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Preamplifier Operation / Modes
cHannel Select MoDe (a/D converter off)
figure 4 / channel mode (a/D converter off )
This is the default power on mode. In Channel Select mode the rotary encoder is used to select one of the eight
visible channels on the LCD display for adjustment. When selected, the settings for a channel can be adjusted
with the +48, PHASE, or DATA controls. Pushing the +48V or PHASE button toggles that function on or off for
that channel. Pushing the DATA control enters the Gain Adjust mode. While in Gain Adjust mode, the gain nu-
meric display characters at the top of the screen are highlighted and the rotary encoder adjusts the gain up or
down in 1.5dB steps. Pushing the DATA control again exits the Gain Adjust mode and returns to the Channel
Select mode. You will notice that changes can be made from the front panel of the preamplifier or at the RCU
and both units will always show updated data.
The bar graph meter at the right edge of each channel section is a 15 segment peak meter which indicates pre-
amplifier output levels from –35dBu to +25dBu. Unlike the typical log scale level meter in a tape recorder, the
m802 meter represents level in a mostly linear dB scale. This allows for a meter range of 60dB and useful peak
output level information up to 4dB of the output clip point. When using the peak hold feature, you will notice
that the peak hold indicator is a small line for all levels 25dBu, which is indicated with a square “box”. The
clipping level of the m802 is +25dBu. It should be noted that the bar graph meters in the m802 have an integra-
tion time that is approximately that of the DIN 45406 PPM meter standard. This means that it is possible to clip
the preamplifier on transient program material without the meter indicating a full level. This is unlike the typical
“over” indicator in a digital system which responds instantaneously to an overload.
Note: You will notice that the meter ballistics will at first seem sluggish, but this arrangement actually provides more useful infor-
mation about your peak levels and headroom status than a typical log scale meter.
cHannel Select MoDe (a/D converter on)
figure 4 / channel mode (a/D converter on)
When the optional A/D converter is installed and enabled, the m802 Channel Select Mode provides additional
A/D converter related features and display information. Control of channel parameters (Gain, Mic Power and
