Randall RM100 Owner's Manual - page 6

Rear panel special features and controls:

MIDI in/thru:

Connect the included 7-pin MIDI footswitch and cable to the MIDI in.  The thru can be run to any external effects processor, which can then

be used to program effects to your different module channels.      

Tube Bias Section:

This amplifier includes a biasing section for changing or replacing your power tubes.  When changing power tubes it is very important you

bias each tube correctly for optimal preformance.   See the bias section on page following page.

Impedance select: 

From the factory your head has been preset to the 8 ohm position. When using an external speaker cabinet, you may adjust this switch for

proper ohm load of you external speaker cabinet.  

Parallel effects loop:

Used to connect any outboard effect processors.   Use the parallel effects loop for “time based” effects,  such as delays, reverb, etc. The

desired effect can than be adjusted using the front panel mix control.  See detailed uses of the parallel loop on page 9-10 of this manual.

Series effects loop:

Also used to connect your outboard effect processors.  A general effects loop, not to be used with the front panel mix control. See detailed

uses of the parallel loop on page 9-10 of this manual.

Effects loop tubes:

Each effects loop utilizes two 12AX7 tubes to buffer your processing gear.   Any outboard effects processing used through the effects

loops, go through the tubes to warm the sound of any signal processing.

Common Input tube:

Each module also utilizes one common input tube, installed on the top panel of the amplifier.  Your guitar signal always passes through this

input tube first before each module,  so each preamp modules uses three 12AX7 preamp tubes to help generate the pure tube tone.