Design Features
•High efficiency Digital Power Processing output stage for cool operation
•Small signal analog processing
•> 800 watts short term continuous power output capability in Mono mode
•Optimized balanced and
•THD and IMD <0.01%
•Damping Factor >100
•High thermal stability in all stages
•Fully regulated, low noise supplies for all analog stages
•Audio Grade decoupling capacitors and resistors used throughout
•Soft clipping performance with uncompromised low level distortion performance
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•High efficiency for ‘green’ amplification
•Protection circuitry outside signal path
The eVo Digital Output Stage and Digital Power Processor
The Bel Canto Design eVo digital output stage is of unique simplicity. The output uses 2 N channel MOSFET switches which are switched between the power supply rails. These switches turn on and off within 30 billionths of a second and provide an on resistance path to the supply of less than 65 thousandths of an ohm. These switches switch alternately between the supplies at a rate over 600,000 cycles per second (600 kHz). When no audio signal is present, the ratio between the time at the positive supply and the negative is balanced to provide no audio frequency output. The switching stage is isolated from the loudspeaker by a single Inductor/Capacitor. This 80kHz
second order low pass filter is used to reject high frequency energy and optimize phase response – while preserving high frequency information.
Furthermore, the digital power processor adds small levels of high frequency dither to insure that an inherently linear output stage characteristic is maintained from very low to very high output levels. The audio frequency information modulates the output stage by changing the time relationship between the positive and negative supply rails. The critical timing information is controlled by the digital power processor and the effective switching frequency is changed over a 200 kHz to 1500 kHz range. This spreads the digital energy created by the amplifier over a wide bandwidth, greatly reducing the energy at any one frequency. This permits using a simple LC filter to remove the digital energy and maintains excellent phase response. Feedback is taken from the common node of the output switches before the LC filter and fed back to the digital power processor. This feedback is used to insure that any variations in the switching speed of each output device are compensated for, optimizing the linearity of the output stage.
Warm-Up
The eVo200.2’s sonic performance will start to stabilize after approximately forty (40) hours of continuous power up.
eVo200.2 Owner's Manual | Page 4 |
