Ampex Model 970 (1959)
Two different machines wore the 970 badge - a late-fifties domestic tape recorder and a late-seventies UREI video bar-graph display. Neither is what you probably think it is.
Overview
The number "Ampex Model 970" was used twice, for two unrelated products, roughly two decades apart. Confusion is the default state. This page sorts it out.
The earlier machine is the one most people mean. According to a Studio Sound retrospective on Ampex's product history, the Model 970 was one of two domestic recorders - alongside the Model 1200 - introduced after JH Orr Associates, a tape manufacturer dating to 1946, merged into Ampex and gave the company its own tape brand. The same retrospective dates that introduction to 1959. It was a domestic machine, the kind a serious home recordist or semi-pro would have bought, not a studio workhorse.
The domestic 970 shows up in the British audio press of 1961. Through that year, Nusound Recording Company - Ampex's appointed London dealer, at 35 Craven Street off Trafalgar Square - ran a recurring advertisement listing the Ampex range available for demonstration: the Model 953 tape deck and pre-amps, the 961 complete stereo recorder, and "Model 970 (below)." The copy pitched these machines to "the semi-professional, and the serious home recordist," and asked "4-track? 2-track? Stereo or Mono?" Studio Sound (June 1961, p.34) carried the same Nusound dealer notice, confirming the 970 was on the floor at the London showroom that summer.
That is about all the surviving documentation says about the domestic 970's identity. Track configuration, speeds, heads and price are not preserved in the sources available here, and this archive will not invent them. It belonged to Ampex's first push into the home market, a lineage the retrospective traces from the 1955 Model 612 (billed as the first 4-track domestic recorder) forward.
Now the second 970. By the late 1970s the number had been reassigned to a product that had nothing to do with tape. The UREI "Vidigraf" Model 970 was a bar-graph display generator. Trade coverage described it as a device that operates into any NTSC standard video monitor - or, with an inexpensive accessory, into any black-and-white TV set - and generates 16 or 32 simultaneous VU channels with standard VU ballistics, an adjustable 0 VU reference, and a 30 dB dynamic display range. The point, as the magazine put it, was to stop recording engineers from getting "cockeyed looking at up to 24 VU meters" across a console, by putting all that metering on one compact screen.
The Vidigraf did more than VU. It could display real-time frequency spectrum on ISO ⅔-octave frequencies, and could show 16 VU channels plus 15 bands of spectrum plus a composite full-spectrum level at the same time, which helps when adjusting equalization. It could also display 16 VU channels alongside 16 channels of automation control voltages. Built-in programmable character generators eliminated the need for screen overlays and masks. Input capability ran from DC to 20 kHz, from balanced or unbalanced sources, which is why UREI pitched it for multitrack recording, disc cutting, and film sound work. The company also noted that the wide input range opened up general DC or AC analog voltage measurement. A 1978 Mix equipment listing put the main frame list price at $696.00.
The same model number landed on both a 1959 tape recorder and a 1978 video metering system, and the two are routinely conflated in listings and forum threads. A seller advertising an "Ampex Model 970" almost certainly has the tape machine. A studio-surplus listing with a CRT and a rack frame is the UREI Vidigraf. Confirm which one you are looking at before money changes hands.
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