F-03A

The Esoteric F-03A Class-A integrated amplifier

The Esoteric F-03A combines a fully balanced preamplifier with a Class-A power amplifier. Both sections are derived directly from the Grandioso range of separate amplifiers, bringing their circuit design, materials and development experience into an integrated configuration. Its dual monaural construction continues through every stage, from the preamplifier inputs to the final power amplifier output stage, maintaining left and right channel independence throughout.

The F-03A is designed to reproduce the warmth, texture and tonal shading of music while providing the functionality and expandability associated with an integrated amplifier. Its analogue amplification circuitry is inherited from the Grandioso series, with the overall design developed around the fundamental requirements of amplifier construction and the practical advantages of an integrated format. The amplifier also provides tone control facilities beyond those commonly found in separate preamplifier and power amplifier combinations, together with compatibility with Esoteric K and N Series digital players.

A Fully Balanced Preamplifier

The fully balanced preamplifier section is derived from Esoteric C Series preamplifier models. Its low-impedance signal amplification is designed to reduce the effect of noise while maintaining a direct signal path.

Dual Monaural by Design

Complete left and right channel separation is maintained through the preamplifier and power amplifier, including the final output stage. Independent circuit construction and the use of materials developed for Esoteric amplifiers support the F-03A’s channel separation and dual-monaural operation.

ESOTERIC-QVCS

The proprietary Quad Volume Control System uses 4 precision switched resistor ladder networks. These operate together to control the left and right channels, along with their positive and negative phases, independently and electronically. QVCS maintains audio clarity, channel separation and phase accuracy, while removing volume control wiring from the audio board. This shortens the signal path, reduces potential signal degradation and achieves low distortion.

QVCS: Quad Volume Control System

Ultra-Low-Noise Logic Control

Control lines are electronically separated from the main preamplifier circuitry by isolator elements integrated into the front panel. This arrangement is used to counteract noise.

High-Precision Ball Bearing Control Knobs

The F-03A’s volume control knobs and selector switches use the same high-precision bearing mechanisms as Esoteric Grandioso components. They provide smooth operation without mechanical play and an analogue operating feel. All panel knobs are custom-machined from solid aluminium.

Dual Mono Phonostage Preamp

The MM/MC phonostage preamplifier has independent power sources and independent circuits for the left and right channels.

High-Quality Headphone Amplifier

The headphone amplifier provides ample output for driving high-end headphones with high impedance and demanding power requirements.

3-Band Tone Control (Treble/Middle/Bass)

Each tone band uses a balanced dual-monaural arrangement of 4 circuits for the left and right channels and their positive and negative phases. Electronic control allows adjustment of up to ±12dB in 0.5dB steps, without requiring changes to the signal path associated with the original source.

The variable bands extend towards the high and low frequency ranges, with treble centred at 14kHz and bass at 63Hz. This allows detailed adjustment of those bands. The middle band can be used as a loudness preset when set to the minus side and combined with the Tone Bypass switch.