Regards, Porto, Harold-n-t-Barrel: Raul is owed the honors for bringing the AT20SS to our attention. For the first twenty or so hours it was a disappointment. Anemic was, IIRC, my description. Around thirty hours it started waking up, enough so that tweaking alignment actually made a difference. On the 12" Pio. arm, it's simply glorious. The Acutex's went the other way. Fortunately the EPA-250/SP15 is now doing duty in an office system, the Acutex are restored to their former glory through a serviceable Kyocera A-710 MOSFET integrated and modest Tannoy DC-3000 floor-standers.
A 320 (described as low hours) on a headshell, plus a SaturnV integrated headshell with an extra generator is offered on ebay. Search if interested. No association.
Porto, does your cat demonstrate a preference for the LPM 320 ;) ?
Peace, |
Regards, Porto: The question was one of genuine curiosity. I have a cat, Pi' sant, who's main goal in life seems to be the shedding of copious amounts of hair. She'll join me in listening sessions, sometimes for lengthy periods if she approves of my selections. In adjusting anti skating I've learned to trust her ears. She's very attentive to soundstage depth/width & center image.
Pi' sant tolerates Pink Floyd but disdains electronica in general. You mentioned your cat's dubious acceptance of Harry Belafonte, Lenco Heaven, the "Acutex...Bar" thread.
Wishing you good listening &
Peace, |
Regards, Raul: It was a PC-330, not the 400. There's one to be found at Top Choice Audio. Someone thinks a lot of it, $200. Flaking paint but the "beryllium" tag is still on it. 0.5 conical & 3mv output.
1973. "The people" would gather, relax (ahem) & actually listen to music. Frisbees in the park. Robed "Moonies" with their paper flowers, bothering "civilians" in the airport. "The Rev. Moon loves you".
So. I had this Sansui integrated, an AU-5(something), ceramic/MM switch on the back. It hissed like a snake without needing to be antagonized first. The first series to have the really cool black faceplate. I gave it to my (then) 17 yr. old brother. He still has it. Occasionally he threatens he'll give it back. A Dual 1219, Shure M75 & some Sansuii 8" 2-ways.
A friend, just back from four years in the service, 1975(?), brought home a Pio. system. SA-9100, CS-99a's & (might have been) a PL-12D table with the PC-330 cart. Solid bass, sweet hfs & mids with a spooky presence. It sank my Sansui stuff.
Off to the Hi Fi emporium. Magnepans & Phase Linear 400s were the hot items. Sam Wherry, the owner, would crank them up, LOUD, & then just stand there, a far-away look in his eyes & sales spiel totally forgotten. I wanted to hear some real bass. EPI towers & Marantz sounded VERY nice together. They did bass. I'd read up on neutrality so double large Advents in the utility cabinet & a Kenwood KA-9800 integrated came back. 9800 HAD to be better than 9100, it's a bigger number. Nada.
It was the cart. Sorry to relate this to you, Raul, but it was the beginning of my reluctance to make any claim to being an audiophile, an enthusiast since.
Not a PC-400, it's a 330. Top Choice, $200.00. Would someone buy it? Please?
Peace, |
Regards, Raul: Lucky you! I'm going through nearly the same situation with an EPC-U25. Same family as the Technics P23 or EPC-205 and with a solid 1/2" mount. One stylus from Nagaoaka, another "generic", not impressed. Have ordered a JICO SAS for the U25. With laminated cores, single point cantilever suspension and relatively low inductance, the cart should perform better than it does now. Jico shipping notification last Fri.
A red generic for the AT-20SS? Want it?
Peace, |
Regards, Grbluen2: If the cantilever is simply rotated and not bent then you may be able to correct it yourself. Pull up the AudioKarma turntable forum, find "Search", enter "rotated cantilever" & click on Google site search. This is not an uncommon occurrence.
If inspection of the "V" magnets proves them to be in the correct 45* position relative to the pole pieces but the stylus is not vertical then replacement/repair should be considered.
A user initiated cantilever swap is another option. It is more easily accomplished than might be thought. Research & deliberation are advisable, incantations optional. Our contributor "Fleib" has given good advice regarding the CA modded AT95 (last year) in this thread, perhaps he'll check in?
Peace, |
Regards, Acman3: Hi, Danny. If your carts are of the LPM series, the 312 stylus is bonded, on a round bushing. Eff. tip mass is higher, 0.6mg versus 0.5 for either the 315/320. All three are on a titanium tube, the 312 & 315 a straight cantilever, the 320 is tapered. Compliance, tracing and ch. balance for the 312 is lower than either of its big bros. To elevate performance into the LPM 320STR 111 range a total rebuild may be necessary. Have you looked into VdH options? Lots of good reading here: http://www.vandenhul.com/userfiles/docs/Phono_FAQ.pdfAND a few opinions. ;-) Peace, |
Regards, all: All this discussion of exotic headshells has given me inspiration. I intend to head for the shop and lash together a double-wishbone suspended design, gyroscopically stabilized and with a "smart fluid" sensor controlled hydraulic adaptability to compensate for warps and off-center Lps. A patch of exquisite wood from a particularly endangered species, some gold plating for the required "bling" factor.
680gm, a perfect match for any tonearm. You've never heard your carts sound like this!. Drop this baby on your favorite Lp & observe with amazement as your tonearm demonstrates no eccentric movement. As a matter of fact it won't move at all! Eliminate skipping! Create your own grooves! Resurface your vinyl!
Availability to be announced. Sometime soon. Investor opportunity!
Peace, ;) |
Regards: IMHO Lew is on the right track, anyone tried something as simple as blue tack or self-adhesive drawer bumpers placed in strategic locations? Wood mount is an easily heard improvement.
Still seeking investors for headshell. Prefer unmarked U.S. $. Considered labeling it "Betty" or "Jughead", prefer the classier "Veronica".
Peace, |
Regards, Raul: "In the mean time have fun." Yes, that's important. I hope none took my "project" seriously, it seemed there was more "heat" than "light" in recent communications here, & my foolishness served to "lighten" things up .
BTW, it should be mentioned that the Acutex 4XX carts are much improved through a mount fabricated of wood. Easier said than done, it is a convincing demonstration of the resonances contributed by the supplied mount. A Shure M75ED T2 is also residing in a cocobolo mount. Tonal balance remains and neutrality is improved. My listener involvement has, however, diminished. It's just not quite as engaging.
Excluding the superb Shure ML140 HE, it seems I'm one of Dgarretson's "long nose" listeners ---but then the ML140 DOES have a prominent proboscis---
Peace, |
Regards, Raul: I must admit envy of those who listen to one TT, one TA & one cart.
Resonance can be constructive or destructive, a blessing or a curse. Underdamped, over damped, bloom, glare, grain, steely, glassy, woody, dark, analytical, the list goes on & ---.
After going through almost exactly half of the carts & etc's you've mentioned, I've been fortunate to find four combinations concerning which I find little to criticize, two that provide consistent reward and one that is superb. This one must be heard in the absence of critical intent. Without preconceived expectations there comes a nearly subliminal recognition of excellence. Subjectivity cannot be excluded but once a certain level of performance is identified, even minor variations might become objectionable to a demanding listener. There are many who are able to find enjoyment in a variety of presentations and fortunately (IMHO) I've found only two carts that I'd not care to listen to again.
If you've managed to build a TA, headshell and matt that, individually or as a system, allow a well designed cartridge to be heard free of the almost inevitable editorializing these components convey then you are to be congratulated.
Meanwhile, few have heard this gear and like a certain headshell, should be considered innocent of transgression until proven guilty.
Perhaps it is appropriate that the articles offered by yourself and an unmentioned designer are judged by a jury of audiophiles and found to have merit, and that both persons are rewarded in a manner which enables them to meet their obligations, perhaps to profit greatly. In such a scenario, audiophiles individually and as a group benefit. What could be better?
Peace, |
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Regards, Frogman: Gestalt – "essence or shape of an entity's complete form". Loosely, a theory that the brain is holistic, parallel, and analog, with self-organizing tendencies. The perception of stimuli in their entirety precedes the perception of their constituent assets, the product of complex interactions among various attributes. Behaviorists approach the understanding of these elements through cognitive processes, the casual "Gestaltist" might use the phrase "The whole is greater than the sum of the parts". Although this is a deviation of Koffka's original phrase, "The whole is other than the sum of the parts", Gestalt theory allows for the isolation of contributing elements relative to the perception of the whole, a perception of what it really, holistically, is.
In audio there is a need to conduct "real" experiments in contrast to classic laboratory situations, experienced in real conditions, in which it is possible to produce with greater variance that which would be habitual for a listener.
There are "laws" of perception which seem inadequate in describing the individual's emotional connectivity with art. Evaluation through exposure and experimentation enable the listener to identify the qualities that "resonate" with his sonic goals. Diversity is a condition of nature, conformity the opposite of sophistication.
One can answer this question only for one's self, never for another: If, as the roguish Frenchman posited, "Best is the enemy of Better", then at what point does "Good enough" become the enemy of "Better"?
The Acutex 420 is a remarkably engaging cart. Sound staging, balance and dynamics are commendable. You are not alone in finding it a cart worthy of attention. Actually, it seems to command it. The 412 is slightly less dynamic, more focused in the midrange region. Should you have the opportunity to hear either the LPM 320 or 315, they both will leave a favorable impression. Most would agree these are "Good enough" for an extensive listen, if there are "Better" is for you to decide.
I believe you might find experimentation in reducing the resonance of the mount interesting, perhaps even wrapping it with some of Lew's audiophile grade rubber bands?
Peace, |
Regards, Dover. Off now from an ADC mag. headshell and on an Orto. LH-8000 wooden version, an EPC-U25 (half-inch mount) cart is causing me frustration. I hope you can give a fresh perspective.
Tried with two styli previously, one reputedly "OEM". The cart is of four laminated coils, 500 ohm output inductance, 2.5mv output. All the major ingredients for excellent performance are in place. With the two previous styli, macro dynamics were poor, bass muddled and hfs lacked extension. This leaves midrange for consideration. Confused & lacking articulation, it wasn't all that either.
Improved on the Orto. headshell and now with a Jico SAS at twenty hours, hfs are edgy and while bass has gained substance and transient slam, upper mids are heard with an unnatural glare. Jico boron cantilevers have been measured to resonate at 12k Hz; good for air, not so for glare.
Determined to prove my intuition concerning the cart, and considering your years of experience, could you offer an opinion? To rule out one option, tempted, but no, I won't throw it away. :)
Peace, |
Regards, Dover: In the late 70s Grado dealers would include (for the asking) a pentagonal aluminum plate with three dimples, both tiptoes and isolation for one's cart. Purists scoffed, others said "well, it does something, use it if you like it". Haven't looked up the specific compliance of the Jico SAS, there is a universal recommendation from the maker to run it at 1.4gm VTF.
This is the difficulty with AM styli, with the better offerings "caveat emptor" is perhaps too stern, "close, possibly excellent but different" is the best one can hope for.
Interesting, your comments on headshells. The ADC magnesium models are light enough to permit accurate tracking with high compliance carts (arm dependent, of course), EXTREMELY rigid, but prone to ringing. Removing the washer at the union with the collet helps to evacuate resonances, an isolation "device" is helpful in reduction of ringing, especially apparent with a plastic mounted cart. Curiously, a thin sheet of malleable metal is effective in this capacity, the dissimilar materials curb boundary resonant energies while still providing an effective path for draining these energies through the tonearm.
And those made of wood-. Different densities, specific gravities, as I have read you've not only been a dealer in audio but also extensively in the implant industry as well as recently in timber, I'm sure theres little about the qualities of either material, metal or organic, that you're unaware of.
Energy is, however, transmitted through radiation (acoustic), reflection (boundary resonance), convection or conduction (transmission through a material). Insulation and isolation are closely related concerns, the most effective natural insulation is, perhaps surprisingly, trapped air.
Follow, please, comment as you wish. An old, tried and proven technique for reducing port "boof" in speakers is the introduction of drinking straws. The degree of damping is determined by the number used. Because they are hollow, internal volume of the speaker is largely undisturbed.
Now, wood. Wood is comprised of three structural identities. Growth rings, longitudinal cells and transverse rays. Growth rings contribute to rigidity along the length, transverse raying unifies the longitudinal straw-like cell structures, which in heart wood are vacant of anything other than air. This is especially evident in the end-grain of species such as oak, hickory, ash or pecan. These fall into the group of ring-porous woods.
So here one may observe attention to insulation, isolation, density and specific gravity. Wood is a traditional material in the construction of plinths and, certain carts such as Nikolas' Virtuoso, and speaker cabs, it's use as an isolation platform is not unheard of. Bamboo, actually a grass, in a laminated form is becoming more frequently utilized in this capacity. Other than cost & strength-to-weight, there must be good reason.
Self resonance is variable with density. Boundary resonance is internally damped and as it is a material differing from most cart mounts, also serves to reduce the resonant interaction at that junction. Conduction is, it should be remembered, not always a good thing. Tonearms are subject to this too and as Raul recently mentioned can provide a path for mechanical or acoustic energies being transmitted back to the cart.
Please continue your lack of conviction that wood is appropriate for this usage, those who have actually explored their qualities promise tolerance. A precautionary "note" though---the typical matching requirements being met, those who anticipate bass bloom or "organic" mids may be surprised.
Anyway, the EPC-U25 continues to be an enigma. Haven't tried it on a graphite/plastic headshell yet. Current arm is a upper-mid mass carbon graphite pipe on a Pio. PL-70L-11. The Sumico/Jelco/Zupreme is a good model, two pins for lateral stability but at 12gm begins to boost eff. mass into a high mass area. As is, the cart sounds better at 47k ohms than 100k, just a little recessed in the hfs at 0 ohm. Running a 100pf shunt sounds about right.
So it's been a running battle with the thing for six months now. As a micro-line stylus has never been a first choice, and as boron is both lighter and more rigid, but also more resonant than beryllium I'll consider the stylus first. Perhaps a HE nude on aluminum?
Thanks for your response, it offered several points for consideration. And Don, for your generous offer.
A'gon contributors are typically informative and considerate, those who post here among the finest.
Perhaps the Arche/Orsonic debate is significant enough to deserve it's own thread (again)?
Peace, |
Regards, Halcro: Apologies for the prior & somewhat windy post, submitted & caught yr comment.
I've a ML140 HE. Rarely mount it up as my other carts are resentful of it. It and a spare NOS stylus can be found in a cushioned air-tight container, next to my pristine TK7LCa stylus.
And Henry, please do save a few of those ?s for the rest of us(?) ;)
Peace, |
And Henry--I left out a "gloat" in my previous address, it was I assure you wholly unintentional.
You will at some time treat us to one of your wonderfully entertaining reviews of the Shure? I'm looking forward to it with relish. Oh, yes!
Good listening, enjoy the ML140 HE. It's a treat.
Peace, |
Regards, Dover: Damping or dumping, this is an instance where it is easy to agree with both theories but not nearly as much fun as arguing the point ad infinitum. It might be best to consider it on a case-by-case basis. Plastic mounts are not my first choice, sometimes we have to take what we're given and do what we can.
The EPC-U25 has real potential. It can be heard with the SAS but then there's that annoying 12k bump. If you've noticed the same exists at the 8k range with carts having more than (+-) 1200 ohm output inductance, at 22-2300 ohm every defect of your, no, my vinyl is magnified. A four coil generator with laminated plates to reduce eddy currents, the next higher evolution would be toroidal, the "air core" equivalent in MMs. Call it tweaking or tuning, coloration or whatever, the ability to finesse the character of these carts is, for me, much of the allure of MMs. They can be surprisingly rewarding. Aggravating too.
Your thoughts concerning an adjustable damping headshell are interesting. You might consider a development and design program, the Dover Dampster. You might anticipate some degree of controversy though.
Lew's audiophile grade rubber bands are still another option, I understand there are cheap copies everywhere---
Thanks for your continued interest.
Peace, |
Regards, Raul: Thanks for the cart info. The U25 came on an NOS Astatic headshell, the much (and correctly) maligned waffle type. It was so inexpensive I thought it a good opportunity to investigate the qualities of each. An AT13Ea with a NOS clear diamond 0.2 x 0.7 nude on tapered aluminum is now strapped to the Astatic headshell, not up to "review" status but it is an entertaining cart with convincing bass and mids easier on the ear than expected from the sharp elliptical. The hfs are nicely extended but with a slight "tizzy" quality that can probably be laid on the doorstep of the AT headshell. An AT-MG10 headshell is in the drawer, I really should move the 13Ea to it and give it a more serious listen. The MG10 headshell is, btw, 4mm thick and seems to substantiate the reported resonance handling abilities of constructions of that dimension.
Correct, the U25 is in the EPC-250 family, as is the EPC-P23. With the available OEM boron cantilever and fine elliptical, the P23 was, in it's day, favorably commented on. The cart continues to stubbornly resist.
"Men all know the disposition by which we attain victory, but no one knows the configuration through which we control the victory. Thus a victorious battle is not repeated, the configurations of response are inexhaustible. One who is able to change and transform in accord with the enemy and wrest victory is termed spiritual". Sun-tzu.
Peace, |
Regards, Geoch: Sun-tzu, from the Chinese "Waring States" period, 2nd cent. BC, possibly offering a little audio advice? Remember my post concerned a cart?
1: Know the requirements for success 2: The required configuration may not exist. 3: What works once may not work in other circumstances. 4: Be flexible.
Still taught in military academies and required reading in many corporate boardrooms, one may play a game of substitution and insert "adversary", "mother in law" or "that pesky squirrel".
Or, would one rather have it that at the first sign of opposition one tucks the tail & insists resistance is not virtuous?
Try another reading: "know the disposition by which we attain victory, but no one knows the configuration through which we control the victory. Thus a victorious battle is not repeated, the configurations of response are inexhaustible. One who is able to change and transform in accord with the enemy and wrest victory is termed spiritual"
One of my favorites from our warrior-philosopher is "Wait beside the river long enough and the body of your enemy will float by".
Best not interpreted as a literal prescription?
Peace, |
Regards, Danny/Dover/Geoch: "The General cannot engage in battle because of personal frustration. When it is advantageous, move; when not advantageous, stop. Anger can revert to happiness, annoyance can revert to joy, but the dead (cart) cannot be brought back to life. This is the Tao--" The Art Of War, Sun-tzu.
Always pleased to exchange info. on my favorite thread, the Moving Maginot one. Put your headshells on, the blitzkrieg resumes!
Armistice, |
Regards, Fleib: Would like to lay that one on dang auto correct but my bad, a very early morning post. Output impedance. The most immediate illustration would be the AT-20 @ 500 ohm compared to the 440MLa, 3200 ohm. Ever hear the AT-20 referred to as an "ear biter"?
A few others: Shure V15-111, @ 1350, V15-xMR, 650 ADC XLM (varies), 360 to 760, the PSX 10 through 40, 3600 ohm.
Not many of the higher impedance carts are discussed here, the (borderline) Grace F9-E is one, 1700 ohm. "Back in the day", it was considered by some to have a response tilted in the hfs, IIRC Martin Colloms was one. The higher output (mv) F9-L was on his "Recommended" list for 1977, the F9-E, not. An illustration that there are other factors (loading, stylus/cantilever, yada, yada) involved in voicing a cart but if one cares to do a listening comparison it's there (IMHO) to be heard.
If you're curious, measuring device is an ancient Pio. SG-9500 equalizer. A remnant from the days when people still recorded to cassette. Switched out of the equally ancient rig except for doing the Fletcher-Munsen smiley face thing at rare low level listening, it's useful for identifying the range of suspected anomalies.
Lesson learned, not to post before second cup of coffee. Thanks for catching that.
Peace, |
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Regards, Dover: Fleib made, earlier, the suggestion that it might be interesting to share notes concerning the characteristics of carts found to be of noteworthy performance. I'd suggest that most with an output of 3.5mv or less (there are, IMHO, exceptions) are capable of nimble transient response. In spite of it's 2.5mv output, resonance in the 12k hz region continues with the Technics EPC-U25/ML stylus and is NOT one to recommend to friends. I give up on it, perceiving a response more brittle than a poorly rendered Joni Mitchell CD. Bass however is quite good. Your comment on "ginormous" distortions due to higher output is one that may result in shedding additional light on general qualities to be aware of in selecting an unreferenced, or even referenced cart. If would you be so kind, give an opinion of the level at which output derived distortions are observed? Determined to conquer the U25, I followed up on your suggestion to examine the offerings of Peter Belt & found several fairly recent references in Stereophile, revived some memories: http://www.belt.demon.co.uk/As to the U25, the designation seems somehow submarine-like & there are several ponds on the property--- Peace, |
Regards, Harald-n-t-b: Suggest you look at the download of Grace "Stereo Pickups" in the Vinyl Engine Library, draw your own conclusions.
I've both the F9E & F9L. Being a midrange junkie, the F-9L is among my ten or so favorites. Outvoted by those who have had the opportunity to compare the "L" to the "E" & Ruby. The F9F (blue stylus ass'ly) is usually considered the premier edition.
Peace, |
Regards, All: Headshells? Recently realigned the Empire 4000D-111 on a boxwood headshell. Very clean bass, pleasing mids & balanced hfs. So pleased, the OEM 4000D-lll stylus on ebay was considered. IIRC $99.00. Visited my stock portfolio & while wiping the tears from my cheeks someone else picked it up, a bargain for the level of performance the Empire brings to the table.
In case anyone is interested there are also three AT-13ea carts with "working" styli for less than $50.00 (ebay). With a .2 x .7 nude elliptical the hfs are a little forward (to my taste) but strong output, no reluctance in delivering lively bass performance and the fine alu. cantilever contributes to good mids, a cart worth experiencing.
Lew: I've both the EPA-500H and 250, each on their own B500 base. VTA adjustment is fluid in adjustment and responds accurately in adjustment. If yours is recalcitrant in movement it's likely the lube needs refreshing. I've both 100k & 30k weight silicone lube picked up from a hobby shop, the 30k is probably too viscous, the 100k definitely so.
Raul: Still curious about: (1) your "reference" LOMC, (2),the HOMC you picked up with the Sony arm, and perhaps of most interest to many who follow this thread, (3) your impressions of the carts you mentioned that were up for reauditioning.
Will the moderators review this post? 11-08, 6:20 PM Central Time, let's see--- (click)
Peace, |
Regards, Halcro: Masochist? Did someone whisper in your ear, the cursed EPC-U25 was given another chance to prove itself listenable?
Although flagellation is, in certain circles, an acceptable practice under no circumstance is this particular torment to the ear justifiable. In contradiction to it's (from memory) low impedance/low inductance, both in the 500mH & ohm range & a "should be ideal" 2.5mv output, there is a peculiar resonance in the 12k range due (I suspect) to the combination of boron cantilever, SAS/ML stylus and the dreaded plastic mount. It makes the Acutex LPM 415 sound warm (quite an accomplishment) and it's available, CHEAP!
Congratulations on the TK7LCa, the OEM line contact styli are of exceptional quality and quite difficult to source. As to the LPM 420, the cart continues to justify it's chameleon genes. When things get slow with the MM thread a mention of "Acutex" is sure to inspire comment.
While the TK7LCa remains my "go to" cart, the Shure ML140 HE, Acutex LPM 320STR or Empire 4000D-111 might be selected for an evening of good listening. Not much mention of Nagatron or Nagaoka? The Nagaoka MP500, boron cantilever/LC stylus & 3mv output looks interesting.
Just curious, anyone have information on the configuration of the 4000D-111's stylus? On the packaging my example was supplied with it's described as "4 Dimensional". The Empire, previously somewhat turgid in the bass, moved to a Yamamoto boxwood headshell and with particular attention to alignment the cart has gained in clarity, tonal balance and a quite welcome reduction in unwanted resonance. Should a "recommended cart list" ever be compiled from the favorites mentioned in this thread, the 4000D-111 might find a mention?
Peace, |
Regards, Raul: Thanks. I'm familiar with the Orto, about five grades above the MC20 I'll occasionally drag out. The Spectral, unheard.
Thanks again,
Peace, |
Regards, Raul, In_Shore: Thanks for the stylus info, it raised my curiosity and here's what I found. First, a little support for a personal preference, a J. Carr quote: "Too large of a major radius makes azimuth adjustment more critical than most users (and many tonearms) want to deal with, and too small of a minor radius tends to create edges on the stylus that are sharp enough to chew up the groove. Based on my own experiences and observations, I like the maximum major radius to be in the 70~80um range, and the minor radius to be in the 2.5~3um range". It might be conjectured that with a less than perfectly flat LP, an extreme major radius would suffer from vertical "scrubbing", essentially a greater likelihood of introducing VTA error, bridging groove modulations and affecting slew rate/transient attack negatively. So it would seem to me. In_Shore, here's what I found concerning the Empire "Gold" 4000D3. A crude but practical means of converting mils to microns is to multiply by a factor of 2.5. Your given profile of .25 x 2.5 then compares to a 6uM x 62uM minor/major radii, a moderately "fat but tall" line contact. For comparison, a .2 x .7 elliptical is .6 x .18um major/minor. This is where it gets interesting. Popular Mechanics, Apr. 1975 reviews a number of 4-channel carts, the stylus dimensions are as supplied by Raul, the "4 Dinensional" stylus at .1mil, which would be (approx.) a 2.5uM minor radius, well within Shibata dimensions. Further, the PM (yeah, I know) article states B&O's Pramanik, Stantering's Quadrahedral and Empire's 4-Dimensional styli are Shibata variants. More! Empire Scientific patented the "paralinear" designation in 1983, the Gold D3 is interchangeable with the Empire 5000LAC, or "Large Area Contact", stylus. This might be an interesting cart, with a given inductance of 270mH, one might keep an eye open as to its availability. With the (presumably) original silver D3 stylus, it could be a winner. Some more esoteric info. here: http://www.lencoheaven.net/forum/index.php?topic=3351.15. It appears the original stylus is Shibata, the later (1983-) a line contact, both Empire's variants, a minor variation to avoid patent infringements of Shibata's original design. In_Shore, I'd also like to comment on the boxwood headshell, it seems to do a good job of controlling spurious bass resonance, concentrating the mids while still maintaining hf extension. I find it to be a neutralizing influence, on the right arm & matched to the cart it's good headshell. "You can tune a cart but you can't tunafish"- was that Joe Walsh or Mott The Hoople? :) Any corrections to the above are welcome but I think I've got it right---. Peace, |
Regards: Decimal points gone wild there. Make that multiply by 25, not 2.5. Advice is to proof read for errors in late night posts.
Peace, |
Regards, Halcro: There was some discussion of the ML140 HE in this thread several years ago, tone arm compatibility is a definite factor in extracting the potential of this cart. A HE stylus on a beryllium thin wall tube, transient response is excellent.
Perhaps of general interest (since Thuchan has brought up Shure carts), Some cut/paste from the cart designer, Les Watts:
"The V15 III was an excellent cartridge. I ran one for years. I personally preferred it over the IV, but that's just me. It was designed by my predesesor. About the Beryllium...let me explain. The holy grail with things like carts and speakers is the transverse speed of sound of the material. It's a measure of specific stiffness. In the III and the IV in order to get a low mass the cantilever first non rigid body resonance had to be in the audio range. In the III that made for a small sag and peak. In the IV it made for a lesser sag and two peaks. They were all well controlled. But Beryllium... with it's speed of sound between two and three times higher than aluminum allowed us to get that cantelever resonance well out of the audio range without compromising mass. A high moving mass will just rip apart record groove modulation. Another part is the geometry of the cantelever. Materials like boron and diamond have a speed of sound similar to Beryllium, but it's not so easy to make a geometry like the microwall tube so you can take advantage of the properties. An airplane could be made of the very best high strength aerospace alloys, but if it were a solid piece it would never get off the ground. That's the problem with many boron and ruby carts.
(A)nd about 80% of a cartridges sound is determined by the stylus. the IV had beryllium in it too....in the form of a short rod filling the hollow aluminum stepped shank right at the magnet. A Microwall Be cantilever will be a dark steel brown/gray color. The only ratshack I recall with one is the v-15rs. It had the cantilever of my ml140HE, but an older type magnetic structure. It was as good as a V. BTW the IV shank was I think the most complicated and expensive one we ever did."
The ML140HE:
"All I can say is that I tried to make the ML series the best i could. I wanted to make it the best ever. I was pretty new there, and was assigned to do a second tier beryllium line. I sure didn't get to tell the marketing people what to do. They came up with stuff like "parafold biflux" and such. There are things they would not let me do, but I wasn't ordered to design to a specific performance level...just a specific cost level. I was free to get as much performance as I could, but restricted to half the cost.I was also ordered to have a very different look, and told to get in the industrial design artists in on it early. I personally wanted lower sprung mass, so no metal body parts other than shielding, core , winding, and pins. I made the magnetic circuit lighter, and everything smaller. I made a new bearing system, which was 90% of the work. If there was any real compromise I had to make, i guess it was the HE stone. I was happy with the tip geometry but not the mass. So I tried to dump (moving) mass elsewhere.
There's one thing we wanted to do that was deemed impractical. We used x-ray window material for the cantilevers. It came in two thicknesses: 0.5 mil and 0.3 mil. ---We used the 0.5 mil for all production---, but made 0.3 mil MLs and 5s in the lab. I took the 0.3 stuff and mounted a stone with the clylindrical shank portion carefully cut off, using the diamond cleaving technique jewellers use. The tiny bit left was butt glued onto the cantilever. You could hardly even see it. It was so fragile as to be almost impossible to put on a record by hand. The slightest dust fiber would render it unuseable, since the stone only protruded a few thousands below the cantilever paddle. A smaller magnet was used too. So output was low. It had a crazy high resonance frequency.
But if the record was perfectly flat and clean, it could track pretty much any commercial pressing at 0.1g , not including dynamic stabilizer force.
But I agree it was impractical. I used these on my personal home system at a higher tracking force though.
I suppose I come off as being biased. I guess. I generally like my stuff. I'll agree to one thing...ML is the worlds ugliest cartridge."
Les L M Watts Technology
Rare, Henry? The styli can be still be found, priced from anywhere between $50 (from someone who doesn't know what they have) to $499. Finding the generator is the thing. In comparison the TK7LCa is a common cart and I've never seen one of the Signets with a four-digit serial number.
About the ML140 HE stylus- there is also a ML120 HE, the original was also equipped with a be. cantilever but with a less well polished stylus. The cost/performance ratio was so heavily weighed in favor of the 120 that savvy buyers purchased the 120 rather than the more expensive MASCAR polished 140. Marketing noticed the sales disparity and production was directed to change the 120 cantilever to aluminum. I've both, the 120 (with a red, rather than white dot on the grip), although a nice assembly does not compare well to the 140/be stylus.
Long post, excuse one last observation: The ML140/Ultra 300/Ultra 400 cantilevers are reputed to be interchangeable, have never (Thuchan) read a disparaging comment on any of the above.
Henry: read your comments on the Glanz thread & laughed, I suspect it was your wish that the lucky owners of the carts would have their (umm) "Glanz" fall off that finds you now in the position of meeting the Greek's recommendation of "In moderation, everything".
Peace, |
Regards, Halcro: Henry, your insults are superb. The forum, and particularly this thread would suffer without them, more so than with. :)
"Syntax" made a comment several years ago, he found the ML140 HE was very good on the AT 1010 arm, a Signet TK10-11 suffered on the same arm. I've been looking for the AT arm since. Another scarce item, could Nikola's passion for tonearms be contagious?.
Shure's HE is a Shibata variant. Following a Thanksgiving feast, too lazy right now to look it up but IIRC, 1.5 x 45uM. I have it for the V15-111, IV and V as well as the ML140 HE, a very balanced sounding stylus profile capable of good weight in the bass, commendable hf extension and no ragged edges in the mids.
I'm working with a Pio. PC-330 cart at the time, a 0.5mil conical on titanium. This cart was sent by a gracious fellow forumer. Another gentleman provided a compatible replacement stylus for the PC-770EX. This is a fine nude elliptical on al. Quad capable, 10-60khz! At 2.5mv output, fast transients & quiet in the groove. Not an exceedingly wide soundstage but very good channel balance, excellent depth & imaging, dynamics can be startling. A Shibata (also 10-60K response) for the PC (Pioneer cart)-1000C is available. Line contact or Shibata profiles are attractive to my ear & I'm hot on the trail for the PN-1000C stylus. There is also a PN(Pioneer Needle)-550, ellipt. on beryllium. By the time I'm through exploring the available styli for this quite competent generator I may have as much tied up in a "gimme" cart as any in the stable.
What a bunch of enablers (and I can't thank them enough)!
Peace, |
Regards, Nandric: For the relatively unrecognized Pio. cart mentioned above, there are about ten styli available, a mix & match of conical, elliptical & Shibata on al., titanium and beryllium. Pick just about any AT or Signet, options abound. Mainstream Shure carts like the V-15 series? Again, stereo or mono, 33.3 or 78 rpm, conical, ellipt., HE, ML & cantilever builds are yet another elective. ADC? Covered. Pfansteil, Goldring, EVG, JICO, Nagaoaka, Ortofon, even Radio Shack is expanding their catalog. I think the point might be made that with MM/MI (etc) carts, that even though the original styli are becoming both more scarce and costly, the options are available. Peter Lederman will provide a respectable line contact on ruby for a nom. $250, nude ellipt. on al for less. An entirely different case with MC carts. With these the owner is indeed at the tender mercy (?) of the retipper. No association & no personal experience but getting good feedback: http://www.phonocartridgeretipping.com/index.htmlAny "color"you want, any color at all! Peace, |
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Regards, Thuchan: One wishing to assess Shure carts has their work cut out for them, VTA and Loading are "all over the map". A Gramophone review, June 1984 of the ML140HE:  "Overall sound quality had a transparent brightness which immediately lifted this cartridge into the upper hi=fi bracket. ---"The effect was of smoothness in the middle register with bass clearly extending down to the audible limits.---"With a capacitance loading of around 150pF, the response is of ruler flatness, sloping very gently by a mere 1dB @ 20kHz--- (T)his smoothness extends to well above 30kHz." Also noted was a "Sharp rise time, absence of unwanted resonance". Shures' recommended ML140 HE Cap. is 250pF. An experienced reviewer (John Borwick) with the gear to accurately measure response found differently. Possibly an input from their marketing people, intended to make the cart more attractive to "home stereo" owners who either didn't care to, or have the facilities to make loading adjustments? The V15 gained its moniker from an early recognition of the advantages of standardization of cantilever tracking angle. In this instance 15* from which the V15 series gained its identification. As RF interference is eliminated at loading above 400pF, your V15-111 was designed for suggested loading at 400-600pF. A slightly tail-down VTA should be tried. An early offering of carts with laminated plates, the mounting shroud was extended in depth as a measure of controlling resonance. The HE stylus response is rich in the mids. Solid bass & nicely resolving in the hfs, avoiding the somewhat forwardness of the upper range some observe with either the elliptical or ML styli. The al cantilever effects a midrange warmth and lively bass. Legendary tracker, listening to "Gaucho" with mine now, you may suspect I enjoy the V15-111/HE? The M75, M91, M95 & M97 progressed with the V15 carts, configured from flat to pentagonal casings. "Junior" V15's, styli are frequently interchangeable within the "family", sometimes requiring a consideration of "plastic surgery". The M97xE to V15xMR is an example. The V15-IV, a love-hate cart, a possibly "un-Shure" first step into "neutrality", let us know your impression? The V15-V, IIRC there were thirteen options, styli, damper brush & P-mount. Well regarded cart, the 300/400 Ultra, ML120/140HE & M97E/ML/HE were siblings. Running out of ink, early Shures are moderately capacitance insensitive. Bumped up into the 400-600pF range in the mid/late 70s & back into the 200-300pF range in the '80s. VTA needs attention. US mfg. styli are of good quality, some later imports are of suspected QC deficiencies. There is also a M24H, hyperbolic nude, 20-50kHz response. Shure's only (AFAIK) cart specifically designated for CD-4 play, an attractive 3.0mv output & 510 ohm output impedance . One offered now, someone reading this really needs this cart. ;) Here: http://www.ebay.com/itm/Genuine-Shure-M24H-Wide-Range-Dynetic-Cartridge-Stylus-New-Sealed-in-Box-NOS-/321029684535?pt=US_Record_Player_Turntable_Parts&hash=item4abedc3d37NOS styli also available, same search. No association with either. Am casually looking for an Ultra 500, reports from owners are of the "from my cold, dead hands" category. Peace, |
Regards, In_Shore: A pencil eraser is both abrasive and gentle enough to remove oxidation from headshell contacts, cartridge out-pins & etc without damaging plating.
Peace, |
Regards, Harold n-t-b: Were I in the market, this one looks 100% correct: http://www.ebay.com/itm/150955609685?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649On pg. 161, this thread, Grbluen2 discussed a problem with a rotated AT stylus, see his 09-09-'12 post. There were several suggestions made & the problem was resolved. AT styli are fairly sturdy assemblages. If rotated they can be (sometimes, a la Grbluen2) "tweezed" back into a usable azimuth. If off-axis and unlistenable, you might try pushing against the compliance donut at the base of the cantilever with a blunt rod. A wooden matchstick comes to mind. This should be done with due deliberation. Of course. If loaded above 200pF the 20SS tends towards brightness. With a VTF in the 1.3-1.4gm range and aligned by the cantilever, should the response still seems grainy or etched then it seems likely the stylus assembly is defective. As an alternative, consider an ATN-15XE stylus. Elliptical on aluminum, slightly diminished detail & apparent extension but a capable performer with a slightly warmer character. Good luck! Peace, |
Regards, Pickering admirers: Might take a look: http://www.pickeringuk.com/spex.htmlThe TL4S is a P-mount design, styli should be compatible with your Stanton carts. Hopefully Griffithds (hi, Don) will consult his resources and confirm? Might also take a peek at the fairly obscure Stanton 7804S as described on the VE database. Those familiar with this cart report a positive experience. A current production alternative to the 881, an elliptical from Stanton manufactured (AFAIK) in their Florida location, anyone know this cart? [url]http://www.musiciansfriend.com/pro-audio/stanton-890-fs-mp4-cartridge-for-finalscratch--matched-pair-2-rm[url] The description is imaginative, "2 matched cartridges mounted on tone-arm like devices (that would be headshells) ---."2 spherical styli---. 2 elliptical styli are designed for hi-quality playback for recording of records into the FinalScratch system or any other application where sound quality is critical." The 890AL would seem to be the most attractive alternate to the classic 881, 900 ohm impedance as compared to 1300 ohm imped. for the 890FS offered above. Thuchan reminded me to dig out one of my Shure V15-111s. Sporting the HE stylus, the slightly abrasive quality heard with the elliptical stylus (on my ancient SS rig) is corrected, resonance related artifacts in the upper registers are relegated into obscurity and the bass moves with an agile strength supporting the status of the V15-111 being, for some, a reference cart for forty years. Thanks, Thuchan, have listened to nothing else for a week & apologies to the Stantering crew for thread drift. Peace, |
Distortions in politics are the norm. In audio it's a BUZZZZZ word.
Pax, |
Regards, Raul: Distortion is most often understood to mean IGD, OGD, FIM, TIM, sometimes even PMS. Music is generally considered an art and the elements constituting "good" art, it's tone, texture and structural elements have yet to be empirically defined. The consensus among the cognoscenti is that the agreement of informed persons is sufficient. It seems there are a number of respondents in this thread who meet that criteria.
Concern as to wether electrons in a fuse are bumping into each other from right to left or left to right, for some, just may be a distraction from the hypothetical core of our pursuit, which rightfully should be the reproduction of music in a manner the listener deems pleasurable?
The purists' perspective is unassailable and entirely respectable. However, & since we're not all of the same mold, using the example of an audiophile whose hearing acuity above, say 12kHz, was diminished would it be considered unacceptable if he were to turn up the treble just a teensy bit, or would it be better to say-
Regards & enjoy the music?
Peace, |
Regards, Raul: Although agreeing that the pursuit of the ideal is a worthy goal, the assertion that there is a single solution for all applications is itself questionable. “Beware the man of a single book.” ― St. Thomas Aquinas
Having spent twelve years playing clarinet (b-flat, B-flat bass & E-flat contra bass) as a student, amateur and unpaid semi-professional until economic realities intruded, and having participated in symphonic, woodwind and operatic ensembles the evidence is adequate to satisfy myself that no two examples of the same instrument, nor the tone, texture and technique of the performer will be the same. Experiences as a poor musician, cabinetmaker and educator leave me quite content to remain a simple enthusiast in audio. Consequently I think it best to avoid unsupported conclusions concerning the awareness or priorities of others.
Speakers are Paradigm Signature series, the S4. A 2 1/2 way design, response is 35-45k, +- 2db. Midrange runs full range, beryllium tweeters are surprisingly non-intrusive. Four speakers, each bolted on an Atacama stand, lead shot/kitty litter filled & anchored to a 12 x 12 x 2" walnut block.
At the foot of each is a comparably voiced Paradigm 12" DSP active sub, front ported and integrated in (according to my HT oriented friends) a perhaps overly conservative manner. Front speakers are eight feet apart, three feet from the front (long) wall, rears are more towards the corners and toed to face the fronts. All four arrayed an equal distance from the primary listening position. Ambience, soundstage and imaging is satisfactory. Fronts are powered straight from the amp, rears and subs through a Niles selector with volume control. Rears are run -3db. The "media" room is 18 x 22 x 10'6, large oriental carpet & leather furniture.
Patch cords. "The Wasatch cables possess a kind of presence factor, or rather a coherence thing that I find alluring as well as musically engaging. The impression remained with everything I threw at them." (Clement Perry, Stereo Times, 1/11/2001). Wasatch Cable Works, before they became ZU.
Amplification is gratifyingly absent of anomalous contributions, old-but-maintained Pioneer SX-1980 (a RECEIVER oh, the shame). Offers distortion response of 0.03% @ 135 watts/1 hour, TIM 0.01%. Dual coffee can sized tororidal transformers and four 22,000uF capacitors, two per channel. Clarity & balance is not a concern. Not the ultimate, but as far as neutrality, power reserve & resolution it serves it's purpose in an uncolored workman like fashion. Take it as you will, there is no one thing that stands out about it.
I must confess, your's & Dgarretson's comments concerning "Fuses that matter" are intriguing. Response & integration of the subs is satisfactory, even at the low gain implemented there are times when I've an impression they're lagging.
Current TT is a Pio. Exclusive PL 70L-11. Order would be P3. P-10, then PL-70, a stable hanging rotor drive & resonance free performer.
There are days when it all works together in a superlative manner, others when I wonder what went wrong. Soundsmith notified me yesterday that the ruby/optimized LC rebuild of a ceramic bodied ML150 OCC I sent in Sept. is finished, anticipating it'll provide a few more days of the superlative type. Hope it gets here before the Apocalypse, Dec. 21. I'll consider fuses for the subs, but no movement there until the 22nd. ;)
Now, back to fuse directionality?
Peace, |
Regards, Raul: Thanks for your comments. As mentioned, there are days when my modest rig exceeds expectations and occasionally keeps me captivated into the early hours. There are other sessions when the components seem to not want to have anything to do with each other.
Although not exactly given away with a purchase of ten gallons of gas and even though the subwoofers are nicely timbre matched to the speakers, in comparison with the alacrity in transient behavior and definition the mains are capable of, and if specific attention is given, the DSP 3200's simply fail to keep pace. This is heard as overshoot. Not of the Signature series, Paradigm appears to have given more attention to rise time and range (23hz, extension to 18hz) than to quieting excursion at termination of signal.
If opportunity to audition the Velodynes is presented it should be interesting. The figures you give for distortion are, for a subwoofer, very impressive.
Looking forward to your impressions of the Precept, IIRC the 440 is ML/beryllium?
Peace, |
Regards, Halcro: Condolences, Henry. Having given it considerable thought, there is a suspicion of meteorological impact. Living in the "sticks" is a dubious advantage, have my own personal transformer & the old rig is on a dedicated twenty amp line, voltage swing and noise in the line are not excessive.
Observed is a limbering-up period of a half hour and the expectation that a cart that has laid idle for a while will need some run-in. Listener's (re)acclimation may contribute. For those who enjoy speculation, as a cartridge is an electrical generator, some degree of Joule heating is another potential candidate. The correct perspective is that resistance also depends on temperature, usually increasing as the temperature increases. For reasonably small changes in temperature, the change in resistivity, and therefore the change in resistance, is proportional to the temperature change.
In the U.S., voltage at its peak hits about +170 V, decreases through 0 to -170 V, and then rises back through 0 to +170 V again. 120 volts is actually a kind of average voltage, the peak really is about 170 V. It's not difficult for an armchair theoretician to anticipate severe spikes in voltage frying a resistor, hopefully your repair will be an easy fix.
In 2009, the U.S. midwest experienced a severe ice storm, service was interrupted to tens of thousands of customers. Here, it was necessary to rely on a generator for eleven days before power was restored, consideration was given to surges as service was reconnected. Did a little research & obtained a power conditioner with battery backup, a Furman F1000-UPS Uninterruptible Back-up Power Supply unit with non sacrificial surge protection and 120v regulation within 5%, protection rather than regeneration was the concern.
Will proceed to compile data on barometer, humidity, ambient temperature, planetary alignment & regular consultation of the crystal ball.
Hope you get your rig up & running quickly, otherwise, still listening to the Virtuoso?
Season's best & Peace, |
Regards, Griffithds: Following your saga of the TL4S with interest. As reports drift in, looks like the TL series may be a winner. It's interesting that the PickeringUK site identifies it as "line contact", can you confirm the "S" designation refers to "Stereohedron"?
Peace,
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Regards, Lewm: That surprising bit of data is from Boston University, Department of Physics. In the most sincere manner possible, if anyone can supply other figures it would be appreciated. AC is measured on a time scale (Hz), cyclical & there is an average at the receptacle. Here it averages 124v AC. A quote, again from Boston College: "Voltage from a wall socket is known as the root mean square, or rms, average. Because the voltage varies sinusoidally, with as much positive as negative, doing a straight average would get you zero for the average voltage". Voltage is then an average of the range from positive to negative. BTW, 117v rms is my observed low, 128v rms for high. R(oot) m(ean) s(quare) value is obtained: first, square everything second, average. third, take the square root of the average. For a clear description: http://www.raeng.org.uk/education/diploma/maths/pdf/exemplars_engineering/8_RMS.pdfHaving dabbled around with pencil & paper for a tormented moment, the broadest possible expression is that rms voltage is a (nom) 70% of peak. 67% was a repeated outcome. As this is a square root calculation involving infinite variables, neither figure should be taken as correct. Peace, |
Regards Griffithds: The Stanton/Pickering carts have me puzzled. Vinyl Engine Data Base is often incorrect, glad to have a Stantering Guru on board. That would be you, Don.
Thanks for keeping us informed.
Peace, |
Regards, Halcro: Humidity at 76%, barometer is 29.66 millibars. Outside temp. 48F, foggy this morning. Elec. service is holding a steady 125v. Old rig is cranking out out some pretty good soundstage, dynamics & ambience.
Running in an AT ML150 OCC on a Yamamoto HS-2, bronze plate above cherry/10.5gm mass. Crystal clear optimized line contact on ruby. Sounds good, Soundsmith does beautiful work & everything's "in the groove".
Turning over every stone for a DTL-4S, have both XV-15 & 681 MI generator bodies (thanks for that info, Don), keeping a sharp eye out for a TL body. Vinyl Engine Data Base is a WIKI, caveats apply.
Horoscope says Justin Beeber loves me today, crystal ball says if your name is Henry it's a good day for vinyl in Oz.
Life is good, best wishes for this holiday & any other season.
Peace, ALL. |
Regards, Lew: Apologies for not having qualified that figure, leaving you in the position of an informed audio enthusiast deliberating the merits of a Soundesign "1,000 watt Peak Power" boom box at the supermarket.
Peace, |
Regards, Griffithds: Thanks again. A reminder, the painted white, gray, then silver and gold XV-15 motors are of increasingly tighter spec., calibrated 681 bodies (this also implies a lab-matched stylus) will be engraved with a registration #. Twin sons from different fathers, both are four coil generators.
Peace, |
Regards, Lew: Not sure of the exact date, CE 1977/78? Claims for output, "bigger is better" became so outrageous that truth in advertising laws were invoked. Ratings were tied to continuous maximum output for one hour without clipping and statement of distortion of all species were required to be lab validated.
Sometime in the late '80s, televised ads were supplied to broadcast stations with elevated bias. There was an FCC edict that this would cease. In the hey-day of loudness wars, compression was substituted for volume.
Last week this was reaffirmed. How quickly we forget.
Crystal ball says 64* F & a chance of rain in the Sydney NSW area. Clean power for the next several days. I understand Aussies have four seasons; street paving, elec. service repair, typhoon & fire up the barbie.
Peace, |
Regards, Halcro: FYI, my crystal ball is calibrated to two nines. You slept through some great weather. :)
The Virtuoso is holding your interest?
Peace, |
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, |
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, |
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