Klark Teknik DN780
A British digital reverberator that promised a new generation of realistic acoustic simulation. It also left a paper trail of PROMs, lithium batteries, and a 15 MHz crystal for anyone brave enough to keep one alive.
Overview
The DN780 was Klark Teknik's bid to redefine what a digital reverberator could be. Contemporary advertising in the studio trade press called it "the first of a new generation of reverberation equipment." It was built around Klark Teknik's own Very Large Scale Integration technology paired with a "superfast" Digital Signal Processor. The pitch ran repeatedly through 1984 and 1985 issues of Studio Sound. It promised greater realism: natural concert hall reverberation, credible small-room and plate sounds, and an "infinite space" setting that went beyond the usual reverb presets.
This box did not hide its complexity behind a friendly interface. The DN780's internal documentation reads like a small computer. There is a microprocessor board running a 4 MHz crystal and a 16K x 8 EPROM, a DSP board with its own 15 MHz crystal, a converter board built around PCM53 D/A converter ICs, and a display board with 7-segment orange and green displays. Klark Teknik designed it as a system of interconnected boards rather than a single monolithic assembly. That is why surviving units are a restoration project as much as a piece of outboard gear.
The marketing language was confident. "British designed, British made / Trusted throughout the World" ran as a tagline in Studio Sound (July 1985, p.19), alongside the claim that the DN780 combined intuitive control with a more natural "added density" in its sound. Whether it fully delivered is a question for anyone who has heard one in a working room. Klark Teknik positioned it at the top of the acoustic processing market and priced it accordingly.
Key Features
VLSI and a Superfast DSP
The DN780's main selling point was its processing architecture. Klark Teknik's advertising described Very Large Scale Integration technology working alongside a superfast Digital Signal Processor. The company said this combination allowed "the world's first practical application" of variable-space reverberation simulation. In plain terms, an engineer could dial in anything from a tight plate to a sprawling hall without swapping hardware. The DSP board carries a 15 MHz crystal, and the converter stage uses PCM53-series D/A converter ICs.
A Multi-Board Architecture
Open a DN780 and you find a stack of purpose-built boards: an audio in/out board, a DSP board, a microprocessor board, a converter board, a display board, a power supply board, a front panel assembly, and a separate remote PCB assembly. The microprocessor board runs a 4 MHz crystal and a 16K x 8 EPROM (a 27128), backed by 2K x 8 CMOS SRAM. The DSP board carries multiple 1K x 4 SRAM chips and a bank of 74LS-series TTL logic. This modularity made the DN780 serviceable in an era when board-level repair was the norm. It also means every board is a potential failure point decades later.
Orange and Green 7-Segment Displays
The display board uses HD1107-series 7-segment displays in both orange and green, alongside a mix of green, yellow, and red 3mm LEDs. The front panel and remote assembly add further red LEDs. The remote PCB assembly has its own BC184 transistors and a bank of red LEDs, which suggests Klark Teknik expected the DN780 to be operated from the desk rather than rack-side.
Effects Programmes Beyond Reverb
Reverb was the headline, but the DN780's advertising also pushed its "effects programmes," which extended the unit beyond straight reverberation. The company billed the combination of reverb and effects as making the DN780 "the most powerful acoustic processing package available" at the time. That is marketing copy, not an independent verdict. It does show Klark Teknik saw the DN780 as a studio's central acoustic processor.
Lithium Battery-Backed Memory
The microprocessor board carries a lithium battery (a LIM2016P1) to back up memory. This is the most important detail for anyone considering a DN780 today. A dead lithium cell means lost settings, and a leaking one means corroded traces on a board that is already difficult to source. Treat the battery as a service item.
Collectibility & Value
The DN780 sits in an awkward spot in the collector market. Klark Teknik's own advertising framed it as the first of a new generation, and its VLSI-plus-DSP architecture was ambitious for its moment. But it is also a complex, multi-board digital device from the mid-1980s. The lithium battery on the microprocessor board is a known service concern. There are also many socketed ICs - 24-pin DIL sockets, 28-pin lock IC sockets, 18-pin DIL sockets - so a working unit is only ever one failed chip away from silence.
Prices are difficult to pin down from the available documentation, and no reliable current market figures appear in the sources consulted. The DN780's value rests on two things: whether it powers up and passes signal, and whether the battery has been replaced before it caused damage. A DN780 with a clean, corrosion-free microprocessor board is a different proposition from one that has sat with a leaking cell for a decade. Buyers should ask for board photographs, not just a front-panel shot.
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