grace design
m
902
owner’s manual
10
DIGITal InPuTs
- The m902 provides the following digital input sources: AES3, S/PDIF, TOSLINK
and USB. The AES3, S/PDIF and TOSLINK inputs support audio data with sample rates from 32kHz to
192kHz and resolution up to 24-bits. The USB input supports audio data with sample rates of 44.1kHz
and 48kHz of 16-bit resolution.
usB InPuT seTuP -
To use the m902 USB input, the host computer must be properly configured.
This procedure varies from computer to computer, but the general steps are as follows:
Once the m902 and host computer have been connected via USB, the host will automatically recognize the m902 as a
1.
USB Audio Device.
In your computer’s hardware setup, you must then select the m902 (USB Audio Device) as the playback hardware.
2.
Once this is done, any audio being played on the host computer will be sent to the m902. It is recommended that all
3.
output volume controls be set to max on the host computer software. Depending on the application, failure to do so
will result in a digitally attenuated signal, causing a loss in resolution.
operaTInG headphone and lIne ouTpuTs
Both the headphone and the line outputs feature precision level control. Each output is completely
independent of the other in terms of level and balance control (see the submenu section below for
description of this feature).
The output selection indicator LEDs show the user which output is currently under user control. To
toggle the output control selection, simply press and release the rotary level encoder. You will see the
selection indicator change.
The rotary volume encoder is used to adjust the level of both the headphone and line level outputs
independently. The level of the currently selected output is displayed in the 7-segment display.
Turning the rotary encoder clockwise increases the output level and counter-clockwise decreases it.
The m902 features an extremely high precision analog volume control. Step size is 0.5dB and channel
matching is within 0.05dB for all settings. Also, embedded within the volume control architecture is a
3 stage acceleration curve. The rotary encoder has 24 positions. Turning it one revolution slowly will
result in a change of 12dB (24 x 0.5dB). As the rotation speed increases, each step goes from 0.5dB to
2.0dB and then to 4.0dB. This allows not only precise control but also convenience when large volume
changes are desired.
Any changes made are reflected in the 7-segment display. Level range is from 0.0 to 99.5. NOTE: The
least significant digit’s decimal point (.) is used to indicate 0.5dB increments
abouT s-loCk
Tm
s-Lock
tm
is our new PLL (Phase Lock Loop) circuitry that has been specifically developed for the m902
and its big brothers the m904 and multi-channel controller, the m906. The truly wonderful thing about
s-Lock is that regardless of the condition of the external clock used as a reference for the m902, s-Lock
