User manual ART DIGITAL MPA II

[. . . ] DIGITAL MPA IITM ART DIGITAL MPA IITM Microphone Preamplifier USER'S GUIDE IMPORTANT SAFETY INSTRUCTIONS ­ READ FIRST This symbol, wherever it appears, alerts you to the presence of uninsulated dangerous voltage inside the enclosure. Voltage that may be sufficient to constitute a risk of shock. This symbol, wherever it appears, alerts you to important operating and maintenance instructions in the accompanying literature. Please read manual. Read instructions: Retain these safety and operating instructions for future reference. [. . . ] Common to both is the output signal of the tube circuit. The Digital Level control is variable from +10dB to - (fully muted). Located before the Digital Level control is the insert jack, allowing processing to be added before digital conversion. 7 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 adjustment 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. 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 failure), the optical Output select switch will blink. (You may see this switch flash once between changing 8 sample rates, indicating the fraction of a second it takes to settle to the new rate. NOTE: When using the ADAT Input as a sync source, the maximum sample rate is limited to about 50KHz. Dither settings The DIGITAL MPA II possesses a 24-bit A/D converter. When the output of the unit goes off to a system that can handle only 16 bit data, the 8 least significant bits of data are ignored (truncated). This leaves the sound with gritty "digital" sounding signals at very low levels. [. . . ] 15Hz to 48 kHz (+0, -1dB) @ normal plate voltage 15Hz to 120 kHz (+0, -1dB) @ high plate voltage Dynamic range:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . >110dB ("A" weighted) CMRR: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . >90dB THD: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <0. 005% (typical) Equivalent Input Noise:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ]