LEXICON MPXR1
User Guide

The MPX R1 as a Dedicated MPX 1 Controller

Using the MPX 1 and the MPX R1 in a Preamp/Power Amp If you are using the MPX 1 in a dry/wet (3-way) rig, refer to the following section on using a parallel effects loop. Rig or a Dry/Wet (3-Way) Rig

If you are using the MPX 1 between a guitar preamp and power amp, refer to the following section on using a series effect loop.

On the MPX 1: Press System and make the following adjustments. � Set Pgm Bypass to Bypass. � Set Audio Bypass Level to �3dB. (These settings will ensure that audio will be smooth and uninterrupted during program changes.) � Set Bypass Mode to Bypass. (You will hear dry guitar when bypass is on.) � Set Mix Mode to Program so that each program will load with its own independent master wet/dry mix value. (The master mix value for each preset is initially set to work with the MPX 1 in a series effect loop.) Adjust Mix and Level Values as follows: � To adjust the overall mix of dry guitar to all effects in any program: press Mix, select Mstr Mix, and change the value to suite your taste. � To adjust the mix or level or any of the effects in the program: press Mix, select the Mix or Level parameter for the desired effect block and adjust. If you want to make the changes permanent, be sure to store your changes before loading a new program. Set Input and Output Levels: Before powering up the guitar amp, make your audio connections, turn the MPX 1 Output Level all the way down, and turn your guitar amp master volume all the way down. This can be a little tricky, since you must set the MPX 1 output level to match the level of the preamp with nothing connected in the loop. If the levels are too low, the amp will not have its usual power and tone. If the levels are too high, you may overload the power amp � causing unwanted distortion. If your amp has a loop bypass (like a Mesa/Boogie Mk IV), it�s pretty easy to match the levels. If not, it will take a little more work. The extra effort is worth it � when the levels are properly matched, your amp�s tone will be unaffected and you will be able to use phase shifter, tremolo, wah and other �in-line� effects to their fullest potential. � Power up the amp. � Load MPX 1 Preset 100 Guitar Solo. � Press Bypass. � Set the preamp controls to the highest gain settings you�ll be using. � Turn up the MPX 1 Input Level control so that the 0 dB lights occasionally, then back it off a bit.

Using a Series Loop

What kind of effects loop do you have?
In a series effects loop, the entire preamp signal passes through the MPX 1. (If you turn down the MPX 1 Output Level control, no sound comes out of the amplifier.) In a parallel loop, the preamp signal is routed directly to the power amp and the MPX 1 output is mixed with it. (If you turn down the MPX 1 Output Level control, you still hear the guitar at normal level.) Some amps have a mix control for the loop. This is sometimes a switch labeled �50/50� or �mix,�or a mix pot with a range of 0-100%. These controls allow you to use the loop as either series or parallel. With a switch, the 50/50, or mix, position corresponds to parallel, the other position corresponds to series. In the case of a mix pot, 100% corresponds to series and all other positions are parallel. (Halfway or 50% is a good starting place.) 3-5