ATI Audio DMA103 - Manual (Page 2)

ATI Audio Inc. ■ Tel: 856 -719-9900 ■ Fax: 856-504-0220 ■ [email protected] ■ www. audio.com
DESCRIPTION
Your DA103 and DMA103 Audio Distribution Amplifiers are inexpensive high
performance amplifiers designed to split and isolate audio signal lines.
The DA103 accepts a line level input, balanced or unbalanced audio at -20, -10
or +4dBu nominal level and provides a line level output at +4dBm nominal to
balanced or unbalanced output lines. The DA103 input/output connectors are two
piece solderless “Phoenix” types, individual for each input and output line.
The DMA103 accepts a microphone level input signal and provides either line
or microphone level outputs to drive balanced or unbalanced lines. Phantom
microphone power is provided and all audio connections are made using XLR
type connectors.
CIRCUIT DETAILS
The DA103 accepts a maximum line input level of +22dBu to high impedance
(20Kohms) balanced instrumentation amplifier input (A1) and drives three servo
balanced 600-ohm (minimum load) outputs (A3, A4, A5) up to +22dBm
maximum. An internal input gain setting jumper plug optimizes the input stage
gain, noise and headroom for nominal inputs at -20, -10 or +4dBu. The Master
Gain Control (R14a) adjusts all outputs simultaneously to compensate for input
signal changes while individual output trimmers accommodate differing nominal
output level requirements from -10dBu to +8dBm. Up to 40dB maximum gain is
available. The servo-balanced outputs automatically detect single-ended (one
side grounded) loads; remove the drive signal from the grounded output and
double the signal applied to the ungrounded output thus maintaining equal gain
for both types of loading.
The DMA103 boosts a microphone level input up to line level with up to 80dB
gain. A low noise transformerless input stage (A1) allows internal DIPswitch (S1)
selection of input gain from 10, 20, 40 or 60dB to optimally match low or high
output microphones. A Master Gain Control is provided and individual front
trimmers match differing output level requirements from -10 to +8dBm. Phantom
microphone power at regulated +20.2 VDC from A10 is selected with an internal
DIPswitch and is sufficient for most powered microphones. +48VDC phantom
power is also available as a plug-in option (PH48-1); consult factory. Three
servo-balanced output drivers drive balanced or one-side-grounded loads and
individual jumper plug 54dB output attenuators (P1, P2, P3) provide -50dBm
microphone level outputs if necessary.