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MA250

Stereo Power Amplifier



The MA250 is a high caliber, reasonably priced stereo power amplifier designed to meet the needs of custom installed systems where superior sound is a specific requirement.

Knoll engineers designed the MA250 as a plasma TV stereo booster amplifier with many unique features making it valuable in a wide variety of applications. One of its most advanced features is the stereo inputs that are directly connected to the speaker outputs if the amplifier is not powered up. This allows whole house music from other systems to pass through, and then be overridden when the local MA250 amplifier is required.

Power on and off can be accomplished by the use of the power switch on the front panel, a 12-volt trigger input, a video signal or when sound signals to the amplifier are detected. All controls on the MA250 are rear-mounted, except for the power button, to ensure there are no maladjustments once the amplifier is installed.

Key Features:

· Manual and Automatic Power On and Off. The MA250 stereo power amplifier turns on when a video signal is detected, music or sound is sensed, the 12-volt trigger is activated or the front panel power switch is pushed on. Power off is automatic in all modes except the front panel power button.

· Whole house music override. In homes, yachts, businesses and motor home applications (typically with plasma or large screen TVs) the MA250 features amplifier inputs so that whole house music systems can be heard on the local speakers (without the MA250 being switched on). When the local source (TV, dish, etc.) needs amplifier power, the whole house music automatically switches off and the MA250 amplifier switches on and plays the local source.

· Automatic protection circuitry. Each MA250 channel is individually and completely protected against low impedance, overheating, overloading, over voltage and under voltage. The protection circuitry automatically restores the amplifier channel as soon as its parameter returns to the safe operating area.

· Individual input gain adjustment. All of the MA250 channels feature an input gain adjustment pot to adjust each channel for gain and speaker sensitivity variations. The gain adjustments are on the rear of the amplifier so installers usually set the gain.

· Stackable 17" chassis. Two MA250’s can fit side-by-side and be stacked for applications that require more than two amplifier channels.

Specifications:

Inputs Gold RCA input and output jacks with adjustable gain
Input impedance 55,000 ohms
Outputs Detachable four position plug
Output power 50 watts RMS per channel into 8 ohms
70 watts RMS per channel into 4 ohms
Peak output power 90 watts per channel (8 ohms)
Ideal impedance 4 - 8 ohms (will work at 16 ohms)
Frequency response 10 Hz - 40 kHz +/- 1dB (1w)
S/N Ratio Over 95 dB A weighted (50 watts)
THD distortion less than 0.1% 20 Hz to 20 kHz
IMD distortion less than 0.01% 60 Hz 7 kHz 4:1 (SMPTE)
Trigger Control 12 VDC (35 mA) on a mono 3.5 mm jack
Dimensions 8.5" x 3.5" x 11.5" (432 x 89 x 292 mm) 1/2 width rack
Power 140 watts at 117 VAC
Weight 8 lbs (3.6 kg)

Note: Specifications subject to change without notice.



© Knoll Systems 2006