Universal Audio LA-610 Channel Strip - Manual (Page 8)

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level output, such as keyboards, sound modules and drum machines. The LA-610
may be used as a “tone box” in this configuration, offering a variety of sonic colors
based on the front panel control settings.
• Hi-Z: Selects the signal from the front panel, unbalanced Hi-Z 1/4”connector. This
input can have an input impedance of 47K
or 2.2M
and is intended for bass,
guitar or any instrument with a magnetic or acoustic transducer pickup. The 47K

setting is best suited for -10 dBv level signals, typically found on active basses and
guitars. The 2.2M
setting is appropriate for instruments with passive pickup
systems. Since an instrument’s output impedance may be somewhere between the
active and passive levels, feel free to experiment to achieve the best sound at the
desired level.
Gain
The Gain control adjusts the gain of the input stage in 5 dB increments. Turning the
switch clockwise reduces the negative feedback, which raises the gain. In addition to
changing the volume, the Gain control also alters the amount of the tube’s harmonic
distortion, a major contribution to the warm sound characteristic of tube equipment.
Level
The Level knob is the master volume control. It determines the amount of signal from the
preamplifier gain stage sent to the compressor stage. The cleanest signal is attained by
setting the Level knob between 7 and 10 on the scale, then turning the Gain knob until the
desired level is attained. Altering the Gain, Impedance, and Output controls together
provides many useful tonal variations. The numeric values on the front panel for the
Level control denote magnitude and are NOT specific dB values. The Level control also
effects the threshold point where the compressor begins to affect the signal level. With
the level up high, the compressor PEAK control will need to be set lower for subtle
compression. With the LEVEL set low, the compressor PEAK control will need to be set
higher for agressive compression.
Pad
The front panel toggle switch labeled PAD will attenuate the Mic input level by 15dB
when the switch is “up”. When undesired distortion is present at low gain levels it is
recommended to engage the Pad switch then turn up the GAIN control as needed.
Polarity
The front panel toggle switch labeled IN 
and OUT  determines the polarity of the
LINE OUTPUT. When IN  is selected, pin 2 is hot (positive). When OUT  is
selected, pin 3 is hot (positive).
+48 V (Phantom Power)
Most modern condenser mics require phantom voltage to operate and we recommend
checking the requirements of your microphones before connecting them. It is good
practice to keep phantom power off (switch down) when it is not required. To avoid loud
transients, always keep the phantom power off when connecting or disconnecting
microphones.
EQ Controls
The 610 has both low and high frequency shelving-type equalizers, each with two
controls: