Electro-Voice AP2300 (1989)
A rack-mount amp built for installs that never get to shut down.
Overview
The AP2300 is a dual-channel power amplifier from Electro-Voice. The documentation that survives on it - owner's manuals, service manuals, a data sheet - points to a single year of record: 1989. It was aimed at professional sound reinforcement, the kind of permanent installation where the amp sits in a rack and runs for hours at a time. Electro-Voice's own data sheet described it as a two-channel amplifier whose channels "can operate independently or be bridged into an 8-ohm load." The company's marketing language billed it as the choice "for serious professional installations which demand the highest quality at high power levels for extended periods of time." That's advertising copy, so it tells you what they intended, not what the amp did.
One eBay listing title identifies it as "2 Channel 150W/4ohm Power," though no per-channel power rating is confirmed in the surviving documentation. A separate eBay product page for the AP2300 lists it at 560W. That figure almost certainly refers to AC power consumption rather than audio output, so don't read it as a per-channel rating.
The front panel carries only the power switch and the indicators - a power LED and two clip LEDs. That is install-rack layout. The AP2300 was never trying to be a hi-fi amp with a pretty face.
One caution on identity. Sources call this amplifier the AP2300, AP2300/SA, AP2300-SA, and AP2300SA, and no source in the available documentation explicitly states the relationship between the base model and the SA variant. The service manual listing on 838dz.com bundles both names into a single entry, which suggests they share documentation. Still, treat the suffix designations carefully and don't assume the two are interchangeable.
Key Features
Dual Mode or Bridged Into 8 Ohms
The amplifier runs as two independent channels or as a single bridged monophonic block, and the documentation calls out the bridged configuration specifically as an 8-ohm load. Bridging is why these amps turn up in subwoofer duty and in installations driving a single high-power cabinet. You give up stereo separation and gain roughly the sum of both channels' output.
CX1 Two-Way Crossover Module
The AP2300 accepts plug-in modules, and the one that shows up most often in the documentation is the CX1. It is a two-way crossover, 24 dB per octave, with switch-selectable high-frequency attenuation and a choice of 500 or 800 Hz crossover points. On an install amp, that means you can biamp a two-way system straight off the amplifier's own module bay instead of adding a separate outboard crossover. Crossover points of 500 and 800 Hz cover a lot of the classic two-way horn-and-woofer designs that Electro-Voice itself was building speakers for.
Clip Indicators, One Per Channel
Each channel gets its own clip LED, plus a single power indicator. On an install amp that matters in practice: when one side of a stereo pair starts clipping and the other doesn't, the LEDs tell you right away that the problem is upstream in that channel's signal chain rather than in the amp's shared power supply.
Built for Rack Duty and Long Hours
The documentation consistently frames this amp around reliability under sustained load - "exceptional power and reliability," in the data sheet's phrasing, for "professional sound reinforcement systems." Whether it delivered over decades of service, the surviving documentation doesn't say. There's no repair history or owner testimony in the record, only the manufacturer's stated intent.
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