Интегральные усилители — Audiolab 6000A

The 6000A is an integrated amplifier from Audiolab, launched in October 2018 at GBP 599 in silver or black as part of the 6000 Series alongside the 6000CDT CD transport. Lead electronics designer Jan Ertner had worked on the 8300A and redeveloped its circuits for this cheaper model. Unlike its analogue-only sibling at the time, it adds digital conversion, so digital sources connect without an outboard DAC, and it also carries an MM phono stage, Bluetooth and a headphone amplifier. The model is now discontinued.

Key specs that matter

Rated output is 2 x 50 W into 8 ohm and 2 x 75 W into 4 ohm at under 1 % THD, and maximum output current reaches 9 A. The power stage has 29 dB of gain and stays below 0.003 % distortion at 40 W into 8 ohm. Line inputs need 720 mV, present 10 kohm, give up to 8 dB of gain and measure under 0.0004 % distortion at 2 V. The phono input needs 3.1 mV, loads the cartridge with 47 kohm and 100 pF and provides up to 55 dB of gain. A-weighted signal-to-noise is above 110 dB for line and 76 dB for phono. The preamp output has 120 ohm impedance and up to 2.3 V, and response is 20 Hz to 20 kHz within 0.1 dB. Connections cover three line inputs, the phono input and four digital inputs, two coaxial and two optical. The case is 445 x 80 x 330 mm, it weighs 7.8 kg, and standby draw is under 0.5 W.

Engineering and use context

The discrete Class AB output stage uses the CFB complementary feedback topology and is supplied by a 200 VA toroidal transformer with four 15,000 uF reservoir capacitors, 60,000 uF in total. The converter is an ES9018K2M Sabre32 Reference chip using the 32-bit HyperStream design plus jitter elimination in the time domain, and handles PCM up to 24-bit/192 kHz with a choice of fast roll-off, slow roll-off and minimum phase filters. A Class A active filter follows the DAC, whose distortion is under 0.0006 %, noise more than 112 dB down and output 2.05 V. The phono circuit is JFET-based, and analogue volume runs from -80 dB to +8 dB. Bluetooth supports the aptX codec. The dedicated current-feedback headphone amplifier has 2.35 ohm output impedance, accepts 20 to 600 ohm loads and stays under 0.01 % distortion at 50 mW. A central OLED display sits between the rotary controls.

Pairing

Three operating modes decide how it fits a system. Integrated mode joins both halves, Pre-Power mode separates them so an AV processor can drive the power section in a home cinema setup, and Pre mode turns it into a preamplifier for a separate power amp. The 6000CDT transport plugs into a digital input so that its data is decoded by the internal converter.

Alternatives

The Audiolab 8300A is the higher-positioned integrated amplifier whose circuits Jan Ertner reworked for the 6000A.