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REAR PANEL FEATURES

 

(Left to Right) 

 

1. 

VOLTAGE SELECTOR SWITCH:

 Set the Voltage Selector Switch to correspond to your 

local mains voltage. USA voltage is 115V. 

 

2. 

POWER INLET: 

Connect the appropriate power cord to the inlet, and then connect to a 

properly wired, grounded power source.  The AC mains fuse and a spare fuse are 
located in the small compartment at the bottom of the inlet.  Replace these fuses with the 
same rating and type as indicated on the voltage chart on the left side of the chassis. 

 

CAUTION: NEVER DEFEAT OR REMOVE THE GROUNDING PIN ON THE AC 
CABLE.  SERIOUS SAFETY HAZARDS COULD RESULT FROM THE REMOVAL OF 
THE SAFETY GROUND. 

 

2. 

SPEAKER JACK:

 The speaker jack is used to connect the UC4 to the built in speaker. 

NEVER CONNECT A LOAD THAT IS LOWER THAN 8 OHMS TOTAL IMPEDANCE TO 
THE UC4.  DOING SO COULD DAMAGE THE UNIT AND VOID THE WARRANTY. 

 
3. 

SPEAKER ON/OFF SWITCH:

 Used to switch the speaker on or off.  Uses include silent 

practice with headphones, or studio use. 

 
4. 

GROUND LIFT SWITCHES:

 These switches are used to eliminate ground loops when 

the Direct Out and Preamp Out XLR jacks are used.  The lift position disconnects pin 1 of 
the XLR jack.  Use the position that results in the least noise and hum. 

 
5. 

PREAMP OUT XLR JACK:

 This is a balanced, line level (0 dBm) XLR output. It is post 

EQ, post effects and post Master Volume.  It is normally used to drive an external power 
amplifier, or as an additional high level direct output.  This output is phantom power 
protected. 

 
6. 

DIRECT OUT XLR JACK:

 This a balanced, microphone level (-40 dBm) XLR output.  It is 

pre EQ, pre effects and pre Master Volume.  This output is normally used to send a 
signal to a P.A. system or recording console.  This output is phantom power protected. 

 
7. 

EFFECTS SEND: 

This unbalanced, ¼” jack sends a line level (0 dBm) signal from the 

channel effects sends to an external effects device.  This jack may also be used as an 
additional line output.  

 
8. 

EFFECTS RETURN:

 This unbalanced, ¼” jack receives the signal from an external 

effects device.  Use the Input, Output and Mix controls on the external device to control 
the relative level and wet/dry mix of the processed signal. 

 
9. 

BALANCED MIC INPUTS 1 – 4:

 These inputs accept standard, balanced XLR type 

cables.  Either dynamic or condenser low impedance microphones may be used.  If using 
condenser microphones, switch on the Phantom Power BEFORE turning on the power to 
the UC4.  DO NOT OPERATE THE PHANTOM POWER SWITCH WHILE THE 
AMPLIFIER IS TURNED ON!  A VERY LOUD THUMP COULD OCCUR WHICH COULD 
DAMAGE THE SPEAKERS, YOUR HEARING, OR BOTH!  

 
10.  

INST. INPUT 1 – 3 AND LINE INPUT 4:

 These inputs accept standard, unbalanced ¼” 

instrument cables.  Channels 1 – 3 are for low level sources such as Hi-Z microphones, 
most acoustic guitar pickups, and most keyboards.  Channel 4 will accept high level 
sources such as CD players, tape decks, some keyboards and some acoustic guitar 
pickups with very hot preamps. 

 

 

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