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ESOTERIC S-03 Stereo Power Amplifier
S-03 Stereo Power Amplifier
Grandioso Lineage Representing the next generation in a proud lineage of audio excellence, the C-02X Stereo Linestage Preamplifier and S-03 Stereo Power Amplifier feature state-of-the-art circuitry in a discrete dual mono configuration that dramatically conveys all the power and energy of music. Assembled one at a time in Esoteric's Tokyo factory and  incorporating all the knowledge and technology of the flagship Grandioso line, these two new models accentuate the refined qualities of audio reproduction with expert craftsmanship and handmade precision.

Best Buy Components 2018->2019    Stereo Sound "Best Buy Components 2018->2019"
Power amplifier category (500,000 - 1,000,000Yen)
HiVi "Best Buy 2018 Winter"    HiVi "Best Buy 2018 Winter"
Power amprifier II (500,000 - 1,000,000Yen)
The fourth prize
Stereo "Best Buy Component 2018"    Stereo "Best Buy Component 2018"
Power amplifier category (550,000 - 1,200,000Yen)
The third prize
HiVi "Best Buy 2018 Summer"    HiVi "Best Buy 2018 Summer"
Power amprifier II (500,000 - 1,000,000Yen)
The third prize
Best Buy Components 2017->2018    Stereo Sound "Best Buy Components 2017->2018"
Power amplifier category (500,000 - 1,000,000Yen)
HiVi "Best Buy 2017 Winter"    HiVi "Best Buy 2017 Winter"
Power amprifier II (500,000 - 1,000,000Yen)
The fifth prize
HiVi "Best Buy 2017 Summer"    HiVi "Best Buy 2017 Summer"
Power amprifier II (500,000 - 1,000,000Yen)
The fifth prize

  • Stereo "Best Buy Component 2017"
    Power amplifier category (550,000 - 1,200,000Yen)
    The second prize

Best Buy Components 2016->2017    Stereo Sound "Best Buy Components 2016->2017"
Power amplifier category (500,000 - 1,000,000Yen)
HiVi "Best Buy 2016 Winter"    HiVi "Best Buy 2016 Winter"
Power amplifier category (above 500,000Yen)
Ongen Publishing "Visual Grand-Prix 2017"    Ongen Publishing "Visual Grand-Prix 2017"
Power amplifier category (500,000 - 1,000,000Yen)

  • Stereo "Best Buy Component 2016"
    Power amplifier category (550,000 - 1,200,000Yen)
    The second prize

Ongen Publishing "Visual Grand-Prix 2016 Summer"    Ongen Publishing "Visual Grand-Prix 2016 Summer"
Power amplifier category (above 500,000Yen)
Ongen Publishing "Audio Excellence Award 2016" Silver Prize    Ongen Publishing "Audio Excellence Award 2016"
"Silver Prize"
Stereo Sound "Best Buy Components"    Stereo Sound "Best Buy Components"
Power amplifier category (500,000 - 1,000,000Yen)
The third prize
Ongen Publishing "Visual Grand-Prix 2016"    Ongen Publishing "Visual Grand-Prix 2016"
Power amplifier category (below 1,000,000Yen)

Concealing the overwhelming potential of Esoteric's premier Monoblock M1, and Stereo S1 and S-02 amplifiers, the S-03 inherits all the knowledge and technology embodied in the core principles of Esoteric power amplifier development, and expands the scope of Grandioso lineage into new realms of listening enjoyment. Offering a range of power and dynamism comparable to the finest high-end components, the S-03 imbues music with ever more vivid sensations of being truly live.

Master Sound Works

Audio expression, symphonic beauty, artistic passion, the concert hall's spatial feel, the excitement of the audience. Esoteric's Master Sound Works is an audio product concept that recreates all of the music information in original master recordings with the most state-of-the-art technology available today.


S-03 / C-02X

The Sound of Life Unleashed - High Power Creates Spaciousness and Dynamism

The indescribable feeling of spaciousness that comes when sound is unleashed -and the sense that the music you're hearing is truly live- can only be generated by amplifiers that offer abundant power to properly drive the loudspeakers. Esoteric's amplifiers use the finest components and massive power supplies to achieve the high output power this demands. The new S-03 Power Amplifier extends the legacy of Esoteric's premier Grandiose M1, setting free every nuance of sound, and imparting to music all the vibrancy and richness of life.

Exceptional Power Linearity for Outstanding Dynamics

Loudspeaker impedance can vary widely depending on the frequencies being reproduced. The fast attack of deep bass imposes demanding loads on an amplifier, requiring not only continuous high power output, but also repeated bursts of peak power. Unless the amplifier's power supply is capable of consistently meeting these demands, musical dynamics will be compromised. The S-03's generous power supply capacity enables this nominally rated 145W into 8 ohms amplifier to deliver an impressive 580W into 2 ohms - a testament to the linearity of a power supply that faithfully reproduces the full spectrum of sound dynamics at all volume levels.

2x2 Dual Mono Power Supply Provides Stereo Output with Monoblock Thinking

The main feature differentiating Monoblock and stereo amplifiers is the configuration of their power supplies. In conventional stereo amplifier designs, one power supply is shared by both channels, since space and efficiency limitations tend to preclude a dual mono configuration. Starting with our flagship Grandioso models, Esoteric's stereo power amplifiers have consistently featured a unique 2x2 Dual Mono power supply design which separates the left and right channels of the front and drive stages into four independent dual mono sections. By isolating the power supplies for the front (voltage amplification) stage, which handles weaker input signal, from those for the drive (current amplification) stage, which much contend with huge current fluctuations, the S-03 effectively realizes more clearly focused details and breathtaking dynamics, even when driven to full capacity. Moreover, by optimizing this independent dual mono configuration-from the secondary windings of the transformers to the rectifier circuit-the S-03 is also able to achieve clear channel separation on par with the finest Monoblock amplifiers.

Power amplifier module Power amplifier module

Large-Capacity Custom Power Transformer - The Heart of the Finest Power Amplifiers

Large Bipolar LAPT Transistors Class -leading 2x2 dual mono power supplies are only capable of revealing their true worth by way of the investment of enormous resources. A robust power supply is critical to an amplifier's ability to deliver high power in a linear manner, and this is especially true for the power transformer. Therefore, particular attention was paid to material selection, core size and even the mounting of the S-03's custom-made EI-type power transformer. Popular among avid audiophiles, this transformer was selected for the full-bodied, high-quality bass it provides. To preserve sound purity, this large-core 940VA transformer features separate windings for left and right channels, and is securely mounted on a rigid, 5mm-thick steel base plate. Three parallel 4,700 F capacitors per channel shorten charge and discharge times, and provide a tighter, faster sound. Power supply wiring uses heavy-duty cables fitted with crimp terminals, which are tightly bolted together to reduce impedance to the lowest levels possible.

Breathtaking Speaker-Driving Power Ensures Accurate Damping for Large Woofers

Optimizing the S-03's loudspeaker drive capability required reducing the output impedance to an absolute minimum. To achieve this, a total of nine bus bars were used for each channel, while the output coil was eliminated. Strenuous efforts were also made to simplify the circuit design and widen its range, resulting in an exceptional damping factor of 1,000, considered a guideline for woofer drive capability. Even large-diameter woofers are provided with accurate damping for precise sound reproduction, giving an expansive feel across a wide range that reaches to even the lowest frequencies.

Balanced Input Stage Configuration Enables High-Clarity Signal Amplification

The S-03's audio input signal enters through discrete balanced input buffer amplifiers, and is relayed to the amplification stage by way of a balanced low-impedance signal path. An outstanding dynamic range is assured by clean, noise-free signal amplification that provides the fine sensitivity needed to reproduce nuanced gradations between musical crescendos and silence.

Large Bipolar LAPT Transistors Deliver 34 Amperes of Instantaneous Output Current

Large Bipolar LAPT Transistors The S-03's large bipolar LAPT* transistors are twice the size of more commonly used power transistors. They also boast an exceptional continuous current capacity of 17 amps and an instantaneous peak capacity of 34 amps. In addition, they offer superior high-frequency characteristics that contribute to accurate reproduction of subtle tonal qualities.
* LAPT=Linear Amplified Power Transistor

3-Stage Darlington Circuit with 5 Parallel Push-Pull Configuration

Large Bipolar LAPT Transistors The power amplifier module uses bipolar LAPT transistors in a threestage Darlington configuration with five parallel push-pull sections. To realize the superior high-frequency characteristics of these devices, a simplified amplifier circuit was developed to reduce the number of components and parallel elements.

LIDSC (Low Impedance Drive Stage Coupling) Provides Loudspeaker Drive Capability Approaching That of the M1

The S-03's unique LIDSC circuit reduces the drive section's second stage to final stage output impedance while enhancing current supply capability. This makes it possible to maximize amplitude within the available power supply voltage while reducing distortion, and so give this compact Stereo Power Amplifier a loudspeaker drive capability approaching that of the Monoblock M1.

Block diagram

Minimized Negative Feedback (NFB) For a More Energetic and Natural Sound

Simplifying the amplifier circuitry and reducing the previous stage's gain results in greatly reduced Negative Feedback (NFB) for a more natural and life-like sound.

High-Precision Chassis Construction Optimizes Vibration Suppression

Maintaining Esoteric's traditional dual-level configuration, the S-03's chassis features a 2mm-thick sheet steel internal framework that segregates circuit blocks into specialized compartments for the shortest signal path possible. This compartmentalized internal construction is built on a rigid base of 5mm-thick steel and enclosed by thick aluminum panels. Esoteric's original milled steel isolation feet provide structural rigidity, while eliminating resonances.

S-03 / C-03Xs

S-03 / C-03Xs

Rated power output 145W + 145W (8Ω)
290W + 290W (4Ω)
Maximum power output 580W + 580W (2Ω)
Frequency response 5Hz - 100kHz (+0dB, -3dB, 8Ω)
Signal-to-noise ratio (S/N) 115dB (IHF-A)
Total harmonic distortion 0.003% (1kHz, 8Ω, 145W)
Gain 29dB
Damping factor 1000
Analog audio input jacks RCA x 1 pair
XLR x 1 pair
Input impedance 22kΩ (RCA)
44kΩ (XLR)
Power supply 230V AC, 50Hz / 120V AC, 60Hz / 220V AC, 60Hz
Power consumption 440W (no signal: 160W)
External dimensions
(W x H x D)
445 x 221.5 x 476mm (17 5/8 x 8 3/4 x 18 3/4″)
(including protrusions)
Weight 48kg (105 7/8 lb)
Included accessories Power cord x 1 / Felt pads x 4 / Owner's manual x 1 / Warranty card x 1
- This product is made available in three different power supply variations, as shown in the chart above.
Make sure that the voltage shown on the rear panel matches the AC line voltage in your area.
- The shape of the AC inlet and plug of the supplied power cord depends on the voltage rating and destination country.
- Specifications and appearance are subject to change without notice.
- Weight and dimensions are approximate.

S-03 S-03 S-03
S-03 S-03 S-03

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