VINTAGE TECHNOLOGY ARCHIVE / AUDIO / ESS / AMT-1B

ESS AMT-1B

Documentation on the ESS AMT-1B is thin. No full-length period review of this specific model has surfaced in the archive. What survives is a handful of directory entries and a passing mention in a 1977 product round-up. That is enough to place it: this was a complete loudspeaker built around the company's Heil air-motion transformer, not a tweeter component.

The AMT-1B appears in a product round-up in Audio (October 1977, p.180), listed alongside the Dahlquist DO-10, JBL L65, Infinity IIA, and AR-107T. By 1980, High Fidelity's equipment directory (1980, p.158) listed it as a passive-radiator design pairing a 10-inch cone woofer with the Heil air-motion transformer, priced at $349. The cabinet was a tall, tapered floor-stander: 38 inches high, 17⅜ inches wide, and narrowing from 9½ inches deep at the bottom to just 4½ inches deep at the top. Each speaker weighed 55 pounds. The same directory entry quoted response from 38 Hz up to 24 kHz.

The earlier AMT-1 shares its Heil lineage with the 1B. Audio reviewed it (December 1973, p.65). The review described a rotary tweeter-level control with detents from BRIGHT through NORMAL to SOFT. It was a small circular knob that was easy to turn by accident and hard to read, and setup meant tipping the speaker and checking it with a flashlight. The review also noted that ESS supplied excellent hookup instructions, and that the Heil unit carried a lifetime original-owner warranty while the rest of the system was covered for five years.

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