Electro-Voice P1200

A 2U workhorse that sat between the analog touring amps of the '80s and the processor-controlled rigs that followed.

Overview

The Electro-Voice P1200 is a two-channel power amplifier in a 2U rack chassis, part of the company's Precision Series line. It is rated at 500 watts per channel into 4 ohms and 250 watts per channel into 8 ohms, with a bridged mono rating of 1000 watts into 8 ohms. That lets one rack unit drive a small PA or handle the top end of a biamped system without breaking a sweat. It is an amp meant to be racked and forgotten, not fussed over.

The architecture is a Class AB sliding-bias design. That topology puts linearity ahead of raw efficiency. Class D amps of the era traded distortion performance for lighter weight and cooler running, while the P1200's sliding-bias circuit was engineered to keep the output devices in their most linear region across the signal envelope. As Mix (May 1996, p.154) noted in its coverage of the Precision Series, the result is an amplifier that behaves predictably under load. That counts when you're pushing a pair of 4-ohm cabinets through a long set.

The rear panel shows the intended use. Inputs are electronically balanced XLR, factory-set to 0dBu (775 mV) sensitivity, and internal jumpers let you reconfigure to +6dBu or 26 dB gain. Maximum input level is +21dBu (9.0V), which leaves plenty of headroom for hot console outputs. The speaker outputs are Speakon connectors - two channels plus a bridged mono output. The amp is rated for 4-ohm and 8-ohm loads per channel, or a single 8-ohm load in bridged mode. That bridged 1000 watts into 8 ohms made the P1200 attractive for subwoofer duty, where you need to move air and don't care about stereo separation below 100 Hz.

Protection is comprehensive. The P1200 guards against overload, RF interference, shorted outputs, and DC faults. Power-up relays delay connection to the speakers for approximately two seconds to avoid thumps. A SOAR (Safe Operating Area) circuit monitors the output devices and steps in when they're pushed past their safe dissipation limits, and the Protect LED flashes when it engages. A short-circuit current limiter caps output at approximately 30 amps peak into a 1-ohm load, which suggests the designers expected the amp to be abused. The built-in output limiters switch between fast and slow operation. The factory preset is slow, which responds after two to three signal periods to tame distortion without audibly pumping.

The fan is thermally controlled. It doesn't run when the amplifier is cold, so in lightly loaded applications the P1200 can be effectively silent. When the heatsink temperature rises, the fan engages and ramps as needed. For studio or low-level installation use, that's a useful feature. For touring, it's one less thing to fail.

The service documentation gives the power consumption: 80 to 120 watts at idle, rising to approximately 1950 watts at nominal operation. The rated mains voltage is 120 V at 50-60 Hz, with a tolerance of ±10%, and the amp can be internally configured for 100 V operation. At 1950 watts, this is not an amp you want to share a 15-amp breaker with a bunch of other gear.

In the Precision Series, the P1200 is a transitional design. It's a linear amplifier, not a processor-controlled switching amp, but it was designed to work alongside the company's processor-controlled models like the P1250. In active 2-way systems with subwoofers, the P1200 was frequently paired with the AC*ONE* controller, which handled the crossover and equalization externally. The AC*ONE* documentation lists the P1200, P2000, P3000, Q44, and Q66 as the linear power amplifiers intended for these high-performance installations, with the P1250's processor section simply switched off when used in the same role.

The input sensitivity options are flexible. The factory setting of 0dBu (775 mV) for rated output is a professional line-level standard, and the amp can also be reconfigured to +6dBu (1.55V) or +9dBu (2.24V). That matches it to a variety of console output stages without external padding. The input routing switch allows dual/stereo operation or bridged mono. The HI-LO-CUT switch (factory preset to ON) provides a high-pass filter to protect speakers from low-frequency content they can't reproduce. That is a sensible default for a touring amp that might be connected to anything from full-range cabinets to horn-loaded tops.

The limiter is one of the more sophisticated parts of the design. The FAST/SLOW switch controls its time constants. In SLOW mode (the factory preset), the limiter responds after two to three signal periods, which is slow enough to avoid pumping on musical transients but fast enough to catch sustained overload. In FAST mode, it engages within one to two signal periods, which is more aggressive and better suited to protecting drivers from sustained feedback or runaway levels. The clip test in the service manual shows that with the limiter engaged, increasing input by 10 dB beyond the onset of clipping only raises output by approximately 3 dB.

The P1200's service documentation is unusually thorough. The manual includes complete test procedures for the output offset voltage (specified at ≤±10 mV), the limiter, the power-on delay, the fan control, the SOAR protection circuit, the short-circuit current limiter, and the DC voltage protection circuit. The level calibration procedure is documented with specific test points and expected voltages.

The P1200 sat in the market as a mid-tier professional amp: more affordable than the flagship models, but built to the same standards and intended for the same applications. It shows up in installs, rental inventories, and small touring rigs. The 2U chassis, the Speakon outputs, the protection circuitry, and the integration with Electro-Voice's controller ecosystem all fit that use.