Aurora Audio GTM822-2GN - Manual (Page 2)

All signal paths on the GTM (except the headphone jack socket on the front
panel) are balanced line level (0VU = +4dBu = 1.228 volts ac). The XLR’s are
pin 2 hot and the jack sockets are all 0.25” stereo tip/ring/sleeve type. Phone
type jack plugs should not be used, as the smaller diameter tip will not connect
properly with the TRS jack sockets.
Besides the standard channel inputs and mix outputs, there are pre-fade
insertions for the channels and stereo output, inputs for the Stereo effects return
path (which also constitute Channels 9 and 10) and Stereo playback to monitor.
The latter input allows for a quick A – B comparison of the recorded stereo
image to the original.
3. Channel functions
The GTM has 8 identical channel paths and can be extended by 8
channels at a time by plugging in additional 8 channel add-on
units.
It was always a feature of the design concepts of the GTM that it
should be easy to use and provide comprehensive information
about the signal. The channel has a stepped gain control with a
30dB range and steps of 10dB. Beside it is a fast acting LED VU
meter with a >23dB range. The LED's are three colors with –
20VU to –1VU in green, 0VU to +2VU in yellow, and +3VU in
red.
To select the appropriate channel sensitivity and maintain the best
headroom and noise figures, just rotate the input gain control
until the VU lights most LED’s but the red +3VU LED is only lit
occasionally (i.e. flashes momentarily) rather than on constantly.
If the red LED is on constantly, rotate the gain switch one click
anti-clockwise.
NB. A further 10dB gain is available at the fader.
The input channel has at least 20dB of headroom above the +3VU
(+7dBu) red LED so, provided the input gain is set at the optimal
position, the channel can accept signal levels of > +47dBu = over 55
volts of audio.
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