An amplifier remains the beating heart of any high-performance audio system, a truly versatile integrated amp needs to cover many bases – digital and analogue sources, wireless connectivity for portable devices, a phono stage to cater for vinyl playback, amplification for headphones as well as speakers… That’s a lot to pack in, whilst keeping performance high and the price tag affordable – and yet, that’s exactly what the 6000A delivers.
The Sound of Science
Outwardly, the 6000A bears strong resemblance to the 8300A with its rotary controls and large, central OLED display. Unlike its costlier, analogue-only sibling, it incorporates high-quality D/A conversion, enabling digital sources to be connected directly without an external DAC. It supplies four digital inputs, three line-level analogue inputs, an input for a turntable, wireless connectivity via Bluetooth and a dedicated headphone amp, in addition to its ability when driving loudspeakers.
Classic Hi-Fi for the Modern Age
To incorporate all this functionality, there must be compromise under the lid, right? Wrong. The 6000A’s lead electronics designer is Jan Ertner – the same man responsible for the 8300A, as well as many other award-winning audio components over the years. When challenged to deliver 6000A at such a low price point, Jan returned to the technologies he implemented in the 8300A and painstakingly redeveloped them, whilst adding high-quality digital circuitry to the mix. The result is a new-generation amplifier evolved from the architecture of its pricier sibling, delivering exceptionalsound quality alongside those flexible facilities.
Digital circuitry
Much effort has been made to ensure the 6000A’s digital circuitry delivers the level of quality one might expect of a high-performance standalone DAC. As ever, Audiolab has turned to the ES9018 Sabre32 Reference chip family to perform D/A conversion, utilising ESS Technology’s 32-bit HyperStream architecture and Time Domain Jitter Eliminator to deliver ultra-low noise and high dynamic range.
No company knows more about making the most of this technically excellent, but challenging, DAC technology than Audiolab.
Analogue circuitry
The 6000A’s discrete Class AB power amp stage delivers 50W per channel into eight ohms, with a maximum current delivery of 9 Amps into difficult loads. The output stage of the discrete power amp circuits uses a CFB (Complementary Feedback) topology, ensuring superior linearity and excellent thermal stability, as the idle current is kept independent of the temperature of the output transistors. A substantial 200VA toroidal transformer, followed by 4x15000uF reservoir capacity (60000uF in total), helps the amp to maintain firm control of the music whilst enabling excellent dynamic range. The preamp section is kept as simple as possible to maintain signal purity, with line input signals passing to a precision analogue volume stage. The latter covers the range from -80dB to +8dB in steps of 2dB and 1dB (step resolution increases with volume position). Much effort has gone into the physical layout of the 6000A’s circuitry, protecting the sensitive preamp section from noise interference.
Turntables and Headphones
In recognition of the recent vinyl revival, Audiolab has included a phono stage for moving magnet phono cartridges – a high-quality, low-noise, JFET-based circuit with precise RIAA equalisation.
Similarly, an increasing number of people are using headphones for music listening, so Audiolab has incorporated a dedicated headphone amp with current-feedback circuitry. Its gain bandwidth and high slew rate ensure a dynamic, detailed and engaging performance with all manner of headphone types – more boxes ticked for this most integrated of integrated amplifiers.
Operational Modes
The 6000A’s flexibility with digital and analogue sources is not the only thing that makes it so versatile; it also offers three distinct operational modes, reflecting the amp’s discrete internal architecture and enabling it to adapt to its user’s evolving requirements. The primary mode is ‘Integrated’ – this combines the pre and power amp stages, for the connection of digital and analogue sources to the amp’s inputs and a pair of speakers to its binding posts.
Flexibility Without Compromise
Jan Ertner, the project’s lead electronics designer, commented: “The majority of audio components that I design retail for upwards of £1,000, so the 6000A was a tremendous challenge – an integrated amp with a full roster of digital and analogue facilities at a target retail price of just £600. What’s more, it had to deliver the excellent sound quality for which Audiolab is famed, without compromising one aspect of performance in order to accommodate another.
“I’m proud of the results we have attained. On DAC performance alone, the 6000A will match standalone DACs in the £500-£600 range. As for the analogue pre and power amp stages, we’ve worked long and hard to ensure that the 6000A delivers class-leading sound quality. As a package – a high-quality, affordable integrated amp for the modern age – the 6000A represents excellent
value-for-money.”
