Front Panel
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- 4 -
(1)
Gain -
Adjusts the gain of the input stage in stepped 5 dB increments. Turning the Gain switch
clockwise raises the gain. Because this also has the effect of reducing negative feedback (
see
page 24
), the Gain switch also alters the amount of the input tube’s harmonic distortion, a major
contribution to the “warm” sound characteristic of tube equipment. The higher the Gain setting, the
more coloration the LA-610 will impart to the incoming signal.
(2)
Input Select -
Determines which of the following three inputs is active: Mic, Line, or Hi-Z.
The Mic and Hi-Z inputs each provide two different impedance settings.
Mic -
Selects the input signal coming from the rear panel balanced XLR MIC INPUT
connection. (
see #3 on page 8
) The impedance for the Mic input can be set to 500 ohms
or 2.0K ohms. Switching between these two positions while listening to a connected
microphone may reveal a different tonal quality and/or gain difference (be sure to carefully
level-match when doing comparisons because louder tends to sound better). Typically, a
microphone preamplifier should have input impedance roughly equal to about 10 times the
microphone output impedance. For example, if your microphone has an output impedance of
approximately 200 ohms, the switch should be set to the 2.0K position. However, making
music is not necessarily about adhering to technical specifications, so feel free to
experiment with the settings to attain the desired sound: you will not harm your microphone
or the LA-610.
Line -
Selects the input signal coming from the rear panel balanced XLR LINE INPUT
connection. (
see #2 on page 8
) This connection has an input impedance of approximately
13K ohms
and is intended to accommodate mixers, DAWs, tape machines, other mic
preamps, signal processors, or any device with a line level output, such as keyboards, sound
modules and drum machines. Using this input, the LA-610 can act as a “tone box” for line-
level signals, offering a variety of sonic colors based on front panel control settings.
The LA-610 MkII makes improvements over the orginal LA-610 with regard to the accuracy
of the stepped Gain switch’s presented dB value. (for example, -10 dB truly is -10 dB).
