Усилители мощности стерео — Esoteric S-05XE

The S-05XE from Esoteric of Japan is a Class A amplifier with two channels and the XE version of the S-05. Esoteric states that it follows the design approach of the Grandioso S1X and adds a new fully symmetrical balanced input buffer and a revised power supply.

Key specs that matter

In stereo the S-05XE is rated at 30 W per channel into 8 ohm in Class A and 60 W per channel into 4 ohm, for loads of 4 to 16 ohm. In BTL mode it delivers 120 W into 8 ohm, with 8 to 16 ohm loads. Gain is 28.5 dB in stereo and 34.5 dB bridged. Frequency response runs from 5 Hz to 100 kHz within 3 dB, S/N is 104 dB IHF-A through XLR, distortion is 0.007% at 1 kHz and 30 W, and the damping factor is 500. Each of the three input pairs - ES-Link Analog, XLR and RCA - is single, and XLR and RCA present 10 kohm. A 12 V trigger input and a trigger through jack are fitted. The unit measures 445 x 191 x 443 mm, weighs 25.6 kg and uses 215 W, or 195 W with no signal.

Engineering and use context

Bipolar transistors run in pure Class A as three push-pull pairs in parallel with single-pole phase compensation, no output coil and minimal negative feedback. All output transistors sit in one row at the lowest point of the amplifier block so they share the same temperature, which lets idle current settle quickly after switch-on. Boards use 105 um copper tracks, cables are bolted rather than clipped, the drive stage has eight 1.0 mm OFC bus bars, and MOSFET switches are used at the speaker outputs and at every switching point in the signal path. The input buffer converts all signals to balanced form, and a photocoupler isolates it from the control circuitry. The XE power supply uses a new 1,000 VA toroidal transformer mounted without a cover and a smoothing circuit split per channel with four 10,000 uF capacitors each. The chassis relies on aluminium blocks, a top panel on a semi-floating mount with a Dual Honeycomb Grille vent pattern, wave-shaped heat sinks and stress-reducing isolation feet.

Pairing

Esoteric proposes the N-05XE network DAC preamplifier as a partner over ES-Link Analog for a two-box system. A mode switch also allows bi-amp operation, where two units feed the treble and bass terminals of bi-wire speakers at the stereo rating, or a second S-05XE can be added for a bridged mono pair.

Alternatives

The Esoteric Grandioso S1X is the Grandioso series Class A stereo amplifier whose design approach this model follows.