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Stereo Automatic On/Off Amplifier |
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The MA252 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 MA252 as a plasma or LCD 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 MA252 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 MA252 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 MA252
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
MA252 features amplifier inputs so that whole house music systems can
be heard on the local speakers (without the MA252 being switched on).
When the local source (TV, dish, etc.) needs amplifier power, the whole
house music automatically switches off and the MA252 amplifier switches
on and plays the local source.
· Automatic protection circuitry. Each MA252 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. Both MA252 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.
Specifications:
| Inputs |
Gold RCA input and output jacks with adjustable gain |
| Input impedance |
55,000 ohms |
| Outputs |
Detachable four position plug |
| Output power |
52 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 |
17" x 3.5" x 11.5" (432 x 89 x 292 mm) |
| Power |
170 watts at 117 VAC |
| Weight |
11 lbs (5 kg) |
Note: Specifications subject to change
without notice.
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