C/M Laboratories Model CM912 power amplifier (Equip. Profile, June 1975)

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"Transistor sound?" Our new power amplifier is too fast for it.

Reducing harmonic distortion in most amplifiers requires a great deal of negative feedback. Which means a lot of voltage gain is needed--and a lot of voltage gain stages.

As a result, an electrical signal takes so long to be fed back within most amplifiers that you end up with transient intermodulation distortion (or "TIM") and "transistor sound" an acoustical signal with a harsh edge to it.

Our revolutionary new Model CM912, however, requires relatively little feedback--and only two voltage gain stages instead of the customary five or seven. So the electrical signal travels a lot faster, the TIM is virtually eliminated and the resulting sound is remarkably smooth, natural and un-transistorish.

As specialists in components for the professional and for the serious audiophile, we knew we could do away with transistor sound by combining skilful design with the use of top-quality components--because better components mean we don't have to compensate by using as many of them. And this, in turn, reduces the amount of feedback we need.

Name-Brand Components THROUGHOUT:

So we specified high-speed Motorola transistors in a fully complementary common-emitter arrangement, Allen-Bradley low-noise resistors, General Electric 24,000-µF power supply capacitors and oversized extruded aluminum heat sinks for maximum heat dissipation. We also insisted on glass epoxy printed circuit boards.

Our determination to make our dual channel power amplifier a quality unit didn't stop there either. We've incorporated such unusual features as high accuracy power meters, positive-latching speaker relays, a thermostatically controlled cooling system and fully modular construction as well.

If your dealer doesn't yet carry the CM912, just drop a line to:

C/M Laboratories, 327 Connecticut Avenue, Norwalk, Connecticut 06854.

We'll not only mail you additional information, but, if you wish, we'll arrange a demonstration for you at a dealer in your area. (No obligation, of course.)

Hear the CM912--and move ahead to the sound of the future ... fast!

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KEY SPECS:

POWER OUTPUT: 225 watts RMS per channel into 4 ohm, 150 watts RMS into 8-ohm, with less than 0.2% total harmonic distortion, both channels driven, at any frequency from 20 to 20,000 Hz.

IM DISTORTION: Less than 0.1% up to rated power.

FREQUENCY RESPONSE: ±0.1 db from 20 to 20,000 Hz. ± 0.25 db at 12 watts from 5 Hz to 130 kHz.

OVERLOAD RESPONSE: Recovery from clipping less than 2 µ sec.

DAMPING FACTOR: Better than 50 at 8-ohm, 20 to 20,000 Hz.

HUM AND NOISE: 100 db below 200 watts RMS.

STABILITY: Will drive any load up to 6 uF at full power from 20 to 20,000 Hz.

CIRCUITRY: Fully differential input, fully complementary common-emitter output.

SPEAKER PROTECTION: Relay type.

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C/M LABORATORIES

C/M Laboratories, 327 Connecticut Avenue, Norwalk, Connecticut 06854.

EXCEPTIONAL COMPONENTS FOR THE EXCEPTIONAL EAR.

 

 

(Source: Audio magazine, Jun. 1975)

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