Dec 032013
 

Introduction

It could be argued that the Breuer Dynamic pick-up arm was the first of what was to later become known as ‘super arms’: those high-end arms where the designers pays particular attention to the fit and finish of the materials, particularly the bearings, so that the arm displays a minimal number of (well damped) resonances and is an essentially neutral platform on which the cartridge can be allowed to perform optimally. The Breuer Dynamic arm was thus the forerunner of, and the inspiration for such later arms as the Sumiko; the Linn Ittok and the SME V.

Designed by Herr Breuer, a retired watchmaker working in Lucerne, Switzerland, the Breuer arm first came to the attention of the UK audio fraternity in 1978, when Linn Products imported a limited number of the arms for use with the Linn/Naim tri-amped PMS system. [1] Until then, Linn partnered their LP12 turntable with the Japanese Grace 707 arm, but felt the 707 was the limiting factor in the PMS system.

Breuer started his career as a watchmaker, and then made parts for the Swiss watch industry, before becoming a highly specialised toolmaker (apparently supplying components to the European Space Agency). It is said he designed and built the pick-up arm for his own use, since he was dissatisfied with other commercial designs, as these did not measure up to his high musical and technical requirements. Like the original Sugano-built Koetsu cartridge, Breuer went into small-scale production, working alone and making no more than he could comfortably turn out to his exacting standards. Thus each and every Breuer arm is hand built and tested: Breuer personally signs the warranty card supplied with each arm.

Technical description of the arm

From outward appearances the Breuer Dynamic 5A pick-up arm looks quite ordinary. However this belies the fact that the arm employs some 120 parts, many of which are hand made and the arm is assembled by hand; so good is the fit and finish it just oozes Swiss precision. It looks ‘right’ – in much the same way a Leica rangefinder camera looks right.

The Breuer Dynamic 5A is a straight arm of effective length (arm pivot to stylus tip) of 228mm with a fixed headshell providing an offset angle of 25.5°. When set up correctly the stylus overhang is 20mm. (There appears to be some discrepancy between the manufacturer’s installation instructions and the conventional procedure for cartridge alignment to minimise tracking error – but more of this later.)

The arm tube is a thin-walled aluminium tube having an outer diameter of 10mm. In early versions the arm tube was given a pale gold-coloured anodised finish; later models (post 2000) the colour was changed to black. Fitted to the arm tube, at the cartridge end, is a thin-walled perforated aluminium headshell. It is said that Herr Breuer considered a bent arm tube, but rejected this after having observed, over a period of many months, a very small relaxation in the angle of the bend. This gives one an idea of the fastidious research that went into the design. The arm has a very low effective dynamic mass of 4g.

The arm is statically balanced with a conventional two-part counterweight assembly. One part is a very snug fit to the arm tube using a PTFE sleeve. The second, heavier, part screws onto the first part, with an O-ring seal to provide a precision fit and to offer a certain amount of decoupling from the first part. Owing to the airtight seal provided by the O-ring, a tiny hole is drilled in the rear of the counterweight so as to allow the two parts to be screwed in and out. The counterweight component parts are machined from brass and given a clear lacquer finish. The mass of the counterweight assembly is such that the arm is able to counterbalance cartridges of 2 – 8g in mass. This is sufficient for the great majority of cartridges, but not all. The exceptions being the gemstone-bodied Koetsu cartridges, both the EMT HSD-6 and JSD-6 models and the Denon range.

Probably the most important part of any tone arm is the bearing assembly, and it is here, with Breuer’s experience in the watch industry, that the Dynamic 5A arm excels. Sadly I cannot give you precise details of the bearing used: whether they are needlepoints running a jewelled cup, or precision ball-race types, suffice it to say they are precise with absolutely no play whatsoever. Such is the quality of the bearings that it is said they can take a 50Kg load and still the arm will move if breathed upon! The quoted bearing friction is 10mg in either plane. One of the (vertical plane) bearings has a knurled knob that provides dynamic tracking force adjustment using a hairspring. Likewise, the upper (horizontal) bearing has a similar knurled knob to provide anti-skating bias, again via the use of a hairspring. The axis of the bearings in the vertical plane is at right angles to a line running through the cartridge cantilever. This is the correct geometry, allowing true vertical motion to occur when the stylus rides any record warp; unlike the arrangement used in the Series II SME arms, whereby any record warp causes the stylus to ‘roll’ slightly in a counterclockwise sense, as seen from the front.

A hard Nylon-like material is used for the bearing block attached to the arm tube. There has been some criticism of the choice of this material: Nylon is slightly hygroscopic and can swell due to absorption of moisture – with some unsubstantiated claims that the arm’s performance is sufficiently variable that “ getting one to work for a whole side of an album was reputed to be quite an accomplishment.” [2] It is difficult to respond to this observation, save to say that perhaps the arm was being used outside of its operating temperature range (the operating instructions clearly state “the tonearm must be at room temperature (at least 72°F or 22°C); this temperature applies to the air in the vicinity of the tonearm, not to the air in the room, which may be cooler.” Again it difficult to imagine that such a carefully designed and built arm would suffer such a failing, given Breuer’s obsessive attention to detail. In my nearly thirty years experience with this arm, it has behaved flawlessly. Of course it is possible that the negative comments regarding bearing performance was due to a rogue sample, however given that each arm is hand assembled and tested by Breuer himself, the chances of such a rogue sample ‘slipping through the net’ is unlikely.

Within the headshell, the cartridge pins are connected to the arm wiring with gold-plated solid silver tags that connect to very fine silk insulated wires running through the arm tube and down to a 5-pin DIN plug (240° version) situated at the base of the arm pillar. Although these wires are distinguished by different coloured insulation, the distinction is not very clear and it is recommended that short lengths of coloured sleeving be fitted over the cartridge tags. The arm wiring itself has very low capacitance (5pF) as do the 1.2m long coaxial signal leads (80pF) that connect to the arm base plug and terminate in RCA ‘phono’ plugs. The phono plugs themselves are of a most indifferent quality, such as may be found fitted to Ortofon arms, and their replacement with better quality types, such as Neutrix ‘Profi’ is recommended.

There is no headshell finger lift supplied. This is a deliberate design feature, since Herr Breuer believed the arm should not be cued by hand; instead the (damped) cuing device should be used to raise and lower the arm, which can be moved horizontally by sliding it along the cuing support with one finger.

There are a couple of optional accessories that may be fitted to the Breuer arm. These are a fluid damping dashpot, similar in design to the SME FD200, and an arm height adjusting device allowing real-time adjustment of vertical tracking angle. This latter device, although now prevalent on several up-market arms, was unique at the time. Unfortunately I have no experience of these two items, so cannot discuss them further.

Installation of the arm

Mounting

Instructions for the installation of the arm are most precise and very detailed. The arm needs to be mounted on the turntable arm board such that the distance between the axis of the turntable spindle and the centre of the arm-mounting hole (arm pivot point) is exactly 208mm. Most arms come with some sort of mounting template, usually made of card, but for the Breuer arm this is a precision metal device available from the dealer. Consisting of an aluminium strip with a hole at one end that slides over the turntable spigot, and at the other end a much larger hole into which a template tube can slide through the template strip and thence into the arm mounting collar. In this way the arm-mounting collar can be located on the turntable arm board so as to provide enough clearance for the tonearm when the turntable dust cover (if used) is closed. Once the correct location is found, one of the mounting collar fixing holes is marked out, drilled and the collar fixed with one screw. Then, being careful not to move the collar, the template tube is removed and moving the template to one side, the remaining two fixing holes and the large centre hole of the collar are marked and drilled. Once the collar is fixed a final check is made with the template and tube.

Cartridge Mounting

The Breuer Dynamic was designed to be used with those cartridges that can achieve good tracking with vertical tracking forces of 1 – 2 grams. In fact the Breuer arm was designed specifically for the Breuer Dynamic cartridge: a modified EMT moving coil design, though there is no reason why the arm cannot be used with high quality cartridges regardless of their generator design. The low effective mass permits the use of both high compliance designs as well as those having a lower compliance. Indeed the Breuer was one of the few arms available recommended by Sugano for use with the original Koetsu cartridge. The only real limitation on choice of cartridge is the internal width of the underside of the headshell. The widest cartridge width that can be accommodated is 18mm, however the only cartridges to my knowledge having widths greater than this are the Linn Asak and it successors, and possibly the Fidelity Research MC201 and MC202 designs.

Being a fixed headshell design the tonearm wires are fixed and somewhat delicate. First mount the cartridge in the headshell with the supplied screws. Should longer screws be needed they could be obtained from the dealer, however there is no reason why suitable fixings from an alternative supplier should not be used, despite Breuer’s recommendation to the contrary. When fitting the cartridge into the headshell, the nylon washers supplied should be fitted under the heads of the screws, on top of the headshell. Next fit the cartridge tags. Being made of pure silver they are fairly soft and can be bent easily to fit various pin sizes.

Cartridge alignment

According to the user instructions, the cartridge should be moved in the headshell (which has slotted cartridge fixing holes to allow this) so the stylus tip is exactly 4mm in front of the forward edge of the headshell. Now this is a difficult dimension to achieve: it is virtually impossible to measure this distance with sufficient degree of accuracy. One way might be to assume the cartridge manufacturer has followed the IEC specification whereby the distance between the stylus (when the cartridge is tracking at the recommend tracking force) and the cartridge fixing holes is 9.5 ± 1mm. This would imply the distance between the centre of the cartridge fixing screws and the front edge of the headshell is thus 5.5 ± 1 mm. Clearly this is insufficiently accurate and not all cartridges conform to this IEC specification.

The obvious solution is to use an alignment protractor. However, as alluded above, a discrepancy arises between aligning the cartridge using a protractor designed using the tonearm geometry, and Breuer’s own advice. One of the difficulties is given the tonearm’s effective length; the offset angle and overhang are fixed provided one of the accepted tracking optimisation procedures is followed [3]. There are three prescriptions that are accepted as being ‘optimal’, they are: Baerwald, Löfgren, or Stevenson. None of these prescriptions lead to an overhang of 20mm and offset angle of 25.5° for an arm having an effective length of 228mm [4]. It is thus clear that a commercially available alignment protractor cannot be used as the great majority of these are marked with the null-points corresponding to the Baerwald prescription.

In situations such as this, the recommended course of action is to calculate the protractor null-points, given the arm geometry [3]. When this is done the two null-points are at 67.9mm and 128.4mm. These dimensions were rounded up to 68.0 and 128.5mm and marked on an existing alignment protractor (as shown in [3], an error in the position of the null points of no more than ±0.25mm, permits the correct overhang to be achieved to ±0.1mm). Using these null-points, the cartridge was moved in the headshell such that the cartridge body was exactly parallel to the main axis of the headshell. In this position it was found the stylus was about 2mm in front of the forward edge of the headshell and not 4mm as recommended by Breuer.

Why should this matter? Well given the importance Breuer places on precision and the care he has taken with the design of the arm and its geometry, it is surprising (and puzzling) that the above discrepancy manifests itself.

With the cartridge arm alignment set up using null-points at 67.9mm and 128.4mm, the peak second harmonic distortion due to tracking error is calculated to be 0.99% at the inner groove (at a radius of 60.375mm), 0.73% mid record (at radius of 89mm) and 0.46% at the outer groove (radius 146.05mm).

Tonearm height adjustment

The arm is provisionally balanced by moving the counterweight so the arm comes to rest in the horizontal position after swinging free of the armrest and cueing support. Small balance corrections can be made by turning the outer part of the counterweight. A provisional tracking force of 1g is applied by adjusting the dial on the right side of the tonearm pivot assembly and the stylus allowed to rest on a record. The tonearm height is adjusted by slackening the setscrew in the arm-mounting collar that holds the arm column in place. Breuer advises the height of arm be such that it slants slightly downward (the cartridge end being about 1° below horizontal) when the stylus is resting in the record groove. Breuer claims this last adjustment is essential if severe intermodulation distortion is to be avoided, however the best advice is for the listener to make these adjustments by ear.

These adjustments are somewhat tedious. To help, the fitting of the arm height adjustment device is recommended as it was designed to permit fine adjustment of tonearm height. Before mounting the arm, the arm height adjustment device is slid onto the arm column, then the arm is mounted on the turntable and the height adjusted as described previously. Lock the fine-adjustment device so that it will support the arm at the same height, having assured the device is turned so that the vertical adjustment screw is beside the cuing lever but does not interfere with it in any way. Release the locking screw in the arm collar and make the final height adjustment with the vertical fine adjustment screw. Turning the screw by one division on the scale changes the arm height by 0.05mm (resulting in a change of 0.75 minute of arc in arm angle); a full revolution equals 0.5mm (resulting in a change of 7.5 minutes of arc).

Tracking force

The use of a good stylus balance is recommended, as is the use of a good test record in order to set up the correct tracing force as recommended by the cartridge manufacturer. Breuer recommends that half of this figure should be achieved by adjusting the counterweight and the other half by turning the tracking force dial on the side of the arm pivot assembly.

Anti-skating adjustment

Turn the anti-skating dial on the top of the pivot assembly about 1/3 turn counter clockwise for a tracking force of one gram and correspondingly more for higher tracking forces. Again the use of a good test record is recommended to help find the correct setting.

Performance

It is always difficult to separate the inherent sound of a pick-up arm from that of the cartridge that it carries. To assess the sound performance of a pick-up arm in isolation, one has to audition it with several cartridges and try to extract a ‘common denominator’ to the sound. This is especially difficult to do with fixed headshell arms.

However after using this arm for thirty years, though not used constantly throughout this time, with half a dozen cartridges (both fixed and moving coil designs), some characteristics do emerge.

Compared to the Breuer Type 5, most other arms sound slightly opaque, dull and slow. This effect applies to the whole frequency spectrum; there is no curtailment of performance at the frequency extremes, as there are with say the SME Series II designs. The Type 5 is extremely dynamic, transparent and open, with no trace of overhang: as such, it would be interesting to hear how the Decca cartridge would sound mounted in the arm.

The soundstage presented by the Breuer is wide and deep, but there is a narrowing of the perceived stage width with depth. Dependant on the cartridge used, focus and ‘solidity’ of the individual musicians can be very good indeed – permitting a very believable illusion for the listener of being transported to the performance.

With an effective mass of only 4g, the Breuer can be used with a wide variety of cartridges, however the maximum cartridge mass of 8g that can be counterbalanced by the arm, might be a limiting consideration. I have used it with the ADC 25 (fixed coil, having an absurdly high compliance of 50 cu), with secure tracking at 1g at one end, to the Ortofon moving coils, (compliance 25 cu) tracking at 1.5g at the other. Some recommended combinations are as follows –

Moving coil designs:
the Koetsu ‘Rosewood’ cartridges (these have a mass of 9g, so the extra 1g that cannot be counterbalanced will form part of the tracking force); the Ortofon MC20, ‘Rohmann’ and ‘Kontrapunkt’ cartridges, as well as Breuer’s own modified EMT design.

 

Breuer modified EMT cartridge
(Image: Audio Markt)

Fixed coil designs:
the ADC 25 and 26; the AKG P8ES and the B&O MC20CL. And, as has been speculated, the combination of the Breuer with the Decca Reference cartridge (mass 6.5g) is a very tempting proposition.

Other Breuer arms

Shortly after the introduction of the Type 5A, Breuer developed the 5B and 5C designs as well as the Type 6, 7 and eventually the Type 8.

The 5B and 5C designs had the same length (228mm) as the 5A, but the 5B had a lower dynamic (or effective) mass of 3.3g. The Type 6 had an effective length of 262mm and a dynamic mass of 3.9g, whereas both the Type 7 and 8 have effective lengths of 249mm with dynamic mass of 4g.

The Type 8 is a 10.5″ arm, but due to the compact arm base, it can usually fit modern tables that can only accommodate a 9″ arm. It will also counterbalance a greater range of cartridge masses, such as the heavy stone-bodied Koetsu range.

Only the (improved [6]) Type 8 was available in the early 2000s, though Breuer Dynamics would restore and furbish old Breuer arms, as well as perform rewiring to bring them back to specification. Sadly, however Breuer Dynamics now no longer seem to be in existence. Though not a Breuer design, the Brinkmann 10.5 arm is clearly based on the Breuer Type 8, both in visual appearance and specification, and is now the closest one will get these days to an original Breuer arm.

References and Notes

[1] News item: Hi-Fi News and Record Review, January 1978, p.63.

[2] Quoted from a letter published in ‘Hi Fi Answers’, September 1980, p.7.

[3] http://theartofsound.net/forum/showt…earm-alignment

[4] This data taken from: thevinylengine.com.

If the geometry of the Breuer arm had followed either the Baerwald, Löfgren, or Stevenson prescription, the figures for overhang and offset angle would be (18.14mm, 24.2°), (18.74mm, 24.2°) and (16.04mm, 22.9°) respectively.

Clearly the overhang of 20mm is correct, since the distance of the arm pivot to the centre of the turntable is 208mm and the arm has an effective length of 228mm.

It is not clear where the figure of 25.5° for the offset angle originates. It is not quoted in the installation instructions. If it is a measurement supplied by a user, then the measurement could be in error. However with a stylus to arm pivot distance of 228mm, and with the stylus 4mm in front of the headshell, if the offset angle is 25.5°, the distance from the centre of the front edge of the headshell to the arm pivot can be calculated to be 224.4mm. It is difficult to measure this distance precisely, but I measured it to be 224.5mm. Given the similarity of these figures, the quoted value for the offset angle of 25.5° can be taken with confidence, as can the 4mm stylus to headshell front edge dimension.

[5] http://vantageaudio.com/info/breuer.htm

[6] Compared to the original Breuer Type 8 arm of the 1980’s, the changes made to produce the Type 8C III include:

elimination of the DIN connector at the arm base,
colour changed from pale gold to black anodising and from brass to stainless steel,
headshell design,
elimination of a slight coloration, made by replacing brass with stainless steel, with an improved coupling of counterweight to tonearm,
use of silver internal wiring.

Barry Hunt 

 

© Text Copyright and all photos 2013 Barry Hunt, except where noted and the Copyright there belongs with the named party. 

NB No part or portion of this article may be reproduced or quoted without written permission, failure to do so may result in legal proceedings.

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