A Memphis owner asked if he could use the Memphis Thirty power section as a separate power amp for use with an external preamp.
The loop return directly feeds the power amp stage (bypassing the reverb of course). To use the power amp stage only, simply activate the loop and set it to Series mode. Then use the Level switch for sensitivity range and the Level knob for volume adjustment. Note that the Loop HI/LO Level switch in this case will seem to do the opposite as it is labeled. This means that on the HI setting, you have to have a hot signal level coming out of your preamp. LO means you have to have a low level signal coming out of your preamp.
There are also a couple of tricks to set the power amp operation. The power amp stage voicing changes when switching channels. It is looser and more open in the Clean mode and tighter in the Drive mode. To select your preferred response pattern, simply switch the channel selector from Clean to Lead. On whichever channel you have selected, that channels Power Shift switch will also set the power amp stage to 18 or 30W mode.
These are very cool power amp features that will give you a lot of textural variety in your preamp settings.