Ampex AG-350 (circa 1968–1980s)

A broadcast workhorse whose paper trail is mostly classified ads — which tells you plenty about who owned it and how long they kept it.

Overview

The Ampex AG-350 survives almost entirely in the back pages of trade magazines, not in brochures or review columns. The documented evidence includes a classified in Audio (February 1968, p.75) offering "Ampex AG-350-2 Recorders" in unmounted condition - $1,850 with a 3-position head configuration, $1,900 with a 4-position head. It also includes a 1974 listing of an "AG 350-2," and a Mix-Magazine (May 1983, p.113) ad still trying to move an "Ampex AG350 2-trk."

The AG-350 is a professional quarter-inch tape recorder sold to broadcasters and studios who mounted it in their own consoles. "Unmounted" means buyers got a transport and electronics package, not a self-contained portable. Contemporary descriptions split between a half-track monaural machine and a two-track stereo deck. The "AG-350-2" suffix presumably marks the two-track version, though no surviving document spells out the naming convention. One owner on Gearspace described an AG-350-2 as having four heads that shift for stereo.

The dates don't line up cleanly. Analog Soundware places the model's era at the mid-1950s to 1960s, and individual units surface described as "vintage 1966" and "1967" examples. The classified record only begins in 1968 and runs to 1983. Both can be true, with early production followed by a long secondhand life. But no source pins exact production start or end years, so treat any precise date range with suspicion.

Key Features

Quarter-Inch Tape, Half-Track and Two-Track Configurations

The AG-350 ran standard quarter-inch tape. Sources describe the base machine as a half-track monaural configuration and the AG-350-2 as a two-track deck, and one listing calls it "HALF TRACK" outright. The 1968 classified's "3-position" and "4-position" head options probably denote different track-format arrangements, but that is inference, not documentation. Nobody has surfaced a period sheet explaining the terminology.

7½ and 15 ips High-Speed Transport

High-speed versions of the deck ran 7½ and 15 ips with NAB equalization. A surviving transport schematic references a "2 speed S503" selector and a reel-size safety interlock (S501/S504). Speed and reel-size switching were built into the transport as mechanical facts, not afterthoughts.

Tube-Based Electronics

Per the manufacturer's own documentation, the AG-350's amplifier section was solid-state and all-transistorized. That is worth flagging because the AG-350 name gets confused with other Ampex designs of the era. Anyone shopping for one should verify what's actually inside the chassis before assuming a particular circuit topology.

Console and Rack Mounting

Sold unmounted as a transport-and-electronics package, the AG-350 was meant to go into a studio's own furniture. One surviving listing gives approximate dimensions of 25 inches long, 29 inches wide, 47 inches at the rear and 32 inches at the front. That is a single uncorroborated measurement, so take it as a rough footprint, not a spec.

Historical Context

The AG-350's customers were broadcast and recording studios that built their own consoles, and the classified record bears that out. The 1983 Mix-Magazine listing sold an AG350 2-trk alongside an Ampex 354 two-track, another professional Ampex deck aimed at the same general market. The model's documented service life stretches well into the 1980s. Surviving units carry the marks of long institutional ownership: one reportedly spent its entire life in a single Southern California recording studio, and another sat unused in storage for roughly twenty years.

Collectibility & Value

Complete AG-350s turn up as "vintage" and "rare" listings on Reverb, eBay, and specialist dealers, though captured sale prices are thin. The parts market is easier to read. Asking prices on eBay include $200 for an Ashland capstan motor, $750 and $999 for pairs of untested preamps, and $350 for a four-track playback head. That last one was listed for AG-300/AG-35 fitment, not the AG-350, so don't read it as an AG-350 part price. All of these are undated asking prices, not confirmed sales.

Maintenance lore is sparse. A Tape Project forum post recalls a Bay Area shop that resurfaced AG-350 capstan motors with a bead-blast finish. Service documentation survives as an AG-350/AG-355 Recorder Reproducer Service Manual and an Operation & Maintenance Manual, both sold separately by manual dealers. Manufacturer documentation gives a frequency response of ±2 dB from 30 to 18,000 cps at 15 ips, signal-to-noise ratios of 60 dB full-track and 55 dB two-track at 15 ips, and flutter below 1.11% rms at 15 ips. No weight figures have surfaced in any source reviewed, so buyers are largely assessing condition and completeness rather than paper specs.