Electro-Voice Sentry 100EL
A Sentry 100A with its own 50-watt amplifier bolted on — the powered monitor that saved rack space before anyone called it that.
Overview
The Sentry 100EL is a Sentry 100A that never needs a separate power amp. Electro-Voice took the reproduction components of its compact Sentry 100A monitor and added an integral 50-watt amplifier matched to the requirements of the speaker system. The whole thing went into a compact, rack-mountable enclosure. The pitch for a single-channel monitoring position - a video editing booth, a remote truck, a cramped control room - was simple: why buy a speaker and an extra amplifier channel when one box does the job?
The amplifier lives inside the cabinet, so there is no speaker cable run between amp and driver. That means no power loss from the resistance of a lengthy speaker cable. Fewer cables and connectors also mean simpler setup and fewer interconnect points to go wrong. Electro-Voice's own advertising billed it as a monitor that "provides its own power," fits tight spaces, and reproduces sound with "test-equipment accuracy." It also said the on-board amp, being perfectly matched to the speaker, removes the risk of damage from inadvertent signal overload. Collectors and engineers tend to repeat that last point: a matched amp can't be overdriven into a driver the way a mismatched outboard amplifier can.
The underlying speaker is the Sentry 100A, which the company described as the oldest member of the Sentry family and something of an industry standard for reliability. Its published response is a flat 45-18,000 Hz with wide 120° dispersion at 5,000 Hz. It uses an 8-inch direct radiator woofer in an optimally vented enclosure and the Super-Dome tweeter, which handles a remarkable 25 watts of input power on its own. The 100EL carries those same reproduction components. The addition is the amplifier. Contemporary coverage put the system's frequency response at 45 to 18,000 Hz with a 3 dB variation. Mix (October 1985, p.171) ran the powered-monitor announcement describing the integral 50 W amplifier, and DB Magazine (1985, p.15) carried the same "with on-board amplifier" pitch to the studio crowd. Electro-Voice announced the 100EL as the fourth member of the Sentry studio monitor family. It framed the line around linear response and uniform polar patterns, which the company treated as mandatory for stringent quality control. Recording Engineer (April 1984, p.57) covered that announcement directly.
Distributor literature of the period listed the Sentry 100A at $255.00 each and the Sentry 100EL at $524.00 each. That is roughly double, which is about what you'd expect once a 50-watt amplifier is folded into the cabinet. Buyers were paying for the amp and the integration, not a different speaker. The drivers and tweeter are Sentry 100A parts, so the value sits in the completeness of the powered package.
The 100EL fits the single-channel job. In a video editing booth or on a remote, one self-powered box replaces a speaker plus an amp channel plus the cabling between them, in a rack-mountable footprint. The trade-off is built in: the amplifier is integral and matched, so there's no swapping in a bigger amp later. Servicing means dealing with a combined speaker/amplifier unit rather than two separate pieces of gear.
Production years for the 100EL aren't confirmed in the available documentation. The period coverage runs from the 1984 announcement through 1986 advertisements, which brackets when it was being actively sold but doesn't pin down the run. Original pricing is documented at the $524.00 list figure. Dimensions, weight, connector types, and the amplifier's own specs aren't documented, so they stay unstated.
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