This unit is from Japan and extremely rare. It powers up but does not produce sound. METRON A-4000 POWER AMPLIFIER The Cerwin-Vega Metron A-4000 represents an unprecedented value in the field of high power amplification. With a price well in reach of those who demand the finest in audio reproduction, the wealth of features incorporated into the design of the A-4000 place it solidly in a prestigious class of power amplifiers. At the very core of an amplifier which exhibits so many impressive features is the A-4000's symmetrical, differential, full complementary circuitry from input to output. This circuit design is notable for its meticulous reproduction of even the most complex musical waveforms, and operates off of massive, independent, toroidal potted transformers for each channel. The power rating of the A-4000 - 350 watts RMS per channel into 8 ohms from 20 Hz-20 kHz at less than .02 % THD - and the characteristic low noise of its design (-76 dB re 1.0 volt) ensure a tremendous dynamic range of 112 dB. With these capabilities, the A-4000 will provide extended headroom under even extreme operating conditions. One of the most critical concerns in modern amplifier design is the ability of the power amplifier to respond to the intense transients which are present in all musical programs. The speed of the A-4000, with a slewing rate of 50 V/,us, fully allows the dynamic impact of explosive transients to be reproduced with unstrained, undistorted accuracy. Under close inspection, the A-4000 reveals the care which has been used in the construction of this power amplifier. The Metron engineers have utilized only the finest audio signal processing electronics and components throughout the design. The precise step attenuation (1 dB increments) of the gain controls is positive and effortless. The oversized sample and hold peak reading meters which dominate the front panel provide a highly accurate indication of peak output of the amplifier, and are calibrated with a range of 50 dB. In all respects, the operation of the A-4000 reflects the sophistication of its design refinements. The circuitry of the A-4000 is housed in an attractive and rugged chassis designed with both the discriminating enthusiast and sound professional in mind. By incorporating main left and right amplifier sensors, thermostatically controlled forced air cooling, and a completely independent output protection circuit, the A-4000 will unconditionally protect itself and all associated speaker systems for the duration of any unsafe operating condition. Due to its rugged construction and the use of high grade components throughout, the performance lifetime of the A-4000 can be expected to be considerably longer than that of competitive units using conventional design techniques. To operate and hear this unique product is to experience the success of the Metron philosophy. The construction is refined and precise; the performance is the fullest expression of the enlightened listening experience in high power amplifier technology.
Power Amplifier Specifications Output Power 350 watts RMS at no more than .02 % THd into 8 ohms, 20 Hz-20 kHz (both channels driven, 120 VAC) Minimum power at clipping into 4 ohms 550 watts RMS Total Harmonic Distortion (THD) .02%; from 20 Hz-20 kHz at 250 mW to rated power output Intermodulation Distortion (IM) .02%; from 250 mW to rated output power using SMPTE method (4:1 ratio of 60 Hz, 7 kHz) Frequency Response - 3 dB 2.5 - 200 kHz, -1 dB 5 -100 kHz Signal to Noise Ratio (unweighted) greater than 110 dB Slewing Rate greater than 50 V/µs Damping Factor greater than 200 Input Sensitivity (nominal) 2.0 volts Input Impedance (nominal)10 k ohms Power Requirements 125 watts at idle (110-125 V AC or 220-250 VAC, 50-60 Hz) 1800 watts at maximum Cooling System temperature sensing two-speed fan Overload Protection a) low impedance electronic sensingcircuit limits output current below 2 ohms (VI limiters) b) thermal sensing of inadequate ventilation Loudspeaker Protection a) relay circuit disconnects loudspeakers when exposed to low frequency oscillations, excessive VI limiting, and plus or minus DC output b) a turn on/off sensing circuit prevents transients from reaching speaker outputs Dimensions 480 mm (W) x 200 mm (H) x 470 mm (D); 18.9" (W) X 7.87" (H )X 18.5" (D) Weight 38 kg, 79.38 lbs.