Transcript
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WHY A RECORD STABILIZING RING? In the beginning of the era of the Lp (Columbia’s trademark had a capital L and an under case p) the equipment for playback was (in hindsight) rather simple. Records were generally played using ceramic cartridges or crystal pick-ups by Acos and Ronette for example, and moving iron cartridges made by General Electric, Tannoy and Decca. The moving magnet cartridge had yet to be invented by AKG. In most cases a record player was connected to the amplifier stage of a radio. Although the transistor had been invented, it was not ready for commercial use yet. The amplifiers were tube amplifiers. Most did not deliver more than 10 Watts, but well enough to drive loudspeaker units that could boast of a high efficiency. Only in the homes of the die-hards, cartridges of Ortofon and Fairchild working along the moving coil principle were used, and also the loudspeakers were more sophisticated. The crystal pick-ups did not read all of the high frequency content of a record. Their frequency bands were limited as was the compliance. The sapphire tips were conical and had a large tip mass. They were big. The record itself was rather heavy and so were the arms of the record players and gramophones, as a maximum playing weight of 10 gr. was mostly indicated.
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The evolution of the art of recording and the manufacturing of records is amazing. Labels like Mercury and Westminster made outstanding recordings in the mono era. Despite the fact that Remington was a low budget, low quality label, it was Robert Blake, Don Gabor’s recording engineer, who made the first stereo recordings in November of 1953 in Cincinnati’s Music Hall with the Cincinnati Symphony Orchestra conducted by Thor Johnson and with the Helsinki University Chorus. This was before RCA, Decca and Mercury taped their first stereo recordings in the following years.
DISTORTION By the end of the nineteen fifties the long-playing stereo record had become a product with very refined technical qualities if compared to the early Lp presented to the world by Columbia in 1947 and marketed from 1948 on. Now lacquer cutting and plate making had been brought to a much higher standard. Sound recording tape had finer emulsion and better coating, and it was more stretch resistant. Tape heads had narrower gaps and they were less demanding on the tape surface. Vinyl was getting purer. With it the frequency band was extended and with the development of better amplifiers and mixing consoles the dynamics were improved. The signal of one channel was engraved in a lateral movement, the left-right meandering as was the technique of Emil Berliner, the inventor of the Gramophone and the flat record. And the signal of the other channel was cut in a vertical movement as it was originally devised by Thomas Alva Edison in his Phonograph, first in the cylinder and later used in the thick records. (His system was only adopted in the early nineteen hundreds by Pathé in France.) The vertical movement has a very limited range and has therefore poor dynamics and less detail. As a result the distortion in the vertical engraving is very high if compared to that of the lateral groove. The engineers found a way to overcome this phenomenon by dividing the distortion evenly over the two signals by turning the groove as it were by 45°. Now both signals were read in a similar way. The improvement in the designs of equipment and the record itself led to the possibility of making high quality stereo recordings and pressings, but only if the record company decided to do so and if the customer wanted to pay for such a quality product. The manufacturers of playback equipment did not sit still either. Both AKG and Shure introduced the first moving magnet cartridges as early as 1956 and their stereo versions were ready by 1958 when the stereo disc was introduced.
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SME designed the arm to match. It made all necessary adjustments possible for optimum tracking of the stereo groove. These new cartridges were much lighter in weight if compared to the heavy moving coil cartridges mounted in head shells that generally also housed the small, but relative heavy step up transformers. The newly launched elliptical stylus reduced the contact surface of the tip with the groove. It was capable of retrieving far more information, with greater detail and it would generate less distortion. The standardization of the Vertical Tracking Angle (at least in cartridges and not necessarily followed by the cutting engineers) helped somewhat to minimize groove distortion as well. Much of the distortion though is caused by the difference in the way the record is cut and the way it is played back by the turntable. While cutting a record, the cutting head moves in a straight line, starting at the outside of the lacquer disc. However most turntables and record players have radial or pivotal arms. Tangential arms that imitate the parallel tracking of the cutter head are few. They were manufactured by Rabco, B&O, and Goldmund, and still are produced by Souther and Air Tangent. They are in use by knowledgeable and very demanding audiophiles and music lovers in their sophisticated systems like those of Rockport and Clearaudio.
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The continuously changing position of a radial arm changes the angle of the diamond tip to the wall of the groove. A greater or lesser difference in time between the two channels will occur in most instances, except on the two spots were the alignment is exact. A tangential arm does not suffer from this problem and will generate minimal distortion at all times.
There is a second cause of distortion. It occurs at the end of the record. As the radius of the groove is becoming smaller and smaller towards its end, the speed (velocity) is decreasing. Although the record turns at its nominal speed (33.33 or 45 RPM) the signal has less groove length and distortion is increased. To minimize this distortion, RCA devised a method by which a second, counteracting signal is fed to the recorded signal. This was to make records better listenable when played on ordinary record players and sophisticated turntables alike. Neither the use of a tangential arm, nor the electronic correction as devised by RCA,
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do eliminate the most disturbing distortion, the source of which is the vinyl itself. It is a known fact that the vinyl record can easily pick up vibrations that interfere with the engraved signal. This phenomenon is generally not considered as being serious. Most record manufacturers thought (and sometimes still think) that the modern cartridges with high compliant cantilevers do not need thick and heavy vinyl any longer. Record companies tried to minimize the production cost and wanted to keep a high sound quality at the same time. This is of course a contradiction, as was proven by the introduction by RCA of the Dynaflex type of pressing in 1969. Dynaflex meant economizing on vinyl. But the flimsy discs were vulnerable and not always flat and certainly not at all appreciated by the serious record collector. Consequently RCA had to discontinue their much-advertised gimmick. Yet most record companies tried to make the vinyl record as light as possible. This was the more urgent in the nineteen seventies when the world had its first oil crisis in 1973. But the analog fan was always looking for heavier pressings and still is in favor for the 180 gr. Type of record.
THE COUPLING OF THE RECORD TO THE TURNTABLE Audiophiles aiming at a high fidelity reproduction in their homes (the first issue of High Fidelity magazine was published in the summer of 1951) knew right from the beginning that there are differences in the physical and mechanical properties of arms, platters and motors of record players and gramophones. Much experimenting was done to find the best mechanical and acoustical isolation from the motor, the plinth, and the surroundings. By mid nineteen sixty Mitch Cotter invented the floating sub chassis turntable that was quite revolutionary. It separated (de-coupled) the motor from the platter by means of a belt. Since the chassis with platter was spring loaded, mechanical and acoustical feedback from the surroundings were reduced to the max. With it the signal had gained in precision and fine detail. The design was marketed by Acoustic Research and was later adopted by Thorens and Ariston, and much later by Linn who copied the Thorens (TD150) and the Ariston turntables. However it would take audiophiles and manufacturers another decade to discover that by placing a weight over the spindle, the signal retrieving was improved significantly. Yet perfection had not been achieved. The complaint remained that the record was sensitive to vibrations mostly originating from the cartridge and this was leading to much distortion. In order to eliminate this distortion, better turntable mats were proposed and phono amplifiers were designed. At the same time the understanding of the behavior of tone arms took a big step forward. Also cartridges were getting better and better. Some designers of turntables made their turntables as heavy as possible, not just to improve speed constancy but also to help resolve the problem of vibrations that occur in the record. They added clamps or heavy turntable weights to hold the record still. Furthermore it was becoming clear that cables had a very important function in the suppression of distortion (not the elimination of it) and rendering a harmonious sound. Although not every constructor and audiophile was able to name the cause, a few people realized that the record was still somewhat acting like a loudspeaker cone.
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It was Trio/Kenwood who brought the solution to this problem in 1980. Their engineers designed a very sophisticated turntable, the L-07D, with a stabilizing weight to be placed over the spindle, and on top of that they designed a ring that would clamp the record at its periphery to the platter/turntable mat. The ring matched the table to perfection. Now the record really would lay still. The result was the suppression of all the vibrations that occur in the vinyl by the cartridge riding the modulated groove, and which were added to the delicate signal. Now distortion was lowered by many dBs and the signal was as pure as could be. When a lacquer is cut it is coupled to the platter of the lathe by means of a vacuum pump. Kenwood’s solution was mimicking this procedure completely. But how musical was the ring?
MY PERSONAL AIM Since the advent of Kenwood’s ring, I had the desire to have a ring constructed for use on the turntables I designed. The Kenwood ring was specifically designed for the L-07D direct drive turntable. As the ring partnered practically only the Kenwood turntable, there was no use in trying to obtain such a ring. Because of its price, a complete L-07D was far out of reach. My ring should have other measurements in relation to different platters. I asked a machinist from a metal shop what the cost of turning a ring would be and many times I was on the verge of having a ring made. But each and every time it was more important for me to have a platter turned of grade aluminum for another turntable than having a ring made to my specifications.
While constructing turntables (the first one in 1980), I was learning all the time about mechanical and acoustical properties of materials, how to use and combine these and find solutions. This enabled me in the beginning of the nineteen nineties to optimize several CD players, mechanically and acoustically. The mechanical and acoustical aspects are far more important than exchanging capacitors, resistors, opamps, wires and connectors. I also found out that the physical properties of the cabinet, especially the way the metal from which the cabinet has been extruded and the cover has been molded, do contribute to the quality and similarity of the individual channels. Already taking out the plastic rod
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which is attached to the power knob at the front of the cabinet, resulted in a more precise, less make-believe high frequency reproduction. Applying damping material in certain places in order to control vibrations that interfere with the proper reading of the samples, helped me to acquire a lot of knowledge. First the side panels, the metal top of the cabinet and the mechanics of the tray and the clamp that holds the CD down were distinctively treated. The next step is to determine the exact spots were vibrations occur. While damping a Denon CD player with small pieces of bituminous sheet, I followed a specific pattern when all of a sudden the stage opened up, was getting larger and deeper, the harmonics were improved and transient reproduction (the weakest feature of the CD format) sounded more exact and natural. The CD player was cheap compared to the high end machines of Mark Levinson and Krell for instance. But when my optimized player was compared to these expensive giants in the auditorium of a high end shop, the simple player was in the same league in every aspect, except for the ultra low frequencies. There the cheap player lacked strength because of its small power supply. It goes without saying that the player was a multi bit player with Burr Brown converters.
STABILIZING WEIGHT In the nineteen seventies a friend had several turntable weights turned from brass. I immediately heard that the weight of 1 kg. was far too heavy. Not so much for the turntable it was put on (a Thorens TD125Mk2), but for the character of the sound. That is why I designed (in 1980) a much lighter Stabilizer Weight of about 350 grs. That weight did not alter the sound and did not take away the speed and clarity, and at the same time improved the signal. It made it more precise. My desire to have a peripheral ring was never gone and in 2003 I finally realized that, if I could not have one turned or if I could not order one from Clearaudio, Merrill or VPI, the only way to obtain one was to make one myself. At least I could try to make a prototype and see where it led to. I wanted to make a stabilizing ring to improve the contact of record and platter and yet not alter the sound the way the heavy brass turntable weight did.
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WARPED RECORDS My experiments with several prototype rings taught me that a certain weight to flatten warped records was asked for. But what material(s) and what weight should be added? It was also clear that a certain amount of damping was necessary in order to give the signal the right balance. Not only the choice of materials is crucial but also how they would be combined is of great importance. Just adding more of the same is not always the best thing to do. While experimenting, it once again became clear that lead is a material that should be used sparingly or should not be used at all. My rule is to use materials in which the energy can travel relatively fast and die out gradually. In other words: the materials should have properties that allow the dissipation of energy. Lead used pure and as sole or dominant material in turntables and other equipment means the end of music. It works like a steep filter, like a brick wall filter in digital formats. It stops the energy from flowing and dissipating and bounces the energy back to the source.
DISSIPATION Designers know all to well that in amplifiers the bandwidth should be very high. Especially when reproducing the signals of analog sources a frequency band of up to 400.000 Hz. Is asked for in order to reproduce all the refined harmonics, and even though a 6 dB slope just above 20 kHz. Is built in. So if lead is used, it should be best located at the end of the dissipation chain. Copper and brass, aluminum and stainless steel all have their strength and good sound properties. Acrylic comes close to aluminum when strength is measured. But the propagation of sound in aluminum has a higher speed than in acrylic. In all these materials the sound can travel relatively fast although not at the same speed. Rubber and felt have characteristics which differ significantly. Especially felt is a material that should also be used sparingly. Even the small felt ring that comes with the Michell clamp can have a negative effect on the sound reproduction. Various combinations that give gradual dissipation and the necessary damping at the same time are possible. There is still another influence which certain materials can have and that influence is brought about by the way they have been cast, the speed of cooling down and the way they have been extruded or stamped. These influences may be minimal when they are used in thick and relatively heavy blocks or plates and the influence may not be noticeable in practice. Or, when used in thin plates of low weight, they may have a disastrous effect especially as far as pre-amplifiers, CD players and DA converters are concerned. My first ring was made of paper (200 gr.) glued to two rings of cardboard to which pieces of metal were glued. My second prototype was made of an aluminum top ring, supported by cardboard rings to which a copper tube was added. This was the basis on which the Universal Record Stabilizing Ring (RSR) was designed. In order to be able to have the segments of the RSR manufactured professionally, I launched the ring as a project for interested analog fans who would participate in order to obtain a rather inexpensive peripheral ring with good sounding qualities and which was able to flatten records with warps.
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PLATTERS OF 300 MM OR LARGER While constructing the prototypes I had been contemplating to use acrylic as a support ring (as a substitute for the cardboard) or intermediate ring, and also wood as the material of an intermediate ring. Wood is still on my agenda and trials are in progress. One participant of the first production run - who owns a turntable with a platter of 300 mm in diameter - suggested that the stainless steel support ring could be followed by one or more large acrylic rings with an inner diameter close to the diameter of the platter. Since he does not have command of his left hand fully, his objective was that in this way he easily could slip the ring over the platter of his Linn Axis. The idea was OK but the materialization of it was another matter. The large acrylic intermediate ring seemed an option as an additional choice. For centering purposes only four thin strips of plastic or felt, would have to be glued with very thin double sided tape to the outside of the platter. This was a very practical solution only in theory. I abandoned this option when the effect of incorporating one or two large size (340/302.4 mm) acrylic intermediate rings was heard. The mid-band lacked precision and firmness and that is what we all want to avoid. From the beginning it was clear that the RSR should also fit platters with a diameter much larger than 300 mm (the Teres turntables for example). Thus finally the rings following the support ring have the same outer diameter (340 mm) and the same inner diameter (320 mm) so it will fit a belt drive Thorens or Linn, as well as those heavily constructed flagships of Teres, SOTA, VPI, Clearaudio, Verdier, Micro Seiki, and the like.
A SIMPLE DIY STABILIZING RING? My project started with my personal endeavor to perfect the signal. I also wanted to design the ring in order to flatten light warps. And there was my desire to optimize the ring to attain a signal with a harmonic and open sound. Furthermore, the ring should be cheaper than the rings that are available for $600 to up to $1100. The Clearaudio version costs $800, and the ring offered by Nikos Skaloumbakas (Audioclub of Athens) costs $600, not taking into account the cost of packaging and shipment of these rings. My first prototype had an upper ring with 340 mm outside diameter and 297 mm inside diameter. The two cardboard rings had an outside diameter of 340 mm also and an inside diameter of 305 mm. I soon discovered the effect this ring and the various possibilities of added material had on the reading of the signal engraved in the vinyl of the record. When playing records I always use the stabilizing center weight (information can be found on my web site) used by several audiophiles. Either they ordered one or had one turned. The stabilizing center weight meant a vast improvement in sound reproduction: less distortion. Adding the prototype of the ring meant a step further in improving the contact between record and turntable mat and thus improving the signal retrieval. The second prototype with the upper ring cut out of a sheet of 1 mm thick aluminum had the same effect but this changed when further experiments were carried out and various materials were added in order to give the ring more weight.
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GETTING MORE PROFESSIONAL A definitive RSR should have to be better in shape, in precision and have a calculated weight. That meant that the segments would have to be made by professionals in a metal workshop or factory. In the workshop where I generally order aluminum plates for arm boards and for various turntables, the craftsmen said that they would not be able to make what I wanted and they gave me the address of a factory that specializes in cutting metals in all shapes, forms and sizes by means of a laser, steered by a computer program (CAD). The inquiry resulted in a price that would only be acceptable if at least 20 people would take part in a production run.
MEASUREMENTS AND SIZES The experiments resulted in a ring that should be laid on the rim of the record and had an inner diameter of 297 mm, and an outer diameter of 340 mm. I wanted this upper ring to be followed by what I called ‘support ring’ which should add strength to the upper ring and therefore should be as close to the record's periphery as was feasible. I measured many records and came to the conclusion that the maximum size of a record was 302 mm. There were a few records (mostly releases from obscure labels) that exceeded this size. To be on the safe side I determined that the inner diameter of the supporting ring should be 302.4 mm. I also measured the thickness of several records and found that 1.5 mm was the thinnest record I found. This was including the thickness of the groove guard. So the support ring should not measure more than 1.5 mm in thickness otherwise it would not fall over the groove guard but rest on a large size turntable mat. The upper ring and support ring should fit all turntables. Since platters come in various sizes, the further build up of the ring should take the different sizes of platters into account. Since my experiments told me that a very heavy ring could not be used on a turntable with a lightweight platter (2 to 4 kg.) and specifically the suspended turntable type (floating chassis), I opted for two kinds of additional rings.
First a ring of 5 mm stainless steel with an outer diameter of 340 mm and an inner diameter of 320 mm. One or two of these stainless steel rings could be used for turntables with heavy platters (6.5 to 20 kg.) and would come close to the heavy turntable rings of Clearaudio and Audio Club of Athens. I also choose another stainless steel ring with a thickness of 2 mm but with the same outer and inner diameters (340/320 mm) that would weigh less and could be used for the lighter turntables. The insertion of an acrylic ring and adding the 2 mm stainless steel ring also helps in lowering the point of gravity of the ring.
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HEAVY OR LIGHT A few participants ordered heavy rings. But as of the second production run the option for an all metal heavy RSR was dropped because there are alternatives on the market and I myself do not advise the use of a heavy ring because it tends to compress the sound. Right before the start of the first production run in March 2004 I dropped the option for intermediate rings of corian, because this material was not in stock in gray, but only in white, and this was not suitable in my view. Also a constant percentage of aluminum flakes could not be guaranteed. To order rings in gray corian was also too expensive as an entire sheet would have to be ordered. I wanted to keep the project economical. I also found out that a corian turntable mat does have an uneven frequency characteristic. Corian neglects the mid band to a certain extent. Horns in the symphony orchestra do loose their typical round, warm sound and other instruments have an emphasis on a clear top end and lack in mid-band presence and warmth. The use of a corian mat results in less space and openness in that part of the frequency band. In all cases the upper ring is made of 0.6 mm stainless steel with an outer diameter of 340 mm and inner diameter of 297 mm. The upper ring is followed by a support ring measuring 340 mm outer diameter with a 302.4 mm inner diameter, and it is 1.5 mm thick and is also cut out of stainless steel.
SPECIFIC RING FOR TECHNICS SP-10MK2 ? Apart from the exceptional speed accuracy and the practically immeasurable values for wow and flutter, the Technics SP-10mk2 has the quick start and stop facility which makes it possible to instantly let the music play within a fraction of a second. The effective use of the RSR is not possible because it certainly will slip and loose its centered position. In order to keep the start and stop facility fully, blocks with a triangular shape would have to be made, one side of which should be glued to the beveled side of the platter and another should be parallel to the inside of the ring. This vertical (perpendicular) side should make it possible to lower and lift the RSR so it will be perfectly centered at all times.
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Additional blocks glued to the inside of the RSR should embrace the triangular blocks glued to the platter. This construction would prevent the slipping of the ring when using the quick start and stop facility of the SP-10mk2. This adaptation was too complicated and was omitted. However it is possible to adjust the starting and breaking time of the SP10mk2 by loosening the breaking belt that lies around the disc that is positioned on top of the motor. The amount of breaking (slipping) can thus be determined and a smooth start and stop is achieved. When well done the ring can be used and will work perfectly well. If you have a Technics SP10mk2 or Mk3, or have a turntable with the same or similar powerful motor, it is necessary to adjust the breaking belt. If you have difficulty in keeping the RSR well centered, you can start the motor and then take off the CCD.
SPECIFICATIONS OF THE LONG PLAYING RECORD After having placed the order and while waiting for the various rings to be cut I received a mail from Mr. Howard who sent me additional information on the measurements of the Kenwood rings in relation to the internationally adopted measurements of the long playing record. I found that the most crucial measurements of my ring were in accordance with the measurements of the LP. The Kenwood ring has an inner diameter of 298 mm. I choose 297 mm. This is because I found that there were a few records with a rather small outer diameter. The inner diameter of 302.4 mm of the support ring was chosen in order to make the upper ring as strong as possible. I learned that my choice of the 302.4 mm was exactly the international specification of the maximum diameter of a record. The internationally adopted measurements of the 12” Lp record are not always met by the record manufacturers even not always by the pressing plants of the biggest companies.
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THE PLAY BACK SYSTEM IS THE REFERENCE When designing a peripheral ring one should also remember that many years ago the playback system used by the producer, the recording technician and the cutting engineer (who together made the recording), played a significant role in the final product. If there were aspects in the reproduction that were not to their liking, alterations could be made in the final mix and in the dynamics when cutting the lacquer of which the matrixes were made. And the playback system these professionals used at the time certainly did not have a Record Stabilizing Ring. I was of course anxious to try the various combinations of stainless steel and acrylic rings. I tried the heavy rings and the less heavy ones. I also tried a ring with two large acrylic intermediate rings. This ring made the midband somewhat prominent and blurred, imprecise and unclean. This was coloration that we all want to avoid. After trying many possibilities I found that the lighter ring consisting of upper ring + support + acrylic 5 mm ring + 2mm stainless steel ring is the most musical ring. Each and every turntable that the ring was tested on, brought about the precision one would like to have without altering the speed of the signal (liveliness) and the natural color of the instruments, but yet eliminating distortion. The result of this configuration is just that little extra precision what makes the saxophone player a human being, gives the singer soul, and increases the realism of the symphony orchestra. It increases the feeling of ‘being there’. Now one realizes that much of the high frequency content delivered by the cartridge is mere distortion, caused by the minute movement (vibrations) and eventually some distortion from the groove itself. These high frequencies are fantasy-high-frequencies just like the extreme over sampling in digital formats. With the Universal RSR the high frequencies were exact and natural. The turntables the ring was tested on were: Linn Axis with Basik arm and Van Den Hull Grasshopper; Linn LP12 with Linn Itok and EMT Van Den Hul; My DIY turntable with DIY tone arm and Denon DL103; Technics SL1100 with Rabco SL-8E and Shure M75 (what a sound!); Nottingham Analogue Hyper Space Deck with Space arm and NA3 MM cartridge; Lenco L78 with Denon DL103; Micro Seiki BL91 with Origin Live arm and Grado; Technics SP-10Mk2 with Yamaha tone arm and Philips GP422 cartridge; Micro Seiki BL51 with Mission arm and Mission MC cartridge. (And many more) In all cases a record stabilizing weight or record clamp was used. On the Nottingham, the Technics SL1100, my DIY turntable, the Lenco L78 and the SP-10Mk2, the Universal Record Stabilizer Centre Weight (aluminum) was used. On the Linn Axis with Goldmund Mat the special Goldmund Clamp, and on the Linn LP12 the Michell clamp was used. The RSR performs in the same way with all turntable mats: acrylic and various rubber mats, and with no mat at all like on the Nottingham Analogue Hyper Space Deck. There is always that touch of improved harmonics which ads to the realism of the instruments and the recording.
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RSR VERSUS VACUUM MAT There are various vacuum systems. They were devised and marketed in the nineteen seventies by Audio Technica, Micro Seiki, and Luxman. There is a significant difference between the sound read from a record held down by a vacuum and the sound read from a record coupled to the mat/platter by means of the weight of a peripheral ring and a stabilizer weight or clamp placed on the spindle. The difference lies in the weight. By adding a Universal RSR to the LP, additional mass is added to the vinyl. This means that the record itself becomes a different object. This is illustrated by the efects rings of different weights do have on the reproduction. A heavy weight compresses the sound somewhat and alters the natural balance of it. In principle, a lightweight ring (like the Universal RSR) does not alter the sound balance, but only will make the sound more precise. That is why the final version of the Universal RSR was empirically devised and then more or less carefully re-calculated. By making use of a vacuum to hold the record down and couple it to the mat or directly to the platter, there should not be a more, and a less vacuum. Vacuum is vacuum. And the signal should be precise and not more precise or less precise and should remain the same from beginning to end of the record. These vacuum mats do not always work correctly. While the record plays, most of the time the vacuum will become less. Thus the sound can alter during the playing of a disc. It is not only the weight, but also the fact that the Universal RSR is a sandwich construction made of stainless steel and an acrylic layer in between which makes it different. The acrylic is close to the nature of the vinyl and acts as a filter or as a damping agent. The stainless steel top ring is an extension of the record and does hardly act as a damping buffer (brick wall filter), but it lets any resonance (if there are any) die out gradually (dissipation) via the 1.5 mm support ring (the second segment) and only in the end will be "stopped" by the acrylic ring. Furthermore there are the physical dimensions and its point of gravity. If the 2 mm bottom ring is omitted, the RSR does not work and deteriorates the signal. Also when the acrylic ring is omitted, the sound of the reproduction does not come close to the reproduction when no ring is used. The sound becomes light and the frequency response is unbalanced with a different (decreased) low frequency content.
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This all shows that there is an optimum weight and an optimum combination and an optimum distribution of the materials. And these are not attained by using a vacuum pump because the properties of air are very different from those of stainless steel and acrylic. It also shows that a stabilizing ring should not have a sound (ringing) of its own. When tapping the ring with your knuckles, the frequency is in the lower mid band and the decay is relatively fast. The stabilizing ring has the advantage of the center weight or clamp. Also, in this respect the vacuum mat acts differently.
THE BEST SOUND When gluing the first specimen I discovered that the heavy rings can sound relatively well on heavy turntables with heavy platters. The ancillary equipment should be in the high-end category: powerful amplifiers, cables and preferably large loudspeaker systems with a good rendering of the mid band. Each and every ring (heavy or light weight) lowers the resonance frequency of the record in conjunction with the turntable mat and platter. Heavy rings do that in a more drastic way. Depending on the weight and suspension of the turntable and depending on the combination of cartridge and arm (low or high compliant cartridge with heavy or lighter arm), the Universal RSR also lowers and dampens the resonance but does not alter the balance of the signal, while a heavy ring does alter the naturalness of the reproduction of not only acoustic instruments. On first hearing the addition of a heavy ring to a turntable system one is struck by the clean sound and the depth of the sound stage. But the heavier the ring, the heavier and deeper the sound of the instruments will be. The plasticity of the sound increases but at the same time it is noted that there is less speed and the sound is somewhat compressed.
VARIATIONS ON THE SAME THEME The manufacturing of the RSR is a delicate process. Not only every part is essential in order to arrive at the desired product, also the glue and the way the segments are glued together plays a determining role in the effect the RSR has on the reproduction. These aspects should not be underestimated. When I interviewed M. Guisto from Paris, who had invented an interphase by which the signal of the CD player could be connected to the phono stage of the (pre-) amplifier with extraordinary results, he told me that he also modified Satin phono cartridges. The modification resulted in a signal to noise ration of 100 dB. He would do the delicate job on a Sunday mornings, when no stress from his business could interfere with his concentration. He said that out of ten cartridges the modification of only six cartridges succeeded. Four could be thrown away. It is known that cartridge manufacturers label their cartridges after compliance, frequency band and sound characteristic have been measured. So a top model and a budget version can come from the same production run. Loudspeaker manufacturers measure the ready assembled two- and three-way systems by means of a frequency sweep. Their characteristics should be linear within a certain margin. The smaller the margin is set, the more exchangeable the loudspeakers are with the prototype, the original design, and the more they are expensive. When reviewing a pair of Tannoy Mercury two-way loudspeakers, the test result showed that they were excellent. I asked the importer for a second pair. When the second pair arrived and was connected to the same amplifier and source, there was no comparison. The second pair did not even come close to the extraordinary
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transparancy of the first set. There was a large dip in the frequency curve. The Tannoys were sent back. A couple of friends and I bought the same type, same make CD player from the same manufacturer. When we unpacked the players and compared the sonic qualities, they all differed slightly. One machine however had a completely skewed stereo image. When the top was taken of the cabinet, the stereo image was better, but only when the metal top of one of the other players was screwed on this player, the sound image was perfect. The specific player as sold did not meet the claimed quality. There are numerous examples, from pre-amplifiers to cables, from cartridges to speakers. Especially when delicate signals are being retrieved, transported and are being amplified. The Universal RSR is designed to function on practically every make and model of quality turntable. There is of course an interaction between URSR and turntable-armcartidge combination. Neutrality, control and wide frequeny band contribute to the quality of the reproduction to the same extend as amplifier, cables, loudspeakers and properties of the listening area do.
DELICATE MANUFACTURING As the Universal RSR does not come in various quality classes, it is necessary that each and every ring is thoroughly checked by listening to the ring with the same records on the same turntables. Demanding recordings have been chosen: refined chamber music, loud big band music, voices, piano, string instruments. The features are complex passages, close miking and high dynamics. This is exactly what we do. We audition each and every ring before it is approved, packed and shipped. The audible result should be in the same league of the original rings from the first production run. Each RSR is checked on different hi-fi sound systems. One with a two-way loudspeaker system with a 12 dB serial filter which makes it a phase coherent design. Another is a three way active loudspeaker system with mostly 6 db slopes. Sometimes we do check several rings on other systems and speakers as well. All systems will immediately reveal the quality of the ring: frequency band, dynamics, minimized distortion, damping. These speakers will reveal the depth, width and height of the soundstage and the separation of the instruments and singers. They also reveal if a certain section is less controlled.
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The care that is taken in manufacturing the RSR makes it impossible to manufacture a high number of rings in a short time. That is why it can not be a mass product. And that is why it cannot be copied easily. There is no shortcut to success. All other rings on the market are turned from stainless steel or brass. That is why the manufacturing of those rings is practically done in one step. The Universal RSR however, is assembled from rings of stainless steel and acrylic and in several time consuming steps. It is a sandwich construction. The acrylic is for a gradual damping of vibrations. The stainless steel segments of the Universal RSR are cut by a laser. The acrylic intermediate ring is cut by a machine. Yet the finish inevitably shows that the RSR is handmade.
HOW IT STARTED Immediately after my page about the stabilizing rings was published on January 1, 2004, and I invited interested visitors to participate in a production run, the counter soon indicated 400 visitors on one day and in a week over 2000 visitors were counted, thanks also to the positive efforts of Jorma Kokkola from Australia and Holger Trass from Germany, editor of the forum of the Analogue Audio Association (AAA) http://www.analog-forum.de/wbboard/index.htm. They were helping by repeatedly posting messages about the RSR project in order to make more people enthusiastic. The high number of 2000+ visitors looked quite promising. Nevertheless the goal of 20 people was not reached, despite the many emails and the many specific drawings I made to meet the demands of potential participants. The low number could also be the result of the remark of one writer in the AAA-forum who said that there was something wrong with stabilizing rings, but he did not remember exactly what, thus turning away potential participants. Nevertheless, I gave the green light to the project hoping that the rest of the rings would eventually be sold as well and make up the balance. The project was originally meant for those DIY enthusiasts who would order various rings and glue these together (after sanding and polishing). I thought it would be appreciated by some of the participants if the individual rings were already glued together by me and I offered that possibility, knowing that every individual had to invent the procedure anew and the DIY part would not necessarily guarantee a good outcome. The result was that everybody wanted the ring polished and glued. That was actually much more work than I bargained for. Nevertheless I stuck to the offer. I designed a simple crate, to be made of wood, for storage and safe transportation of the ring. Since then the world has turned and we have arrived at producing the Universal RSR for demanding audiophiles and music lovers and the initial project is not a DIY project any longer.
A RING OF BEAUTY IS A JOY FOREVER It did not only take a lot of time to glue your Universal Record Stabilizing Ring, also a lot of time was spent on sanding and polishing the RSR. Yet fingerprints are unavoidable. You need to clean the RSR from time to time. And you can polish it also using metal polish. By doing that, the appearance will improve. Though the RSR is well made and sturdy, you should be careful that the RSR will not bent under a heavy load. So always put it in the crate when not used for a long time or on a flat surface when changing records.
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ARE YOU CONTENT WITH YOUR RING? I thank you for ordering a Universal RSR and I hope that you are content with the ring. If you have a criticism, please let me know. If you like the ring, you may write a short review and send this personal review to me. I will then add part of it to the section User Comments. If you send me a picture of your turntable with the RSR I will publish it on the gallery page of my web site. Rudolf A. Bruil, 2007
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