LR Baggs Acoustic Reference Amplifier - Manual (Page 8)

The indicator leD lights to show that phantom power is “on.” It is generally good practice to keep Phantom Power off when it is not in
use. The button is recessed to ensure that the power does not become accidentally activated. you may use a guitar pick, pen, or long
fingernail to press in the pushbutton switch.
2) GuitaR anD micRopHone input (1/4” anD XlR comBo JacK)
The 1/4” central input is an unbalanced (mono) all discrete input with a 10 megohm impedance. It can be used with passive piezo pickups,
passive magnetic pickups or any standard active system.
The external ring on the same jack will connect an XlR to an all-discrete ultra-quiet balanced microphone preamp. The XlR input is
balanced (mono) like any common microphone input and has an input impedance of 6.8k ohms on each leg of the balanced line. This
input will work with almost any microphone, D.I. system or XlR connection.
3) Gain
The gain control is a very important feature on this amplifier. It combines the gain and individual channel level of both the XlR and the
1/4” input onto one control. The appropriate way to set this control is to increase the gain until the needle on the Vu Meter begins to
peak around “0dB” at your loudest playing level. For more detailed information, read the “setting the gain with the Vu Meters” section of
the TRICks, TIPs AnD HoW To’s section.
4) vu meteR
The Vu Meter gives you a useful visual tool to appropriately set the right amount of signal that will be running into the amplifier. The
signal should be clean well into the red and even just to the “needle-stop” point. However, the best headroom and signal-to-noise will be
found when the needle peaks just at “0dB” when playing at your loudest.
5) mute anD inDicatoR leD
each channel has a mute button that is much like a channel mute on a mixing desk. When the button is in, the signal will be muted. When
the button is out, the signal will not be muted. When muted, the leD above the mute button will light.
Because it is a channel mute, this function will not mute the speaker, only the incoming signal on each of Ch1 or Ch2. The aux input will
noT be muted using the mute functions so that you may play background music. As well, the tuner output and the Vu meters will not be
muted by the mute function.
This mute function may also be controlled by the “footswitch” option on the back of the amplifier. When a footswitch (not supplied) is
used to mute the signal, then both channels will mute at the same time. The pushbuttons on the amplifier will then be disabled from
un-muting the signal. If the channels are muted using the pushbutton mute on the amp then you cannot use the footswitch to bring the
signal out of mute. Mute on the pushbutton or on the footswitch will always dominate any attempt to unmute.
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F R o n T P A n e l
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1) pHantom poWeR anD inDicatoR leD
impoRtant note: You should always have the channel muted, the gain turned down or the master volume
down when activating or deactivating the phantom power button.
This control supplies both +48V phantom power on the XlR input and +9V “pull-up” power on the 1/4” input. use
the 48V on the XlR for microphones requiring phantom power such as a condenser mic. The 48V will also power
an lR Baggs Para Acoustic D.I. if you would like to use one. The 9V power on the 1/4” is for products that require
a “pull-up” supply such as an electret microphone capsule or the lR Baggs Buffer Jack and is supplied through a
15k ohm resistance.