Beosystem 3300: a 2 x 40 watts RMS amplifier, an FM, long and medium wave radio, and a stereo record deck – was all combined into a single unit called Beomaster 3300. The record deck was fitted with the Bang & Olufsen MMC 20E cartridge. Two Beovox Uni-Phase S45 loudspeakers completed this value-for-money system.
Beosystem 3300: blending science and art
Bang & Olufsen designs are always refreshingly different – a pleasure to look at as well as to hear. Which could be why the company has earned itself over the years coveted places in the Museum of Modern Art in New York.
Beosystem 3300 was the latest addition to a collection which fascinated people from all over the world. You could hang it on the wall among your other works of art; or place it where you like – those sleek, modern shapes would always look good.
But Beosystem 3300 had a great deal more to offer than an ultra-modern appearance. With records, tapes, radio and compact discs it was a top quality music system that really knew how to perform, according to the 1988 catalogue.
Beomaster 3300 Type 2951
This receiver was the heart of the system, connected by Datalink to the other equipment and passing on the commands you gave via remote control, or by a light touch directly on the panel.
You could preset up to five radio stations. The amplifier had a power output of 2 x 30 watts and a power handling system which prevented overloading and distortion. Beomaster 3300 was part of Beosystem 3300 although it could be used as a stand-alone item.
Beomaster 3400 Type 2802 was a 4-channel receiver whose out put was stated as 4 x 20W or 2 x 30W, depending on how it was configured.
This receiver was a development of the Beomaster 2000 but as well as being quadraphonic, was FM only. The tuning scale was extremely unusual being a series of vertical scales rather than a single horizontal one. Despite the huge length thus provided, it still only read up to 104!
It was designed to be partnered by the Beogram 3400 which could provide the correct 4 channel input as well as the stereo cassette player, the Beocord 2200. S45 or P45 speakers made up the rest of the system.
Beomaster 3500 was a part of Beosystem 3500 which comprised the Beomaster 3500 receiver, Beogram 3500 CD player, Beocord 3500 cassette recorder, a pair of Beovox RL35 speakers and a Beolink 1000 remote control.
The whole system in the autumn of 1991 cost just 1600 euros (about £1100). The system’s lines were pure with everything superfluous omitted. It was specially designed to hang either on a wall or sit on a shelf or table. A light touch on its illuminated display gave immediate access to AM/FM receiver, CD player and cassette recorder; all of which were the latest and best in their respective fields. The system was completed by a pair of RedLine RL 35 speakers and operated via a Beolink 1000 remote control unit.
The system was similar to Beosystem 4500 but had a matt finish on the top panels as opposed to Beosystem 4500’s shiny panels. The electronics were a cut-down version of its more expensive brother.
This was a variant of the Beomaster 4400 but which had a black fascia instead of the aluminium front seen on the Beomaster 4400. It seemed to be designed mainly for the US market but numbers made seem to be few and it has attained almost mythical status amongst European collectors. Bang & Olufsen themselves have not got one in their collection and in fact did not even have a picture.
However the enthusiast is not so easily thwarted! Thanks to the superb investigating powers of Frede Kristenssen of Classic Audio, we present the Beomaster 4401!
A more detailed description will follow once the model has been serviced, but essentially it has the same design and performance as the Beomaster 4400.
Two of these receivers are known to exist and examination would suggest that these were design studies taken to a production level. Some evidence of prototype wiring is present but clearly the parts are anodised in black.
Investigations have not completely uncovered the status of this model. There is one line of thinking which suggests that a number of these were made – in the region of a thousand with the majority going to the United States. However other insiders at B&O suggest that only a handful exist and it would seem that they are now in the hands of enthusiasts.
Reports of a matching Beogram , the 4001, are not backed up by any official data and unlike the Beomaster 4401, no service manual has yet been found.
In use the Beomaster 4401 is no different from a normal 4400. Except in this case the 4401 was restored by Classic Audio. This means that this Beomaster exceeds all the factory specifications.
How does it sound? Very modern despite it being over 30 years old. Lots of power and superb dynamics and extremely neutral. Many Beomasters have a warm slightly veiled sound but this one is a clear as a bell. It works equally well with small and large speakers and is easily able to control the bass on Beovox M100s which are a bit of a handful.
The tuner is a delight, pulling in weak stations with ease though the pre-sets are no easier to use than those on the Beomaster 3000. The geared wheels on the Beomaster 2200 are vastly better.
Connections are limited to DIN sockets – the useful RCA sockets are no longer there. This receiver also was the last to feature ambiophonics and a switch to activate the rear channels was fitted to the rear of the unit where most users would never see it!
In this users opinion, this is the best receiver made by B&O. The later Beomaster 8000 was more powerful but the 8000 is prone to going off specification very quickly due to the use of a particular type of capacitor. Therefore an 8000 in proper fettle is a rare beast indeed.
The 4400 is therefore a hidden gem; clothed in the skin of the lesser 3000 and 4000, it hides its splendour till called upon to play. Buy one now – these are true bargains!
The Beomaster 4500 radio/amplifier received both FM and AM radio and was your communication link to the other sound sources in the system. Its operation was simplicity itself with an illuminated menu presenting all the options available. 20 radio stations could be pre-set providing you with instant access together with automatic fine tuning.
The 2 x 55 watt/8 ohm amplifier had a newly-developed, well-balanced interplay with the power supply which gave the output extra strength. The power reserve encompassed the entire frequency range and gave stable sound quality no matter what the volume. Beomaster 4500 also had automatic power handling control that prevented overloading, no matter how many loudspeakers were connected, as well as a special loudspeaker socket which ensured optimal utilisation of BeoLab active loudspeakers.
Beomaster 4500 could be used as part of the Beosystem 4500 hi-fi system and could be controlled via a Beolink 1000 remote control terminal. Later models of Beomaster 4500 could be controlled by the two-way Beolink 5000 and had the extra benefit of programmable timer functions (note that only Beomaster 4500 models with a software version of 2.1 and higher were able to handle two-way communication as well as the timer function.)
Highly selective and sensitive FM stereo tuner with low-distortion multiplex adaptor featuring a high degree of channel separation. It has a 4-section gang-tuned radio-frequency amplifier with separate oscillator, five-stage intermediate-frequency amplifier, automatic frequency control, and automatic stereo/mono switching.
Large tuning meter facilitates pin-point tuning and provides relative signal-strength indication. An automatic data-processing centre switches from mono to stereo when the signal-to-noise ratio permits stereo reception (and if the set is tuned to a stereo broadcast). Moreover, it automatically cuts out the signal if the field strength drops below the critical level – and between channels, during tuning. The automatic frequency control circuit also ensures that the set stays accurately tuned at all times. The remarkable sensitivity of the Beomaster 5000 is due to the use of multi-stage radio-frequency and intermediate-frequency amplifiers, and the large number of intermediate-frequency circuits provide knife-edge selectivity. An amply-dimensioned true slide-rule dial with station markers ensures easy and rapid tuning.” – taken from the 1967 – 1968 Bang & Olufsen product catalogue
Bang & Olufsen’s Beomaster 5000 FM tuner, Beolab 5000 amplifier and Beovox 2500 Cube loudspeakers were among the first product series designed by Jacob Jensen in 1967. The first was Beomaster 1000 in 1964.
The traditional style for tuning knobs was replaced by an exact measuring instrument akin to the slide rule which was considered an innovation in changing the future of radios and amplifiers. The interface, in its precision and simplicity, proved to give the user optimal functionality. This solution had never been seen before and laid the foundation for the future form language of B&O. Beomaster 5000 was an FM tuner, with elimination of static between stations and a built in ‘data base’ which automatically tuned in on stereo broadcasts.
Partner to Beomaster 5000 was Beolab 5000, an amplifier with a similarly-designed slide rule interface.
At the 1967 spring fair in Hanover, B&O received the IF award for Beomaster 5000, BeoLab 5000 and Beovox 2500 Cube for outstanding and user-friendly design.
Long, medium and FM wavebands were featured on this high-technology 2 x 55 watts receiver that served as the heart of Beosystem 5000 introduced in 1983.
A frequency-synthesized tuner with automatic fine tuning and two-speed manual drive all contributed to fast, accurate location of radio programmes and superb reception quality. Nine station frequencies (on any combination of wavebands) could be stored in the Beomaster’s microcomputer memory for instant recall.
The low-distortion stereo amplifier included a very advanced feature, unique to Bang & Olufsen: Automatic Power Handling Control. This special circuit continuously monitored the dynamic range and power of the signal and instructed the microcomputer to decrease volume if the combined effects of these two parameters threatened to cause amplifier “clipping” or damage to the speakers. This type of overload became increasingly common since the introduction of the Compact Disc, which can produce signals of enormous dynamic range, but it could not occur in Beomaster 5000.
An internal, variable-speed fan ensured the proper dissipation of heat, even when the Beomaster was used in a stack format. Direct operation of all primary functions was available on the Beomaster itself should the Master Control Panel not be to hand. These controls were located beneath a hinged cover which sprang open at a touch
Beomaster 5000 had no visible controls. Normal operation was by means of the Master Control Panel – a slim, table-top keypad that gave chair-side access to all functions including microcomputer programming and storage, timer facilities, status check, day and clock display, volume, tone and stereo balance adjustments and control of all sound sources. A programme-sequencing facility allowed you to pre-plan a whole evening’s listening composed of record, radio and cassette music in any order and combination. Once set, this “command performance” would play continuously as instructed without further use of the controls
The Beomaster 6500 receiver was the brains behind the sound system.
In part a powerful receiver for FM/AM and LW broadcast bands. In part the control centre that created the connection between your commands and all the sound sources in Beosystem 6500. You could preset up to 20 stations and a light touch on the Master Control Panel automatically initiated the search and fine tuning functions.
2 x 110 watts/8 ohms output gave you a power surplus that provided a detailed sound picture even at low volume. The receiver also had Bang & Olufsen’s automatic power handling control that prevented overloading no matter how many loudspeakers you connected. It also had a newly-designed socket which provided optimal utilisation of BeoLab speakers.
Beomaster 6500 could be used as part of the Beosystem 6500 hi-fi system and could be controlled with with the Master Control Panel 6500 or Beolink 7000.
Beomaster 7000 was a receiver of high specifications and contained the system infra-red transceiver for communication with Beolink 7000 and the necessary computer to process and relay the commands to the other sources. Beomaster 7000 was the audio master and as such defined the system. Besides being a computer with considerable processing power, Beomaster 7000 also contained an FM/AM radio, the switch circuitry and the control- and power-amplifier.
Features:
Radio:
FM/AM frequency synthesis tuner, 24 presets. RDS decoder with access to FM transmitter name and operator. Naming of individual stations, both FM and AM, up to ten characters per station.
Amplifier Control section:
2 x 110 Watts long-term maximum output power. Automatic Power Handling Control, speaker and amplifier protection. Power Link connection for BeoLab active loudspeakers. Speaker Link connection for other loudspeakers (two pairs).
Connection for external power amplifier. Beolink® AV connection and complete AV operation facilities. Connection for Local Control System.
Audio Master:
Microcomputer, ROM capacity 64 KB, RAM capacity 1 KB, for the control of e.g. adjustments, source switching (audio and video), Automatic Power Handling Control, tuning, timer programming etc. Timer programming, 10 timer blocks. Battery backup for timer and clock. Dynamic display readout on Beolink 7000 of frequency, RDS and naming data, all tuning data, preset, FM/AM, sound adjustments.
Beomaster 7000 had a built-in RDS decoder which gave access to the basic 8 character RDS readout, the “PS” or “Programme Service Name”, i.e. an abbreviated readout of the transmitter name, the programme number and perhaps the name of the operator. The RDS data was displayed directly on Beolink 7000, when you selected a station that broadcast RDS information. This applied both when you were tuning or when you selected the preset that you had stored the programme on. Beolink 7000 displayed the RDS data also in situations when you were in a room equipped with Local Control System. Beolink 7000 was the only remote control capable of displaying RDS data.
The channel-naming facility allowed you to give every single radio station a name of your choice, with up to 10 characters, directly on the Beolink 7000. Naming could be carried out on all preset stations. Your favourite name had priority over a RDS name (if available) and was displayed when you selected the channel number.
The RDS and naming facility gave an added convenience with radio reception. The convenience level was paralleled with the reception quality of the FM tuner.
An FM tuner faces conflicting demands with regard to signal reception. It must have a high sensitivity for receiving weak stations (high selectivity), but it must also be able to suppress interference from powerful neighbouring stations. Beomaster 7000 was one of the few receivers that paid attention to these conflicting demands.
Components in high quality (e.g. dual-gate MOSFET transistors) and an optimised electronic design were used. The Intermediate Frequency (IF) stage had a bandwidth of approximately 200 kHz around the 10,7 MHz centre frequency (the IF filter contained three stable ceramic filters). Generally, if the IF bandwidth is broad, the selectivity falls, as does the intermodulation distortion. Conversely, if the bandwidth is narrow, the distortion and selectivity rise. This relationship must be compared with the reception conditions. If stations are close by (and powerful), the ideal is a narrow bandwidth, while distant (weak) stations require a wider band, in order to keep down the intermodulation distortion. In Beomaster 7000 the signal strength was measured for both the stations you received (within the filter range) and for stations that you didn’t want to receive, outside the filter range. This allowed Bang & Olufsen to suppress powerful stations on neighbouring frequencies and counteract intermodulation distortion, giving a high signal-to-noise characteristic for both weak and strong stations.
The stereo decoder gave an optimal stereo channel separation as long as the signal-to-noise ratio in the received signal was above 50 dB. When weaker signals were received, Beomaster 7000 automatically switched to mono. You could also select mono manually.
Tuning
The tuner was of the frequency-synthesis type, based on digital technology and controlled by the microcomputer. Tuning on FM was in steps of 50 kHz, in order to adhere to the cable network frequency allocation of 50 kHz. Tuning was carried out from Beolink 7000, either as a search tune up or down in the frequency range, or by direct frequency selection. There was automatic or manual fine-tune, with a precision better than 1 kHz.
AM Tuner
The (then) newly-developed AM tuner had a high reception sensitivity and was very stable and reliable. It was optimised for the Bang & Olufsen loop antenna, type no. 8720038. Automatic tuning was in steps of 9 kHz (USA: 10 kHz). The fine-tune operated in steps of 0.25 kHz.
Presets
24 presets were available. You could store any FM or AM station in any order and information such as fine tune, FM stereo/mono and AM manual tune was stored on the preset.
The Power Amplifier
The power amplifier in Beomaster 7000 was rated at 2 x 110 watts long term max. output, and it featured Automatic Power Handling Control as a protection for both the loudspeakers and the amplifier in case of overload or shorting. The circuit monitored the critical stage in the output amplifier and if prescribed limits were exceeded, the microcomputer lowered the volume to below the critical level.
The temperatures of the cooling surfaces were also measured and if the temperature got too high, the volume was also cut down. If the limits were exceeded again, the procedure was repeated. If the cause of the overload was eliminated, the volume could be turned up above the previous critical level. You would only under very special circumstances experience the Automatic Power Handling Control’s circuit overruling your volume setting, but when it did, it could save the system from serious damage. The circuit might have been activated, for example, if you connected several pairs of normal loudspeakers and played very powerful music extremely loudly. Another example could be if the loudspeaker outputs were short-circuited, in which case the Beomaster was simply switched to stand-by to protect the amplifier in an effective way. Similarly, if a defect occurred in the amplifier, the circuit protected the loudspeaker against direct current, which would otherwise destroy them.
If you connected BeoLab Penta or other active BeoLab speakers via the Power Link sockets, there was an independent protection circuit in the loudspeakers to protect them in a similar way.
Active cooling
Beomaster 7000 was very compact and in order to liberate heat from the power amplifier efficiently, a low-noise fan was placed at the bottom of the cabinet. If the cooling ribs of the output transistors reach a temperature of more than 50 degrees, the fan started up at low speed, rising to a maximum speed when the temperature was around 95 degrees. The amount of heat generated by the amplifier depended on how loud you played and for how long a period the volume was turned up. Only by playing very loudly for a prolonged time would the temperature rise and the fan start up, or the Automatic Power Handling Control interfere. Note also that if the recommended BeoLab Penta loudspeakers were connected, the power amplifier in Beomaster 70000 became inactive (or perhaps used to drive a Local Control System).
PowerLink Connection
The PowerLink connection in the receiver was used to connect BeoLab active speakers. The signal is a volume-adjusted line level signal and both left and right signals are carried in one cable, with data signals for a BeoLab status display. This means that it is no longer the socket on the Beomaster that decides whether it is the left or right channel. Instead a switch on the BeoLab loudspeaker has to be set to the correct position. PowerLink is very flexible with regard to connections. A pair of loudspeakers can be connected the usual way, with one cable to each loudspeaker, a BUS system can be applied where the signal is looped through one of the loudspeakers and then on to the next, or both methods may be combined if more than one pair of speakers needs to be connected. No matter which method is used, the correct setting of the L – R switch on the loudspeaker is essential. Up to 10 pairs and 100 metres of Power Link cable is recommended.
Socket Panel
The socket panel on the back of Beomaster 7000 was placed in a cut-out to prevent the connectors from protruding too far. As a consequence, the effective depth of Beosystem 7000 was virtually the same as the actual depth of the components. Apart from the CD, Tape 1, Tape 2, Phono and PowerLink sockets there were also connections for TV (or AUX), 2 pairs of Speaker Link for normal loudspeakers and Local Control System, FM/AM antenna sockets and a Line in/out socket for an external unit, e.g. an equaliser.
Note that the RIAA phono-preamplifier was placed in the Beogram 7000 and if a Beogram without RIAA was to be connected, a RIAA kit must be mounted in Beomaster 7000 by means of a minor service operation.
The battery backup in Beomaster 7000 retained all information in case of a power cut, where a quartz crystal was used as a reference for the clock.
Beomaster 7000 could, ideally, be used as part of Beosystem 7000.
This continued the B&O theme of receivers with built in speakers, the receiver at the centre of the product being the Beomaster 901. Very slim and elegant if inordinately long!
