LS3/5A Inspired Designs
They say that imitation is the sincerest form of flattery and given the sucess of the LS3/5A design it was inevitable that over the years it would produce other designs influenced by it. Some, like the Jim Rogers' JR149, have direct links to the LS3/5A. Others, like the KEF CS1 and Falcon Monitor Compact kits, attempted to bring a LS3/5A like speaker to the home constructor.
More recently there have been several loudspeakers that use the LS3/5A designation but are not licensed by the BBC. Nor do they use the original KEF drive units. (But then the new "genuine" BBC licensed LS3/5As from Stirling and KEF do not use the original KEF drive unts either). Presumeably there is no interest in the BBC, or from the current licence holders in legally challenging the use of LS3/5A on a loudspeaker. Some of these may indeed be good loudspeakers but they are not BBC licenced. Caveat Emptor.
The JR149 is probably the best known of the LS3/5A spin-offs. Rogers, under Jim Rogers issued a press release in 1974 to say that they intended to exhibit at SONEX '74 the LS3/5, the BBC Research Department designed predecessor to the LS3/5A. But the LS3/5 was never to be released to the public. Problems in the design led to a re-working of the speaker by BBC Design Department under which it became the LS3/5A. Rogers meanwhile went into receivership and the company was bought in 1975 by Michael O'Brien with Brian Pook as Managing Director. The rest is history and Rogers went on to become the most prolific manufacturer of the LS3/5A.
Jim Rogers as J R Loudspeakers Ltd, went on to release the JR149 in 1977 which used the same drive units as the LS3/5A in a cylindrical enclosure made from aluminium. Trevor Attwell, in his review of the JR149 in the May 1977 HiFi News and Record Review says, "A direct comparison between the JR149 and the LS3/5A is also of obvious interest.... An AB test showed the general quality was very comparable, the LS3/5A being marginally smoother in the midband, but the JR149 having a slightly better bass response and being less hard in the top. The LS3/5A image was rather more forward and analytical- probably a function of the relative directivities."
JR149s do sound very good and come up for sale on the secondhand market for lower prices than LS3/5As. Unfortunately the foam covers rotted and all pairs seen secondhand are likely to be naked, or have had replacement covers made up by their owner.
Kef sold a set of drive units and simplified crossover network based on the LS3/5A called the CS1. In the CS1 leaflet they describe how to build a cabinet which is very similar to the LS3/5A. CS1s come up from time to time on the secondhand market and if well constructed can be easily mistaken for the LS3/5A.
In the construction leaflet KEF readilly acknowledge the anticedence of the CS1, "This miniature bookshelf system is based on the famous BBC monitoring loudspeaker type LS3/5A which is used in outside broadcast applications and other situations where space is at a premium and very high sound levels are not required. The system employs the same KEF drive units originally specified for the LS3/5A with a somewhat simplified dividing network giving a similar overall frequency response characteristic."
The Linn Kann
When Chartwell went into receivership their cabinet maker sold approximately 100 pairs of LS3/5A cabinets to Linn which were used to make the first batch of Kans. Later Kan cabinets used chipboard instead of the plywood of the LS3/5A.
The Radio People Ltd Spectrum was produced as a copy LS3/5A in Hong Kong. Spectrums are quite rare and have become quite collectable in their own right. Thanks to Tim Yung and to David in Hong Kong for information and pictures.
The Falcon Acoustics B110/T27 Monitor Quality Compact.
Falcon Acoustics have had a long association with the LS3/5A. As well as making crossovers for RAM and Goodmans, Falcon did make some full BBC specification LS3/5As probably as part of their application for a licence. The BBC were limiting the number of companies they permitted to manufacture the LS3/5A and Falcon lost out to Goodmans. So only a very few Falcon LS3/5As exist. Their compact monitor has much in common with the LS3/5A. The following instructions are reproduced with kind permission of Malcolm Jones.
Click on the images for a large version.