Simaudio 740P Preamplifier - Manual (Page 9)

740P Dual-Mono Preamplifier
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The “‡ Input ˆ” buttons allow you to choose which
input source you wish to listen to. The MOON 740P
dual-mono preamplifier has a total of five (5) inputs;
The first two (2) inputs are fully-balanced and use
XLR connectors labeled B1 and B2. The next three
(3) inputs are single-ended and use RCA connectors
labeled S1, S2 and S3. Assuming that you’re
currently listening to a source component connected
to input B1, the “ˆ” allows to sequentially scroll
forward through the available inputs from B2, then
S1, S2 and S3. The “‡” button allows you to
sequentially scroll backwards from S3 to B1.
Holding down either the “ˆ” or “‡“ button will allow
only a single change of the selected input. You must
press the button again to select the next or previous
input.
The rotary “volume” control determines the gain
setting, which ranges from ‘0.0dB’ (no output) to
’80.0dB’ (full output). This control does not function
like a typical volume: When you rotate the dial,
either clockwise to raise the volume or counter-
clockwise to lower the volume, you are actually
engaging a precision optical encoder which selects
very high quality metal-film resistors that the audio
signal passes through. The result is a proprietary
gain circuit, called M-eVOL2 that doesn’t degrade
the audio signal regardless of the setting, unlike all
potentiometer based circuits. Since this circuitry
operates in a fully balanced differential mode, no
noise is introduced to the audio signal.
Furthermore, there are no actual moving parts, so
this technology has a minimum life expectancy of
one million rotations.
The MOON 740P Preamplifier provides a range of
five-hundred and thirty (530) unique volume
settings. This is achieved as follows: Within the
0.0dB to 30.0dB range, you can increase and
decrease the volume in 1.0dB steps. From the
30.0dB to 80.0dB range, you can increase and
decrease the volume by either 0.1dB or 1.0dB steps;
By rotating the volume control slowly, the level will
change by 0.1dB increments. A quicker rotation will
change the volume in 1.0dB increments.
The “Setup” and “OK” buttons are used for
programming the numerous software functions
available on this preamplifier. The next section,
entitled “Software Setup”, explains their usage in
detail.