Signal Path Flow; Signal Path Flow Diagram; Operating Instructions; Obtaining The Best Noise Performance - Art DIGITAL MPA User Manual

ART Digital MPA™ Microphone Preamplifier

SIGNAL PATH FLOW DIAGRAM

The signal path of the DMPA consists of a discrete class A microphone pre-amp followed by a Hi
Pass Filter, a balanced differential tube circuit with a 20dB Gain switch and then the phase switch.
At this point the signal passes to both the analog output and the Insert jacks. The insert jacks
allow processing of the signal before its' level is adjusted by the Digital Level control and passed
to the A/D. You can use the A/D converters of the DMPA independent of the analog functions by
simply inserting a signal into this insert point.
DMPA OPERATING INSTRUCTIONS
Obtaining the best noise performance with the DMPA
Start by turning down the Input Gain knob and centering the Analog Output knob. Use the analog
meter to view the operating level by depressing the switch under the center of the analog meter.
The meter will now indicate how much tube headroom there is. Set the +20dB switch to the out
position.
Increase the Input Level knob until the meter reads above –10dB. If you have turned the input
knob fully clockwise and the indicated level is still below –10dB on the meter, center the input knob
and depress the Gain switch. Increase the Input Gain until there is sufficient level.
This procedure optimizes the gain elements to provide the widest dynamic range possible.

Adjusting the Input Impedance

The same microphone can sound different on various pre-amps. One reason is that every pre-amp
presents a different load to on its' input, some even change as gain is changed! Our third genera-
tion discrete front end was designed to be absolutely transparent. Every nuance of the microphone
is maintained providing detail masked by inferior pre-amps. The Input Impedance control is one
key element in providing new versatility in voicing microphones.
10