Esoteric F-07: Compact and powerful integrated amplifier

The smallest of the Esoteric F-Series integrated amplifiers, the F-07, unlike the F-05, has slightly less output power (100 watts into 8 ohms), is equipped with two tone controls instead of three, and only one balanced input on XLR connectors. The Esoteric F-07 also operates in Class AB, has conventional steel chassis supports, but weighs less than the F-05 and is more affordable. The Dual Monaural design most clearly reflects the philosophy of the Grandioso Series, maintaining the left and right channels completely independent at all stages, from the input to the power stages. Like other Esoteric integrated amplifiers, major investments have been made in circuitry and materials developed over many years, which has allowed it to achieve excellent channel separation and such high sound quality that it surpasses everything else in its class.

Esoteric-QVCS: The F Series’ dual-mono design is centered around the proprietary Quad Volume Control System (QVCS), which uses four precision resistor networks that switch synchronously when the volume knob is turned. This provides superb clarity, excellent channel separation and extremely accurate phase response. Additionally, by eliminating all volume control wiring from the audio circuit board, the shortest signal paths are ensured, extremely low distortion and minimizing sound degradation.  Ultra-low-noise control circuitry: All control signal wires are electrically separated from the main preamplifier block by isolators built into the front panel.  Control knobs with precision bearings and the same mechanism as those found in the Grandioso Series components. The F Series’ volume and selector knobs rotate exceptionally smoothly, giving an “analog” feel to operation. Despite the expense, they are all milled from solid aluminum.

The phono preamplifier (for MM/MC heads) is also designed as a “dual mono”, with independent power supplies for the left and right channels and separate circuits.  A high-quality headphone amplifier produces a signal powerful enough to effectively drive even high-end headphones with their high impedance.  3-band tone control (Treble/Middle/Bass): the desire to ensure quality at the level of the best high-end components led to the creation of a balanced configuration of the “dual mono” type, consisting of four circuits (L/R, –/+) for each frequency band. This system allows you to adjust the tone without fear of degradation of sound quality. Shifting the bands further than usual to the edges of the audio range (14 kHz/63 Hz) allows for more subtle adjustment of the bass and treble frequencies, without negatively affecting the original signal from the source. Fully electronic control also allows fine tuning of the sound within ±12dB in 0.5dB steps. The midrange can be used as a preset for tone compensation when set to minus, as well as together with the Tone Bypass switch. The  input section of the power amplifier is also balanced – in accordance with the principles laid down in the separate S-Series components. Its low impedance, clean and noise-free amplification expands the dynamic range.

To reduce the output impedance, the designers used 8 buses of high-purity OFC oxygen-free copper 1 mm thick, and in the output section – MOSFET switches without mechanical contacts. The need for inductors (coils) at the output was eliminated to increase the load capacity.  Large bipolar transistors LAPT (Linear Amplified Power Transistor), the same as in the Grandioso Series models, are capable of continuously delivering a current of 17 amps, and in peaks – an instantaneous current of up to 34 amps. They also have a wide bandwidth, necessary for the highest tonal fidelity.  LAPT transistors are arranged in a three-stage Darlington configuration with three parallel push-pull modules. The proprietary LIDSC (Low Impedance Drive Stage Coupling) driver stage coupling scheme reduces the transient impedance and increases the ability to deliver high currents, almost the same as separate amplifiers. The depth of the overall negative feedback NFB has been minimized in order to achieve a more natural and lifelike sound.  The 3D-optimized chassis of the F Series is a solid construction with separate compartments for each circuit block. This effectively minimizes mutual interference and keeps the length of the connecting cables as short as possible. The outer part of the chassis is made of thick aluminum panels according to Esoteric’s uncompromising philosophy. As a result, this powerful structure weighs over 32 kg, which is an exceptional figure among integrated amplifiers. Four proprietary ESOTERIC point supports ensure the stability of the heavyweight body and the absence of resonance for the F-03A amplifier.

The F Series preamp and power amplifier sections are as sophisticated as Esoteric’s separate components, but they can be used as stand-alone units and even switched off individually when not in use. The PRE-out features a powerful buffer amplifier, while rear panel XLR connectors allow a balanced configuration.  The Esoteric F-07 amplifier can be upgraded without any loss of sound quality. A plug-in card slot facilitates installation of the optional OP-DAC1 D/A Converter Board, which provides full compatibility with 11.2 MHz DSD and 384 kHz/32-bit PCM signals.