Beomaster 6000 (1974)

Product : Beomaster 6000

Produced from : 1974 - 1977
Designed by : Jacob Jensen
Finish : Rosewood, Teak, White
Desirability : 5

Technology changes at a pace, and with this in mind Bang & Olufsen brought out its innovative and beautiful-looking Beomaster 6000 to reflect the then current trends in technology.  Quadraphonic - or four-channel - sound was all the rage in the mid-1970s even though the actual sources which to play was rather limited (unlike today’s MP3, DVD, Blu-Ray technologies providing 5.1 sound, or even 7.1 channel sound). In these years it was only LP records and perhaps FM radio stations at certain times of the day which were the only available sources which could offer a ’surround sound sensation’ and so the choice was rather limited, and also rather expensive.

Looks-wise Beomaster 6000 was typical Jacob Jensen; designed from the bottom up to be attractive, covered in acres of aluminium sheet and used Jensen’s trademark slide-rule scales to control different levels of sound or tuning in of radio stations.

Operation of the receiver was simple: the large top, flat panel had incorporated within it everything that you needed for day-to-day operation: programme source selection, volume, balance, bass and treble controls. Secondary functions - that of loudness control, hi and low filters and so on - were smaller push buttons and hidden discretely from view. The whole of the top ‘deck’ was sophisticated-looking yet easy to use.

Beomaster 6000 at the heart of the Beosystem 6000

Impressive though the Beomaster 2000 is, it is totally eclipsed by the superb Beosytem 6000. This four-channel system appears to have very nearly everything the audiophile may want for the next ten years. Its heart is the Beomaster 6000 which is a very sophisticated four-channel amplifier with stereo tuner, which supplies 40 watts per channel to each of the new P50 Sound Panels. These three-unit loudspeakers are only 5 1/2 inches deep and are designed for wall-mounting. The controls are all servo-operated so that there are no knobs to turn. Not only that, the whole system can be controlled from the ease of one’s armchair by the 6000 Commander. This is an ultrasonic remote control which operates in just the same way as the switches on the panel of the amplifier. The system can provide reproduction of CD-4 discs, SQ matrix discs and conventional stereo records in ambiophonic mode. The part of the system which deals with this is the Beogram 6000, developed from the parallel tracking 4000 reviewed by John Borwick last month. The cost of this system is 1,014.50 GBP complete.

Taken from ‘Gramophone’ Dec 1974 (page 196)

Of the sound which it produced, the Beomaster 6000 had moved on from ambiophonic sound (offering pseudo surround sound) to one which was able to deal with true 4-track sound from a black vinyl disc or from FM radio. Beomaster 6000 had a 4-channel amplifier with a built-in tuner. It also combined its own built-in SQ decoder (4-channel matrix) and was offered as a fully remote-controlled system. Five FM radio stations could be pre-set with manual tuning possible on the large illuminated FM scale. Producing a generous 40 watts RMS to each of its four channels, the amplifier could reproduce one, two or channels with ease. The encoded-records which it could decode were specifically CD4 discrete and SQ matrix.

Of the two available four-channel systems it was CD4 (Compatible Discrete 4-channel) - or the ‘TRUE 4-channel system’ as it was called - which was favoured by audiophile purists as this system produced high-quality sound reproduction with a high degree of channel separation.  However, as is always the case with new formats and each company thinking that their own system was better than the others, the SQ system became the more popular of the two as it was easily transmitted over FM broadcasts with SQ records being able to be played on a high quality stereo record players. However, less channel separation was produced compared to the CD4 system. Within Beomaster 6000 an SQ matrix decoder was included whose task it was to reconstruct sound information for the two rear speakers. With CD4 recordings this reconstruction took place in the turntable itself, namely the Beogram 6000.

An effective system, but as is always the case, technologies, if not taken up by the buying public, are quietly dropped as other newer technologies - often much simpler and cheaper - come along to replace them. This was certainly the case with the Beomaster 6000 system which finally lost its cause to stereo once more when its own special cassette deck - the Beocord 5000 - a stereo-only machine, was introduced in 1975.

A cordless ultrasonic remote control handset for use with Beomaster 6000 could be bought as an extra.  The Beomaster 6000 Commander was simple yet effective in being able to carry out instructions from afar when it was used for controlling volume and individual balance to both the front two speakers and the rear two loudspeakers. Each of the five pre-selected FM stations could be summoned as well as a selection of external programme sources. The turntable, tape/cassette deck could also be simply controlled as well as switching on the Beomaster and putting it into stand-by.  So for its day the remote control handset was really a very handy tool to possess as well as being really rather sophisticated for its day.

ANY readers who have noticed the price in the heading of this review—and who are nevertheless prepared to read on—will have realised that the Beosystern 6000 is a very expensive audio system indeed. It may be asked why we devote space to such a luxury product when so few readers can possibly be in the market for it? Well, our answer is that the Beosystem is technically of great interest and a study of its features may well provide pointers to the way other equipment (at hopefully lower prices) will go in the future.

To begin with, the Beosystem is a fully quadraphonic installation, with built-in facilities for both CD-4 discrete and SQ matrix gramophone records. The complete price of £1,014-50 includes four Beovox P50 loudspeakers, which retail separately at £49.50 each (and so account for £198.00 of the system price). The Beogram 6000 turntable unit retails at at £298.50 and includes a built-in CD-4 demodulator and the MMC 6000 pickup cartridge with the special stylus and design necessary to encompass the frequency range up to 50,000 Hz demanded by CD-4 records. The Beomaster 6000 tuner-amplifier retails separately at £471-00 which is not at all exceptional for a 4-channel unit, with a power rating of 4 x 40 watts per channel, incorporating an SQ decoder and a cordless remote control box, etc.

Description of the units

With so much to describe, I will summarise the details and refer readers to the manufacturer’s literature for more information.

The Beomaster 6000 receiver is a large, low profile unit, measuring 26 by 12 by 3 inches and having no projections of any kind. The front portion of the top panel consists entirely of a brushed aluminium strip divided by sawcuts into pressure activated switch controls, with a rotating circular platform at the right hand end for manual radio tuning. All other primary functions are controlled electronically by an electric servo-motor and magnetic clutches. This has two big advantages: first, the actual operation can be reduced to the lightest of finger pressures; second, the functions can be duplicated on a remote control unit— the Commander—and ultrasonic sound waves used to obviate the need for a trailing cable. In all cases, the amplifier is muted for a brief moment on switching, to eliminate clicks.

There are three groups of five pressure controls on the Beomaster panel. The left hand group covers volume, bass, treble, left/ right balance and front/back balance; large The Bang & Olufsen Beosystem 6000 will reproduce CD-4 and SQ quadraphonic records and has an ultrasonic remote control unit illuminated scales above these have red light pointers which indicate the settings individually. The right hand two groups constitute input selector switches for standby (on/off), FM, auxiliary, pickup, tape, and preset FM stations 1 to 5. Again, illuminated signs on the black dial panel indicate the source selected. When FM (manual) is selected, the 10-inch long tuning scale is also illuminated. In all cases of manual or preset radio reception, the word “Stereo” is illuminated if a stereo signal is incoming and two wedges of light can be set for equal brightness to indicate accurate tuning.

The individual thumb-wheel controls for tuning the five preset stations are tucked away under the sloping front of the base casing and have tiny frequency scales to show the approximate tuning position. Also, on this recessed panel are two stereo headphones jacks for front and rear. At the remote part of the top panel are pushbuttons for front and rear speakers, loudness contour, low and high filters, mono, stereo, SQ matrix, ambio and AFC on/off, which brings in a silent tuning (muting) circuit in the ‘on’ position.

With both front and rear speakers switched in, the mono button feeds a composite mono signal equally to all four speakers, the stereo button feeds Left channel to both left speakers and Right to both right speakers. The ambio button leaves stereo on the front speakers and feeds an out-of-phase signal to the back speakers to give simulated quadraphony from normal stereo signals.

On the underside of the unit are 5-pin DIN sockets for a 4-channel tape recorder (stereo front and back) and auxiliary (for a stereo pickup or playback from a further stereo tape recorder). There are also sockets for a 300 ohms balanced or 75 ohms coaxial FM aerial. No aerial is provided, but B&O can supply an indoor telescopic aerial for £14.50. The usual 2-pin DIN sockets are fitted for loudspeaker connecting (stereo front and back) and there is a wire stay to tilt the receiver up at an angle of about 20° if this is preferred. The Commander remote control unit measures 6 by 4 by 1 inches and comes complete with a small 15 volt battery which should last for many months.

The Beogram 6000 is the latest development of the Beogram 4000 unit which we reviewed in November 1974. Like the matching Beomaster 6000, it has finger-pressure controls of matt aluminium. This, coupled to the unique motor-driven carriage-way supporting the short radial tracking pickup arm, gives the user extraordinarily flexible control over the operations. Simply touching the start button causes the belt-drive motor to rotate and the arm to track along and lower gently into the run-in groove. Unless overridden manually, the arm will sense the presence of a 12-inch or 7-inch record and select the 33 or 45 rpm speed accordingly. If there is no record on the turntable, the pickup wilt traverse across the platter and then return to its rest and switch off. There are separate buttons for slow forward or back arm traverse, raise/lower and stop.

The straight-line radial tracking arm eliminates tracking error completely and special light-sensitive diodes activate the carriage motor to keep the arm tangential to the groove at all points across the record. The built-in CD-4 demodulator is switched on by the presence of the 30 kHz carrier tone on a CD-4 discrete quadraphonic record. It then lights a “4 Ch” beacon lamp and sends the 4-channel quadraphonic signal to the Beomaster 6000. If an ordinary mono, stereo or matrix record is played, the demodulator does not function and the output of the pickup is sent as a simple 2-channel signal.

The Beogram 6000 is supplied complete in a low profile cabinet, measuring 18 by 14 by 3 inches, which exactly matches the Beomaster 6000. The hinged, tinted cover will stay open at about 80° or any angle more than about 40°. The MMC 6000 pickup cartridge (MMC stands for moving micro-cross, the electrodynamic construction employed by B&O for many years) is the latest refinement in the long series of B&O magnetic cartridges. All dimensions have been reduced: only a tiny tip of diamond is employed for the stylus and the use of beryllium for the cantilever has brought down the effective tip mass even further—it is quoted as 0.22 mg. A special shape of stylus tip is obligatory for CD-4 records and B&O, instead of purchasing Shibata styli, have developed their own design of polished multi-radial stylus, called Pramanik after its B&O designer.

The cartridge is integrated, that is the stylus assembly does not slide out for replacement. The user must purchase a new cartridge when the old one comes to the end of its useful life. In this way, a factory tested unit is obtained, and every MMC 6000 cartridge is supplied with an individual calibration card and penrecorded frequency response curve, from 20 - 45,000 Hz. The cartridge is most beautifully packed, with matching screwdriver, stylus pressure gauge and cleaning brush.

The Beovox P50 loudspeaker was specially designed for four-channel use within the Beosystem 6000. It is technically complex, but drastically reduced in physical size, particularly in depth, to simplify the installation. The sides are finished to match the rest of the system, with a thin fillet of aluminium around the black grille cloth. There are four drive units, 2 x 5 inch for bass, 3-inch mid-range and a 1-inch dome tweeter. The crossover frequency is 2,000 Hz.

The units are mounted on a hard plastic moulding of which the upper half, carrying the high frequency units, is angled forward slightly. This, together with a series of alternative mounting holes on the back panel, allows the speakers to be hung on the wall at any convenient height. An instruction leaflet shows how to hang the speakers so that they are angled downwards, if above head height, and pointing straight ahead if at or below head height. It is also possible to hang the speakers either vertically or horizontally. Wall plugs and screws are supplied (but I managed to make a satisfactory temporary fitting by hanging the speakers on strong wire from hooks on my picture rail). Each speaker comes with a 4-metre cable having a 2-pin DIN plug at one end and a DIN socket at the other. I expect that extension cables would be needed to make a neat installation in most rooms, but this should not be difficult to arrange.

How it performed

I experienced no troubles in setting up the Beosystem 6000 but I feel strongly that, at this kind of price, you should be entitled to ask the dealer to install the system in your house.

The Beogram 6000 is a little fiddly to set up, since transit screws have first to be removed before the top plates can be assembled. I had experience of the Beogram 4000 but even so found that it took me two attempts to arrange the cable attached to the pickup arm carriage so that it would not foul the rotating platter when a record had been played about half way through.

The turntable performed superbly well and of course its pressure-plate automatic operation gives a unique sense of luxury. The unit arrived properly set up for a 1-gram playing weight and my checks showed that the simple weight adjustment was accurately calibrated. For heavily modulated discs I did increase the playing weight to about 1.1 grams, but I dare say most people would not find this necessary.

Auditioning gramophone records occupied many hours because so many possibilities exist. When playing stereo records, for example, the sound can be left to emerge only from the front pair of loudspeakers. Yet, if a more spatial effect is wanted, one can press either the Stereo button (which sends the sound to the back pair of speakers and slightly attenuates the front speakers to preserve the overall loudness level) or the “Ambio” or “SQ” button (which produces a pseudo-quadraphonic spread of sound). I did not much care for the former effect (4-speaker stereo) but the pseudo-quadraphony was quite pleasant on many instrumental or choral records.

I was particularly interested to sample my collection of CD-4 discrete ,quadraphony records. Previously I had listened to these via a number of CD-4 type cartridges (JVC, Ortofon, Toshiba) and such loudspeakers as B & W DM2 (four) or AR LSTJI (two) with Lecson (two) etc. The results with four identical Beovox P50 speakers hung above head height symmetrically in my squarish diningroom came very near to perfection—where directionality is concerned. The JVC “Fireworks” record (413-108), for example, has some undistinguished sound effects and a mixed bag of musical excerpts. However, it is technically well recorded and, reproduced through a properly symmetrical system, makes a very persuasive advocate for discrete quadraphony. The pop group tracks are perhaps the most spectacular, but the classical excerpts (from Carmen, Marche Joyeuse and Brandenburg No. 5) demonstrate well enough to recreate the illusion of concert hall ambience.

The total quality on stereo and CD-4 records left me in no doubt that the Beosystem 6000 as a whole deserves the name of high fidelity. The disappointing lack of extreme bass, tendency to distortion and wear after a few playings on many CD-4 discs was unfortunately revealed with extra clarity. The splendid Ormandy/Philadelphia recording of the Shostakovich Symphony No. 15 (RCA ARD1-0014) however was reproduced extremely well.

The built-in SQ decoder dealt effectively with all the SQ-matrix records I tried. These ranged from such excellent classical items as the Karajan/Berlin Philharmonic recording of Tchaikowsky’s Pathetique Symphony (HMV Q4ASD28I 6) to the swinging arrangements of Paul Simon’s “There Goes Rhymin’ Simon” (CBS CQ32280). Incidentally, I have to report a strange phenomenon. When playing the Johnny Keating “Space Experience” LP (Columbia Q4 TWO 393), the CD-4 demodulator was momentarily switched on occasionally, suggesting that frequencies are present on this disc up to 30 kHz. It was therefore necessary for me to switch off the demodulator during this record.

Technical measurements substantiated the maker’s claims on all counts. Using the auxiliary input, I found the frequency response across a 4 ohms resistive load to be ruler flat within +1dB from 20-20,000 Hz with the tone controls at their optical centres. The claimed performance of the tone controls and filters was similarly confirmed and the sensitivity on all inputs agreed substantially with the specification. I was easily able to achieve the stated 40 watts per channel into 4 ohms before clipping occurred (and operation of the protective circuits). Total harmonic distortion was 0.1% at just below 40 watts. The radio frequency performance seemed excellent: tuning of the preset stations was simple and no drift occurred during weeks of use. Stereo reception, with a loft aerial, was wide-ranging and with a silent background.

The Beogram 6000 turntable was for all practical purposes free of wow and flutter, and rumble was below audibility. Measuring the cartridge response at the output of the CD-4 demodulator showed that the comparatively modest 20-15,000 Hz ±15dB was met comfortably enough. I was not able to run high frequency tests on the response beyond 20 kHz without disconnecting the pickup leads from the demodulator but the consistency with which the 30 kHz pilot lamp was lit, the ease of balancing all four channel outputs and the excellent quality from known CD-4 test and music discs left me in no doubt that the HF response accords with the A Rating laid down byJVC.

The loudspeakers performed well and certainly give an acceptable frequency balance when used as directed. They are not excessively directional at high frequencies and the bass, though lighter than from a full-size monitor, is adequate for 4-channel reproduction in any room where floor-standing speakers cannot easily be accommodated. If space allows, then B&O recommend their Beovox 3800.

In short, the Beosystem would seem to have accurately hit its design targets, namely to offer simple, stylish and technically advanced means for the reproduction of all stereo records and radio, plus four-channel sources including CD-4 or SQ matrix quadraphonic records.

From the ‘Gramophone’ magazine - April 1975 (page 136)

The Beomaster 6000 was included within New York’s Museum of Modern Art (MoMA) Design Collection in 1975.

Beomaster 6000 with its handy remote-control handset, was Bang & Olufsen’s first remote-controlled hi-fi system. Beovision 4402 represents Bang & Olufsen’s first television with remote-control as an option; both remote-controls used ultrasonic sound rather than infra-red which is prevalent today.

Beosystem 6000

BeoMaster 6000 (1974) type:

Market: Type: Intro. year:
2702 1974

Details:

Power output 1000 Hz RMS 4 x 40 W / 4 ohms
4 x 30 W / 8 ohms
Music power 4 x 75 W / 4 ohms
4 x 40 W / 8 ohms
Speaker impedance 4 ohms
Harmonic distortion < 0.06 %
Frequency range 20 - 30,000 Hz
Bass control +/- 17 dB
Treble control +/- 14 dB
FM range 87.5 - 104 MHz
Power supply 110 - 130 - 220 - 240 V
Power consumption 10 - 350 W
Dimensions W x H x D 67 x 8 x 32 cm
Weight 16 kg

Connections:

AUX
Phono
Tape front
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