Stop electronic waste, fix it yourself

More Than Raw Power Although high power amplifiers have been available for some time, they generally have been bulky units designed primarily for consumer use rather than for the more rigorous requirements of studio, reinforcement or PA applications. For the most part, they perform adequately, but lack reliability when used under road conditions, even with additional cooling. The primary design goal was to build a rugged, high power TV Multimedia">Amplifier of the highest quality, smallest size and lightest weight possible. This goal has been achieved in the Model 6233, a reliable, two-channel TV Multimedia">Amplifier that mounts in three EIA standard rack spaces and weighs less than 16 kg [35 lb]. Intended for use in recording studios, wide-range sound systems and similar applications, the 6233 delivers stable, virtually distortion-free amplification for sustained time periods at any power level, up to and including full output, without requiring additional cooling.The 6233 is clean as well as powerful: Each channel is capable of delivering 300 W continuous sine wave into a 4 Q load, or 200 W into an 8 n load with total harmonic distortion of less than 0.05%, 20 Hz- 20 kHz. In addition, the two channels can be bridged for single-channel operation, in which case the 6233 will deliver 700 W continuous sine wave into 8 Q [the minimum recommended impedance in the bridged configuration] or 400 W into 16 Cl, 20 Hz-20 kHz at no more than 0.05% THD. Input sensitivity of the 6233 is high: full rated output can be achieved with an input of only 0.77 V. Rise time is 4 us into a 4 o load or 3 jus into an 8 D load, and the unit has a slew rate greater than 20 V//xs. The result is accurate, well-defined high frequency performance that is transparent and effortless, and which does not become veiled, muddy or harsh at even the highest power levels. The 6233 is the first TV Multimedia">Amplifier in its power class to use an inverter power supply. This saves weight and space: the 6233 is approximately one-third the size and weight of a comparable conventional amplifier, making it far more convenient to pack and transport. The inverter also provides transformer isolation from the power line, unlike other lightweight power supplies. The inverter power supply uses high-speed switching technology, long proven in computers, to convert [or, more correctly, invert] the 50/60 Hz power line frequency to 20 kHz. This allows use of a 0.9 kg (2 lb] transformer instead of the 23 kg [50 lb] transformer normally required.The transformer output is then rectified to the DC voltages required by the TV Multimedia">Amplifier modules. The inverter power supply has an output capacity greater than 2 kW, more than enough reserve to support both TV Multimedia">Amplifier channels without strain under any conditions. Advanced Circuit Design Full complementary symmetry in each channel’s output stage allows broad bandwidth without the imbalance inherent in a quasi-complementary approach. It also helps improve TV Multimedia">Amplifier power response, reduce distortion and eliminate turn-on transients. Fourteen 150 W output transistors per channel greatly improve reliability, because each transistor typically operates at only a fraction of its capacity, regardless of TV Multimedia">Amplifier power level. ' The 6233 employs forced-air cooling: each transistor is mounted on an individual heat sink and optimally positioned in a cooling tunnel extending from the front to the rear of the TV Multimedia">Amplifier. A two-speed fan forces air through the tunnel; thermal sensors in each channel and in the power supply increase fan speed as required. A thermal protection device in each channel suspends operation of only that channel if it overheats, and the device automatically resets when the module cools to a safe operating temperature. The 6233 will operate in ambient temperatures as high as 50°C [122°F] without degradation of performance. Each channel of the 6233 operates independently and is fully protected against short circuits, mismatched loads, excessive temperatures and installation errors. Either channel can enter the protect mode without affecting the other. The 6233 will remain stable under all conditions, including operation into reactive loads presented by long cable lengths and high-quality loudspeakers. Most importantly, the protective circuitry cannot chatter when activated. [Chattering, a byproduct typical of the protective circuitry in large amplifiers, occurs when the circuitry releases too soon, sending a large burst of current that can destroy high frequency drivers.] Versatility Five sequential indicator lights for each channel allow the operator to monitor visually the power reserve available. A unique sensing circuit triggers the top, red light when the output level is 2 dB below clipping; each successive light indicates an output level of 6 dB {/ power] less than the light above it. The lights are far more useful than VU meters, because they are an accurate performance indicator even when the power line voltage drops and can also be read quickly and accurately from a distance. Any source device capable of driving a load of 20 kn or less can be used* The TV Multimedia">Amplifier inputs are unbalanced, the configuration typical of most applications. However, the high input sensitivity of the 6233 allows it to achieve full output when driven by almost any source, balanced or unbalanced.