Dan D’Agostino Progression S350 Stereo Amplifier
“The Progression S350 Stereo Amplifier adds a potent stereo option to the Progression family. Leveraging our innovative Super Rail circuitry, the Progression S350 Stereo Amplifier exploits this unique technology delivering remarkable control and fidelity to any connected loudspeaker.
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. Our 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. The result is improved dynamics, lower distortion, and a fierce grip of the speaker.
Abundant power is required for realistic sound quality and is a cornerstone of Dan D’Agostino Master Audio Systems’ amplifier design. The Progression Stereo continues this practice. A graceful anodized Aluminum chassis houses a 2,000 VA power supply transformer coupled to nearly 100,000 microfarads of power supply storage capacitance. Paired to this foundation is a fully complementary driver stage, and output circuitry outfitted with 48 power transistors – 24 each for the left and right channels generating an imposing output. Initially used in the Relentless Mono, the output power device provides the foundation for an upgraded output stage. This transistor extends high frequency response, increases power handling 50%, 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. Higher operating bias lowers crossover distortion improving instrument timbre and tonal reproduction. The Progression Stereo delivers 350 Watts into 8 Ohms and delivers 700 Watts into 4 Ohms, and properly doubles its output again into 2 Ohms, with a 1,400 Watt power output. The essence of live music, dynamic contrasts, are faithfully reproduced with leading edge transients spectacularly depicted.
Inspired by the elegant faces of classic Swiss watches, the Progression S350 Stereo is fronted by an exposed movement power meter. Featuring two 90° needle swing arms, a high-speed ballistic circuit enhances the meter’s responsiveness. Longer swing arms improve readability across the amplifier’s entire output range.
Drawn directly from the Relentless Mono Amplifier, each heatsink is milled from a single, 48.5-pound (22-kilogram) aluminum billet slab. This highly efficient elliptical form dramatically improves the cooling ability of the design and assures that the Progression S350 Stereo Amplifier runs safely and reliably even when delivering its full-rated power. Standard finishes include silver and black with custom painted finishes available on request.
Combining innovative circuitry and significant power, the Progression S350 Stereo amplifier provides loudspeakers the control element they need to achieve their full design expression.”