Otari MX-70
A one-inch multitrack mastering deck that promised to grow with your studio — from eight tracks to sixteen — without ever leaving the rack.
Overview
The MX-70 is a machine built around a single, unusually practical idea: that a studio's track count shouldn't be locked in the day the tape machine arrives. Otari's own advertising in Mix (November 1984, p.4) announced the deck as "the MTR-90's little brother," a one-inch, 16-channel multitrack mastering recorder that "derives its features from our experience with MTR-90 customers and their applications." That lineage matters, because the MX-70 is not a scaled-down toy — it inherits the transport thinking of a machine the company sold into serious rooms.
What separates it from a garden-variety eight-track is what Otari called its "3-way" design: the deck can run as 1-inch 16-track, 1-inch 8-track, or ½-inch 8-track, with conversion done right in the studio. The pitch was refreshingly honest — each session could be cut on a different format, and as a client's needs grew, the machine would follow them all the way up to sixteen tracks.
The transport is the other half of the story. Otari fitted the MX-70 with a microprocessor-governed, constant-tension, servo-controlled transport — the same philosophy that made the deck attractive to post-production houses chasing SMPTE timecode. The company's advertising in Recording-Engineer (April 1985, p.49) was explicit that the constant-tension transport was "ideal for use with SMPTE time code-based video editing systems, machine controllers, and synchronizers." For a mid-1980s facility wiring a multitrack into a video suite, that was the difference between a tape machine and a system component.
Speed options came in field-selectable pairs: 7½/15 in/s or 15/30 in/s. The deck also carried timed bias ramping for gapless insert recording at any speed, logic-interlocked controls, and a full-function remote session controller as standard equipment — not an extra. Otari's period literature also lists switch-selectable IEC/NAB equalization, adjustable phase compensation, electronically balanced inputs and outputs at +4 or −10 dB, switching logic for interfacing to any noise reduction system, and an LED multi-function tape/time display. An optional autolocator with multiple memory storage, search, and repeat shuttle was available, and an RS232C/RS422 serial communications port could be ordered for facilities that wanted machine control.
Price was the headline the company leaned on hardest. Otari's suggested list was $14,955.00 — a figure that put a one-inch 16-track within reach of rooms that couldn't justify a full MTR-90. The used market tells its own story: a classified listing in EQ magazine advertised an MX-70 with dbx and auto locator, low hours, at $12,000, which suggests the deck has held meaningful value among engineers who know what it is.
The MX-70 found its way into real production rooms rather than just showroom floors. Broadcast production was a particularly strong fit — period accounts describe stations running the deck as the heart of an eight-track production room, paired with consoles like the Wheatstone SP-5 or Pacific Recorders ABX, cutting promos, jingles, and comedy bits. That's the honest picture of where most of these machines worked: not major music rooms, but busy radio and post facilities that needed multitrack flexibility on a budget and valued the format-conversion trick when a session called for it.
The caveats are the usual ones for a machine of this vintage and complexity. The constant-tension servo transport is a marvel when it's healthy and a headache when it isn't, and the logic-interlocked control circuitry doesn't forgive neglect.
What the MX-70 offers is a specific kind of value: a one-inch multitrack with genuine Otari transport engineering, a documented path from eight to sixteen tracks, and a price that undercut the company's flagship. It is not the MTR-90, and Otari never pretended otherwise — but for a studio that wanted to grow into sixteen tracks without buying a new machine every time the client list expanded, the MX-70 was built to be the last tape machine you'd need to buy for a while. That it still commands real money on the used market says the design delivered on at least part of that promise.
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