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Substantial Power Supply Comparable to a Separate Amplifier
The power supply is the most important component in realizing a rich sound stage for amplifiers that constantly require large amounts of current, and the F-01 boasts extremely dynamic musical expression thanks to a unique power supply design that incorporates a great deal of Esoteric's expertise.
Large Bare-Mount Power Supply Transformer
The F Series uses the largest EI transformer that can be installed. By using a transformer that is much larger than the product originally requires to meet its output power, the F Series is able to follow dynamic changes in the power supply extremely well, resulting in a dynamic and open sound. In addition, suppressing transformer vibration also suppresses current flow. For this reason, the transformer is bare-mounted without a housing.
Less is More
In the F Series, the signal path from the preamp to the power amplifier is as short as possible, and the bipolar transistor 3-parallel push-pull amplifier circuit is remarkably simple.
The phase compensation circuit is a minimal single-pole configuration, and the output stage is a coil-less design. By minimizing NFB (negative feedback), the circuit enhances the dynamics of the music. The minimalist circuit philosophy allows the harmonics (overtones), which are the most important but easily lost in the signal chain, to be preserved and the music to be reproduced like a real sound.
Amplifiers generate a lot of heat, and internal temperature stability is extremely important. For this reason, we have optimized the location and circuitry of the temperature compensation circuit to stabilize the temperature of the entire amplifier block. This helps to speed up the stabilization of the idle current after the power is turned on and allows the transistors to operate at their best performance.
Low Impedance
A 105μm thick-walled copper conductor is used for the substrate tracks, which are key to internal signal transmission quality. The eight bus bars in the power stage are luxuriously made of 1.0 mm high-purity OFC material. Important wiring from the primary side to the power supply section, drive stage, etc., is connected with ultra-thick cables with screw connections to eliminate connector losses. MOS FET switches without mechanical contacts are used in the speaker output section. Every detail has been carefully designed to reduce internal impedance. As a result, the amplifier is able to handle even large-diameter woofers, and has an excellent driveability (damping factor: 500) that easily reaches the limit of the low-frequency range.
Mechanical Perfection
To achieve the single design goal of "reproducing the master sound," the F-01 chassis optimally controls all vibrations that affect sound quality. The mechanical engineering of the F-01 is like that of a Formula 1 racing car, with the balance between rigidity and flexibility pushed to the limit. The heavy construction with a total mass of 32 kg, which is unprecedented for an integrated amplifier, shows the fullness and completeness of the product. The enclosure, which requires rigidity, makes extensive use of aluminum blocks to ensure non-resonance. On the other hand, the top panel has a semi-floating structure for an open sound. Esoteric's unique patented isolation foot, which integrates a spike and a saucer, also has a special structure to reduce mechanical stress. In addition, the large heat sinks of the amplifier block have a unique wave shape that disperses the peak resonance of the fins.
Flexible System Upgradability
Achieving a level of perfection in the separate amplifier class, the F Series can be used in a variety of system upgrades that go beyond the limits of an integrated amplifier.
By connecting the S-05 class A amplifier to the pre-outputs (XLR/ES-Link Analog), a multi-amplifier system can be built. To improve the quality of the preamp, an external power supply, the PS-01F, can be added.
There is also a slot for adding an option board. Two option boards for the previous generation F Series models (DAC board OP-DAC1 and ES-Link Analog input board OP-ESLA1) are compatible with this slot.
Other Features
Independently adjustable input gains (±18dB; 0.1dB steps)
L/R channel balance (0.1dB steps)
AV through output (volume bypass) ensures seamless coexistence with AV systems
Aluminum body remote controller (RC-1339) can also be used to operate Esoteric's SACD players and network players
Displayed source device names can be programed
Mute, dimmer and automatic display-off functions
Control functions (RS-232C, trigger input / output)