After doing this mod what I did is add a aux. speaker jack to the back that disconnects the main speaker and pluged the amp into a 12" Jensen. You could also change the 2) .01 caps going to the final output tubes to .1
As of September 2011 I have change the .o22 just after the second gain stage to a .0056. To tell you the truth I think this amp makes a great acoustic guitar amp. try it