Lexicon Model 102 Delta T (1974)
A 90 dB digital delay line that studios specified by name. Lexicon itself treated it as the reference point for everything it built afterward.
Overview
The Model 102 is a digital time delay system from Lexicon, Inc. of Waltham, Massachusetts. It was announced for recording studio, sound reinforcement, and laboratory use. Lexicon's own announcement billed it as a second-generation system in the Delta T line. The headline number was a 90 dB dynamic range, a figure the company repeated across the series. The Model 102 was introduced in 1974. By the end of the decade Lexicon was describing it in print as the standard of the industry, the system specified by users seeking the ultimate in performance and reliability (Recording-Engineer, October 1980, p.149). That is a manufacturer talking about its own product, so take it as positioning and not an independent verdict. Still, Lexicon kept using the 102 as the yardstick for its smaller, cheaper models years later.
The design is modular, and that is the whole point. A single Model 102 main frame offers up to 320 ms of total delay in 5 ms increments with 40 ms modules, or up to 128 ms in 2 ms increments with 16 ms modules. It carries up to five delay outputs, each adjustable from the front panel. For bigger installations, additional slave units can be cascaded. Lexicon claimed up to 50 outputs with no degradation of audio output. Take that claim with a grain of salt until you hear it in a room, but it is what the documentation states.
The inputs and outputs are both transformer coupled. That helps if you are patching one into a console in a facility with grounding problems. A five-position LED headroom indicator lets the operator verify operating settings at a glance. Lexicon built the series with what it described as computer-quality components and construction for high reliability. That is marketing language, but it fits the price point and the intended market.
The Model 102-S is the stereo variant, and it differs from the standard 102 in one important way. The standard 102 is a delay system. The 102-S packs two independent delay units into one chassis and adds a VCO module. The VCO turns the box from a delay line into a time-domain processor. The documentation lists double tracking, flanging, vibrato, time delay panning, extreme pitch modulation, and signal transformation among the effects it makes possible. The two delay lines can run completely independent signals - the example given is simultaneous delayed echo and doubling - or the VCO can modulate one channel while the other stays clocked by the crystal. Per channel, the 102-S is specified at 192 ms of delay with 3 ms taps, 0.2% total noise and distortion, and dual five-position LED headroom indicators. Like the mono unit, it is fully modular. A buyer could start with an economically configured mono system and field-expand later through plug-in modules. Lexicon's own pitch was that a studio that would normally buy two delays could save in excess of $1,000 by going this route when adding the second delay.
The 102 did not stay at the top of the line forever, and Lexicon's own advertising shows the trickle-down. By late 1979 the company was running a trade press campaign that positioned the Model 91 as the Model 102's technology "packaged for small budgets" - churches, schools, colleges, community auditoriums. The Model 93 was pitched at studios and entertainers (Studio-Sound, October 1979, p.15; the same advertisement ran in DB-Magazine in June 1980, p.13). The framing in those ads is that the 102 is the big-system reference the cheaper boxes are measured against. The 102 also turns up in the kind of work you would expect. A 1980 account of theatre sound design for a stage production describes a rig using two Model 102 Lexicon units alongside an Altec 9430A digital delay, a Lexicon Varispeech 27, and a Putney VCS3. The rig was deployed for multi-channel effects and for using digital delay to expand the apparent size of a room or localize sounds without panning (Recording-Engineer, October 1980).
Anyone chasing one today should expect the usual caveats for gear of this vintage. The modular construction that made the 102 attractive to facilities in the 1970s also makes a complete, working example harder to find. Main frames, module complements, and slave units were bought and expanded piecemeal, so two "Model 102s" on the used market may be very differently equipped. The transformer-coupled I/O and the LED headroom metering should make a unit easier to integrate into a modern patch bay. The documentation available does not describe failure points, recap intervals, or current market pricing, and nothing here is a serviceability guarantee. Verify the actual module population and confirm the unit powers up and passes signal before buying.
eBay Listings
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.