The problem is a misunderstanding of how the amp works. On certain Mesa/Boogie models (a list is below), turning on the amp’s effects loop not only engages the effects but also activates the Solo level for all channels. Because of this, the effects loop send level must be turned up to an appropriate point (usually 50% is a good starting point) in order to drive the Solo level function. Raising the effects loop send does not increase gain, rather it sets the volume level when the loop is engaged.
- Low settings of the Send level will result in low volume from the amp.
- Medium settings will result in the best performance.
- High Send level settings may overload the amp resulting in a muddy sound.
Amps with Mesa/Boogie’s Loop Driven Output and Solo Feature: