Klark Teknik DN 71
A small box that turned a digital delay line into a harmoniser, a flanger, and a swept-effects machine - provided you already owned the delay line.
Overview
The DN 71 is not a standalone effects unit. It is a Klark-Teknik sound effects generator and controller for the DN 70 digital delay. Buy a DN 71 on its own and you have a very well-made paperweight. The two units are a pair, and collectors should treat them as one.
What the DN 71 adds to a DN 70 is control and movement. According to period coverage, the DN 70 offers three separate digital delays with a maximum of 652ms. The DN 71 unlocks remote operation of those delays, plus a set of swept digital effects - harmonising, phasing, and flanging among them. It also has a hold-and-repeat facility, which lets the memory content be continuously repeated. That makes it more than a modulation toy. The delay line becomes something closer to a primitive sampler, freezing a phrase and looping it while the engineer works.
The DN 70's own clocking ran at 50kHz with frequency response to 15kHz, per the AES convention previews of the period, and the DN 71's effects are built on top of that engine. The swept effects are digital, not analog. This is a 1979-vintage digital processor, which is early territory for studio outboard. The harmonising function was a notable claim for the era. A delay line that could shift pitch enough to serve as a harmoniser was not a common thing in a British studio rack at the end of the 1970s.
Klark-Teknik showed the DN 71 for the first time at the AES 62nd Convention in 1979, alongside the DN 70, the DN 34 analogue time processor, and the company's graphic equaliser line. Studio Sound (June 1979) reported the debut, describing the DN 71 as an optional digital controller that enabled the DN 70 to generate harmonising and flanging effects. The same magazine's October 1980 issue noted that the Finnish Broadcasting Company had purchased five DN 70 time processors and five DN 71 sound effects generators. A state broadcaster buying the pair in quantity says the combination saw serious professional service, not just trade show demos.
The DN 71 stayed in racks well past its introduction. A 1989 studio inventory from Britannia Row in London lists both a Klark-Teknik DN 70 and a DN 71 among the outboard, sitting alongside AMS, Lexicon, and Eventide units. That is a decade after launch.
Klark-Teknik's own advertising of the period ran repeatedly through Studio Sound in 1979 and 1980. It billed the company as manufacturing "the ultimate in signal processing products," with each unit representing "the very best in its specific technology." That is marketing copy, not a verdict, but it fits the build quality and the price tier these units occupied. The DN 71 is a professional accessory from a firm that positioned itself at the top of the British signal-processing market.
Ownership comes down to the pairing problem. The DN 71 has no value without a DN 70, and DN 70s are not common. The sensible approach is to buy them together or not at all, and to verify that the controller and the delay line actually communicate before money changes hands. The remote and swept-effect functions depend entirely on that link. When the pair works, you get harmonising, flanging, phasing, and a hold-and-repeat function that foreshadows the looping tools that came later. It is not a plug-in, it is not convenient, and it does not do anything on its own.
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