The power supply rails maintain a constant voltage during audio peaks. Consequently, the peak power output of the AHB2 does not vary with line voltage or audio loading. This active regulation is much more effective than capacitive energy-storage. This control loop responds to audio-frequency load changes and keeps the supply voltage constant without the use of a large bank of capacitors. In contrast, the AHB2 uses a tightly regulated resonant switching power supply that includes a very fast control loop. These linear supplies are usually unregulated and the capacitors help to remove ripple produced by the audio and by the AC line.
Most high-quality power amplifiers have linear power supplies, large toroidal transformers, and large banks of energy-storage capacitors. The AHB2 rivals the efficiency of class-D amplifiers while exceeding the sonic performance of power-hungry class-A designs. These tracking rails significantly improve the overall efficiency of the amplifier while the error correction keeps distortion nearly nonexistent. The feed-forward error correction also allows the use of class-H tracking power supply rails without the usual distortion-performance penalty. The AHB2 only draws 12 W when idle, and less than 1/2 W in standby. The benefit of low bias current is that very little power is wasted as heat when the amplifier is idle. Benchmark has chosen to maintain a small bias current in the output stage, but this bias current is not critical to the distortion performance of the unit. The THX-patented feed-forward error correction used in the AHB2 is so effective that biasing of the class-AB bipolar output devices can be reduced to unusually low levels. High Efficiency - Green Never Sounded so Good! The feed-forward system virtually eliminates the errors that would have been produced by the output devices in the main amplifier. Like a class-A amplifier, the AHB2 shows no signs of crossover distortion. The correction amplifier actively drives the output while the main output devices transition between push and pull states.
The THX-AAA Technology includes an ultra-clean low-power error-correction amplifier that runs in parallel with the high-power main amplifier. In contrast, feed-forward networks can prevent errors before they occur. Feedback networks attempt to correct errors after they occur. Unfortunately, these feedback systems have a limited ability to reduce the abrupt transients that are caused by output device crossover transitions. Traditional class-AB designs attempt to control distortion through the use of feedback. The AHB2 Outperforms all Traditional Class-AB and Class-A Designs this improvement comes at the expense of high power consumption, poor damping, and limited output power. This eliminates the push-pull crossover region and this eliminates crossover distortion. In contrast, class-A amplifiers eliminate crossover distortion by keeping all output devices turned on at all times. This crossover distortion can be especially problematic at low playback levels. Traditional class-AB amplifiers generate crossover distortion every time the push-pull output stage crosses 0 volts. The THX-AAA Technology provides accurate cancellation of zero-crossing errors, exceeding the performance of the best class-A amplifier. The AHB2 has a bipolar class-AB output stage that delivers high output current and low noise. In contrast, the revolutionary AHB2 was specifically designed to deliver true high-resolution performance. Most power amplifiers are well matched to the limitations of the CD format, but they fall well short of the capabilities of high-resolution formats. Power amplifiers are a weak link in most audio systems.
The musical details and emotion captured on today's finest High-Resolution-Audio recordings can only be fully appreciated when every component in the signal chain is capable of true high-resolution performance.
#Benchmark ahb2 power amp full#
With the AHB2, you will discover previously overlooked nuances, dynamics, and detail in your favorite recordings and experience the full potential of the latest high-resolution 24-bit PCM and 1-bit DSD audio formats. The frequency response of the AHB2 extends beyond 200 kHz. The dynamic range of the AHB2 is 132 dB, making it 10 to 30 dB quieter than some of the very best reference-quality power amplifiers. Benchmark's AHB2 power amplifier delivers musical details without introducing the masking effects of amplifier noise and distortion. The AHB2 is the ideal match to the performance limits of High-Resolution-Audio (HRA) formats. From the first watt to the last watt, no audio power amplifier offers lower noise or lower distortion than the revolutionary amplifier Benchmark AHB2.
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