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The S-05 is a Class A stereo power amplifier that is thoroughly focused on the unique tone that can only be expressed by this model. It incorporates many of the development results of the flagship model "Grandioso M1X" to refine its overflowing driving power and pure performance.



Class A amplifiers are dense with little distortion. This general Class A characteristic alone does not begin to describe the S-05's appeal. Passionate and vivid colors, like a direct-heating tri-tube amplifier. The overwhelmingly high speed sound start-up, backed up by the abundant idling current. Powerful drive capability and open-ended dynamism.... Regardless of the amplification method, the S-05 is a new milestone in Class A amplifiers, a sincere pursuit of what an amplifier should be, and the culmination of ESOTERIC's commitment.



With the flagship Grandioso C1X/M1X, ESOTERIC has challenged the limits of fidelity in pre-power transmission and opened up new horizons. ESOTERIC's unique current transmission "ES-LINK Analog" is the ideal method for pre-power transmission, where signal levels are extremely low in actual use.

This Grandioso technology has been carried over to the S-05. Compared to conventional voltage transmission, ES-LINK Analog transmits approximately 100 times more current. Therefore, it is less susceptible to noise, and all the energy of the music is transmitted from the preamplifier to the power supply.

In addition, in principle, the output signal from the preamplifier and the input signal to the power amplifier are not affected by the impedance of the connecting cables, so the output signal from the preamplifier and the input signal to the power amplifier can be kept identical to each other to an extremely high degree.The power is so overwhelming that its size is unimaginable. The source of this power is ESOTERIC's carefully designed power supply. The power supply is the most important component in realizing a powerful and rich sound stage for the amplifier block, which always requires a large current for Class A operation.

Thanks to ESOTERIC's unique power supply design, the S-05 boasts dynamic musical expression that transcends its size. Bare mount over-sized power transformerThe S-05 uses the maximum capacity that can be installed (940VA EI core transformer). By using a transformer with a much larger capacity than the original product performance, the S-05 is able to follow dynamic changes in current supply extremely well, resulting in a dynamic and open sound.

The suppression of transformer vibration also results in the suppression of current flow. For this reason, the transformer is bare-mounted without a case.Power rectification circuit with dual mono configurationUnless the sound source is monaural, the left and right music signals are different. The power rectification circuits are not shared by the left and right channels, but are dual mono circuits, which avoid mutual interference between the left and right channels, resulting in clear channel separation and resolution. Multiple block capacitors in parallelIn the S-05, the rectification system also incorporates the special attention that is unique to this model. The block capacitors are Grandioso grade high quality custom capacitors. Dual mono and parallel configuration of four 10,000μF capacitors per channel is used. The rectification operation is time-delayed in parallel to stabilize charge and release, thereby ensuring a large current supply required for Class A operation at all times. Therefore, it can faithfully and agilely follow the dramatic changes in the music signal and fully express its dynamism. Low impedance designCritical wiring from the primary side to the power supply section, drive stage, etc., is bolted with extra thick cables. The response of the power supply is maximized by ensuring a low impedance.


  • Manufacturer's Description

    Speaker output  
    Rated output power 30W + 30W (8Ω, Class-A)
    60W + 60W (4Ω)
    120W (BTL mode, 8Ω)
    Compatible Speaker Impedance 4Ω to 16Ω
    8Ω to 16Ω (BTL mode)
    Analog audio inputs  
    ESL-A 1 pair
    XLR 1 pair
    RCA 1 pair
    Power consumption 245W (210W at no signal)
    External dimensions (W×H×D)  445 × 191 × 444mm
    17-½" × 7-½" × 17-½" (including protrusions)
    Weight 30.7kg / 67-¾ lb

    UK Shipping: 

    APC Overnight (up to 30kg). The premium Next Day service is upgraded on request to 12 noon delivery / SECURITY / Saturday and various options. We have found APC to be a reliable, courteous and predictable service.


    Europe, EC, and abroad: 

    For every despatch we use a professional broker to organize the fastest and highest quality shippers, and we normally use DHL or UPS depending on territory. Our broker monitors the documentation and Customs Clearance carried out by these two reliable carriers.

    Above 30kg: 

    For UK and overseas we use pallet shipping which is a professional service and avoids risks of mishandling and loss. It is not expensive under our contractors and worth a quote.


    The Music Room enjoys a 40-year tradition of customer care and at time of writing, full 5-star Google reviews. In addition UK customers enjoy the legal rights of mail order and distant selling. 

    We have exported happily for many years and most probably have happy customers in your country who will confirm our reliability and refund in the event of mishaps. 

    Refunds can only be made by the same payment form and to the same account to avoid possible fraud or money laundering.

  • The Music Room price matching...

    The Music Room price matching...

    We are an official Esoteric dealer and offer the best UK prices. If you have seen this product cheaper elsewhere, Let us know; we will match or beat any price.

"See us at the NorthWest Audio Show, 22-23 June 2024" 
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