Интегральные усилители — Esoteric F-01

The F-01 from Esoteric of Japan is an integrated amplifier running in Class A that also carries a phono stage and a headphone amplifier. Esoteric states that its preamp section borrows technology from the Grandioso C1X preamplifier and that its power section follows the circuit concept of the Grandioso S1X Class A stereo amplifier.

Key specs that matter

Rated output is 30 W per channel into 8 ohm in Class A and 60 W into 4 ohm, with 4 ohm listed as the lowest compatible load. Three XLR inputs switchable to ES-Link Analog and three RCA inputs all present 10 kohm. The dual mono MM/MC phono input offers 47 kohm or 100 ohm. Pre-outs come as one ES-Link Analog pair and one XLR pair at 100 ohm. The quoted response runs from 10 Hz to 100 kHz at -3 dB, S/N is 104 dB IHF-A, THD is 0.008% at 1 kHz and 30 W, and damping factor is 500. Power amp gain is 28.5 dB and preamp gain reaches 18 dB. Pre-out S/N is 110 dB from line inputs, 97 dB from MM and 78 dB from MC. The chassis is 445 x 191 x 471 mm and weighs 32.2 kg, drawing 255 W in use and 230 W with no signal.

Engineering and use context

Level adjustment uses the UFA-1792 stepped attenuator module, part of the Ultra Fidelity Attenuator System, in 1,120 steps of 0.1 dB. Input switching uses FET elements instead of relays. A 940 VA EI transformer is bare mounted without a housing, and rectification is dual mono with four 10,000 uF capacitors per channel. Three bipolar pairs work in parallel push-pull in a coil-less output stage with single-pole phase compensation and low negative feedback. Circuit boards use 105 um copper, eight 1.0 mm OFC bus bars feed the power stage, and MOSFET switches replace relays at the speaker terminals. The balanced headphone amplifier delivers 600 mW per channel into 32 ohm on a 4-pin XLR jack and 300 mW on a 6.3 mm jack, with gain adjustable in steps. A 3-band tone control gives up to 12 dB at 63 Hz, 630 Hz and 14 kHz in 0.5 dB steps and can be preset per input. Each input gain is adjustable in 0.1 dB steps, volume returns to zero at power-off and to the last setting at power-on, and the signal fades when inputs change. RS-232C, trigger in and out and an AV through mode are included, and the RC-1339 remote also runs Esoteric disc and network players.

Pairing

Esoteric suggests adding an S-05 Class A power amplifier to the pre-outs for multi-amp use and the PS-01F external supply for the preamp section. An option slot accepts the OP-DAC1 DAC board or the OP-ESLA1 ES-Link Analog input board.

Alternatives

The Esoteric F-02 uses a chassis of the same size but a 120 W per channel power section based on the Grandioso M1X design.