ATI Audio DA1008-1 User Manual
Page 2
Audio Technologies Inc. | 154 Cooper Road #902 | West Berlin, NJ 08091 | Voice 856-719-9900 | Fax 856-719-9903 | www.
audio.com
DESCRIPTION
The DA1008/2016 output stage is capable of driving 600 ohm loads directly to
+26dBm with total freedom from crossover distortion, high inherent linearity,
100dB open loop gain and 50MHz gain bandwidth product make this an ideal
device for highest quality audio distribution. The absence of Transient
Intermodulation Distortion may be detected by the smooth effortless high
frequency output capability, the absence of the harsh, raspy sound typical of IC
amplifiers driven to full output at high frequencies and the freedom from
increasing harmonic distortion vs. frequency. A minimum of 40dB of loop gain is
available for 100: 1 distortion reduction even at 20kHz.
INPUT
Input audio feeds a unity gain balanced differential input buffer stage (A1), which
presents 30,000-ohm bridging impedance to the source. The input network is
protected by clipping diodes (Dl-D4) from over voltage inputs and bypass
capacitors (C3 and C4) for RF protection. A balance Potentiometer (R7) allows
setting a precise null for common mode hum inputs. The second half of Al
monitors the differential voltage appearing across the input terminals of the input
buffer IC to detect clipping. The input clip LED on the front panel will light if audio
inputs in excess of +26dBm peak.
OUTPUTS
Audio from the input buffer feeds eight output level adjusts potentiometers.
Output stage gain is set for approximately 24dB so that for normal unity gain
operation the audio taper pots are at 12 o'clock and provide a smooth, high-
resolution adjustment. More or less gain can be provided by changing only the
value of Rx1 (R21-R81), see Modifications.
+26dBm output level Distribution Amplifiers (-1 and -2 models) omit the current
boost stage components shown on the schematics (Q10, Q11, Q12, Q13, R13
and R18 in output 1). R13 and R18 are replaced with jumpers.
Transformer Outputs, +26dBm:
DA1008-1, DA2016-1
The outputs of A2, A4, A6 and A8 are AC coupled to the output transformer
primaries. The coupling capacitor prevents small DC offsets at the IC output from
biasing the transformer and causing low frequency distortion. Transformer
winding resistance and IC current limiting protect the outputs in the event of an
accidental output short.