Simaudio MOON i-1 User Manual download pdf (Page 5)

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Australian Hi-Fi78

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Australian Hi-Fi

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result

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equipmenT review Moon i-1 Stereo Integrated Ampliﬁer

is struggling with what it’s being asked to

do, clearly evidenced by the appearance of

‘sidebars’ around the fundamentals and har-

monics. The 8Ω trace is relatively clean, but

the same can’t be said about the 4Ω trace.

There’s also quite a bit of distortion present

in the output and although it’s still relatively

low at 8Ω (where only the third and ﬁfth har-

monics are higher than –90dB) the odd-order

harmonic components are mostly higher than

the even-order components, whereas it’s pref-

erable for it to be the other way around, with

the even-order harmonics more prominent

than the odd-order. The same trend is evident

in Graph 4, with the additional note that the

individual distortion components are much

higher. However, all harmonic distortion com-

ponents except the ﬁfth (which is at –75dB,

or 0.01% THD) are more than 80dB down.

However, to put all this in its true perspective,

the combined overall THD+N ﬁgure measured

by Newport Test Labs was just 0.01%, meaning

that even when combined, all the distortion

components would be completely inaudible at

all output levels.

Graph 6 shows the performance of the

Moon i-1 when it’s driven by two high-fre-

quency test signals spaced 1kHz apart (at

19kHz and 20kHz). Ideally, all we should re-

ally see are the two test signals, whereas in this

graph, we can see not only two HF sidebands

sitting a bit more than 80dB down, but more

importantly a regenerated intermodulation

signal at 1kHz sitting at around –47dB (0.5%

THD). This high level of regeneration at 1kHz

is more typical of a valve ampliﬁer than a sol-

id-state device.

Ampliﬁer noise was low, as you’ve prob-

ably already noticed from the noise ﬂoor on

the graphs, with Newport Test Labs measuring

signal-to-noise ratios of 84dB unweighted re-

ferred to one watt, improving to 90dB with

‘A’ weighting. Referred to rated output, the

S/N ratios measured were 98dB unweighted

and an excellent 106dB A-weighted. Output

impedance was also low, meaning the Moon

i-1’s performance will not be affected by the

impedance of the speakers it’s being used

with, and the high damping factor that results

means you will get excellent control over even

the largest of bass drivers.

Mains power consumption was relatively

high—and particularly so in Standby mode,

where the Moon i-1 draws only very slightly

less than when it’s actually switched on: 10.9-

watts versus 12.3-watts. No doubt Simaudio’s

engineers are already working on the 2012

models in order to ensure they will comply

with the standby power consumption legis-

lation that will be introduced in Australia in

that year, requiring that all mains-powered

hi-ﬁ components will have to draw less than

1-watt in stand-by. At rated output, the Moon

i-1 will draw 203-watts from your GPO yet,

despite this, and despite the lack of dedicated

heat-sinking, most of the case runs surpris-

ingly cool. It’s only at the bottom of the case,

where the output transistors are attached, that

the casing becomes more than comfortably

warm after extended operation at high power

levels.

Steve Holding

“the high damping factor that results

means you will get excellent control

over even the largest of bass drivers.”

50-56Mooni1 HFSep09.indd 78 3/09/2009 9:08:47 AM

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