US Acoustics Kristy | 4 Channel Class D Amplifier | 4 x 100w

Full Power, Almost No Footprint

The US Acoustics Kristy is rated at 100 watts RMS per channel into 4 ohms, 165 watts RMS per channel into 2 ohms, and 330 watts RMS x 2 bridged into 4 ohms, all at 14.4 volts. The chassis measures 8.26 x 4.68 x 2.04 inches. For context, the Barbara Ann makes the same 100 watts x 4 in a 17.7 inch chassis, so the Kristy delivers that power in a case less than half as long.

That is the whole point of this amplifier. Under a seat, behind a kick panel, in a center console, on a motorcycle, or in any powersports install where a full-size four-channel simply will not fit, the Kristy still puts real power on all four speakers. The output stage is a full-range Class D design, so it runs tweeters and midranges as happily as it runs midbass, and it draws far less current doing it than a Class AB amplifier of the same rating.

Conformal Coated for Marine and Motorcycle Use

The printed circuit board is conformal coated, a thin protective film applied over the board and its components that shields them from moisture, salt air, dust and vibration-borne contaminants. US Acoustics specifies it for marine and motorcycle applications, and it is the reason this amplifier belongs on a bagger, a side-by-side or a center console boat rather than only inside a sealed cabin. It is not a substitute for mounting the amplifier out of direct spray, but it is the protection that lets a small amplifier live in a hard environment.

Independent Crossovers on Each Channel Pair

Channels 1 and 2 and channels 3 and 4 each get their own gain, high-pass and low-pass controls. The high-pass is a 12 dB per octave filter adjustable from 20 Hz to 8 kHz, and the low-pass is a 24 dB per octave filter adjustable from 50 Hz to 8 kHz. Both filters have their own on and off switch, so either pair can be run full range with the crossovers bypassed entirely, which matters when the amplifier is fed from a DSP that is already doing the filtering.

Gain on each pair takes anything from 200 millivolts to 6 volts, so the Kristy works behind a factory head unit with a line output converter, behind an aftermarket deck, or behind a processor without fighting the input stage.

Three Ways to Run the Kristy

Four Speakers, Full Range

100 watts to each of four speakers, with an independent high-pass on the front and rear pairs. This is the straightforward upgrade for a factory system where there is no room for a large amplifier.

Front Stage Plus Bridged Subwoofer

Run components on channels 1 and 2 with the high-pass engaged, bridge channels 3 and 4 for 330 watts into a 4 ohm subwoofer, and set the low-pass on that pair. One small amplifier, a complete system.

Powersports, Marine and Motorcycle

The conformal coated board and the compact case are built for exactly this. Four speakers on a bagger or a UTV, or a pair of speakers plus a bridged sub on a boat, from an amplifier that hides almost anywhere.

Kristy or Barbara Ann?

Both make 100 watts RMS per channel into 4 ohms. The Barbara Ann is a Full Complementary Class AB amplifier with audiophile op amps, distortion below 0.01 percent, signal-to-noise above 97 dB and crossovers wide enough to run an active front stage, and it is the one to pick when measured sound quality is the goal and the space is there. The Kristy trades those last few decibels of measured performance for a chassis less than half the length, Class D efficiency, a conformal coated board and a lower price. If the amplifier has to fit somewhere a full-size four-channel cannot go, the Kristy is the answer.

Built to the US Acoustics Standard

Protection circuitry covers DC, short circuit, thermal and overload conditions, with green power and red protect LEDs on the end panel for fast troubleshooting. Every Kristy sold by Audio Intensity is brand new from US Acoustics with a 2-year warranty through authorized dealers.