One result of the lavish attention given to the development of the F Series is the preamplifier's fully balanced configuration, which derives from our highly esteemed C Series preamplifier models. Impervious to noise, it delivers pure and powerful signal amplification at ultra-low impedance.

The one design feature of these amplifiers that most clearly reflects Grandioso thinking is their dual monaural configuration, which maintains complete left and right channel independence through all stages, from preamplifier to the power amplifier's final stage. As Esoteric integrated amplifiers, the major investments made in circuit construction expertise and materials developed over the years yield excellent channel separation and a measure of sound quality that transcends the class.

Playing a significant role in the F Series' balanced dual monaural configuration is the proprietary Quad Volume Control System (QVCS), which incorporates a total of four precision switched resistor ladder networks operating in unison to electronically and independently control the left and right channels and their positive and negative phases. This system helps maintain superb audio clarity, excellent channel separation and highly accurate phase characteristics. Further, by eliminating all volume control wiring on the audio board, the resulting shorter signal path minimizes deterioration of sound quality while realizing exceptionally low distortion.
* QVCS: Quad Volume Control System

As a countermeasure against noise, all control lines have been electronically separated from the main body of the preamplifier with the use of isolator elements integrated into the front panel.

Employing the same high-precision bearing mechanisms used in our Grandioso components, the F Series' volume control knobs and selector switches provide exceptionally smooth operation with an analog feel free of any mechanical play. Sparing no cost, all panel knobs are also custom-machined from solid aluminum.

The dual mono phonostage preamp (MM/MC) features independent left and right channel power sources and independent circuits.

The powerful headphone amp provides abundant output to effectively drive even difficult to power high-end high-impedance headphones.

Commitment to achieving all the quality associated with high-end components results in a balanced dual monaural configuration consisting of four circuits (L/R, -/+) for each band. This system enables users to adjust tone settings free of any concerns about sound quality deterioration. Shifting the variable band more than usual toward the high and low frequency ranges (14kHz/63Hz) permits fine adjustment of bass and treble without adversely affecting the original source signal. Fully electronic control also permits fine adjustment of up to ±12dB in 0.5dB steps. The middle band can also be utilized as a loudness preset when set to the minus side and used in conjunction with the Tone Bypass switch.

The power amplification section's front stage is balanced in line with the thinking behind our S Series separate amplifiers. Its low impedance and clean amplification further enhance the dynamic range.

The power supplies of the F Series feature large-core 940VA custom EI power transformers and 40,000µF block capacitors for each channel in a dual monaural configuration. Large-gauge cable is used in all connections to help minimize impedance. As in our separate power amplifiers, this outstanding power section achieves a theoretically linear power output ranging from 120W at an 8Ω load to 240W at 4Ω for faithful reproduction of every musical dynamic.

Utilizing eight 1mm-thick bus bars formed of high-purity OFC, the speaker output section employs MOSFET switching with no mechanical contacts. Coils have also been eliminated from the output stage to minimize impedance and enhance drive capability.

Featured in Grandioso models up to and including the M1, large bipolar LAPT* transistors deliver an outstanding continuous current capacity of 17A, and 34A of instantaneous peak power. Their superior high frequency characteristics also play a critical role in the accurate reproduction of the most delicate tones.
* LAPT: Linear Amplified Power Transistor

Derived from our flagship Grandioso line, the F Series' amplifier modules feature a three-stage Darlington configuration that utilizes three parallel push-pull sections to faithfully bring out the superb high-frequency characteristics of their LAPT transistors. Proprietary LIDSC* circuitry reduces the drive section's second stage to final stage output impedance, achieving loudspeaker drive capability nearly equal to that of our separate amplifiers. NFB has also been minimized to realize a more natural sound quality brimming with life.
* LIDSC: Low Impedance Drive Stage Coupling

The F-Series' 3D Optimized Chassis features robust construction that gives each circuit block its own dedicated compartment. Interference between circuits is effectively minimized while achieving the shortest possible cable routing. Chassis exteriors are formed of thick aluminum panels manufactured without compromise following the same design philosophy imbued in Esoteric's separate amplifiers. As a result, their heavy-duty construction tips the scales at a total weight of 32kg, exceptional among integrated models. The machined steel insulators support the F-05 at four points in order to minimize the negative effects of vibration.

The preamplifier and power amplifier sections of the F Series boast the same degree of refinement as Esoteric's separates, and can both be used as standalone devices, or even disabled if not in use. The PRE-out employs a powerful buffer amplifier, while XLR outputs achieve a highly effective fully balanced configuration. System upgrades can also be performed with no compromises in quality, and an optional board slot facilitates the installation of an optional board, such as OP-DAC1 D/A Converter Board or OP-ESLA1 ES-Link Analog Input Board.