GB2120446A - Holding apparatus for a disc record signal pickup stylus - Google Patents

Abstract

Disc record pickup stylus holders are designed to provide vertical decoupling of the pickup stylus from the stylus support. The compliance designed into the holder gives rise to mechanical resonant modes which affect the recovered signal in the audio range. A rigid damping element (19) secured to the compliant section of the stylus holder by a lossy adhesive or a lossy mass rigidly secured to the compliant section of the stylus holder reduces the amplitude of the resonant modes. Alternative embodiments are detailed (Fig. 2B, et seq, not shown). Materials are exemplified. A stylus holder substrate of varying flexibility across its thickness is mentioned. <IMAGE>

Description

SPECIFICATION Holding apparatus for a disc record signal pickup stylus This invention relates generally to disc record playback apparatus and more particularly to signal pickup transducer (stylus) holders for disc type systems, for example, of the capacitive type.

In capacitive disc systems, such as described in U.S. Patent 3,842,194, the recorded signal is recovered from the disc by a stylus tracking recorded information tracks on the surface of the disc. The stylus is secured to one end of a relatively long stylus arm, the other end of which is compliantly secured to a carriage mechanism.

The carriage mechanism translates the stylusstylus arm assembly radially across the disc at a speed in consonance with the radial movement associated with the stylus following the information track.

The stylus arm is arranged so that it is substantially tangent to the information track from which signal is currently being recovered. An armstretcher transducer is coupled to the end of the stylus arm and secured to the carriage for the purpose of creating longitudinal motion in the stylus arm. This motion is used to maintain stylusdisc relative velocity in a direction along the track being traced. In addition a further transducer is coupled to the stylus arm for selectively producing lateral or side-to-side translations of the stylus.

In order to facilitate incorporation of these features in the player the stylus arm must be relatively long and relatively rigid or stiff. However, in order for the stylus to track over vertical disc imperfections (i.e., normal to the disc surface) without being lofted from the disc, requires that the stylus be secured to the stylus arm by a means which affords a degree of vertical decoupling.

Thus it has been found to be advantageous to mount the stylus in a resilient holder, e.g., plastic, which in turn is fixed to the stylus arm. These holders have a longitudinal section generally colinearwith the long axis of the stylus arm and yield vertically to permit the stylus to ride over bumps on the disc independent of the vertical inertia of the stylus arm itself. See for example U.S. Patent No. 4,030,124.

It has been found that a resilient stylus holder can experience resonant modes of vibration. These stylus holders provide very satisfactory performance in disc players which produce monaural signal for reproduction in monoraul television receivers where the audio bandwidth is typically below 7 KHz. It was discovered, however, that when wide band stereo signals are reproduced from a disc record an erratic tone is present in the recovered signal located in the audio band, e.g., at about 10 KHz, which is manifested in the output as a hissing sound. This tone is produced by a mechanical resonance of the stylus holder which tends to cause an AM modulation of the recovered carrier as well as a phase modulation of the recovered carrier.When the recovered audio carrier is demodulated both AM and phase modulated components contributed by the stylus holder resonance appear in the base band audio at the same frequency.

Attempts to stiffen the stylus holder and thereby to push the resonant frequency beyond the audio bandwidth proved to be unsuccessful.

In the present invention, a stylus holder is provided which is improved by the addition of a damping element to substantially eliminate the effects of mechanical resonances in the audio frequency spectrum. The stylus holder comprises a generally resilient member having a first end configured for receiving and holding a signal pickup stylus. having a second end configured for rigid attachment to the end of a longitudinal stylus arm and a center section between the ends. A small mass, e.g., 1-10 milligrams, is located between the ends of the center section.

In one embodiment, a rigid mass is secured thereto by a mechanically lossy adhesive. Rather than simply lowering the resonant frequency the added mass coupled via the lossy adhesive tends to absorb the energy at resonance and diminishes its effect on the signal recovery system.

Alternatively a generally mechanically lossy material (mass) may be provided on the stylus holder by e.g., a non-lossy adhesive or other suitable means to achieve substantially the same effect.

FIGURES 1 and 2 are top and side views of two embodiments of a stylus holder equipped with a mass for absorbing mechanical energy at the resonant frequency of the holder.

FIGURE 3 is a cut-away side view of a video disc player signal pickup cartridge; FIGURES 4 and 5 are perspective views of a portion of a video disc signal pickup arm embodying the principles of the present invention; FIGURES 6a and 6b are plan and side views, respectively, of a stylus holder embodying the principles of the present invention; and FIGURE 7 is a perspective view of a portion of a video disc signal pickup arm having a stylus holder coated with a flexible material embodying the principles of the present invention.

FIGURES 8A and 8B are top and side views of an embodiment of a stylus holder equipped with a mass for absorbing mechanical energy at the resonant frequency of the holder.

In the drawings, elements designated with like numbers are the same or similar items in the various figures.

FIGURE 1 A is a top view of one particular embodiment of a stylus holder 10 in which resonant modes occurring at audio frequencies are reduced and FIGURE 1 B is a cross-section of a side view of the same holder. The holder 10 includes a first section 1 8 at one end for receiving and holding a signal pickup stylus 16 and for securing one end of a leaf spring 17 which provides stylus-disc engaging pressure when the stylus is in its operative position.

Section 18 is connected to a longitudinal center section 11 which is defined generally as being that portion of the central beam which, in one example, has a uniform cross-section. The center section 1 1 provides some compliance between the ends of the holder 10 to permit limited movement of the stylus independent from the opposite end of the holder. The compliance enables the stylus to ride over disc imperfections free from the average inertia of the total pickup apparatus, i.e., the inertia of the stylus-stylus arm combination.

The center section 1 1 of the stylus holder 10 is connected to a second end section 9 which has a recess 1 5 therein for receiving the end of a supporting stylus arm 14. The stylus holder 10 is secured to the stylus arm 14 either by compressive force developed between the holder and the stylus arm, for example, where the inner dimension of the recess is designed smaller than the outer dimension of the stylus arm or it may be held in place by an adhesive. An alternative configuration is to design the second end 9 of the stylus holder 10 to be received into a recess in the end of the stylus arm. Typically the end sections and center section will be integrally molded from a plastic material.

The stylus holder includes an extension 12 for the purpose of supporting a permanent magnet 13 having a polar axis perpendicular to the long axis of the center section 11. The extension 1 2 also serves as a stop which cooperates with further elements not shown to limit the instantaneous side-to-side travel of the stylus-stylus arm combination. The magnet 13 cooperates with electromagnetic coils (not shown) which are mounted in the player to selectively generate forces on the stylus holder for translating the stylus in a direction into and out of the drawing (with reference to FIGURE 1 B).

The center section 11 is dimensioned to afford sufficient vertical compliance or decoupling of the stylus 16 from the stylus arm 14, that the stylus will reliably track the disc record. (The vertical direction as referred to herein is the direction perpendicular to the surface of the disc record, which direction is generally parallel with the long axis of the stylus 1 6 as shown in the Figures.) Typically, however, when this criteria is met the stylus holder will exhibit mechanical resonance which is excited by disc imperfections and which are located in the audio frequency spectrum, e.g., in the range of 7~1 1 1 KHz. It is believed that the resonant mode causes the center section 11 of the holder to flex about an axis normal to the plane defined by the intersection of sections 1 1 and 12.

The flexing is cyclically correlated and modulates the pressure at which the stylus engages the disc, thereby tending to amplitude modulate the recovered signal. In addition, the flexing creates an oscillatory relative stylus-disc velocity component which phase modulates the recovered signal.

Ultimately the amplitude and phase modulated signal components due to the mechanical resonant modes of the stylus holder are manifested as a hiss in the audio output of the receiver.

A mass 19 is secured to the center section 11, preferably approximately at its midpoint to reduce the effect of the mechanical resonance. Ideally the mass should be located at the point on the center section corresponding to the antinodal point, i.e., the points of maximum deflection.

For a stylus holder with a center section having a uniform cross section the antinodal point will typically be located midway between the ends of such section. On the other hand if the center section is tapered toward one end the antinodal point will be nearer the smaller end.

The mass 19 is a relatively rigid material and must be attached to the stylus holder 10 by a lossy adhesive, e.g., silicone grease such as "High Vacuum Grease", manufactured by Dow Corning Corp., Midland, Michigan, USA. Note that if the rigid mass is rigidly secured to the stylus holder it will affect the dynamics of the holder by raising or lowering the frequency of the resonant modes and not their amplitude response. Experimentally it was found that rigidly securing a rigid mass to the center section of the stylus holder tended to lower the resonant frequency to a more objectionable frequency band without significantly lowering its amplitude response. However, the use of a lossy adhesive to secure the rigid mass 19 to the center section 11 does produce a reduction in the amplitude response at resonance.This phenomenon is believed to result from the fact that the added mass 19 does not intimately follow the motion of the stylus holder, i.e., the inertia of the added mass tends to maintain the mass in some average position. The lossy adhesive 20 may be considered to couple the added mass to the center section 1 1 by predominantly frictional (viscosity) forces which generate heat in the adhesive as the resonant motion of the midpoint of the center section moves away from and toward the average position of the mass 1 9 thereby damping (reducing) the motion of the stylus holder. Tests on a currently available stylus holder for a commercial video disc player have shown that the resonant peak amplitude can be reduced by 15 dB by a judicious choice of adhesive and mass size. The 15 dB reduction renders the effect of the resonant mode substantially unnoticeable.

In FIGURE 1 , the added mass 19 is shown secured by lossy adhesive 20 to the underside of the centre section 11. Alternatively the mass can be applied to the upper side of section 1 1 and is shown as the phantom element 21 in the figure.

There are various other possible arrangements and placements such as a "U" shaped mass draped over the holder near the midpoint of section 1 1.

Lossy adhesives for securing a damping mass to the stylus holder, though they significantly enhance player audio performance are generally not dynamically stable substances. Over time they tend to migrate or crawl or dry out or harden, and these changes can ultimately alter the resonant characteristics of the stylus holder. In anticipation of future problems with lossy adhesives, the present inventor pursued the problem further by considering the use of a mechanically lossy mass secured to the stylus holder. As used hereinafter a mechanically lossy mass is a non rigid body capable of dissipating energy in being deformed. It will generally store and release energy during deformation but the ratio of dissipated to stored energy will be high, generally 0.5 or greater.

A mechanically lossy mass attached to the holder may be considered as a continuum of separate independent small elemental masses each elastically and frictionally secured to the holder. Each elemental mass will obtain some average vertical inertia and position with respect to the holder. The frictional part of the coupling of each elemental mass to the holder will dissipate energy (as heat) as the holder moves toward or away from the average position of the mass elements, and thereby tend to reduce relative vertical displacement of the holder. It is noted that the vertical displacement referred to above pertains to relative displacement of incremental portions of the holder (particularly the center section) with respect to each other and not to an average vertical displacement of the stylus holder as a unit.In the resonant mode the midpoint of the center section will tend to be moving 180 degrees out of phase with its end points in a standing wave. Limiting the motion (damping) of any part of the resonant member, e.g., the mid point, will damp the movement of the remainder of the member.

It was found advantageous to secure a mechanically lossy mass over the entire length of the stylus holder center section 1 This embodiment is shown in Figure 2 wherein a lossy element 24 conformally shaped on two edges to mate with the holder is rigidly cemented (25) to the holder 1 Again, if the lossy mass is considered as a continuum of elemental masses secured to the stylus, it should be appreciated that for the case where the lossy mass extends over the entire center section, the elemental masses also interact with each other tending to damp each other oscillatory motion and thereby effecting further damping of the overall structure.

Experiments with a lossy mass 24 of approximately 3 mg. weight and made from butyl rubber produced an amplitude reduction of 12 dB in the resonant mode. It can be shown by theoretical analysis, however, that a 15 dB reduction in the amplitude response due to resonance should be achievable. It was also found that use of the rubber rudder shaped element had the further beneficial effect of reducing lateral stylus holder resonant modes, i.e., in the direction into or out of the drawing (FIGURE 2B), and thereby enhancing the accuracy and reliability of lateral stylus translations (i.e., selective track skipping).

Referring to FIGURE 3, there is shown a cut away view of a signal pickup cartridge 32. The cartridge has side walls 34 (only one shown) and a top wall 36 rigidly holding the side walls in a spaced apart relationship. The bottom plane of cartridge 32 is open. The top wall 36 and side walls 34 of cartridge 32 form an enclosure to which a signal pickup stylus 38 is coupled.

In the U.S. Patent Application Serial No.

413,424, filed August 1 982, by Ronald K.

McNeely, pickup stylus 38 is mounted to a stylus holder 40 formed from a piece of shim stock material which is rigidly attached to one end of an elongated, lightweight, tubular stylus arm 42.

Illustratively, stylus arm 42 may be made from aluminum tubing .04 inches in diameter, having a wall thickness of .002 inch. In a preferred embodiment, stylus arm 42 is formed in a crimp 39 to hold stylus holder 40. The crimp is offset from the centerline of stylus arm 42 so that the bottom edge of the crimp is substantially tangent to the bottom edge of the tube, in order to provide improved clearance of arm 42 from the disc surface. The other end of stylus arm 42 is suspended from the top surface 36 of cartridge 32 by compliant suspension 44. Leaf spring 46, deformed in a compressive arc, is connected between stylus 38 and a shelf 48 integral to cartridge 32, and arranged to tend to expel stylus 38 through the bottom plane of cartridge 32.Leaf spring 46 is typically electrically conductive and serves the dual functions of (a) providing the necessary stylus-disc interactive pressure when the cartridge is positioned for signal recovery (as shown in FIGURE 3), and (b) for providing electrical connection between the pickup stylus electrode and the signal processing circuitry (not shown).

In the FIGURE 3 configuration, stylus 38 is shown engaging the top surface of the disc 52.

The end of stylus arm 42 nearest suspension 44 is hollow for reception therein of a permanent magnet 54 having north and south poles aligned along the longitudinal axis of stylus arm 42.

Magnet 54 is designed to cooperate with an electromagnetic coil (not shown) mounted in the player to provide longitudinal translations of stylus arm 42 for the purpose of performing stylus-disc velocity corrections, i.e., arm stretching, during signal recovery.

A second, generally elongated, permanent magnet 56 is mounted perpendicular to the longitudinal axis of stylus arm 42 and arranged so that its longitudinal axis is substantially vertical.

The width of magnet 56 is less than the diameter of stylus arm 42 and is inserted in a hole punched therethrough. The north-south poles of magnet 56 lie along its longitudinal axis. Magnet 56 is arranged to cooperate with a second electromagnetic coil (not shown) mounted in the player for the purpose of twisting the stylus arm to effect lateral translations of the stylus. Reference may be made to U.S. Patent No. 4,183,059, entitled "TRACK SKIPPER FOR A VIDEO DISC PLAYER," issued on January 8, 1 980, to R.C.

Palmer for an illustration of a groove skipper for a grooved video disc system.

A damping mass 28 is provided to damp resonant modes of stylus holder 40. Stylus holders without damping mass 28 provide satisfactory performance in video disc players which produce monaural signals for reproduction on standard television receivers where the audio bandwidth is typically below 7 KHz. It was discovered, however, that when wideband audio signals are reproduced from a disc record, an erratic noise is present in the recovered signal located in the audio band typically between 5 and 15 KHz and is manifested as a hissing sound. This noise is produced by the mechanical resonance of the stylus holder 40 which tends to cause amplitude and phase modulation of the recovered carrier. When the recovered audio carrier is demodulated, both amplitude and phase modulated components contributed by the stylus holder resonance appear in the baseband audio at the resonant frequency.

Cartridge 32 employs both a mechanically lossy mass 28 and a lossy material for securing the mass to holder 40. Lossy mass 28 is formed in an annular shape, e.g., donut, and secured to the upper surface of stylus holder 40 at approximately the midpoint with silicone rubber (e.g., Dow Corning No. Q3-6527AB or Dow-Corning No.

734TV). Damping mass 58 may be easily produced by cutting sections (0.050 inch) from a length of rubber tubing (0.045 O.D. x 0.019 l.D.

silicone rubber, durometer 30-40). In one particular example, a 1.5 mg. section of silicone rubber tubing installed on a shim stock stylus holder having a 0.15 x 0.02 x 0.02 inch center section (approximately) will satisfactorily reduce the undesirable resonance characteristics in the audio spectrum.

As discussed above, the use of a damping mass glued to the stylus holder, for example, stylus holder 40 shown in FIGURE 3, has several drawbacks. The stylus holder-damping mass combination is generally expensive to manufacture. Further, the assembly and gluing operations may damage the delicate parts associated with a video disc stylus arm.

In accordance with a further embodiment of the present invention, a stylus holder is provided which may be manufactured from a piece of flat shim stock material laminated with a layer or layers of damping material. This holder is easy and cheap to manufacture. Tooling costs are minimal, e.g., a small punch and die set is all that is required.

Another advantageous feature of the further embodiments present invention is that the stylus may be staked into the shim stock stylus holder without the aid of some other holding means. In other stylus structures such as McNeely, it sometimes has been found to be necessary to add glue to hold the stylus in the stylus holder. In the present further embodiment, it is felt that the stylus may be held in the stylus holder without gluing it in. It is believed that the laminated stylus holder provides enough holding power so that the gluing operation may be eliminated.

Referring to FIGURE 4, a perspective view of a portion of a stylus suspension 60 is shown. Stylus suspensiorl 60 includes a tubular stylus arm 42' (illustratively, a stylus arm 42' may be manufactured from aluminum tubing as discussed above). Stylus holder 40' comprises substrate 62 formed as a rectangular piece of shim stock material. Substrate 62 must be relatively rigid in a direction parallel to a radial direction of the disc record to facilitate tracking of the spiral groove and, at the same time, must be resilient in a direction normal to the surface of the disc record so that stylus 38' is not lofted from the disc surface by disc imperfections.Illustratively, it has been found that a plastic shim stock material works well, e.g., Vinylite (Trademark), clear, rigid 0.010 inch (0.025 cm) thick available from All Plastics, Indianapolis, Indiana, USA, provides the resilience necessary for video disc applications.

Stylus holder 40' must be nonconductive for capacitive video disc applications, as described herein, so that the recovered signal is coupled through the leaf spring to the signal processing circuitry. Further, substrate 62 is formed from shim stock material in a flat shape. In operation, the flat plane of stylus holder 40' is arranged in stylus arm 42' such that it is substantially parallel to the disc surface when stylus 38' engages a groove on the disc.

A crimp 58 is formed on one end of stylus arm 42' to grip stylus holder 40'. Crimp 58 is formed by flattening the end of stylus arm 42' over one end of stylus holder 40'. Crimp 68, which may be made by deforming end 69 of stylus arm 42' by using a flat punch against a flat plate with end 69 interposed therebetween, mechanically holds stylus holder 40' to stylus arm 42'. In general, no other mechanical or chemical bonding is required to hold stylus holder 40'. In accordance with one preferred embodiment, the flattened portion of crimp 68 is formed tangential to the lower surface of stylus arm 42', thus providing clearance between the bottom of stylus arm 42' and the disc surface during playback operations.

Leaf spring 46', deformed in a compressive arc, is connected between stylus 38' and a metallic rivet (not shown) to provide the dual functions discussed herein.

One or more layers of damping material are provided to form a laminated stylus holder 40'.

Referring again to FIGURE 4, overlying substrate 62 are layers 64 and 66 of damping material which have been adhesively applied to the upper and lower surfaces of substrate 62, respectively.

Damping layers 64, 66 aid in suppressing the resonant modes of vibration of stylus holder 40'.

Illustratively, damping material 64, 66 may be formed of an adhesive vinyl tape (e.g., Scotch Brand No. 35 electrical tape having a thickness of 0.007 inch (0.018 cm)) having an adhesive back layer.

One explanation of the operation of damping layers 64, 66 is as follows. A mechanically lossy mass attached to the substrate may be considered as a continuum of separate independent small elemental masses, each elastically and frictionally secured to the substrate and to adjacent elemental masses. Each elemental mass has some average vertical inertia and position with respect to the substrate and adjacent elemental masses.

The frictional part of the coupling of each elemental mass to the substrate and to adjacent elemental masses will dissipate energy as the substrate moves, and thereby tends to reduce the relative vertical displacement of the substrate. It is noted that the vertical displacement referred to above pertains to relative displacement of incremental portions of the substrate with respect to each other and not to an average vertical displacement of the stylus holder as a unit. In the resonant mode, the midpoint of the stylus holder will tend to be moving 180 degrees out-of-phase with its end points in a standing wave. Limiting the motion (damping) of any part of the resonant member will damp the movement of the remainder of the member.

Referring to FIGURE 5, another embodiment of a stylus holder is shown. In FIGURE 5, the layers 64' and 66' of damping material are adhesively applied on one side of substrate 62'. It is felt that application of the damping layers to the surface of substrate 62' opposite the disc surface may prevent interference. Should the damping material peel off from age or the like, it is less likely that it would interfere with playback if it is remote from the playback surface.

FIGURES 6a and 6b are plan and side views, respectively, of a stylus holder 100 comprising substrate 102 and a damping layer 104. A stylus log 106 is staked into one end of stylus holder 100. The number of layers of damping material is a function of the weight and resilience of the structure as a whole. It should be noted that a single layer 104 of damping material may be the correct combination with respect to some stylusstylus holder combinations. Changes in shape, number of layers, width, thickness, etc. may be accomplished in the present invention without incurring substantial expense in tooling and manufacturing facilities. Additionally, experimental designs and shapes may be tried at low cost.

Referring to FIGURE 7, another embodiment of a stylus holder is shown. In FIGURE 7, the substrate 62" is shown in phantom. According to this embodiment, the substrate is coated with a layer of damping material 65. Illustratively, substrate 62" may be dipped into an uncured liquid plastic, such as urethane, which subsequently cures to provide a substantially uniform coating of damping material. The coated substrate is crimped onto one end of a stylus arm 42". It should be noted that other methods may be used for forming the laminate coating 65. For example, coating 65 may be added after substrate 62" is crimped into stylus arm 42". In accordance with this technique, substrate 62" would be dipped into the coating material prior to the staking operation. Another coating method would be to coat the shim stock with the plastic coating prior to punching it into individual stylus holders.

FIGURE 8 is a damped stylus holder which evolved from attempts to find a design which is highly manufacturable. The FIGURE 8 design employs both a mechanically lossy mass and a lossy material for securing the mass to the holder.

Since the mass is a lossy material, changes in the lossy securing material (e.g., adhesive) over time will affect the damping characteristic of the combination to a lesser degree.

The stylus holder 25' in FIGURE 8 is molded with a post 22 located approximately at the midpoint of the center section 11. A lossy annular mass 23, e.g., a rubber donut, is circumferentially installed over the post 22 and secured to the post with a silicone rubber (e.g., Dow Corning #Q3~6527 A S B or Dow Corning &num;734 RTV).

The post 22 serves to position the mass and to hold it in that fixed position. Since the post 22 tends to support the annular mass 23 there is less dependence on the adhesive qualities of the adhesive applied therebetween. As a result the designer has greater latitude in the selection of the adhesive material for damping qualities, rather than e.g., adhesive characteristics. For particular applications the adhesive may be eliminated all together simply by making the dimensions of the donut hole smaller than the dimensions of the post. The donut can then be force fit over the post 22 for self retention. Another alternative consists of a multilayer donut comprised of varying degrees of lossy material, with the layers becoming less lossy toward the outer periphery.The inner lossy layers can be employed to self retain the donut to the post without an adhesive while the outer more rigid layers establish the damping inertia.

The rubber donuts are easily produced by merely cutting sections (0.050") from a length of rubber tubing (0.045 O.D. x 0.01 9 l.D. silicone rubber, durometer30-40). In one particular example, a 1.5 mg section of silicone rubber tubing installed on a commercially available video disc stylus holder having a 0.15" x 0.020" x 0.020" center section (approximately) will satisfactorily reduce the undesirable resonance characteristics in the audio spectrum.

Other embodiments of the invention will be apparent to those skilled in the art. For example, the substrate of the stylus holder may be formed from a material having a variable flexibility across the thickness of the material. The crimp in the stylus arm may capture both the stylus holder and damping material or only the stylus holder; this latter may be particularly advantageous when the damping material is soft or subject to flow under pressure whereby the grip of the crimp may loosen with time. Further, the damping material may cover only a portion of the surface of the stylus holder to which it is attached, to reduce the amount of damping.

Claims (25)

1. A stylus holder for holding a disc record signal pickup stylus comprising: a generally longitudinal member having a first end section adapted for coupling to a supporting element and a second end section adapted for accepting said signal pickup stylus; and a damping mass positioned on said member at least in a center section between said first and second end sections for reducing mechanically resonant modes of the stylus holder.

2. The stylus holder set forth in Claim 1 wherein said first end section, said second end section and said center section are integrally molded in a single unit.

3. The stylus holder according to Claim 1 or 2, wherein said second end section is adapted for securing the stylus holder to the end of a stylus supporting arm and said center section having a limited degree of compliance for decoupling the first end section of the stylus holder from said supporting arm.

4. The stylus holder according to Claim 1,2 or 3 wherein said mass is a rigid mass secured to the member by a mechanically lossy means.

5. The stylus holder according to Claim 1, 2 or 3 wherein said mass is a mechanically lossy mass secured by rigid means to said center section for damping mechanical oscillations of the resonant modes thereof.

6. The stylus holder set forth in Claim 4 wherein said rigid mass is mounted to the center section on a bottom-most surface of said center section, the bottom-most surface being defined as the surface nearest said disc record when the stylus holder is in its normally operative position.

7. The stylus holder set forth in Claim 4 wherein said rigid mass is mounted to the center section on its top-most surface, the top-most surface being defined as that surface farthest removed from said disc when the stylus holder is in its normally operative position.

8. The stylus holder according to any preceding claim, wherein said mass is configured to extend over substantially the entire length of said center section.

9. The stylus holder according to Claim 1,2 or 3, wherein said generally longitudinal member comprises a sheet of resilient material having stylus and distal end sections, said distal end section being adapted to be mechanically coupled to said supporting element, a first layer of flexible material, overlying a first surface of said sheet of resilient material, to said stylus end section of said sheet of resilient material being adapted to accept said signal pick up stylus.

10. The stylus holder according to Claim 9 wherein said first layer of flexible material is adhesively attached to said surface of said sheet of resilient material.

11. The stylus holder according to Claim 9 or 10 further comprising a second layer of flexible material, overlying said first layer of flexible material.

12. The stylus holder according to Claim 9 or 10 further comprising a second layer of flexible material, overlying a second surface of said sheet of resilient material.

13. The stylus holder according to Claim 9, 1 0 or 11 wherein said sheet of resilient material comprises a thin strip of plastic material.

14. The stylus holder according to Claim 9, 1 0, 11, 12 or 13 wherein said first layer of flexible material comprises a layer of adhesive tape.

15. The stylus holder according to Claim 1, 2 or 3 wherein said mass is provided by a generally perpendicular extension of said member between said end sections.

16. The stylus holder according to any preceding Claim, further comprising the support member and wherein said supporting member is a tubular member having one end crimped to the said second end section.

17. The stylus holder of any preceding Claim, further comprising the signal pick-up stylus secured to the said second, or stylus, end section.

18. A stylus holder substantially as hereinbefore described with reference to Figures 1A and B.

19. A stylus holder substantially as hereinbefore described with reference to Figures 2A and 28.

20. A stylus holder substantially as hereinbefore described with reference to Figure 3.

21. A stylus holder substantially as hereinbefore described with reference to Figure 4.

22. A stylus holder substantially as hereinbefore described with reference to Figure 5.

23. A stylus holder substantially as hereinbefore described with reference to Figures 6A and 6B.

24. The stylus holder substantially as hereinbefore described with reference to Figure 7.

25. The stylus hold substantially as hereinbefore described with reference to Figures 8A and 8B.