Simaudio MOON 700I - Manual (Page 3)

Technical information
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 (TI 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 found in our MOON P-8 reference level preamplifier, it provides incremental
adjustments in 0.1dB steps, yielding a total of 530 unique volume steps.
Introduced in the MOON 700i Integrated Amplifier, the benefits of the M-eVOL2
volume circuit, when compared to the original M-eVOL, include:
The M-eVOL2 proprietary volume control circuit yield
virtually perfect signal level matching
between the left and right channels as well as
staggeringly low crosstalk levels.
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 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
Simaudio Ltd. has been designing and manufacturing innovative, leading-edge
audio and video products since 1980. MOON products have been globally
recognized for their world-class performance, garnering numerous accolades
for this outstanding achievement. Our products are engineered and built in
Canada, utilizing advanced, efficient, “green” assembly techniques with strict
quality control. Furthermore, our manufacturing processes are part of our
philosophy, whereas the high quality and long-life of MOON products are the
best way to preserve our environment, avoiding premature obsolesence. MOON
products meet or exceed all international requirements for safety, performance
and durability. At Simaudio, great music matters. However, great music for a
lifetime matters most.
A very high quality volume circuit using a potentiometer will typically have a
variance of as much as 1.5dB
(red) between the left and right channels at the
volume extremities as shown in figure 6. 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.
The transistors used in the MOON 700i’s output stage perform what can be
best described as electrical gain of the music signal. Higher quality transistors
will yield an amplified signal with greater integrity. In addition, since each chan-
nel of an output stage uses numerous transistors, they must all be accurately
matched to each other to maintain this integrity.
MOON amplifiers have always used bipolar transistors in their output stages
for several significant reasons. When compared to other types of amplification
transistors, bipolars offer:
We have managed, at a great expense, to have bipolar transistors manufac-
tured to our own exceedingly high standards and specific requirements. When
compared to more readily available high quality bipolars for use in audio ampli-
fiers, MOON Bipolars offer the following advantages:
The exceptional gain linearity of MOON Bipolars is very significant in the
sense that it results in many of these aforementioned advantages. To illustrate
the significant effect of this gain linearity when compared to a quality bipolar
transistor found in a high-performance audio amplifier, refer to figure 1 below
which shows the difference in DC current gain as a function of the transistor’s
output current:
Optimal sonic performance is always achieved
regardless of the amplifier’s output level.
• Unprecedented gain linearity
• A green component containing no lead
• Lower noise floor
• Even wider bandwidth
• Improved bass response
• Greater signal integrity
• Even greater reliability at higher output levels
• A more consistent hFE (the DC current gain of a
transistor) which allows for more accurate and
easier matching of multiple Bipolars.
• Wider bandwidth
• Lower distortion
• Excellent reliability and a longer life span
• High Efficiency
• High resistance to ESD (electrostatic discharge)