Ampex Model 620 Amplifier-Speaker
A 25-pound companion box that turned a tape recorder into a hi-fi system - and sold for $149.50.
Overview
The Model 620 isn't a tape machine. Get that straight first. It's the companion piece Ampex built to sit alongside the Model 600 recorder - an amplifier and speaker in one portable enclosure, housed in what the company described as an acoustically correct case, weighing only 25 pounds. Pair the two and you had what Ampex marketed as the 600-620 combination: recording plus playback, in a package you could carry like luggage.
The pitch was portability without apology. Ampex's own advertising billed the 600-620 pairing as offering "recording perfection and truly exceptional sound reproduction" wherever you happened to be. It also stressed that the 620 could be lifted out of a custom installation in seconds - as ready to travel, the copy went, as a packed suitcase. That's marketing, not a measurement. It does show what the box was for: a self-contained playback system for someone who wanted their tapes to sound good at home, at a friend's house, or in a hotel room.
The numbers are modest by any later standard. Ten watts of output. Response flat from 60 to 10,000 cycles. That range is the honest limitation here. This is a mid-1950s design, and 10 kHz was a reasonable ceiling for the era, not a defect. Ampex positioned the 620 as a way to improve the sound of record changers, TV sets, and tape recorders. It was also pitched as a portable PA system, a monitor unit for broadcasters, an auditioning unit for ad agencies, and a demonstration unit for music stores. That's a wide brief for one small amplifier, and it explains why the thing sold.
Price at introduction was $149.50. The figure appears consistently in Ampex's own materials and in the contemporary trade press. Hi-Fi-Music-at-Home (July 1955, p.7) described the 620 as offering "magnificent tonal quality in a 25-pound package" when paired with the 600, framing the pair as a portable route to genuine high fidelity rather than a compromise. The same pairing language shows up in Tape-Recording (August 1955, p.5) and High-Fidelity (August 1955, p.26). Both ran the 600-620 combination as a single proposition, recorder plus companion amplifier-speaker, rather than as two separate products.
Audio (November 1955, p.62) covered the Model 612 stereophonic tape phonograph in its new-products column, noting that the 612 system shipped with two Model 620 amplifier-speakers. That detail matters more than it looks: the 620 was the building block Ampex used to turn a mono playback rig into a stereo one. Two 620s, one 612 phonograph, and you had a two-channel system. The 620 wasn't an accessory in the throwaway sense — it was the speaker end of Ampex's whole consumer strategy.
Classified listings from the period show the 620 changing hands as part of complete Ampex outfits. One was a 600 reproducer with two 620 speakers in Samsonite luggage, tapes included, asking $800. Another was a 612 playback unit with two 620 amplifier-speakers in walnut furniture cases, offered at $375 for the three units. A third seller listed a 600 recorder and 620 companion piece together, described as spotless and indistinguishable from new, against an original combined cost of $694.50 and an asking price of $575. These are asking prices from private sellers, not auction results, so treat them as period context rather than a market index. They do show the 620 was rarely sold or resold alone.
Ampex offered the 620 two ways. Buyers could have it in matching wood cabinetry or in a luggage-type case, and the 612 system could be had the same way. The wood version was meant to sit in a living room. The luggage version was meant to leave it. That split explains why the 620 turns up today in such varied condition. A cabinet example that stayed in one room for sixty years looks very different from a travel case that actually traveled.
One more piece of period evidence: a classified notice in the tape press carried a plain wanted ad for an Ampex speaker-amplifier, Model 620 or A692, "must be in good condition and reasonably priced." That's not a review. It does mean people were hunting for these on the used market while they were still current products, which is not the usual fate of a bundled accessory.
The 620 is not a standalone high-fidelity amplifier in the sense a modern collector means. It's a ten-watt integrated box with a speaker inside it and a response ceiling at 10,000 cycles. Anyone expecting it to drive inefficient speakers or fill a large room will be disappointed, and the 60-cycle bottom end won't do much for organ pedals or the lower reaches of a piano. What it will do is make a Model 600 sound like a system rather than a machine, in a package you can pick up with one hand. It worked well enough that Ampex built the 612 stereo system around it.
Today the 620 rarely appears on its own. When it does, it's usually because someone split up a 600-620 pair or a 612 system. Original documentation and the matching cabinet or case are what push a unit from interesting to collectible. The amplifier itself is simple and low-powered, and it should be judged as the companion component it was designed to be, not as a standalone.
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