ATI Audio DA1008-1 User Manual

Page 5

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CAUTION: Active balanced output (DA1008-2, DA2016-2, ) has active drivers for
both Hi and Lo output terminals. DO NOT GROUND either Hi or Lo terminals. To
drive an unbalanced (one side grounded) load, connect it between Hi and GND
terminals and let the Lo terminal float. Two separate 600 ohm unbalanced loads
can be driven from each output without interaction by connecting one between Hi
and GND and the other between Lo and GND. The two loads thus driven will be
out of phase with each other.

ADJUSTMENTS:

The individual output levels of each channel are controlled by the screwdriver
adjust potentiometers accessible through the front panel. These adjustments are
located nearly flush with the panel to provide easy accessibility but good
protection from lurking "knob twiddlers". A front adjustment pot controls the
Headphone output.

The meter calibration switch can set the 0 VU indication to +4, +8, or +18 dBm
equivalent sine wave output. In the +18 position the top meter segment (+6)
indicates the typical clipping point of the output stage and the meter functions as
a headroom indicator.

The common mode adjustment pot on the amplifier board (R7) is factory set for a
80dB null at 60Hz. If disturbed, it can be readjusted by applying a common mode
60 Hz input to Hi and Lo inputs together referenced to ground and renulling R7.
The null typically drops to 40dB at 20kHz due to slightly unequal roll offs in the
input bypass capacitors.

Trimpots R1 and R6 on the Power Supply and Monitor Board adjust the +/-
regulated supply voltages. These pots should be set for equal supply voltages of
18VDC measured at the connectors P2 or P3. Note: +30dBrn output Distribution
Amplifiers require that these voltages be accurately set to +/- 20VDC.

The meter calibration pot R8 is adjusted by setting an accurate +4dBm output
level with an independent audio voltmeter and accurate 600 ohm load and
adjusting R8 for 0 VU meter indication.

MODIFICATIONS

To increase gain by 10 dB, change R1 1 (R21 to R81) to 56 ohms (transformer
output units) or to 150 ohms (differential output units).

For 220 VAC operation, remove jumper J1 and J3 on the Power Supply board
and add jumper J2.

Note: Different types of attachment plugs or line cords may be required for
connection to alternate supply voltages.

This manual is related to the following products:

DA1008-2 DA2016-1 DA2016-2