Instrument / Linefront - RME Audio Fireface UCX User Manual

21.3 Instrument / Line Front
Inputs 3/4 of the Fireface UCX are exceptionally flexible. Several gain and impedance options
make them the ideal receivers for both line and instrument signals.
Line
Inputs 3/4 have balanced line inputs as 1/4" TRS jacks. The electronic input stage is built in a
servo balanced design which handles unbalanced (mono jacks) and balanced (stereo jacks)
correctly, automatically adjusting the level reference.
When using unbalanced cables with TRS jacks: be sure to connect the 'ring' contact of the
TRS jack to ground. Otherwise noise may occur, caused by the unconnected negative input
of the balanced input.
Inputs 3/4 operate in perfect harmony with the rear inputs 5 to 8, as they are identical in all tech-
nical specifications. But they have their own reference level setting, independent from the set-
ting selected for input 5 to 8, and they have
Adjustable Input Gain
Via Gain in TotalMix channel settings, or by using the rotary encoder on the front, an additional
gain can be applied to the input signals of channels 3/4. The gain range is 0 dB up to 12 dB, in
steps of 0.5 dB. This option not only allows for the use of sources with low level output signals,
but also for example to adjust the balance between channel 3 and 4 precisely, already before
the recording takes place.
Three reference levels plus 12 dB adjustable gain turns these high-quality inputs into a univer-
sal connectivity solution that can't be beaten. Be it keyboards, samplers, CD players or what
ever you have: These inputs handle levels from –7.5 dBu up to +19 dBu. Thus the unit can also
be used as Line gain amplifier. But wait, there is one more! Inputs 3 and 4 also handle your
Instrument
The main difference between a line- and instrument input is the input's impedance. Via the op-
tion Inst in the TotalMix channel settings, the input impedance changes from 10 kOhm to 470
kOhm (also called Hi-Z). At the same time the input sensitivity rises by 6 dB.
The instrument input operates unbalanced. Please don't use (stereo) TRS jacks in that mode.
For AutoSet please read chapter 21.2.
Overall the inputs 3/4 can work with levels from –13.5 dBu up to +19 dBu. Two LEDs display a
present signal (from –60 dBFS on) and warn against overload (0 dBFS).
User's Guide Fireface UCX © RME
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