PWM Output Stages
Basically our new E-series amplifiers are what are known as PWM output stages (PWM = Pulse Width Modulation), with a modulator of analogue construction. Our switching output stages have been developed entirely in-house, and are far removed from ready-made “off the shelf” integrated IC amplifiers; instead the output stages are of discrete construction, equipped with the very latest, ultra-fast MOSFET transistors and intelligent driver moodules with high current capacity.
The output stages feature analogue negative feedback, which smooths out the effect of voltage fluctuations in the mains power supply, thereby eliminating signal distortion induced by the power supply voltage; this is an otherwise unavoidable problem in pure “forward concept” circuit designs. However, the negative feedback is relatively weak and frequency-dependent (more pronounced in the bass, where large currents are present, and diminishing in the mid-range / treble). The result is a very controlled, open sound image which never tends towards harshness, characterized by perfectly contoured and well defined bass. The lively, musical nature of this design philosophy is unique.
Switched output stages – if correctly designed – can sound simply wonderful as well as generating tremendous power combined with significantly reduced losses and minimal waste heat.
A particularly important factor in the circuit design is a power supply which is stable under load and capable of delivering high currents. This is necessary in order to deliver energy reliably to the output stages, and not collapse even when the power requirement and peak signals are very large.