Bang & Olufsen's first move into the world of serious hi-fi came in 1967 with the introduction of the Beolab 5000 amplifier and Beomaster 5000 tuner. These defined the European state of the art at the time and were as successful as their high prices allowed. The company then distilled these two units into the Beomaster 3000, which offered similar qualities at a more accessible price. It lacked the sheer power and versatility of the Beolab 5000 but sold strongly throughout a long production run.

These products created a new sector in the company's range – 'high fidelity'. The models were aimed at the serious listener and offered high power output, advanced facilities and what the designers considered to be the best possible sound.

Wide Ranging
This 'high fidelity' line got off to a good start but floundered in 1973 when the Beomaster 4000 was introduced. This was intended as a Beolab replacement and was based on a modified 3000 chassis, uprated to produce 2x60W. Yet its sound was lifeless and unexciting. The 6000 4channel receiver was not as dynamic as it could have been either, suggesting that something had gone seriously amiss in the design of B&O's range-topping models.

This large and flush-mounted flywheel is used to tune the Beomaster 2000's radio. The coloured lights to the left of the wheel indicate the signal strength and tuning balance

It was against this backdrop that the Beomaster 2000 reviewed here appeared. Launched in late 1975 and new from the ground up, it saw designer Jacob Jensen's beloved 'low and wide' look introduced to the serious end of the range. And there were plenty of novel technical ideas inside too. B&O's circuitry typically evolved slowly across inter-related models but most of the 2000 had not been seen before. For example, the AM radio section was B&O's first IC-based design and included a ceramic filter to give precise tuning. The FM section also made extensive use of ICs and included five pre-set stations and a sophisticated active AFC system, which ensured permanently accurate tuning.

The key innovation, however, was the phase-locked loop stereo decoder – B&O's first. Even the more expensive models in the range still used the older regenerative type, so in terms of radio performance the 2000 was a big step ahead. Yet while impressive, none of these features were what made the Beomaster 2000 special.

Low Rider
The really important change was that it was B&O's first amplifier to use DC coupling between the output transistors and speaker load. Dispensing with the transformers or capacitors that previously sat between these two elements meant the amplifier's output impedance could be reduced [see PM's Lab Report, p125] and substantially constant in respect to frequency. This, in turn, paid dividends in terms of the damping factor that could be achieved at the speaker interface and the quality of bass that could be reproduced.

Capacitor Crusade
DC-coupled amplifiers had been made possible by the introduction of matched pairs of complementary power transistors in the early 1970s. B&O was not to be rushed into producing a DC-coupled design but the 2000 proved to be thoughtfully engineered and rugged when it did eventually appear. The output transistors chosen were high-gain Darlington types, a class of component B&O had extensive experience of given their widespread use in a previous series of lower-powered, AC-coupled models.

The Beomaster 2000 is a powerful unit and the amplifiers need plenty of cooling when working hard. Note the generous heatsinks at the rear, hidden from casual view by a grille above them

This was not the end of the story, however. Having eliminated the large aluminium electrolytic capacitors in series with the loudspeaker outputs the designers then systematically eliminated them from everywhere else in the design where it was practical. In the end, only six remained, which were necessary for power supply filtering where no other capacitor technology could yield the values needed. What's more, all the capacitors in the signal path were either tantalum or film types. While a familiar enough performance amplifier technique today, it was a largely unexplored idea in domestic hi-fi in the mid 1970s.

The styling had moved on since the days of the Beomaster 1200 whose tuning control looked like a giant slide rule. The 2000 used a larger version of the flush-mounted flywheel first seen in the 6000 4channel. The temptation to use electronic signal routing was resisted with function selection being performed by oversized push buttons. These too were flush with the fascia when not in use.

Most Beomaster 2000s were finished in matt black anodised alloy with either teak or rosewood veneered cabinetwork, but limited numbers were produced with silver alloy over white. These are highly prized by collectors today. All B&O equipment from the 1970s is stylish, but the Beomaster 2000 takes this to the next level. Despite its mechanical controls it hasn't dated as much as some other B&O models – house guests who clapped eyes on it during my auditioning assumed it was less than ten years old.

The complete Beosystem 2000 in white. Rare then, desirable now. Standard finishes were either teak or rosewood

Flushed With Success
The Beomaster 2000 is also a delight to use – B&O described the push buttons as 'super smooth' and they truly are. The flush tuning flywheel is nicely weighted while the tuning balance and stereo indicator lamps associated with it don't so much flicker as flow, as if they are operated by some ingenious arrangement of viscous fluid. Five pre-set stations are provided on FM, their setting made by a group of tiny scales under a sliding cover on the right of the unit. A similar cover on the left gives access to a tape 1/2 switch and a loudness button (which is best left switched off).

Compared to the other controls, the sliders for the amplifier are a bit stiff and jerky in use. Connections are provided for a turntable and two tape recorders, a pair of headphones and two pairs of loudspeakers. The turntable input is matched to B&O's own moving-iron pick-ups but these are similar enough to modern MM types for there not to be compatibility problems.

Having two tape sockets gives a useful place to connect a CD player, but this is best placed in 'Tape 1' and the recorder in 'Tape 2' otherwise CD-to-tape transfers cannot be made. The loudspeaker sockets are arranged so that one pair is muted when the headphones are connected and the other pair is not. The direct (speakers 2) is the best choice for critical listening, but less convenient in a domestic setting.

B&O claimed DC-coupling eliminated the switch-on 'thump' with loudspeakers that employed capacitors. This is true, but there's an odd soft thud heard a second or so after switching off. The Beomaster 2000 lacks a protection relay and so the speakers are kept safe by four fuses in the supplies to the output stages. B&O recommended that the loudspeakers used had a rating of at least 40W for this to be effective. Finally, like all B&O designs of this era, the amplifier is optimised for a 4ohm load.

Tim Listens
Even after the briefest of listens it's clear that B&O's designers must have celebrated a welcome return to form with the Beomaster 2000.

The receiver still has the familiar luxurious B&O sound but this does not stop it being a lively and vivid performer. It improves noticeably on the Beomaster 3000 and completely trounces the 4000, despite being a third less powerful. The technology employed, which was focused on appealing to the ears of the audiophile, had done the trick – this particular model is a real hidden gem.

The interior of the unit is neat and well ordered. Note the space at the top of the chassis to house the two extra power amplifiers of the Quadraphonic version, the Beomaster 3400

Perhaps the 2000's most attractive quality is the way it can play softly for late-night listening and render detail perfectly but also produce effortless amounts of power for a genuine concert hall experience when required. It lacks the clipping indicator of the Beomaster 4400 receiver so it is up to the listener to judge when the power margin is all used up. But things do not begin to sound rough until the control is almost at the top of the scale and the music is deafeningly loud. Unless your listening room is very large this receiver has more than enough power to cover most tastes. Noise performance is fair too, there being some hiss to be heard when the control is pushed beyond about '7' on the scale, but at normal volume levels the background is as good as silent.

Time To Unwind
Sade's album Diamond Life [Epic CDEPC 26044] satisfied with its creamy saxophone and rich, chewy bass lines when played through the 2000. I did get the impression that the uppermost treble was slightly muted, though, as the snares and percussion didn't sparkle and shimmer in quite the way I know they can.

A graphical representation of a complete system as suggested in the owner's manual. The recommended components are the Beogram 2000 turntable and Beovox 3702 loudspeakers

However, the effect was less obvious when listening to BBC R3 via the receiver's built-in FM tuner section (90.3MHz) and so I can only suspect that the very top end is going astray in the preamp section. Nevertheless, the roll-off is slight enough to be cancelled by selecting a brighter-sounding source. In my case, swapping a Philips CD104 for a Technics SL-P1200 did the trick.

Where the 2000 really scored was when it came to its midrange balance and neutrality. Vocals were perfectly placed in the mix, being neither prominent nor recessed. This made for an instantly attractive sound, and one that proved very easy to relax into. This may seem an obvious requirement, but there are many amps out there that are less compelling.

Keep Your Distance
On a larger scale, the slim Beomaster 2000 proved easily capable of preserving both the space and drama of full-scale orchestral pieces. Mozart's 'Serenata Notturna' played by the Berliner Philharmoniker, conducted by Herbert Von Karajan [Albinoni: Adagio/Pachelbel: Canon; Deutsche Grammophon 413 309-2], showed how a carefully designed amplifier can preserve the impression of distance between the performers if the source component is up to the task of recovering it. Stereo soundstaging was also excellent, as was the rendering of fine textural detail around the strings.

Rear view of the receiver shows that all the connectors are to DIN standards and, as ever with B&O, that there is little room around the sockets for bulky plugs

Singular Appeal
After many more hours of listening I found myself concluding that despite being nearly 50 years old, the Beomaster 2000 has the sort of sound that makes it appropriate for use in a main system. It may lack the final perfection of the Beomaster 4400 and doesn't feel quite as special to own as the Beolab 5000 (although it is less coloured sounding when compared directly), but it has no obvious sonic vices. It also saw Bang & Olufsen escape the doldrums as far as the sound quality of its larger models was concerned.

When the 2000 was replaced by the Beomaster 2200 in late 1977 many of its novel ideas were lost, in particular the decision to avoid the use of aluminium electroltyic capacitors. This makes the 2000 a unique proposition, and one well worth seeking out to hear.

Buying Secondhand
Since the Beomaster 2000 did not sell in the same quantities as the 3000 and 3000-2, good examples can be difficult to find. They are certainly sturdy units but are not without their problems. The cover over the pre-set tuning controls slides off and is easily lost, spoiling the sleek appearance. The tuning drive for the flywheel disc can also fail when the plastic inside that holds the pulleys for the cord drive disintegrates. Repairs are possible but they're not straightforward.

Meanwhile, the circuit for the red and green indicator lamps by the disc is unusually complex. This requires all the lamps (and the one inside the tuning pointer) not only to be intact but to be of exactly the right rating if it's to work at all.

Electronically speaking, it is the FM radio that seems to suffer most problems. The FM discriminator and tuning balance indicator have to be set up correctly for the AFC system and the stereo decoder to work, and they seem to drift over time. Accurate instruments are necessary to bring them back into line. The amplifier sections have proved to be reliable, but it's vital all the fuses are of the correct type and rating.

Hi-Fi News Verdict
The Beomaster 2000 may not be one of B&O's most memorable designs but in performance terms it certainly ranks as one of the company's best. If you are keen to avoid the hard and brittle sound of some amplifiers released around this period then the smooth-sounding 2000 is well worth considering. The top quality radio section is a bonus, which makes this slick-looking receiver even more compelling.

B&O Beomaster 2000 Lab Report

B&O's first DC-coupled tuner/amplifier identically matches the Beomaster 2400-2 for raw power output but otherwise delivers a very distinctive technical performance. In practice our circa-1975 test sample sustained a maximum continuous output of 2x35W/8ohm (40W/8ohm, one channel driven) and 2x55W/4ohm with sufficient reserve to sustain transient peaks (1kHz/10msec/<1% THD) of 42W, 74W, 33W and 18W into 8ohm, 4ohm, 2ohm and 1ohm loads, respectively [see Graph 1, below]. Once again, the 4.3A current headroom is modest, suggesting the 2000 is best used with speakers rated at 6ohm and above, and of generous sensitivity.

Otherwise, the 2000 may be DC coupled but its low bass response is actively filtered, falling from –0.1dB/100Hz to –2.2dB/20Hz and –6dB/11Hz, just as its HF roll-off is influenced by the buffering of its volume control. With the volume slider at maximum (35.8dB gain) the response is flattest – reaching –0.2dB/20kHz and –3.8dB/100kHz – while at reduced volume positions (this is gain, not output level) the HF response is progressively muted. Output impedance is also influenced, but even the lowest 0.3-0.5ohm (20Hz-20kHz) will still cause some further response modification in line with the swings in speaker load. Distortion is more predictable, a steady increase in level from 0.016%/1W to 0.045%/10W and 0.09% at the rated 30W/8ohm (all 1kHz), and with frequency to 0.09%/10kHz and 0.14%/20kHz [all at 10W/8ohm – see red trace, Graph 2 below]. Noise is low too at –78dBV – testament not only to the design of B&O's linear power supply but also the elegant circuit layout – all of which secures a worthy 86.6dB A-wtd S/N ratio (re. 0dBW). PM

Dynamic power output vs. distortion up to 1% THD into 8ohm (black trace), 4ohm (red), 2ohm (cyan) and 1ohm (green) speaker loads. Max current is 4.2A

Distortion versus frequency from 5Hz-40kHz (1W/8ohm, black) and 20Hz-20kHz (10W/8ohm, red)

Power output (<1% THD, 8/4ohm) 35W / 55W
Dynamic power (<1% THD, 8/4/2/1ohm) 42W / 74W / 33W / 18W
Output imp. (20Hz–20kHz/100kHz) 0.28-0.50ohm / 0.48ohm
Freq. resp. (20Hz–20kHz/100kHz, 0dBW) –2.2dB to –0.22dB/–3.8dB
Input sensitivity (for 0dBW/30W) 44mV / 245mV
A-wtd S/N ratio (re. 0dBW/30W) 86.6dB / 101.4dB
Distortion (20Hz-20kHz, 10W/8ohm) 0.025-0.14%
Power consumption (Idle/rated output) 11W / 111W
Dimensions (WHD) / Weight 685x75x270mm / 8.2kg 

Review: Tim Jarman, Lab: Paul Miller

Source: www.hifinews.com