EMT 140 (1957)

Name: EMT 140
Brand: EMT

The first artificial reverb unit, a massive electromechanical plate system introduced in 1957.

Overview

The EMT 140 is the world's first plate reverb unit. EMT (Elektro-Mess-Technik), a German manufacturer, introduced it in 1957. It gave studios a compact, controllable alternative to echo chambers and spring reverbs. An electromechanical transducer vibrates a large metal plate, and pickups catch the result to make a lush, smooth reverb. Professional studios adopted it fast, and it stayed in use for decades. A remote-controlled version exists, with on/off switching via relay. Later models used updated electronics, like the EMT 162 with higher input impedance.

Specifications

Product type	A reverberation plate ("Reverberation Plate EMT 140")
Manufacturer	EMT (Elektromesstecknik), Elektro-Mess-Technik
Country of design/manufacture	German design and manufacture
Production years	Introduced in 1957
Dimensions	2.4 meters (8 feet) long by 1.2 meters (4 feet) high
Weight	270 kilograms (600 lbs)
Output level	-3 dB (.55 V) into 600 ohms at 1 kHz
Input impedance	5k ohm (with EMT 162 electronics)
Input/Output Impedance	May vary between models
Model variants	EMT 140 TS, EMT 140 FB-TS, EMT 140 Solid State Stereo Plate

Design

The EMT 140 uses an electromechanical transducer, similar to a loudspeaker driver, to set a large sheet metal plate vibrating. Early units had a drive coil wound over a heavy brass core. That was later replaced with a lightweight aluminum core to improve frequency response. Some versions support remote operation, with relay-based on/off switching through an external control. A block schematic exists for the stereo EMT 140 TS model, confirming its operational topology.

Context

Introduced in 1957, the EMT 140 was the first artificial reverb unit available to studios. It offered "reverb on tap" and replaced the need for dedicated echo chambers. It was a smoother alternative to spring reverb and became a studio standard. The unit's 600-pound mass made it a logistical challenge, but its sonic quality and space efficiency compared to echo rooms made it highly desirable. It also established EMT as a leader in professional reverb technology.

Market

A 1960s EMT 140 was listed with a new price of $2,257.97, while stereo versions from the same era have been priced as high as $11,430. A mid-90s used unit was listed at $7,800. John Lennon's EMT 140, used during the recording of "Imagine," was auctioned by Bonhams in December 2023. Original manuals and sales brochures have sold for $160.