Many moons ago (yeah, I know), I was given the opportunity to review a compact little integrated amplifier from the Canadian manufacturer SimAudio. It was called the Moon i-3. Outwardly it was a completely no-frills design, beautifully constructed, with a large volume control and a very reasonable price tag. As ever, competition at its price point was fierce. I fired it up... and thought it sounded rather thin and lightweight. Discussing this with the then-editor we came to the decision that it was promising enough to take time over so we kicked the review back a couple of issues. It went into an upstairs bedroom playing on endless repeat for several weeks. When re-installed I had one of those moments in audio that has stayed with me. I was never going to get caught out like that again. To say that it was unrecognisable would be an understatement. It had unfolded and evolved musically to such an extent that it became a truly captivating little thing. It had speed, decent power, lovely tonality, and an unflustered refinement that belied its humble cost (if memory serves, it was under £1,500 at the time). But the name Moon became synonymous, to me, with very lengthy run-in times and I believe I am not alone among reviewers in that view.
So, given the opportunity to audition a new Moon integrated amplifier, I was very keen to hear how things had developed. The lengthy preamble here is merely to give a bit of a background flavour to the history of my relationship with Moon products and the 600i V2 has proved to me that all of those core values of their sound and performance are still there in abundance. I should add here that I have no experience with the V1 version of this amplifier that was in production for around eight years. The source components and speakers I am using are different and very much improved, but Moon and its clear musical focus are still making gimmick-free amplifiers like the 600i V2, which is a very good and reassuring thing. The hereditary line from that little i-3 all those years ago to the very chunky integrated currently sitting across the room is evident every time it opens its mouth.
But, the 600i V2 actually sounded very decent to me, straight from the sealed box. A little ‘green’ perhaps, but essentially all there, so I just left it in the main system doing its stuff and heard it putting on weight, colour, and substance while growing sharper and faster over the weeks. The system I used was purposely chosen to stretch it. A dCS Vivaldi with CD transport and DAC and a full Roon/Tidal streaming capability feeds it while Nordost cabling connects it to a pair of the quite superb Wilson Duette Seires-2 loudspeakers. With such high-end potential, I would usually advocate the sort of amplifier that would cost considerably more. This is conventional advice really for such a system, but I have to say that the Moon has been putting in such a performance that I can only admire the musical completeness of its design and the way that Simaudio have crafted and voiced this little gem. There was certainly a slight thin astringency to horns and a pinched, raw-edged flavour to the attack of cymbals initially but, as the hours and days passed, this vanished without becoming over-smooth or ignoring the instrumental characteristics that should be there.
It is an extremely solidly built, purposeful-looking integrated amplifier. I find the design really nice too. The slope shouldered front panel looks great. The review sample was in black but, personally, I would opt for the two-tone version with the aluminium-edge features. There are no built-in DACs or digital interfaces of any kind on the 600i V2. Its impressive weight is due to a pair of huge toroidal transformers powering each side of the dual mono design. The chassis, power switch and mains socket are the only parts shared by the two channels. It is designated as a NFN or ‘no overall feedback’ amplifier that runs in Class A for the first five watts of its considerable output (125 watts into 8 ohms) But its ‘straightforward’ design features more depth than might initially be apparent. For a start, there is the onboard software that enables you to independently name each of the five line inputs and assign a maximum volume level to each one and create an ‘offset’ level from -10dB to +10dB or even to bypass the control altogether, freeing the amplifier to be controlled by an onboard version on a source component, effectively leaving the 600i V2 as a power amplifier. In a way it’s a shame to do that because the Moon’s volume control is a joy to use. Simaudio have always been good with volume controls. The large knob, with its buttery smooth action is connected to a precision optical encoder where metal-film resistors do the gain work. Moon have obviously taken considerable care with this as it can provide no less than 530 settings. Few will need such precision in practice but the rate of increase or retardation is governed by the speed with which you operate the control. Do it slowly and the increments will be as little as 0.1dB per step. Approach it more robustly and this becomes a single dB. It is therefore easy to make volume changes precisely and indeed minutely. Moon claim that this design has eliminated any unwanted side-effects usually found with potentiometer circuits and I have little doubt that it makes a significant contribution to how clean and precise the amplifier sounds. The onboard software is remarkably comprehensive and way too complex to fully describe here but the amplifier’s custom integration within the system is very much enhanced by its incorporation into the design.