Beomaster 901, by 1977/78 was Bang & Olufsen’s simplest receiver. However, no compromises were made on quality. The tuner section covered Long, Medium and FM wavebands with a very high standard of reception quality.
Tuning was by ways of a slider which moved smoothly along a clearly marked scale. An illuminated indicator and AFC (Automatic Frequency Control) circuit helped to make tuning easy and accurate. The MONO control button disconnected the built-in stereo decoder when correct stereo reception was impaired by bad weather conditions or other interference.
Beomaster 901’s large tuning scale had tuning facilities for FM, Long and Medium wave stations. The tuning slider had small thumbwheels to aid fine tuning. AFC locked the receiver to the desired station
The stereo amplifier had a powerful output of 2 x 20 watts RMS and special Darlington-coupled transistors in the output stages kept distortion to a minimum – less than 0,3% at full power. There were connections for two pairs of loudspeakers and a pair of headphones. Sockets were also provided for the connection of a tape recorder, a record-player and AM and FM aerials. Easy-to-use sliders controlled volume, balance, bass and treble and there were slim push-buttons for selecting waveband or tape or record input.
FM room aerial
In order to receive FM programmes, an FM aerial must be connected to the Beomaster 1001. Within a certain radius of the transmitter you could use the Bang & Olufsen FM room aerial, type 8902010. This aerial was easily fitted and the telescopic elements could be pulled out and positioned favourably.
Beomaster 901 could be made up as part of the Beosystem 901 including the the Beogram 1102 record player, Beocord 1101 cassette deck and 2 Beovox Uni-Phase S25 or P30 loudspeakers.
Beocenter 1500 was a combined FM/AM tuner, hi-fi stereo amplifier and cassette recorder with a specification level that was unique for combination units in that price bracket. In the AM section, which covered long and medium waves, Bang & Olufsen placed an emphasis on the set’s ability to separate stations from each other. The FM section had outstanding channel separation and stereo reception. The amplifier’s technical specifications were way above the average and fulfilled accepted hi-fi norms by a wide margin.
The built-in cassette recorder had its own operation panel but was otherwise fully integrated with the rest of Beocenter 1500. There was a switch for normal and chrome tapes; recording level was monitored on an illuminated indicator: red signified overload and green meant that all was well. The tape heads were of a super Permalloy and had a higher performance level and longer useful lifetime than ordinary heads.
Beocenter 1500 had connections for record player, two sets of stereo speakers, headphones and an extra tape deck.
Beocenter 1500 and Beocenter 1600 were, at the time of their production, two of the market’s most compact audio systems, but despite their small external dimensions they could fill a large room with sound. All the push buttons of Beocenter 1500 were of solid aluminium, and the solid aluminium front panel on the Beocenter 1600 was anodised – a process which was more expensive and more demanding but which also made the set more robust and resistant to marks and scratches.
Top of the range monitor speaker, these were much more like the Beovox S60 than the Beovox M75 that replaced them.
They were 4 way speakers with the tweeter and midrange level with each other and the Phase link and woofer below. They could be fitted with the dramatic trumpet stand and were the speakers specified for the Beosystem 6000.
Beovox Uni-Phase M100 and M75 were the top models in the 1979 – 1980 range of Bang & Olufsen speakers.
They reproduced sound with studio monitor quality, which, in practice meant that even at very high sound pressure levels (volume) they reproduced sound with constantly neutral, linear phase quality. They could also withstand hard-working conditions similar to those met in sound studios, because they were effectively protected against damage from overloading. Their power-handling capacities were specified at 100 and 75 watts RMS respectively; however, their unique overload protection circuits permitted them to handle music passages above these rated capacities.
Special emphasis was placed on Beovox M100’s ability to reproduce clean, powerful bass. That it why it was given a ported bass-reflex cabinet with a 30,5cm woofer. The cabinet’s volume was 89 litres. Bass response went down to 27Hz (measured at +/- 4 – 8 dB).
Beovox M75 had outstanding overall performance too, and was equally suitable for medium-sized or larger rooms. Both models had specially-designed pedestals which could be adjusted to the correct listening height and angle.
Beovox Uni-Phase M100 and M75 were the top models in the 1979 – 1980 range of Bang & Olufsen speakers.
They reproduced sound with studio monitor quality, which, in practice meant that even at very high sound pressure levels (volume) they reproduced sound with constantly neutral, linear phase quality. They could also withstand hard-working conditions similar to those met in sound studios, because they were effectively protected against damage from overloading. Their power-handling capacities were specified at 100 and 75 watts RMS respectively; however, their unique overload protection circuits permitted them to handle music passages above these rated capacities.
Special emphasis was placed on Beovox M100’s ability to reproduce clean, powerful bass. That it why it was given a ported bass-reflex cabinet with a 30,5cm woofer. The cabinet’s volume was 89 litres. Bass response went down to 27Hz (measured at +/- 4 – 8 dB).
Beovox M75 had outstanding overall performance too, and was equally suitable for medium-sized or larger rooms. Both models had specially-designed pedestals which could be adjusted to the correct listening height and angle.
Beovox Uni-Phase P30 loudspeaker handled up to 30 watts RMS power and reproduced sound with neutral, linear phase quality.
They were panel speakers designed to be hung on the wall and are therefore ideal for rooms where space was limited. Only 9cm deep, its volume was 12,9 litres. Fitted with a 16cm woofer and a 2,5cm tweeter. Frequency range 49 – 20000Hz.
The Beovox P30 were effectively a wall mounted S30. They appeared very thin though were in fact slightly deeper than one thought as the resin back protruded a fair bit at the back. Sound quality mirrored that of the S30 with generally good quality sound though they are bass light and must be wall mounted to achieve their best.
Beovox Uni-Phase P45 loudspeaker was a revised version of the Beovox P50 and was a high fidelity panel speaker for wall-mounting.
Weighing only 8kg the P45 had a net volume of 25 litres. Frequency range was 40 – 20 000 Hz with less than 1% harmonic distortion. There were two 12,5cm woofers, a special 8cm Phase Link unit and a 2,5cm dome tweeter.
Beovox Uni-Phase P45 loudspeaker was a revised version of the Beovox P50 and was a high fidelity panel speaker for wall-mounting.
Weighing only 8kg the P45 had a net volume of 25 litres. Frequency range was 40 – 20 000 Hz with less than 1% harmonic distortion. There were two 12,5cm woofers, a special 8cm Phase Link unit and a 2,5cm dome tweeter.
The amplifier section of this receiver had outstanding technical data: harmonic distortion was less than 0.1% at maximum power output and 0.06% at 50 mW. Frequency range was 20-30.000 Hz and effective bandwidth 10-35.000 Hz.
Frequency correction facilities were the LOW filter which reduced rumble on records (12 dB per octave at 80 Hz) and the HI filter which damped hiss (12 dB per octave at 4000 Hz). With the LOUDNESS control you could switch between objective and subjective linear reproductions. Beomaster 4000 had facilities for stereo and ambio reproduction. There were sockets for a record player and two tape-recorders, one allowing A\B monitoring. The headphone connection was placed on the receiver’s front. All inputs could be adjusted to give equal volume from all programme sources. The FM section had six pre-set stations. A light indicator assisted accurate tuning and an illuminated meter indicated the strength of a station. Field effect transistors, ceramic filters and integrated circuits were used.
When combined with a built-in record deck, the music centre was known as Beocenter 3500.
Receivers and amplifiers with the ambio function were products which, apart from stereo, could also reproduce the ambience or sound information of a room. Ambient information was included on most stereo vinyl recordings but could not be reproduced by a sound system with two loudspeakers or an ordinary stereo amplifier. Bang & Olufsen systems with the ambio function had facilities which electronically subtracted the difference signal (i.e. the difference between left and right channels) which contained ambient information. This information was fed into two extra loudspeakers which were placed as side speakers in a room. Ambiophony was an extension of stereo reproduction and enhanced the sense of realism. It could be used with nearly all stereo programme materials.
“Ambio is an extension of the type of sound reproduction known today as stereo.
Ambio is reproduced through four loudspeakers – two more than required for stereo.
Ambio is sensed as being more spatial and acoustically more life-like than conventional stereo. The sound picture has greater depth because you get the added feeling of being present of the concert hall, listening to the actual performance. Ambio is based on the principle that in the concert hall you not only receive sound impressions directly from the performing group, you also get reflections from the wall and ceiling. The spatial sensation is instrumental in providing the auditory experience and even a two-speaker stereo system will not bring it out fully. And you cannot accomplish the effect by connecting additional speakers to a conventional stereo amplifier because you still have the same left and right front signals merely distributed to more speakers.
In the Beomaster 4000 the left and right channels are subtracted from each other electronically and the resulting difference signal contains a certain amount of spatial information which is fed to the two new side speakers.
Many existing stereo records, FM broadcasts and tape recordings contain this spatial effect to a greater or lesser extent. In a concert hall, room acoustics will be recorded together with the actual programme material, appearing as time-delayed signals in both left and right channels. Recordings made in a strongly damped studio contain few time-delayed signals and the spatial sensation will therefore depend on how the producer mixed the sounds from the various instruments, perhaps adding acoustical effects by electronic means.
Multi-channel records such as SQ records, which are intended for use in a four-channel matrix system in order to bring out the sound effects , can be played successfully through the Beomaster 4000.
A good quality stereo turntable will provide ambio reproduction of both stereo and SQ records through your Beomaster 4000″
Beocord 5000 was a superior cassette deck with a Sendust tape head, dual capstans and a special servo drive system which secured low wow and flutter-data. Electronic recording level indicators (Peak Programme Meters) and the Fade in/Fade out functions facilitated exceptional recordings of the most demanding types of music. An automatic demagnetizing device helped ensure optimum signal/noise ratio at all times.
A Hall generator secured the most reliable automatic stop at the end of play. Because it worked electronically it was superior to mechanical systems which are always subject to wear and tear, stress and strain. Naturally Beocord 5000 incorporated Dolby B Noise Reduction circuits. You could also switch from fast forward to fast rewind, or normal play, without endangering your tapes or damaging the drive mechanism.
Despite these technological refinements Bang & Olufsen still didn’t forget the greatest advantage of the compact cassette – that of convenience. That’s why Beocord 5000 was so easy to use. The logically-arranged easy-touch buttons were clearly marked to aid simple, problem-free operation. An illuminated read-out panel told you the operational status of the deck at all times. The display could be read through the black Perspex cover which protected the cassette housing against dust. The unit had two peak programme meters which reacted faster than conventional VU meters in registering recording level and thus ensuring optimum recording quality.
There were two main design models in the Beocord 5000 range:the three head type 4705 was replaced in 1977 with the twin head 4715/4716 models.
What you need to know is that these were the only cassette deck with a B&O designed mechanism. It was designed to be to cassette decks what the Beogram 4000 was to record players. From a technical point of view, it was way ahead of its time.
However it was stupendously complicated and this hit reliability hard. The three head version hardly ever worked fully and the later two head was only a little better. Gorgeous to look at and packed with features, it will break your heart! B&O replaced this with the Beocord 8000, which had a bought in tape transport….
The fact that the Beocord 1100 was equipped with Dolby B Noise Reduction system immediately placed it among the market’s better cassette decks (catalogue 1977 / 78).
It had all the facilities you needed for recording compact cassettes and replaying them through an existing amplifier system. The combined record/playback head was made of Super Permalloy, an extremely durable material which ensured a long useful lifetime and had excellent magnetic properties. Other refinements included an electronic auto stop at end-of-tape and a switch for selecting between chromium dioxide and normal (ferric oxide) tapes.
The setting of correct recording levels was by way of individual controls used in conjunction with VU meters for left and right channels. Beocord 1101 was technically identical to Beocord 1100 but had a different exterior finish.
