ART Pro Audio Digital MPA-II - Two Ch. Mic Pre w/ A/D Conversion - Manual (Page 11)

8
As the Digital Level control is used refer to the Digital Level LED meter which indicates both peak and
average level present at the A/D converter input. This meter helps you get the perfect level adjust-
ment and avoid clipping the A/D. Refer to the section titled “Obtaining the perfect digital level setting”
for more detail on the operation and use of these features.
Sample Rate control
The Sample rate knob determines both the output sample rate of the DIGITAL MPA II as well as the
dither. You can select either AES/EBU (pro) format or S/PDIF (consumer) data format.
The internal sample rate can be set from 44.1KHz to 192KHz. Simply select the correct rate by
turning the knob to the rate you need and the DIGITAL MPA II will use its’ internal crystal controlled
oscillator to accurately generate the selected timing. Each sample rate has the option of either 24 bit
or 16 bit dither (i.e. 44.1K/24 or 44.1K/16).
Be careful in adjusting this control. Some equipment is not capable of the available sample rates and
may produce damaging side effects. Always turn down levels following the DIGITAL MPA II when
changing the sample rate.
External sync sources are Wordclock and ADAT INPUT.
Wordclock is a 5V logic level signal interfaced by a BNC connector on the rear of the unit. The Range
of wordclock accepted by the DIGITAL MPA II is 28KHZ to 212 kHz. It is recommended that you use
wordclock whenever possible, as this will minimize interface errors with other equipment.
NOTE: When using the ADAT optical output, the maximum sample rate is limited to about 50KHz. If
wordclock exceeds this the ADAT output (if selected) will fail.
The ADAT Input on the rear panel is used as a timing reference as well as a source of data to be
passed on to the ADAT output of the DIGITAL MPA II.
If the unit CANNOT sync to an external source (either out of range, not connected or a system fail-
ure), the optical Output select switch will blink. (You may see this switch flash once between changing