(Simaudio Ltd. Proprietary Technology)
The M-eVOL2 volume circuit uses Multiplying Digital-to-Analog Converters (MDAC's)
to vary the amplitude of the music signal based on the chosen volume setting. Since it
is used in a dual-mono circuit topology, there is one MDAC for each channel. As well,
the audio signal ALWAYS remains in the analog domain and is never degraded at
any volume setting.
Each MDAC (a Texas Instruments DAC8812) uses a pair of current steering R2-R ladder
DACs that allows for operation in a fully balanced differential mode. Like the M-Ray
volume circuit, it provides incremental adjustments in 0.1dB steps, yielding a total of 530 unique volume steps.
Introduced in the MOON 600i and 700i Integrated Amplifiers, the benefits of
the M-eVOL2 volume circuit, when compared to the original M-eVOL, include:
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· A blacker background
· An improvement in signal-to-noise-ratio of
+10dB in magnitude
· Improved signal matching between the
left and right channels
· Much more precise incremental volume
adjustments (0.1 db vs. 0.5dB)
· Increased bandwidth
· Closely approaches the performance of
the M-Ray volume circuit
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Crosstalk
Crosstalk typically increases as a function of frequency; the higher the frequency, the greater the amount of crosstalk.
This is a behavioural characteristic common to all volume controls, regardless of the circuit topology. Higher quality
volume circuits will have a significantly lower crosstalk measurement throughout the entire bandwidth:
In the above figure, the perfect scenario would have an identical crosstalk measurement of -140dB
(green)
across the entire frequency spectrum, but this is not realistic. The fully discrete M-Ray volume circuit found in the MOON P-8 Preamplifier yields an astonishing -135dB
(blue)
at 1kHz. The M-eVOL2 circuit, found in the preamplification section of both the MOON 600i and 700i Integrated amplifiers, measures an incredible -130dB
(brown)
of crosstalk at the same frequency. The MOON P-7 Preamplifier with our M-eVOL circuit, produces a remarkably low -126dB
(orange)
of crosstalk at 1kHz. Finally, a very high quality potentiometer based volume circuit will have a crosstalk level -118db
(red)
at best and a ordinary poteniometer circuit may reach -82dB
(grey).
As crosstalk increases in the upper frequencies, the width of the soundstage becomes compromised and consequently diminishes the accuracy of sonic reproduction.
Virtually perfect soundstage reproduction ... a genuine sense
that the musicians are playing right in front of you.
Signal Level Matching
All volume control circuits suffer from imperfect level matching between the left and right channels, especially at low and high output levels.
In simple terms this means that the actual volume level is not identical for both channels at various settings:
A very high quality potentiometer-based volume circuit will typically have a variance of as much as 1.5dB
(red)
between the left and right channels at the volume extremeties as shown above. All three of our volume circuits M-Ray, M-eVOL and M-eVOL2
maintain an extremely low and consistent variance of less than 0.05dB (blue) across the entire volume range .
Perfect level matching between channels that no other volume control can achieve ... Recorded music heard as it was intended to be -
pure, natural and uncolored.
M-LOCK
(Simaudio Ltd. Proprietary Technology)
This is our in-house developed maximum volume lockout circuit. It is a software based design that is end-user configurable for each individual input on
MOON Evolution series preamplifiers and integrated amplifiers. The purpose of M-LOCK is to protect your amplifier(s) and your speakers from possible signal overload;
The logic being that different source components vary with respect to their output voltage levels.
The days of accidentally over-loading your system are over!
