Beomaster 2400 together with Beomaster 1900 were two advanced FM stereo receivers. They had identical technical specification and performance. Both were easy to use and easy to live with.
Beomaster 2400 had the additional convenience of a cordless ultrasonic remote control module by which you could operate radio, amplifier and Beogram 2400 or 4004 record decks from a distance. Both receivers had touch-sensitive controls for operating the features and functions you used every day. All the secondary switches and adjustments were protected beneath a hinged lid, but an illuminated readout panel showed you the set’s operational status at a glance.
Equipped with the slim remote-control module you could select between four pre-set radio stations or record player input, adjust the volume up or down or put the System into Stand-by. The illuminated panel with its large display allowed to to easily see the state of play from anywhere in the room. The phase-locked loop decoder ensured a wide separation between stereo channels and remained stable over a very long lifetime. When a stereo broadcast was received, a symbol ‘S’ lit up automatically on the fascia of the set. Automatic Frequency Control (AFC) kept the selected radio station spot on tune, and a muting circuit cut out inter-station noise during tuning.
The stereo amplifier produced 2 x 30 watts RMS of high-fidelity output and had DIN sockets for the connection of two pairs of speakers, a record-player and a tape or cassette recorder.
A headphone connection was provided beneath the front edge of the unit. Controls not needed every day were situated beneath a hinged lid. These included tone and balance adjustment, FM pre-setting, loudness, AFC and MONO/STEREO switches, and a switch for selecting a basic initial volume level. This facility allowed you to choose the volume at which the amplifier began to play each time it was switch on – no matter how controls were left the previous time. On its primary control panel Beomaster 2400 had no knobs or buttons. The panel functioned electronically and needed only the contact of your finger to activate it. However, the ultrasonic remote control would have proved more useful. The set’s sophisticated indicator system would tell you instantly that your commands had been obeyed.
Beomaster 2400 was superceded by Beomaster 2400-2 in 1980.
Beomaster 3000-2 was a solid state FM stereo receiver. The receiver was the kind of product you wanted to both look and to listen to.
It delivered 2 x 40 watts RMS at 30-30.000 Hz and whose distortion was less than 0.5%. With additions to the receiver like Beogram 3000, a fully automatic record player whose operating functions were executed by one master control, and two Beovox 3800 pressure chamber loudspeakers, Beosystem 3000 formed a complete high-fidelity system which deserved to be included in serious evaluations by those who felt that a quality hi-fi system must be chosen in separate units.
The unit was a high fidelity stereo amplifier in which emphasis was placed on specifications, frequency correction and connection facilities. The LOUDNESS feature permitted switching between an objective or a subjective linear reproduction and the LOW and EH filter controls gave a sharper regulation of frequencies, in addition to the normal bass and treble controls. The LOW filter helped reduce rumble resulting from a poor or defective record. At 80Hz its slope was 12dB per octave. There were sockets and push buttons for two pairs of loudspeakers. The headphone socket was situated on the front of the receiver. The tape connection facilitated AB monitoring and there were two record-player inputs: a high and a low impedance. All input sockets could be adjusted from the receiver’s base so that all signals had the same sound level. This was an extra convenience because one needed not adjust the volume control on the amplifier when it was switched between programme sources. The FM section had six pre-set stations. A light indicator assisted accurate tuning and the indicator registered the signal strength of a station. The FM section was extremely sensitive (better than 1.4 uV, I.E.C.) and harmonic distortion was only 0.4%. Field effect transistors, ceramic filters and integrated circuits were used.
In 1972 the Museum of Modern Art in New York (MoMA) chose seven Bang & Olufsen products designed by Jacob Jensen to be included in their Design Collection as representing excellent examples of the Museum’s criteria for quality and historical importance; design, in fact, which had influenced the twentieth century. Beomaster 3000 was one of those seven products. Two years’ previously Beomaster 3000 won the iF Design Award.
Beomaster 3000-2 was introduced in 1972. Both units could be used as part of Beosystem 3000. The two models were visually indistinguishable except for the model number, but the Beomaster 3000-2 contained a few minor technical improvements. The effect of these was not visually or aurally evident; the improvements were seen as Bang & Olufsen’s desire at that time to offer the customer the best components and aural experience.
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.
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.)
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 extremely distinctive and beautiful FM stereo receiver from Bang & Olufsen used the very latest technology, both in its complex audio circuitry and in the microcomputer-based control systems which made it such an effortless and pleasurable product to use – whether or not you decided to include the optional remote control facility. The specialist radio section concentrated on the superb sound quality available from FM transmissions.
It covered the entire FM band from 87,5 to 108 MHz and incorporated the most advanced techniques for accurate, drift-free stereo reception.
The amplifier gave 2 x 75 watts RMS with an extremely low level (0,8%) of harmonic distortion. Clean, clear sound – always. Two 24-hour timers allowed you to play or record any sound source automatically. You didn’t even have to be at home. Or, if you wanted to be sure of hearing the same news programme every evening you could set the Repeat function to remember for you – day after day.
Connections included sockets for a record deck and two tape decks (DIN or RCA phono plugs) plus graphic equaliser, headphones and two pairs of loudspeakers.
Beomaster 6000 formed the heart of Beosystem 6000 and was designed by Jacob Jensen.
Beocenter 2800 was a unique combination of FM/AM tuner, a 2 x 25 watts RMS hi-fi power amplifier and record player. The tuner section offered Long and Medium wave reception as well as FM. There were facilities for pre-setting the four FM stations you listen to most frequently. Ceramic filters, AFC, split-supply output and a phase-locked loop decoder were some of the features that ensured outstanding reception and reproduction of even distant stations.
The record player was fully automatic – one master switch controlled all operations. The anti-skating device was built into the arms suspension and worked automatically. Electronic Servo Drive (ESD) ensured constantly correct speed. There were sockets for tape deck, two sets of stereo speakers and headphones.
This was a compact, space-saving unit which was easy to use thanks to automatic circuits and logical controls. Beocenter 2800 could be made up as part of the Beosystem 2800, when linked together with other compatible Bang & Olufsen products
The B&O 4-speed record player is an important step on the road to full musical enjoyment, being designed specially with a view to vibrationless and rumbleless operation. This feature is of great importance when playing stereo records as the pickup stylus must be sensitive to vibrations in all directions in order to be capable of “scanning” the record properly.
Understanding the numbering of these Beograms is really quite easy: the ‘V’ in ‘608V’ means that it is powered with AC voltage and ‘F’ means that it has a built-in preamplifier. The designation 608, 609 and so on, indicates the year the product was marketed. There was also a ‘U’ version for both AC and DC voltages. Beogram 608 for example, was a turntable without a built-in RIAA preamplifier and was produced for the 1962 season (internally many were date-stamped e.g. September 1961 would indicate the year it left the factory).
The difference between the models 41xx and 42xx was that the 41xx had a small turntable and the 42xx model had a larger turntable.
