It also features active bias control throughout that manages the temperature and current flow at different volume levels. Signals on the unbalanced input are immediately converted to balanced, so the benefits of ‘Superbal’ are available to both balanced and unbalanced inputs.
It is a symmetrical design with fully electronically-balanced inputs. Meridian’s proprietary ‘Superbal’ circuitry uses shunt feedback to eliminate common mode distortion. Its output impedance is very low – the 857 can drive virtually any quality passive loudspeaker system. Its low open-loop output impedance allows the 857 to achieve excellent measured performance with very low distortion and a high damping factor while only applying modest amounts of negative feedback. Its 1 Hz to 100 kHz bandwidth offers excellent capability for today’s high-res audio. If you use two 857 amplifiers and bridge them, you can achieve 1.5 KW into 4 ohms in a mono block configuration. It is biased to run in Class-AB, the documentation does not indicate how many watts are in Class-A. It provides 250 watts per channel into 8 ohms and 500 watts into 4 ohms. The flagship Reference 857 is the most powerful stereo amplifier from Meridian. The 857 does indeed look like an expensive reference quality amplifier. The aluminium was clean cut with no sharp edges anywhere. The black glass was uniform – no flaws to be seen on the top or front panels. My review unit was in black, of course! The fit and finish was exemplary. Its soft start and shutdown ensured no issues, but it’s best to be safe and do the right thing. Unlike some amplifiers, it didn’t matter if you accidentally broke the cardinal rule of always turning it on last and off first (which avoids any power surges through to the speakers). In all my time listening I only ever saw a blue and green perimeter light the amplifier behaved impeccably. Immediately power it down via the rear switch and check all connections before powering back up. If the perimeter light goes blank (unlit) then it means the amplifier has been ‘tripped’, likely due to an input with a DC offset or a shorted output. If the perimeter light turns red then it means the amplifier has overheated – immediately turn it off and let it cool. If the fans get activated then the perimeter light turns to an amber colour – this is normal operation, the sound quality is not affected. A very soft touch quickly switches the 857 into operation mode and the perimeter light then illuminates in green. The front panel is extremely clean looking with only a large square soft-touch button within an illuminated perimeter light situated in the exact centre of the gloss panel. I suspect that most audiophiles will opt for the black. However, the Meridian Reference 857 is available in pretty much any colour you wish – of course such requests are custom built and do incur a waiting time and premium charge. Invariably, you’ll see Meridian gear in black glass and black brushed aluminium. Henry Ford famously said that you could have his Model T in any colour you liked so long as it’s black. But as well as those reference quality products we also have the subject of this review – the Meridian Reference Two-Channel 857 Power Amplifier. People familiar with the Meridian brand will likely know the Meridian DSP8000 Digital Active loudspeakers, the Meridian 808 Signature Reference CD Player and Ultra DAC. And of course, they created the Sooloos music server, and more recently, MQA (Master Quality Authenticated) which has since been spun off into a separate company. Later they released the world’s first digital sound processor. When the Compact Disc was introduced in 1984, Meridian was the first to release the world’s first audiophile grade CD player, the MCD. Meridian released the first known active loudspeaker into the consumer market – the M1. Meridian Audio has continually succeeded by being one of the best audio and acoustic engineering companies in a market known for intense competition. But longevity in the audio business doesn’t, on its own, keep the doors open. It’s an established audio company that dates back to 1977 – only a handful of high-profile, high-end audio companies can tout a longer history. Meridian Audio is a name known to most if not all audiophiles.