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The PS Audio PMG Signature S400 Stereo Power Amplifier brings the performance and engineering philosophy of the PMG Signature Series into a powerful, space-efficient stereo chassis. Designed for audiophiles who want reference-level amplification without the complexity of separate monoblock power amplifiers, the S400 delivers 200 watts per channel into 8 ohms and up to 400 watts per channel into 4 ohms.
Designed by Darren Myers and engineered by Bob Stadtherr, the S400 combines an advanced active power supply, exceptionally low overall feedback, ultra-wide bandwidth and high-speed circuitry with 5 watts of pure Class A bias per channel. The result is an amplifier engineered to deliver exceptional transparency, control, dynamics and musical detail while remaining remarkably unobtrusive within a high-end system.
The PS Audio PMG Signature S400 Stereo Power Amplifier is available for demonstration in our Hull store by request.
For more information, please contact our Fanthorpes HiFi team or visit us in store for an audition.
The S400 combines the core engineering principles of the PMG Signature Series with the convenience of a single stereo chassis, making it an excellent choice for audiophiles seeking reference-quality amplification without the additional space and cabling required by monoblock amplifiers.
The PS Audio PMG Signature S400 is built around the same core PMG Signature principles found throughout the range, placing two complete amplifier channels into a single chassis. Each channel has a carefully engineered signal path and power delivery, helping minimise interaction between the left and right channels even when demanding music places heavy instantaneous demands on the amplifier.
Delivering 200 watts per channel into 8 ohms and doubling to 400 watts per channel into 4 ohms, the PS Audio PMG Signature S400 provides the current capability and headroom required to drive a wide range of demanding high-end loudspeakers. This substantial power delivery provides excellent control during complex musical passages and demanding dynamic peaks, making the S400 ideally suited to serious two-channel systems.
A key feature of the S400 is its 5 watts of pure Class A operation per channel. Class A amplification keeps the output devices continuously conducting through the waveform, avoiding the crossover behaviour associated with conventional Class AB designs. This is particularly valuable at lower listening levels, where subtle musical information such as instrumental textures, vocal nuances, ambience and natural note decay can be reproduced with exceptional delicacy and continuity.
At the heart of the PS Audio PMG Signature S400 is an advanced active power supply architecture designed to provide stable, responsive power to both amplifier channels. Sudden bass transients, orchestral crescendos and large dynamic swings can place considerable demands on an amplifier, so the S400 is engineered to maintain a stable supply under these conditions, helping preserve channel separation, dynamics and control when the music becomes complex and demanding.
The S400's exceptionally wide bandwidth extends beyond 500kHz, while its slew rate exceeds 200 volts per microsecond. This high-speed amplifier architecture is designed to reproduce rapid changes in the musical waveform with exceptional accuracy, contributing to clean and precise transient reproduction. From the initial attack of percussion to the leading edge of plucked strings and the complex harmonics of acoustic instruments, the S400 is designed to preserve the speed and detail present in the recording.
Rather than relying heavily on global negative feedback to correct distortion, the PS Audio PMG Signature S400 uses a highly linear amplifier topology with strikingly low overall feedback. PS Audio's design philosophy is to achieve as much linearity as possible through the amplifier's fundamental circuit design, helping preserve the immediacy, timing and natural character of music while maintaining low distortion across the audible frequency range.
The S400 is engineered for flat, low distortion across the audible band, allowing the character of the recording and associated components to come through without imposing an obvious sonic signature of its own. The combination of low distortion, ultra-wide bandwidth, high slew rate and low feedback is designed to produce an open and transparent presentation with precise transient response and convincing spatial information.
Instead of accommodating two monoblock amplifiers, two power cables and two separate chassis, the S400 provides two high-performance PMG Signature channels in one amplifier. This makes it an attractive choice for listeners who want the performance of high-end amplification while maintaining a cleaner and simpler system. Its single-chassis design is particularly useful where rack space is limited, while its substantial power output makes it suitable for serious two-channel systems.
The PS Audio PMG Signature S400 is designed by Darren Myers, engineered by Bob Stadtherr and hand-built in Boulder, Colorado. Every aspect of the amplifier reflects PS Audio's focus on high-performance analogue amplification, from its sophisticated power supply and high-speed circuitry to its carefully considered internal layout and construction.
As you would expect from Fanthorpes HiFi, we offer a generous part exchange against the PS Audio PMG Signature S400 Stereo Power Amplifier. If you have any HiFi that you wish to use as part payment, either call us on 01482 223096 or email us at shop@fanthorpes.co.uk, and we will give you a price to change. This is a fantastic and hassle-free way of making the PS Audio PMG Signature S400 more affordable.
Fanthorpes HiFi can also offer buy now pay later on the PS Audio PMG Signature S400 Stereo Power Amplifier, allowing you to spread or defer your payments over a year. If you are interested in taking advantage of our payment terms, email shop@fanthorpes.co.uk or call us on 01482 223096, and we will email an application form to you.
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