C-Audio Pulse Series Power Amplifier

by Will James

Product Points

Applications: Live sound; contractor; installation Key Features: 4-channel amplifier (4 x 300 Watts); 2-channel amplifier (2 x 1100 Watts); switching power supply; XLR and 1/4 inch TRS inputs; Neutrik NL4 and binding post outputs Price: 2 x 650: $1,495; 4 x 300: $1,650; 2 x 1100: $1,850 Contact: BSS Audio at 615-360-0277; www.caudiousa@harman.com; C-Audio Pulse Series Power Amplifiers Plus ð Lightweight, easy-to-handle ð Quick response for accurate sound Minus ð Internal crossover is optional The Score Clean audio from these lightweight, high-powered touring amplifiers.

Founded in Cambridge, England in 1980, C-Audio (now owned by Harman Int'l. Inc.) is a leading power amplifier distributor throughout Europe and Asia. In addition to the Pulse series power amps reviewed here, the C-Audio family includes the SRX series & the GB series.

Features

The Pulse series power amps are unusual and attractive looking. The units I checked out were the Pulse 4 x 300 and the Pulse 2 x 1100 (C-Audio also makes a 2 x 650 Watt model). The most striking feature is the attractive slate-blue faceplate, which also forms its interesting handles.

The front panels of the two-rackspace power amps are concise and to the point. There are two rotary level controls on the two-channel version and four rotary level controls on the four-channel unit. Both versions have a rocker style on/off switch, as well as four LED function readouts that display main power on, level activity, protect and remote operation. Flanking the controls and LEDs are two 4-inch cooling fans, one on each side.

The rear panel features the balanced input connections, which are XLR and TRS 1/4-inch in parallel on the four-channel version, and a TRS coupled to both a male and female XLR connector on the two-channel version. For output, there are both Neutrik NL4s and Neutrik binding post connectors on the two channel models, and your choice of one or the other aforementioned connectors on the four-channel model. The outputs of the power amps may be bridged via a recessed switch (bridge in pairs on the four-channel).

The internal workings feature variable speed cooling fans (blowing rear-to-front), controlled by an onboard microprocessor that constantly monitors for possible faults in the switched mode power supply and/or power amp output sections.

The switching-style power supply provides more consistent power for longer periods. BSS provides the following specs: Model 4 x 300: each of four channels driven-170 W RMS at 8 ohms, 300W RMS at 4 ohms, 330 W RMS at 2 ohms; Model 2 x 650: both channels driven 400 W RMS at 8 ohms, 650 W RMS at 4 ohms, 850 W RMS at 2 ohms; Model 2 x 1100: both channels driven 700 W RMS at 8 ohms, 1100 W RMS at 4 ohms, 1,500 W RMS at 2 ohms. Frequency response is 20 Hz to 20 kHz, and the slew rate is 50 Volts/microsecond.

Each of the models weighs about 24 lbs. Available accessories for the C-Audio amps include fan filters, internal crossovers, rear-rack ears, and input transformers. Also available are two accessory cards. The CP212 Anti-Clip Limiter Card provides limiting for two or four-channel amps. The CP211 contractor card adds a variety of contracting features to a two-channel amp.

In use

At Sedona, Arizona's Jazz on the Rocks festival, which featured nouveau Latin-African Jazz ensemble Los Hombres Calientes, I used the C-Audio 2 x 1100 Model with a pair of Yorkville TX8 double 15-inch, full-range, three-way speaker cabinets, and the 4 x 300 Model biamping a pair of JBL 4704 monitors on two different mixes.

The full-range mains responded with excellent clarity and dexterity. The 2 x 1100 model stayed cool throughout the entire show. The four-channel amp running the monitors handled the mixes containing heavy amounts of full-range percussion, upright bass and grand piano.

For the second performance, I used the four-channel amp to power the 8-inch cone mids and the 2-inch compression tweeters in the Yorkville TX8s. The results were equally good; the amp had plenty of headroom.

Summary

These C-Audio power amplifiers are high quality professional amplifiers. They are easy to use and stay cool. Thanks to their lightweight switching power supply, several of them can be racked without being too cumbersome.

Their internal components are good quality and overall construction is excellent.

Will James, owner and chief engineer of Atlantis Audio and Lighting, is a contributor to Pro Audio Review.