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PS Audio S300 Amplifier
From the deepest bass to the warmest, sweetest highs, the Stellar S300 makes any loudspeaker sing and is our most affordable stereo power amplifier ever.
Breathe new life into your loudspeakers with the Stellar S300, a full-sized, affordable stereo power amplifier that honors the music and controls your loudspeakers better than you ever imagined possible. The S300 combines the slam, linearity, and toe-tapping pacing of a Class D output stage with the warmth, grace, and rich inner detail of Stellar's Class A Analog Cell. The results are nothing short of ground breaking. Liberate a wealth of untapped energy trapped in your media library. Plumb music’s subterranean depths and finally hear the bass your speakers were capable of. Revel in rich layers of fine, full detail. Marvel at the deep, extraordinary, wall-to-wall soundstage. Effortless. Lush. Stellar.
Design
The Stellar S300 stereo power amplifier is a dual mono power amplifier capable of effortlessly driving demanding loudspeaker loads to concert levels. It combines the best of two worlds: ultra linear, high-current, Class D technology for the output stage; a discrete, Class A MOSFET based Analog Cell for the all-important input stage. The S300's rich, warm, and engaging sonic character comes from the Analog Cell. It's powerful, authoritative control over the loudspeaker stems from its high current, ultra-low impedance Class D output stage.
Application
The perfect choice for just about any loudspeaker, the S300 slips into any system, surprising and delighting even the most discriminating Audiophile. Rated at 140 watts per channel into 8Ω and 300 watts per channel into 4Ω, the S300 has plenty of horsepower for even the most demanding loudspeakers. Your musical library will open up in ways you might not have thought possible, revealing nuance and detail covered up by traditional amplifiers.
Technology
The S300 is an extraordinarily musical power amplifier rated at 140 Watts per channel into 8Ω and 300 Watts per channel into 4Ω. Power enough for even the most demanding speakers. The S300 design marries the best of two worlds: an ultra linear high-current output power stage with a discrete Class A MOSFET based AnalogCell input stage. Between them, the S300 delivers powerful, authoritative control over the loudspeakers, while maintaining a perfectly layered soundstage under the most complex musical passages. Designed by PS Audio engineer Darren Myers, who invested hundreds of hours of tuning, voicing, and perfectionist tweaking, the results are extraordinarily musical. Stellar amplifiers never draw attention to themselves, and are one of our highest value offerings in amplification, a rare quality in amplifiers of any price.
The connection between preamplifier and power amplifier is critical, for it is at this junction where most essential musical details are easily lost. Nothing in the design of a power amplifier is more important than its input stage when preserving music's finest nuances. In the S300, a unique topology, called the Analog Cell, has been employed to preserve the rich details found in music. The Analog Cell is the heart of the S300's musicality, where rich overlaid layers of music's inner details are preserved even in the most complex orchestral crescendos. The Analog Cell is a proprietary, fully differential, zero feedback, discrete, Class A MOSFET circuit, hand-tuned to capture the smallest micro dynamics without sacrificing the loudest macro dynamics music has to offer. The Analog Cell makes all the difference.
The Stellar S300 is a dual mono design. This means that each channel has its own, separate power supply. Each of the two channels is a complete and independent power supply and power amplification stage, based on a modern Class D ICE module, designed in Denmark. Class D output stages provide near-perfect linearity, low distortion, and high efficiency. Because Class D amplifiers require an output filter to remove their switching noise, they do not have frequency extremes into the many hundreds of thousands of Hertz. Depending on their design, modern Class D amplifiers, like the type used in Stellar, extend high frequencies to about 50kHz. Human hearing limitations are 20kHz, though most listeners rarely have hearing exceeding half that. The S300 provides excellent frequency extremes, low distortion, high efficiency, high damping factor, and a powerful output of 300 watts per channel into the most common loudspeaker loads of 4Ω.
Features
STEREO POWER AMPLIFIER
DUAL MONO WITH SEPARATE POWER SUPPLIES
POWERFUL MOSFET OUTPUT STAGE
RCA SINGLE-ENDED INPUT
XLR "TRUE" BALANCED INPUT
140 WATTS PER CHANNEL 8Ω
300 WATTS PER CHANNEL 4Ω
2Ω STABLE
VERY LITTLE HEAT PRODUCTION
< 0.1% THD 20Hz - 20kHz AT RATED POWER
DAMPING FACTOR > 550
FRONT PANEL STANDBY BUTTON
ZERO-LOSS INPUT
DUAL, COPPER, PLATED, OUTPUT BINDING POSTS
13 LBS.
INPUT 12 VOLT TRIGGER
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PS Audio S300 Amplifier
The PS Audio S300 pairs a Class A Analog Cell input with a Class D output stage to deliver a remarkably fast, neutral, and powerful presentation. Reviewers at Bob Barrett found the amp consistently ready for dynamic swings, reproducing lifelike vocals and instrument timbre without coloration. Its transient authority and high damping factor give tight, punchy bass and strong control at high volumes, while imaging and detail retrieval keep recordings sounding alive.
Built from a thick, rolled-aluminum chassis with custom-milled terminals and both RCA and XLR inputs, the S300 feels premium despite its modest 13 lb weight. Ideal for listeners moving from receivers to separates in small-to-medium rooms, it stands out as an excellent value—high performance and solid build with a transferable three-year warranty.
Pros
- Hybrid Class A input + Class D output yields exceptional transient speed and musical neutrality, letting vocals and timbres remain lifelike.
- High damping factor and robust headroom produce tight, punchy bass and reliable control even at loud listening levels.
- Premium fit-and-finish with thick rolled-aluminum chassis, custom-milled speaker terminals, balanced/unbalanced inputs and a transferable three-year warranty—strong build and value proposition.
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Cons
- No Line Out for daisy-chaining a second amplifier or driving a second room; limits some multi-room or multi-amp workflows.
- Cannot be bridged to create monoblocks, so scaling power requires buying separate monoblock models rather than bridging the S300.
- Rated power may be modest for very large, inefficient loudspeakers in very large rooms—some users could prefer higher continuous power.
Sound Quality
91/100
Dynamics
92/100
Hybrid Class A input with Class D output plus robust power (140W/8Ω, 300W/4Ω and stable into 2Ω) yields exceptional transient authority and headroom. Reviewer: "I never felt like the amplifier was struggling to keep up...always ready to respond instantly" and praised its "firm grip on the bass" and high damping factor; that language supports an exceptional dynamics rating for this power/output class.
Soundstage Imaging
88/100
The amp is reported to let recordings "come alive" and to reveal detail and scale, preserving imaging and spatial cues even during dynamic passages. The reviewer’s positive comments about lifelike presentation and detail retrieval justify a strong imaging score.
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Build Quality
89/100
Solid fit-and-finish: thick rolled aluminum chassis, custom-milled speaker terminals and a premium feel despite modest weight (13 lb). Stereo chassis (not monoblocks) but well executed construction and quality parts (nickel-plated copper binding posts, robust chassis) merit a high build rating.
Value for Money
92/100
Reviewer repeatedly calls the S300 "affordable," a "very worthy point of entry into the world of high-end separates," and a "terrific performer and an affordable option" — strong positive value language. With 140W/8Ω and 300W/4Ω performance, high damping factors, and premium build + 3-year warranty, the amp is framed as excellent value versus stepping up from a receiver/integrated, justifying a high value score despite the absence of an explicit MSRP in the provided data.
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