In the fifties, sixties and seventies building your own Hifi components was a popular hobby. Many production models were also available as kits.
\nThey could be either sold as a complete kit identical to the original unit like the Dynaco\/Dynakit amplifiers requiring only assembly.
\nThey could be sold as \u201chalf kits\u201d providing the necessary parts but leaving things like the cabinets to the builder.
\nThere were also of course a large number of copied products on the market riding on the popularity of successful designs.
\nCarlsson loudspeakers were heavily copied by different companies selling kits to the market.
\nSonab saw the need for a DIY kit and therefore introduced the OA-5K on the market.<\/p>\n
The Sonab OA-5K is similar to the OA-5 typ 1 (Mk I). It was equipped with the same units as the factory made OA-5. The only visible difference is how the filter capacitor for the tweeters is placed, between the front tweeters above the baffle. The inductors are placed under the baffle and all wiring is made point to point without a printed circuit board.<\/p>\n
RESTORATION HINTS<\/strong> <\/p>\n TECHNICAL DATA Sonab OA-5K Box volume: 47 litres Prices: 1973: 745 SEK per pair (Type II).
\nThe important part with the 1960\u2019s models V1, OA-4 and OA-5 of both Type I and Type II is not to touch the screws holding the damping basket behind the full-range speaker.
\nThe full-range speaker should however be removed and managed. The speaker may otherwise be restored according to the RESTORATION AND UPGRADING.
\nRestoring this speaker is like restoring a standard OA-5 but usually without the problem of the baffles being glued.
\nConsider starting with only upgrading the filter capacitor and check up on the woofers.<\/p>\n
\nAccording to Sonabs handbook and\/or \u201dHifihandboke<\/strong>n\u201d
\n(NOTE! All data below refer to OA-5 Type II, which may have had a slightly larger volume, due to its raised baffle)<\/p>\n
\nMeasures: B x W x D: 24 x 61 x 43 cm
\nWeight: 10 Kg
\nPrinciple: Omni-directional, bass reflex type.
\nIt is not a traditional bass reflex box due to the fact that there are no port tubes, just two tuned ports in the bottom of the cabinet similar to Dynaudios \u201cVariovent\u201d.
\nImpedance: Approx 7 Ohms
\nFrequency range: (DIN 45500): 37-18.000 Hz
\nFrequency response: 42-15.000 Hz \u00b1 4dB on the floor against the wall
\nCrossover frequency: 2700 Hz
\nMid-bass: 1pc 22 cm 8 Ohms Philips 9710 full-range speaker
\nTweeters: 4 pcs 5 cm 8 Ohms Peerless MT20HFC
\nFinishes: Rosewood, walnut, teak, oak, natural pine and white lacquer.
\nAlso available in red, blue or green stain.<\/p>\n
\nSecond hand: 100 up to 1.200 SEK.
\nRestored: If well restored up to 2.500 SEK. They can well be worth this if one is not too critical regarding the musicians\u2019 lateral placement in the sound image. If the baffle is raised and new polypropylene tweeters (Peerless 62CT13) are mounted, new filter cabling, etc. and the speakers otherwise in good condition, the prices may even reach up to 4.500 SEK.<\/p>\n