Where are the active loudspeaker bargains?
15th June 2009 by Tim Jarman
Why not put an AV 9000 system together? Back in the day it was B&O’s top-line offering, the most expensive thing they would sell you. Most of it can now be bought for sensible money and if you are selective you will still end up with something that makes the current offerings look bloated and silly. The fly in the ointment is of course the loudspeakers, you will need four to it properly and they all need to be Beolab active types.
Used Beolab loudspeakers are bizarrely expensive, why should that be? The Beolab Penta first appeared in 1987 (over twenty years ago!) but if you’d bought a pair back then and looked after them you’d still get a lot of your original stake back if you sold them today. The original Penta of course lacked the Power Link type of connection, which is required by the AV 9000 system. Power Link was introduced in around 1990 and featured on a number of B&O models, but early Power Link speakers are still rather expensive, even though a lot of them aren’t, er... very good.
The idea behind the active loudspeaker was to put the power amplifier into the loudspeaker cabinet. There were various technical reasons given for doing this but the main reasoning behind it was to free up space in the source units by removing the bulkier parts of the circuitry. In time this allowed new styling possibilities to be realised, such as the Beosystem 2500. It also made it possible to use active crossover networks but as we shall see this too can be seen as a mixed blessing.
B&O had worked hard to develop an amplifier circuit that had started life in the original Beomaster 2000 and was last seen in the Beomaster 7000. This had some very desirable characteristics and is largely responsible for the excellent performance of the larger Beomaster models. Sadly it was never used in any Beolab loudspeakers. The Pentas used a special arrangement all of their own, B&O ignored the fact that they already had, in the Beomaster 8000, a 150W power amplifier as good as any and instead designed a new scheme with paralleled Toshiba power transistors in the output stage. In fairness this worked pretty well, the only black mark was the rather poor reliability that resulted from using cheap components and a low grade material for the printed circuit board. From then on the technology behind Beolab changed, hybrid chips were the order of the day, low cost power/gain blocks from which an amplifier could be constructed so easily that you could probably do it at home (no, really).
As hybrid chips are primarily designed for smaller, cheaper music systems a lot of them are stereo, they contain two independent channels that you can use however you want. This made it easy to produce truly active models such as the Beolab 8000, where the woofer and the tweeter each get their own power stage and the signals to each come from electronic filters. In principle this is a very good idea but unfortunately B&O seemed to use the flexibility that it offers to use really poor drive units that were too small, in badly designed cabinets and still get away with a half decent sound. On a good day the Beolab 8000 can sound really nice but think how good it would have been if the basics had been done correctly.
Now we have the ICE power/acoustic lens loudspeaker generation, combining two dubious fads into one model. Class “D” amplifiers have their place, usually that of providing loads of power for not too much money. The lenses are really just a visual identifier, something to set B&O apart in the buyer’s eyes. The rest of the serious loudspeaker industry isn’t exactly falling over itself to make something similar but once again B&O’s engineers have managed to make a silk purse out of a sow’s ear and come up with some really quite passable equipment.
The reason that Beolab loudspeakers are so expensive second hand is not their quality but that there is no alternative. You have to have them because they are the only type of loudspeaker cou can connect to most B&O products of the last fifteen years. If you own an Ouverture, a Beosound 9000 or any number of other recent models nothing else will do. This keeps prices artificially high and restricts the listener to a limited number of possible sound experiences.
But is it really true that nothing else will do?
No! There are alternatives, in the Beolab 200 and the MCL 2P. Both of these units can be connected to Power Link equipment and will drive “proper” loudspeakers. Beolab 200s are rare, losts of them have been used to convert Beovox Pentas into Beolabs by now, but there are loads of MCL 2Ps, hidden away in the dusty corners of abandoned Beolink systems. Although fairly basic in hi-fi terms the 2P is a reasonable amplifier, it’s similar to what you get in a Beocenter 9500. You can reveal a whole new side to something like an Ouverture by using it with the MCL 2P and a decent pair of Beovox Uniphase loudspeakers like the S 80.2. It even sounds quite nice with CX 100s!
B&O never chose to mention this trick in their mainstream catalogues, preferring instead for the buyer to be tied into the costly (and therefore profitable) Beolab range. However, now you know, you are free. Why not have a go?