performance that I'm enjoying in my audio system, I just can't even dream that this could and can happen because at the begin of this year the system performance level was IMHO really good and IMHO too nearest to the top as ever.
Right now, I enjoy the music at other level and today I know for sure that exist a lot more information in those grooves that what we normally think.
To appreciate that we only have to work in the whole audio system and I mean in each one and all the links that conforms the complex audio system chain with out forget the room/system relationship and with out forget that the live music is always an excellent reference point to any audio system evaluations.
I'm sure that the kind of experiences I had and have this year were and are similar of what you had and have too.
We have to be congratulated for that!!!°!°!!
Regards and enjoy the music, R. |
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Dear friends: Final stage/step on the SR20 fuses " film/picture ".
I changed the four ML fuses ( these ones in the internal power supply stages. ). To make this task I have to open the ML amplifiers ( take out two face plates. ) because there is no acess from the top of the ML.
This could be an " easy " task on normal system ampliifers set up but my ML's are hard wired input to output at both " sides ": signal and electrical, so it is not an easy task to do it and in the other side I have to make it by my self ( stand alone. ) when each monoblock has a weight over 40kgs.
Anyway, I made it and not a single doubt: worth that job, the rewards came inmmediatly.
This last step was the fourth step and in each one the audio system received benefits with unexpected improvements for the better: not different quality performance level but a better one, always.
What happened this time: well, overall distortions gone even lower given the whole system presentation a better accurate tonal balance, transparency, better dynamics and an unherad before music detail at micro and macro levels. Both extremes of the frequency range improves given the music the " immediacy " precense that only the live music has.
The whole experience in my today system is a really NEW experience that I never had before in any of several audio systems I heard.
The level of neutrality ( near cero distortions/degradations. ) of the system is just astonishing and if you are not accustom at this very REAL kind of audio system experience maybe you could think something is wrong down there. I say this because that's what I experienced and I have to " investigate " more in deep ( through more listening tests. ) what was happening there.
I invite two of my nearest audio friends that have " difficult " ears to satisfy ( each one in different time. ). In both cases they were surprised why the quality system performance level was " degraded ", why my before system losted its " live " its sparkle performance level.
In fact nothing was losted but distortions, every music nuances are there but in a new dimension in a more real dimension in a more " live " dimension.
Today if you listen to the Nardis track on the P.Barber Cafe Blue where through the track the cymbals sound from the left side of the stage are really " busy " once and again there are times where what you heard on those cymbals grooves are a very alive smearing sound that impose to the music performance a grade of " dynamics " that we can take as " alive ". Normaly through those cymbals sound you are hearing " sound " from the harmonics more than the fundamentals, sometimes because the speed of each and the next strokes ( one after one. )on those cymbals and some time because the kind of smearing sound.
Today I can hear any single stroke on those cymbals and I mean: any single stroke and now the harmonics tooks definition too, palpability and not only smear. Now you can " touch " that cymbals system sound. I only heard this kind of music performance at live events.
That's only an example of what is happening. The system dynamic performance is today a lot lot better than before with lower " spark " but with higher neutral and accurate reality .
I made tests with both friends changing the fuses ( the ones that I can change fast. ) for they can take in count what was happening and to confirm what I'm relating here.
Today the natural agresiveness that has the live music is more real than ever because there is not only that agresiveness but a more neutral, precise and defined agresiveness and not only non precise defined " distorted sound ".
IMHO maybe all of you can't understand what I'm trying to explain because mayeb you never experienced but on live music events and translate that to a home system is something that I think we can't " imagine " till we hear it.
Anyway, lower distortions means more MUSIC and more MUSIC ENJOYMENT.
A lower distortions/neutral and accurate audio system permit to evaluate in a better way not only music but any single audio item as cartridges, tonearms and the like. You can have better and truer conclusions on audio item comparisons/evaluations.
Regards and enjoy the music, R. |
Dear Fleib: The 550 fits the PC-440 and I think that AT 440 too.
I don't post yet my Precept 440 experiences because I just changed the last SR20 fuses ( 4 of them. ) in my ML monoblocks that as the other fuses changes makes a difference for the better and I have to re-evaluate not only the Precepts but all the other cartridges ( MM/MI/MC. ) with I used as comparisons.
Btw, I heard the AT 440 in my system ( time ago ) and other system and I found out is a cartridge that not satisfied my " priorities " at both frequency extremes. I would like to try it again if I have the opportunity.
Regards and enjoy the music, R. |
Merry Christmas and the happiest New Year yet,
One and all
As always... |
Merry Christmas everyone.
Hi Raul, Thanks for the Precept stylus info. I saw that the PC-550 stylus is beryllium/ML, but didn't know what series it fit. It seems there are 2 versions of the AT-440ML stylus. The orig 440ML/OCC must have stronger magnets than the MLa. OCC Output is higher, yet motors have identical specs. Regards, |
Greetings All,
MERRY CHRISTMAS & A HAPPY NEW YEAR
John
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Regards, Griffithds: TK5Ea:
Freq. Response: 10-30,000Hz Tracking Forces: 3/4 - 1-3/4 grams Channel Balance 1.0 dB Channel seperation: at 1kHz 29dB, at 10kHz 20dB Output at 5cm/sec: 4.2mV Stylus tip: 0.2 x 0.7 mil nude square shank elliptical Stylus cantilever: Tapered tube Magnetic system: Dual Magnet Vertical tracking angle: 20 degrees Load impedance: 47,000 ohms Cartridge Inductance: 1,000mH DC Resistance: 1,200 ohms Cartridge weight: 6.8 grams
The TK3Ea is 470 mH, 780 Ohm, .3 x .7 mil nude ellipt, the TK1Ea with a .4 x .7 bonded ellipt. The plastic mount of the 1Ea tends to be susceptible to microphonic influence.
I think you'll find the 5Ea slightly more capable in detail retrieval, the 3Ea less aggressive in the mids. The TK1Ea is entry level of this series, IMHO would do better with the AT7V.
Apologies for the short response (Lew, too), am still short on time.
Peace, |
Dear Friends:
M E R R Y C H R I S T M A S A N D
A H E A L T H Y F U L L O F S U C C E S S
2 0 1 3 ! ! !
to all of you along your dearest family.
Sincerely,
Raul. |
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Dear Grbluen2, your thoughts on the progression are correct. If those 1ea and 3ea were to go to auction they would get far less than what their owners are asking.
I am going to point you back to page 69 of this thread, where Professor Timeltel does a thorough job on describing this cart with multiple AT styli.
Merry Christmas to ALL! |
I am quite familiar with the Soundfountain site. It's a nice site but full of one man's opinion and no real science, does not address my simpler question.
Merry Xmas and Happy New Year and thanks the earth did not explode on 12/21. (I had planned to take all my tt's with me, anyway.) |
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Happy holidays to all, I have a question regarding the Signet line. I have picked up a used TK5ea, understanding that this cartridge was probably not on the same level as the Tk9__ series. I have noticed several of the lower lines ( TK1 and TK3 ) selling for more than the TK5. I assumed that there was a progression from the TK1 thru the TK9. Did I miss something, and is there a reason the lower models sell for more?
Don |
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Gosh thanks. I SAID that perhaps Panzerholz AND slate should not be included on my list, because they have grain structure or are not homogeneous. Bronze and brass (and stainless steel) are indeed alloys, but I think alloys DO qualify for this analysis. (Last time I cut into a piece of brass, I did not notice any obvious inhomogeneity.) Acrylic can be considered in the category of an alloy, for this purpose. OK?
Here's a way to phrase my question: "What is the difference in resonant properties between a sphere made of one pound of acrylic vs a cube made of one pound of acrylic?" I could imagine that they could be different, but I wondered whether there are established rules that describe the differences. Timel, does "Young's Modulus" address such issues? (On now to Wikipedia.)
Or would you prefer only elemental materials that appear in the Periodic Table? OK. Iron, nickel, yadayada. |
The only homogeneous material in your list is slate. Bronze, brass, stainless steel, panzerholz & acrylic are all alloys or compounds that may be homogeneous or heterogeneous in their grain structure. If you assume for the purpose of this exercise that they are homogeneous then SPZ is in that group. It is an alloy of aluminium, copper, magnesium, lead, cadmium & zinc. |
my only question was "what is the effect of shape of a solid homogeneous piece of any material on its resonant character?" The key word is "homogeneous"; I am not talking about CLD. The material could be acrylic, bronze, brass, stainless steel, slate, Panzerholz, etc., altho the latter two are "natural" and are actually not homogeneous in terms of grain structure. So perhaps they are not to be considered. Just shape vs resonance. |
Lewm/Timeltel - You may be interested in reading up on the materials used in my Final Audio Parthenon VTT1. Both the platter and tonearm pod are bolted directly to a 40kg slab of superplastic zinc alloy ( SPZ ). The TT was designed to have a rigid loop from cartridge to platter and defined energy paths for getting rid of unwanted energy to ground. The main plinth that the bearing and tonearm pod are directly bolted to is a 40kg 35mm slab of SPZ – superplastic Zinc Alloy. This "metal" even though it is incredibly rigid and strong, actually self damps at a molecular level due to it's superplasticity – from 10-100hz it behaves like a HIDAMET at room temperature. Check out p30-35 in the following link - http://www.interzinc.org/pdf/zinc6.pdfFurthermore the profile of the 20kg solid aluminium/copper platter has a "curved" bottom profile from the centre out designed to squeeze or deal with energy deflection. There is an explosiveness, density of tone and lack of smear from the sound of this deck that I have not heard in any other including the much vaunted heavily modded SP10mk3's. The industrial sized AC motor that came standard back in the 70's with a split phase sine/cosine wave generator and torque controller and driven by an 80wpc power amp probably helps too. |
Raul
"About AT its Sibata ones are different than the Line Contact ones or the MR stylus shape even in what AT name it as Line Contact there are variations and diferent quality on the polish of the stylus or grain oriented and the like.
That is why I questioned PickeringUK's use of the term "Line Contact" for their Stereohedron stylus in their ad. They are not the same but different profiles. Same family but slightly different! Actually the Shibata came 1st. So it should be of the Shibata family, not line contact family.
Regards, Don
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Dear Fleib: Before I bought the Precept 440 I heard the Precept 220 but was a dissapoint I don't like it in any way.
The Precept 110 and 220 you can find out every day on ebay but as you pointed out the Precept 440 is hard to find with 440 original stylus and in good condition, I think I was lucky about.
As with some AT cartridges we can use with the 440 the stylus replacement as the one of the AT 440ML.
I bought a 550 stylus replacement and an original AT 440ML to check about but exist one build design diferencen between these stylus replacements and the original P440: the cantilever of the Precept 440 was made from beryllium where the 550 ( even that the seller of the 550 said it it is an improvement over the original P440 and even that owners of those 550 stylus replacements said the same: I disagree with them. The original cantilever per se make a differences. ) and the AT 440 did not.
That single difference makes a huge difference, at least this is what I'm experienced on my tests. Obviously that the stylus shape is not exactly the same shape and this is a diference too but the cantilever one is more " substantial ".
I'm finishing my tests on the Precept 440 and will share those experiences.
Regards and enjoy the music, R. |
Dear Griffithds: No, are not the same. What I'm telling is that over the years when appeared " line contact " stylus shape: Shibata, Stereohedron, VDH 1 and the like many people name it as " lene contact " because all them have a wider stylus contact area with the groove.
About AT its Sibata ones are different than the Line Contact ones or the MR stylus shape even in what AT name it as Line Contact there are variations and diferent quality on the polish of the stylus or grain oriented and the like.
Regards and enjoy the music, R. |
Dear comrade Don, Imitation is usually interpreted as a compliment but this does not apply by the so called 'intellectual property'. Shibata was a trademark while nearly everybody wanted to participate in 4 channel adventure. That is why we got 'Sterohedron' and other peculiar names for the fake Shibatas. The shape is pretty complex so one can easily change one or the other facet. Mitachi corp. produced 'the same' cart for the Astatic and the Glanz .The only difference was Shibata for the Astatic MF 100 and 200 with Shibata and Glanz 71, 51 and 31 with line contact. Vetterone and I were not able to hear any difference between MF 200 and Glanz 31 L (see the Glanz thread). We should also pay atention to the quality of the used diamonds and the quality of the polishing as Raul already mentioned.
Regards, |
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Regards, Lew: Simple harmonics: http://sharp.bu.edu/~slehar/HRezBook/Chap2.pdfFactors we concern ourselves with: Damping: The dissipation of a vibration's energy into heat energy. This may also be considered as the frictional force that causes the loss of energy Quality factor: The number of oscillations required for a system's energy to fall off by a factor of 535 due to damping where quality factor, Q, is the number of cycles required for resonant energy to fall off by a factor of 535. Given is e2π, where e=2.71828, the base of natural logarithms. An interesting perspective on composition: http://www.principlesofnature.net/number_geometry_connections/more_resonances_between_musical_and_visual_scales.htm Driving force: Any external force that pumps energy into a vibrating system Resonance: The tendency of a vibrating system to respond most strongly to a driving force whose frequency is close to its own natural frequency (eigenvalue) of vibration Steady state: Behavior of a vibrating system after it has had plenty of time to settle into a steady response to a driving force In the example of the CA deck, consider wave cancellation. Hypothetically, as turning point resonances travel axially in sinusoidal form, and if introducing irregular geometry reduces amplitude of resonances through reduction of overshoot, it seems (to me) a structure might be designed so that turning point resonances encounter driving point resonances in a cancelation mode. Your thoughts? This math would fall into the realm of physics, my math is so rusty even my calculator squeaks. How might all this effect what I'm hearing with the cart Peter Leddermann waved his musical wand over? An AT-ML150 OCC, the generator can is fixed to a ceramic mount. A sapphire cantilever has greater mass than boron but is more rigid, IIRC self resonance is 16-17k, boron at 12k. Beryllium by mass is heavier than boron or crystal but a typical Be cantilever's eigenvalue is near 19k. Be aware this is from memory. On a Yamamoto HS-2 headshell & tied to a graphite "S" arm, resonances are damped rather than dumped. In architecture, boundary and air borne resonances are a concern. Think parking structure. There are not only the acoustical resonances (echo), but also the (imagine) mechanical rumble of passing traffic. In less utilitarian settings this is undesirable, constrained layer damping (CLD) is utilized. Shown as most effective, the introduction to a structural component by cladding or interruption by an alternative material is the most effective means of address. Efficiency is improved with integration by bonding or layering. Layering is most effective if, when there is a grain structure, laminations are oriented at 90*. Resonant waves don't like to make turns. As wood has both axial and lateral elements and space exists between these longitudinal and latitudinal structures the resulting effect is one of dislocating resonances. Cut to the chase. Resonant chain: Saphire cantilever, suspension, Mu metal can (sounds like something from Edgar Rice Burroughs), ceramic mount, cherry wood headshell with a bronze plate above. Headshell arbor, graphite curved arm, silicon fluid damped PU-70 arm transitioning to a sturdy laminated wood plinth. Damping is effective. The stylus is SS's optimized LC, tracing faults are not evident. Nuance and detail, initial transients and decay are quite acceptable. Output is 4mv, output impedance a good (to my ears) 530 ohms. Insturments are heard as entities rather than agglomerative. Coils are wound with OCC copper. In comparison, high purity copper has an estimated 1500 grains per foot. Grain boundaries tend to introduce distortion. Oxygen Free High Conductivity (OFHC), 400 grains per foot. Listen closely, there is a definite improvement in clarity. Dynamics are also more apparent. Linear Crystal (LC-OFC), 70 grains per foot. Ohno Continuous Casting (OCC) or "UP-OCC" (Ultra Pure Copper by Ohno Continuous Casting Process) was developed by professor Ohno of Chiba Institute of Technology in Japan. The process involves a heated mold continuous casting resulting in small rods of OCC pure copper. Wire can be drawn which can have Copper grains of over 700 ft length. Bass is vibrant, full and with dynamic impact, decay is precise and without bloom. Upper mids do evidence a forwardness in apparency, there is a consequential impression of clarity and resolution. Hfs are nuanced and with excellent detail. I do miss my favorite resonances. Peace, |
Does anyone recall some earlier Clearaudio turntable designs, where the plinth was made of solid acrylic cast in a "curly" shape, something like that of the top of a baby grand piano? They said it was to control resonance, but I was dubious, because in the first place if you use solid acrylic, it's going to resonate at the frequency of that particular mass of acrylic, no matter what the shape, or so my off the cuff thinking told me. I then searched the internet to find out how and if the shape of a solid object, independent of its mass, of homogeneous material content could affect resonance. I really never found a good treatment of that subject.
At any rate, I notice that the most recent Clearaudio turntables use layers of several different materials to effect CLD, but nothing exotic about their shape. |
Hi Raul, I'm wondering about the Precept 440LC, have you had a chance to listen to it much? I think these might be rare, I've never seen one. Does the stylus fit any other ATs? Apparently there was also a Precept 550ML. It would be interesting to explore these, but they might be hard to find. Regards, |
But the point is whether shape can spread out or smooth the resonant peak of a homogeneous material. It is easy to see that shape can shift the resonant frequency per se. I suppose it can also spread out the energy so that several adjacent frequencies are excited each to a much lesser extent, and it makes sense that an irregularly shaped object could behave in such a manner, but I wanted to see the math/physics that describes and explains that. But if it's true, then Clearaudio was once on the right track that they have since abandoned in favor of CLD. |
Regards, Lewm: It's a simple concept, the math is more than I want to tackle. Resonance is the result of an external force vibrating at the same frequency as the natural frequency, or eigenvalue, of a system. Resonant modes oscillate back and forth axially as helices between two turning points.
This illustration has been offered previously: Consider a clap of the hands in a square, empty chamber, then in a pyramidical or spherical chamber of the same volume. Axial reflections may actually increase amplitude of unintended resonances (ringing), because they lack parallel surfaces, irregular geometrical shapes disperse resonances.
By definition, he point of origin is the drive point. Transfer point measurements can be taken when attempting to identify boundary resonances. Doing so will identify both phase shifts and coherency. With this information, one can develop operating deflection shapes to minimize boundary resonances.
From this thread, post #7405: "Boundary conditions do effect the resonance frequency. The resonance frequency is influenced by Young's modulus, and geometry. --- resonance characteristics (of a beam) are determined by: 1. Young's modulus, 2. The cross-section. 3. The mass per length. 4. The associated eigenvalue, or the self-resonance--- as described by the preceding factors. " There is a probability that not just the primary tone but also the second and third overtones are also excited. Measures to correct this are selection of the material itself, damping--- by external or internal applications, by tapering or curving---". This conversation applied to tonearms.
"Music will depend upon a synchronisation and resonance of many parts and wholes and upon a radical rethink of how we can more harmoniously relate the units of geometry and number." (W. Roberts, 2003.)
Peace, |
Does anyone recall some earlier Clearaudio turntable designs, where the plinth was made of solid acrylic cast in a "curly" shape, something like that of the top of a baby grand piano? They said it was to control resonance, but I was dubious, because in the first place if you use solid acrylic, it's going to resonate at the frequency of that particular mass of acrylic, no matter what the shape, or so my off the cuff thinking told me. I then searched the internet to find out how and if the shape of a solid object, independent of its mass, of homogeneous material content could affect resonance. I really never found a good treatment of that subject.
At any rate, I notice that the most recent Clearaudio turntables use layers of several different materials to effect CLD, but nothing exotic about their shape. |
Raul,
"There are several manufacturer " line contact " versions. It's right the name " line contact for them ? well is IMHO not important what is important is that as the Shibata or the analog-6 or even the MR the Stereohedron has a wider groove contact."
The Signet TK 7SU is a claimed to be a Shibata tip by Audio Technica. Their TK 7CLA is claimed to be a Line Contact. By your above quote, then they both must be the same stylus! Are they? I have both and they sure don't sound the same to me. Regards, Don |
Dear Dover: Something like that was what Cardas made with its cartridge wood body build by Benz Micro and where the BM has not the wood body " holes ".
It is obvious that those " changes " on the build material makes a difference because change its resonances frequencies and how those resonances travel and " broke " through its " trip ".
That's what happen with tapered cantilevers and tapered arm wand tonearms and even on tiny shape differences on headshells.
Regards and enjoy the music, R. |
Ughhh! I actually wrote that. Who knew? I guess you did. Are you archiving my wisdom or lack of same? The term is still rather oxymoronic, even if I wrote it first.
While there are good practical theoretical reasons to eschew wood for a tonearm, I admit I like the Reed a lot. And my one audition of the Talea in someone else's system, but one that is very similar to my own, suggests it is also very fine.
When I look at the Grace 714 and then at the new Durand Telos, I see a lot of similarities, except the Telos obviously is a more sophisticated approach that pays attention to azimuth and VTA adjustment, and the Telos is the subject of cult worship. This makes me wonder whether one could squeeze a lot more performance out of the Grace, if one were to tweak it here and there. |
The Guarnerie suggestion is pukka. Recent studies have indicated that the imperfections, variations in wood thickness, irregular holes, patched wood panels & tweaks to the original instrument are generating that unique sound. The headshell tweaks are a matter of taste. |