LR Baggs Acoustic Reference Amplifier - Manual (Page 14)

3) usinG tHe efX loops
The eFX loops on the back of the amplifier are individual channel effects loops. These loops allow you to plug in external effects devices
such as rack effects units, footpedals, in-line tuners, etc. in line with each channel. A standard mono guitar or instrument cable should
be used to go from the “send” jack to the input of the external effects device. Then another standard guitar cable is to be used from the
output of the external effects device and back into the “return” jack for that same channel.
It is important to not overload the “return” input of the amplifier by turning up the output of the effects device too high. Many rack
devices and some pedals have input and output volume levels. you should try to balance the level so that the signal coming from the
effects device into the amplifier is about the same level as the signal coming from the amplifier into the effects device. you can do this by
unplugging the effects device and seeing if the volume is now much louder or quieter and then balancing accordingly.
The eFX loops are put in series with the signal path of the channel strip inside the amplifier. The signal is not interrupted until a cable is
plugged into the “return” jack. so, if you need a line level output for the individual channel, you may take a channel line out from the send
of each effects loop without affecting the signal path of the amplifier (unless this is shorted to ground - then the signal will mute).
A third use of the effects loop would be to plug a low impedance, high output device directly into the signal path and bypass all of the
eq and input circuitry of the amplifier, if so desired. The signal from the input would be switched off and the signal would come directly
from the “return” jack. However, you could simply use the aux input for this kind of setup.
noTe: see the BloCk DIAgRAM section for a visual overview of the signal routing in the amplifier.
4) WHen, HoW anD WHY to use pHantom poWeR
note: You should always have the channel muted, the gain turned down or the master volume off when activating or deactivating
the phantom power button.
The phantom power on this amplifier is a dual use control. It simultaneously turns on +48V power on the XlR input and +9V “pull-up”
power on the 1/4” input. each channel has its own phantom power switch.
The +48V phantom power on the XlR input can be used to power a condenser microphone that requires external power. As well, it can
be used to power the lR Baggs Para Acoustic D.I. preamp if so desired. The +48V is effectively supplied through two 6.8k resistors which
is the industry standard for this kind of power. Phantom power will not harm most microphones that do not require it. some unique
microphones may be damaged by phantom power so be sure to check the specification of your microphone before proceeding. We do
not warrant against damage to any device from the presence of Phantom Power.
The +9V “pull-up” power is a different type of phantom power than the +48V and is designed to be used with “pull-up” FeT devices such
as microphone capsules, and preamps such as the lR Baggs Buffer Jack. It is supplied through a 15k resistance, which is very common
and used on all of our “pull-up” supplies on other lR Baggs preamps. The +9V is supplied on the tip of the 1/4” input. If you have any other
questions about wiring your particular device, you should check with the manufacturer’s data for that device.
WaRninG: if you are plugging in an active onboard preamp, be very sure that the phantom power is off. +9v power can damage
some active preamps. lR Baggs does not warrant damage to any device from phantom power.
5) HoW to use a footsWitcH
The footswitch output is designed to allow you to use a standard shorting footswitch to activate the mute functions on both channels..
This way you can mute the device with your foot while you tune your instrument. Muting using the footswitch will activate the mute
function on both channels. When the footswitch pedal is used to mute, the mute leD’s will come on indicating that both channels are
muted. If the function is already activated at the amplifier, then the footswitch cannot bring them out of mute and vice versa.
11 12