M550 Mono Amplifier

Exploring New Dimensions
A new power device provides the foundation for an upgraded output stage. This new transistor, first used in the Relentless Mono Amplifier, extends high frequency response, increases power handling by a factor of four and features tighter tolerance gain matching between complementary NPN/PNP pairs. A wider safe operating area and superior gain linearity provides greater thermal stability throughout the amplifiers’ power delivery. Coupling the new output device to the high efficiency heat sink design affords an increase in operating bias. The higher bias specification has increased the Class A operating range of the Progression M550 to 70 watts. The result is improved instrument timbre and tonal reproduction for a great percentage of listening.

Maintained from the original amplifier is the Super Rail topology, a simple concept but complex in execution. Every amplifier employs a voltage rail, actually two, a positive one and its companion negative partner. Voltage rails support the delivery of power to the speaker. The music signal swings between these two rails but due to natural loss, the musical signal never reaches the output rails’ full capability. A Super Rail overcomes this limitation. Borrowing the idea of a turbo in a car engine, the Super Rail employs higher voltage rails in the sections prior to the output stage. This voltage “boost” allows the musical signal to exploit the full capability of the output voltage rails. Extending the musical signal swing closer to the output rails maximizes the performance of the output circuitry design itself. Nearly ideal output stage operation results with improved dynamics, lower distortion, and a fierce grip of the speaker. The output topology employs 48 power transistors anchored by a 2,000 VA power supply transformer and nearly 100,000 microfarads of power supply storage capacitance.

Legendary Purity
The anodized Aluminum faceplate includes the iconic look of the company’s power meters. The Progression M550 Mono Amplifier 180° meter needle is driven by a high-speed ballistic circuit improving the meter’s responsiveness. The longer needle arc covers the amplifier’s entire output range.

With innovative circuitry and virtually unlimited power output, the Progression M550 Mono Amplifiers deliver intimate musical details, three-dimensional sound staging, and startling dynamics not possible from less capable designs.