About the Company
ISI — International Scientific Industries was a U.S. company that appears very briefly in magnetic-tape recorder history, associated with a single consumer reel-to-reel machine in the late 1950s. It did not become a major tape recorder manufacturer and has only one documented reel-to-reel model to its credit.
Brand: ISI (International Scientific Industries)
Country: United States
Reel-to-Reel Era: 1957–1958 (very limited)
Market: Consumer open-reel tape recorder (not studio/pro)
Production History & Known Models
ISI Model 100 (1957–1958)
The only documented reel-to-reel recorder from ISI is the ISI Model 100 — introduced around 1957 and sold into 1958.
Key details of the ISI Model 100:
Category: Consumer reel-to-reel tape recorder
Technology: Vacuum-tube electronics (tube-based circuitry)
Tracks: Half-track (1/2 Rec/PB)
Tape Speeds: 7½ and 15 ips (high speeds for its era)
Reel Size: Up to 7″
Heads: 3 heads (erase/record/playback)
Head Material: Permalloy
Motors: 3 motors
Voltage: 110–120 V (U.S. mains)
Approximate Sound/Quality Rating: Mid-range (collector evaluation 5/10)
The Model 100 was marketed with claims of an “Isimetric drive” using a magnetic differential clutch and brake system designed to keep constant tape tension and speed stability, which was touted as technologically advanced at the time — but it did not lead to wider production or a full product range.
Interpretation & Historical Role
ISI’s presence in the reel-to-reel recorder market was very limited and short-lived, unlike companies that built extensive tape recorder lines through the 1960s and 1970s (such as Akai, Revox, TEAC, etc.). The Model 100’s existence appears to be a single-product foray rather than the start of an ongoing reel recorder business.
There are no documented follow-up models from ISI, and collector registries list only the Model 100 attributed to this brand.
This suggests that ISI’s attempt at entering the consumer tape recorder market was experimental and brief, with the company otherwise not having a noted legacy in reel-to-reel audio recording — unlike many Japanese, American, or European firms that made tape decks a core product.
Summary — ISI International Scientific Industries
ISI International Scientific Industries’ reel-to-reel history is essentially:
Only one known tape recorder: ISI Model 100 (c. 1957–1958)
Manufacturer base: USA
Technology: Tube electronics with unique mechanical tension system
Market impact: Minimal/one-off — not a sustained tape deck product line
Today, ISI’s Model 100 is a rare collectible representing an early experiment in consumer open-reel recorders rather than the output of a major manufacturer.