UREI Model 200 Automatic Response Plotting System
A bench instrument that turns "how does this thing actually measure?" into hard copy, provided you can find one with its plug-in modules intact.
Overview
Search for "UREI Model 200" and you will find at least three different machines: a portable mixer, a battery-powered test oscillator, and a digital reverb. None of them is this one. The UREI Model 200 is an automatic response plotting system - a sweep generator and receiver pair that drives a Hewlett-Packard X-Y plotter and lays down a hard-copy frequency response curve. DB Magazine (October 1976, p.48) said it filled a real gap: a practical system for quick hard-copy response testing had until then been either unavailable or priced out of reach for most shops. Before the 200, drawing a response curve meant a manual sweep, a meter, and a lot of patience.
The design is modular, and that is the detail a buyer today needs to care about most. The 200 is a chassis that accepts plug-in analysis modules. The Model 2010 Level and Frequency Detector, announced as the second module in the series, lets the 200 plot both amplitude and frequency information from coherent signals - prerecorded test tapes, records, and similar sources - according to DB Magazine (April 1977, p.27). The 200 is only as capable as the modules you can find for it, and the modules are the scarce part.
Studio Sound (September 1977, p.39) laid out the specs plainly: the 200 resolves to 0.05 dB with a range up to and beyond 60 dB, holds accuracy to ±0.3 of full scale, and sweeps from 20 Hz to 20 kHz under either automatic or manual frequency control. The automatic rate sensing and control were the selling point. The system adjusts its sweep rate to keep the trace accurate, so nobody has to babysit slow sweeps by hand. UREI's own advertising of the era billed it as an automatic audio frequency response plotter.
The 200 was built to measure tape machine response, telephone lines, room acoustics, speakers and microphones. That range is why it turns up in studio maintenance racks rather than on a hobbyist's bench. It is a service instrument, and it was priced and positioned like one.
One caveat for a modern buyer: this is a system, not a single box. A 200 without its plug-in modules is a chassis and a plotter interface. Collectors report that the value lives in the modules and in the documentation, and that a complete, working example is a very different proposition from a bare mainframe. Confirm exactly which modules are included before putting a number on the listing.
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