Beomaster 1600 Type 1703 could be made up as part of Beosystem 1600, when linked together with other compatible Bang & Olufsen products such as Beocord 1600 and Beogram 1600. FM only version of the 1700 and not seen in the UK.
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
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 radial-tracking record deck had a lightweight turntable (only 400g) to minimise torque at starting. The automatic cueing system was also very fast-acting, so it was only a matter of a few seconds between touching the PLAY control and hearing the music.
The tone arm had built-in anti-skating and carried the MMC 4 pickup, ensuring accurate tracking and excellent sound quality. Normal PLAY and STOP functions were entirely automatic and could be operated with the lid closed; manual buttons for playing non-standard discs were located on the deck plate. In addition to automating the setting of correct speed and cueing position for each record, the Beogram’s built-in microcomputer allowed a REPEAT function, which could be programmed for up to 7 plays of the same record.
Drive was provided by a tacho-controlled DC motor via a flat rubber belt, so turntable speed was always accurate and could not be affected by fluctuations in the mains supply.
When used with Beomaster 2000, an electronic data-link allowed Beogram 2000 to be operated by the Beomaster’s controls. Beogram 2000 could also be made up as part of the Beosystem 2000, when linked together with other compatible Bang & Olufsen products.
Living proof that big sound need not take up more space than a couple of ring binders, Beovox CX50 snuggled in anywhere, even as extras in a Beolink® system.
Beovox CX50 and Beovox CX100 loudspeakers were the smallest loudspeakers from Bang & Olufsen up to the time that the manufacture of passive speakers ceased in 2002. They were mostly used to place within a passive Beolink® system (MCL), although they could also be used as main speakers. Thanks to different colour combinations they blended well into most people’s décor.
Beovox CX100 finally ceased production in September 2003 – the last of a long and successful line of passive speakers.
Description:
Passive loudspeaker, aluminium cabinet, available in black, white and brushed aluminium.
Replacement drive units: Top drive unit for CX50/CX100 Part number: 411743
Mounting Options
BeoVox CX50/CX100 replaced C40 and was designed to be optionally mounted with the wall brackets supplied in the box.
Living proof that big sound need not take up more space than a couple of ring binders, Beovox CX50 snuggled in anywhere, even as extras in a Beolink® system.
Beovox CX50 and Beovox CX100 loudspeakers were the smallest loudspeakers from Bang & Olufsen up to the time that the manufacture of passive speakers ceased in 2002. They were mostly used to place within a passive Beolink® system (MCL), although they could also be used as main speakers. Thanks to different colour combinations they blended well into most people’s décor.
Beovox CX100 finally ceased production in September 2003 – the last of a long and successful line of passive speakers.
Description:
Passive loudspeaker, aluminium cabinet, available in black, white and brushed aluminium.
Replacement drive units: Top drive unit for CX50/CX100 Part number: 411743
Mounting Options
BeoVox CX50/CX100 replaced C40 and was designed to be optionally mounted with the wall brackets supplied in the box.
When B&O’s engineers had discovered that the signals from respectively the bass unit and the tweeter in a loudspeaker do not reach the human ear at the same time, and that as a consequence a very slight distortion occurs, they asked Jacob Jensen to design a loudspeaker cabinet in which the units were skewed in relation to each other.
Jensen illustrated B&O’s technical discovery with an angle: “form follows function”. B&O’s loudspeakers in this way achieved a characteristic visual identity in the 1970s and 1980s.” – taken from ‘Jacob Jensen’ by Christain Holmsted Olesen.
Although the speaker was the tallest in the original line-up of aluminium compact passive speakers, Beovox C75 was no taller than an LP record, yet its reproduction quality equalled some of the full-size Beovox models. The one-piece aluminium log-line casing and separate bass (2 x 10cm bass drivers) and treble drivers (1 x 2,5cm) were specially designed to sound best in small rooms. Power handling was 75 watts RMS. Both the C75 and their smaller counterpart, the C40, benefited from the advantages of the “log line transmission system” and exploited the acoustic properties of small rooms to ensure well-balanced sound reproduction quality from these physically small cabinets.
As part of the Beovox Uni-Phase family, they also had linear phase and linear amplitude characteristics, which meant that they reproduced all types of music naturally. The range of C-type speakers won the ID Award in 1978.
Beovox C75 was eventually replaced by the CX100 in 1984.
Beovox C30 and C40 speakers were two compact bookshelf units offering high performance from deceptively small cabinets. The 10cm woofer and 2,5cm tweeter were mounted in thick aluminium casings to eliminate audible resonance. Log-line transmission ensured wide frequency response and clean, clear sound. Ideal for smaller rooms, their power handling capabilities were 30 watts and 40 watts RMS respectively.
The one-piece aluminium log-line casing and separate bass and treble drivers of the Beovox C75 were specially designed to sound best in small rooms. Power handling was 75 watts RMS
When B&O’s engineers had discovered that the signals from respectively the bass unit and the tweeter in a loudspeaker do not reach the human ear at the same time, and that as a consequence a very slight distortion occurs, they asked Jacob Jensen to design a loudspeaker cabinet in which the units were skewed in relation to each other.
Jensen illustrated B&O’s technical discovery with an angle: “form follows function”. B&O’s loudspeakers in this way achieved a characteristic visual identity in the 1970s and 1980s.” – taken from ‘Jacob Jensen’ by Christain Holmsted Olesen.
Although the speaker was the tallest in the original line-up of aluminium compact passive speakers, Beovox C75 was no taller than an LP record, yet its reproduction quality equalled some of the full-size Beovox models. The one-piece aluminium log-line casing and separate bass (2 x 10cm bass drivers) and treble drivers (1 x 2,5cm) were specially designed to sound best in small rooms. Power handling was 75 watts RMS. Both the C75 and their smaller counterpart, the C40, benefited from the advantages of the “log line transmission system” and exploited the acoustic properties of small rooms to ensure well-balanced sound reproduction quality from these physically small cabinets.
As part of the Beovox Uni-Phase family, they also had linear phase and linear amplitude characteristics, which meant that they reproduced all types of music naturally. The range of C-type speakers won the ID Award in 1978.
Beovox C75 was eventually replaced by the CX100 in 1984.
Beovox C30 and C40 speakers were two compact bookshelf units offering high performance from deceptively small cabinets. The 10cm woofer and 2,5cm tweeter were mounted in thick aluminium casings to eliminate audible resonance. Log-line transmission ensured wide frequency response and clean, clear sound. Ideal for smaller rooms, their power handling capabilities were 30 watts and 40 watts RMS respectively.
The one-piece aluminium log-line casing and separate bass and treble drivers of the Beovox C75 were specially designed to sound best in small rooms. Power handling was 75 watts RMS
When B&O’s engineers had discovered that the signals from respectively the bass unit and the tweeter in a loudspeaker do not reach the human ear at the same time, and that as a consequence a very slight distortion occurs, they asked Jacob Jensen to design a loudspeaker cabinet in which the units were skewed in relation to each other.
Jensen illustrated B&O’s technical discovery with an angle: “form follows function”. B&O’s loudspeakers in this way achieved a characteristic visual identity in the 1970s and 1980s.” – taken from ‘Jacob Jensen’ by Christain Holmsted Olesen.
Although the speaker was the tallest in the original line-up of aluminium compact passive speakers, Beovox C75 was no taller than an LP record, yet its reproduction quality equalled some of the full-size Beovox models. The one-piece aluminium log-line casing and separate bass (2 x 10cm bass drivers) and treble drivers (1 x 2,5cm) were specially designed to sound best in small rooms. Power handling was 75 watts RMS. Both the C75 and their smaller counterpart, the C40, benefited from the advantages of the “log line transmission system” and exploited the acoustic properties of small rooms to ensure well-balanced sound reproduction quality from these physically small cabinets.
As part of the Beovox Uni-Phase family, they also had linear phase and linear amplitude characteristics, which meant that they reproduced all types of music naturally. The range of C-type speakers won the ID Award in 1978.
Beovox C75 was eventually replaced by the CX100 in 1984.
Beovox C30 and C40 speakers were two compact bookshelf units offering high performance from deceptively small cabinets. The 10cm woofer and 2,5cm tweeter were mounted in thick aluminium casings to eliminate audible resonance. Log-line transmission ensured wide frequency response and clean, clear sound. Ideal for smaller rooms, their power handling capabilities were 30 watts and 40 watts RMS respectively.
The one-piece aluminium log-line casing and separate bass and treble drivers of the Beovox C75 were specially designed to sound best in small rooms. Power handling was 75 watts RMS
BeoCom 2 is a visually provocative response to everything looking alike in today’s telephone market. Its curved shape is very reminiscent of telephones used in the 1960’s, particularly in ‘The Prisoner’ TV series on the UK’s ITV network.
The release of BeoCom 2 in March 2002 was undertaken in its basic form. It was not a ‘system’ telephone in the first instance in that only one BeoCom 2 base could support one BeoCom 2 handset. This means there was no data exchange with other BeoCom2 handsets or BeoCom 6000 handsets or bases.
However, October 2002 saw BeoCom 2 become a full system DECT telephone, becoming part of the same 3-component solution that BeoCom 6000 uses. With this software update, customers can now ‘mix and match’ up to six BeoCom 6000 or BeoCom 2 handsets and chargers, using either the PSTN or ISDN base. This free software upgrade – to be carried out in dealers’ showrooms – will be necessary on existing BeoCom 2 phones in order to make them fully functional as a system phone.
Ringing the changes
The unique ringing tone of BeoCom 2 was created by musical composer, Kenneth Knudsen. Born in 1946, Knudsen is a self-taught musician and since graduating from the School of Architecture at the Royal Danish Academy of Fine Arts in 1974, he has chosen music as his profession. Over the years he has appeared on more than one hundred records with groups and soloists including Svend Asmussen, Miles Davis, Shubidua and the Indian violinist L. Subramaniam. He has been a member of, and recorded with groups like Secret Oyster, Coronaria Dans, ANIMA, Entrance, Bombay Hotel and Heart To Heart Trio. His list of compositions includes music for ballet, film, TV productions and jingles, as well as works for string quartet, solo guitar, solo cello, cello and piano, and choir.
In recent years Kenneth Knudsen has composed and recorded music for sound installations in various architectural and artistic contexts. As a soloist Kenneth Knudsen has released a number of CDs in his own name, most recently Sounds and Silence (dacapo DCCD 9419) and Music for Eyes (dacapo DCCD 9433).
Ringing the tune
The old-fashioned bell is nowadays rarely used in modern telephones. Like other bells, the sound from it contains a lot of overtones.
This is why you can both hear it at the bottom of the garden as well as close-by, and still experience the ringing of the bell as a pleasant sound. However the bell takes up too much room and it is too expensive for modern telephones. The technology that replaces it is both cheaper and more compact, but quite different to listen to. The design group found that this development was not exactly a positive one for the user. Therefore Bang & Olufsen turned to the Danish composer Kenneth Knudsen and asked him to compose a different ringing tune.
The Beocom 2 ring sounding like like cow bells is apocryphal! As visitors to Bang & Olufsen’s Struer headquarters know, there are no cows outside the Farm… only sheep! The ring of the BeoCom 2 was based on the sound of a piece of tubing falling on the floor. David Lewis was carrying a piece of metal tubing which he accidentally dropped to the ground. He thought the sound so interesting that a composer was called in to sample the sound and make a ring tone!
Knudsen chose to compose his tune as part of the design for a special telephone – the BeoCom 2 – rather than choosing an isolated, general tone, applied to all telephones. He therefore asked David Lewis, the chief designer of BeoCom 2 to make the final choice to ensure that the ringing tune was in harmony with the rest of the telephone. In this way the qualities of the ring became a harmonic part of the entire aesthetical experience of the new telephone.
To give the new ringing tune full justice the company’s acoustic department developed a small loudspeaker system in its own sealed enclosure within the handset of BeoCom 2 playing through a well defined slim opening within the phone’s aluminium tube.
Calling for attention
During the development of ideas for BeoCom 2, the design group expressed a wish that the ringing tune should call for attention in a polite way: a polite offer to make contact with the user, rather than a dominating, insisting demand.
But what is polite and what is not? How is this determined?
Bang & Olufsen asked the composer Kenneth Knudsen to solve this problem. Kenneth Knudsen came up with a number of solutions, from which designer David Lewis could choose.
Nearly each week of every year David Lewis drives in his car from Copenhagen to the B&O factory in Struer – a trip of 750km. During these long hours he would listen to Kenneth Knudsen’s pre-recorded tunes and discovered that in heavy traffic situations, where he was under pressure, he could clearly distinguish the pleasant call for attention, from other more annoying, ‘insisting’ tunes. He had therefore found the right tune for his new phone!
