Esoteric Grandioso S1X Stereo Amplifier

Robust driving power worthy of a flagship. The source of this power is Esoteric’s dedicated power supply unit. For amplifiers that constantly require high current for Class-A operation, the power supply is the most key component to achieve a powerful and rich sound stage. Thanks to Esoteric’s unique power supply design, the S1X boasts an extremely dynamic musical expression with great precision.

The S1X employs the largest toroidal transformers that the S1X chassis can accommodate. The transformers performance, with a much larger size than the size required for actual use, allows for extremely high follow-through to dynamic changes in current supply, resulting in a dynamic and open sound. Also, suppressing transformer vibration results in limiting current flow. For this reason, the S1X dares to employ a bare mounting with the transformer’s metal cover removed.

The S1X’s high resolution sound is also a major feature, allowing the delicate tones of each instrument to be heard clearly, even at the climax of a full orchestra performance. A power supply section dedicated to the pre-drive stage (voltage amplification stage), which handles low-level signals from the preamplifier, eliminates the influence of the main drive stage, which has large current fluctuations, and improves resolution.
In addition to the two power transformers for the main drive and pre-drive stages, an R-core power transformer for control is installed in a three-transformer configuration to create a pure power supply with thoroughly low noise.

Unless it is a monaural source, the left and right music signals are different. The power rectification circuits are designed in dual mono configuration, not shared by both channels, to avoid mutual interference and achieve clear channel separation and resolution.

The rectification system also incorporates Grandioso’s unique and thorough attention to detail. The Grandioso custom capacitors are employed for the rectifier circuits, while the dual mono and parallel configuration of 6 x 10,000μF per channel ensures the high current supply required for Class-A operation at all times. Therefore, the S1X follows the dramatic changes in musical signals with agility and express dynamism to the fullest extent.

Key wiring sections such as from the primary side to the power supply section, drive stage, etc. employ over-sized pure copper busbars and ultra-thick gauge cables with bolted connections. The low impedance design maximizes the response of the power supply circuits.

In general, a Class-A amplifiers generate a lot of heat, and internal temperature stability is extremely important. For this reason, the S1X optimizes the position and circuitry of the temperature compensation circuit to stabilize the temperature of the entire amplifier block. This contributes to high quality sound because it speeds up the stabilization of the idling current after power-on and allows the amplifier elements to operate with their best characteristics.
The phase compensation circuit is a simple 1-pole configuration, and the final stage is coil-less, while the NFB (negative feedback) is kept to a minimum to enhance the dynamism of the music. The minimalist circuit philosophy allows the harmonics (overtones) that are most important to music, but are easily lost, to be retained and rendered expressively.

Despite the simplicity of the circuit, the S1X has been designed to eliminate any compromise in the quality of reproduction by using a dual monaural configuration from the input stage to the final stage. The components are among the largest in their class, and the board pattern, which employs a 105µm thick copper foil in key components, and ultra-thick gauge cables with connector connections eliminated as much as possible, are full of the boldness and power that is typical of amplifiers. Particularly, the seven busbars in the drive stage are made of luxurious 1.0 mm thick high-purity OFC material, and MOS FET switches without mechanical contacts are employed in the speaker output stage. The reduction in internal impedance provides a powerful grip even on woofers with larger diameters, and the driving force reaches the low-frequency limit point with ease.

The S1X is not only a powerful unit, but one that also delicately creates a gradation between climax and silence. The audio signal is received by a newly designed balanced input amplifier circuit independent of each input stage and transmitted to the amplification stage in a balanced configuration to ensure noise-free and stable amplification. FET switches are also employed for all switching positions in the audio signal path, including input switching, to minimize tonal coloration. Carefully selected high-quality components, such as the IDM-01 (Integrated Discrete-Amplifier Module) developed for the C1X preamp, accentuate the texture of the tones.

The Grandioso S1X behaves not only as a stand-alone stereo power amplifier, but also offers flexibly in a variety of high-end-worthy applications. The system is expandable to a mono-block amplifier by deploying two S1Xs, depending on the matched speakers and the operating environment. A mode selector supports conventional stereo mode and bi-amp mode for multi-way speakers with separate HF/LF inputs. You can freely customize the configuration of the Class-A amplifier system of your dreams according to the quality and characteristics of the sound you desire. Even if you use multiple amplifiers, the power on/off is controllable from the Grandioso C1X preamplifier via DC trigger*, allowing sophisticated use suitable for high-end applications.
*3.5mm monaural mini plug cable for connection is sold separately. Please prepare a cable of the appropriate length for your environment.