Operating instructions

Front Panel
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Hi-Z - Selects the input signal coming from the front panel unbalanced ¼" jack Hi-Z
connection. ( see #6 below) Intended for the direct connection of electric guitar, electric
bass, or any instrument with a magnetic or acoustic transducer pickup, this can be set to
either 47K ohms or 2.2M ohms. The 47K ohms setting is best suited for the -10 dBv level
signals typically provided by active basses and guitars, while the 2.2M ohms setting is more
suitable for instruments with passive pickup systems. Since a particular instrument’s output
impedance may actually be somewhere between the active and passive levels, feel free to
experiment to achieve the best sound at the desired level. ( see page 24 for more
information)
(3) -15 dB PAD - Reduces the mic input signal by -15dB. (This switch has no effect on Line or Hi-Z
signal.) Use this to reduce the incoming signal in cases where undesired distortion is present at low
gain levels (for instance, where especially sensitive microphones are used on loud instruments).
(4) Polarity - Determines the polarity of the LA-610’s LINE OUTPUT. When IN ø is selected (the
normal position most of the time), the signal is in phase, and pin 2 is hot (positive). When OUT ø is
selected, the signal is out of phase, and pin 3 is hot (positive). Polarity reversal may be useful in
cases where more than one microphone is utilized in recording a source.
(5) +48 V - Most modern condenser microphones require +48 volts of phantom power to operate. This
toggle switch applies 48 volts to the LA-610 MIC INPUT when the switch is up (in the +48V position).
( See page 25 for more information about phantom power)
(6) Hi-Z Input - Connect high impedance signal from an instrument such as electric guitar or bass to
this standard unbalanced ¼" jack connector. If a connection is made to the Hi-Z input, be sure that
there is no connection also made to the Mic or Line inputs.
(7) Level - Determines the amount of signal sent to the final preamp output stage. For the cleanest,
most uncolored signal from the LA-610, set the Gain switch ( see #1 on page 4) to a low setting (-
10 or -5) while turning the Level knob until the appropriate output signal is attained.
 Keep phantom power off (switch down) when it is not required.
 To avoid loud transients, always make sure phantom power is off when connecting or
disconnecting microphones, and mute speakers.
 Always check the power requirements of your microphone with the manufacturer before
applying phantom power.
 The LA-610 Mk II differs from the orginal LA-610 with the tube used at the preamp output
stage, and now uses the 12AT7 just like the 2-610, SOLO/610 and 6176. This is a by-product
of the newly implemented “true bypass” for the LA-610 Mk II, making the preamp section
identical to its cousins when in bypass.