I've had a lot of early Fender amps and a few of the Deluxes, really great amps. What I used to do back in the early 70's is take a very short RCA cord (RCA on each end) and plug it into the reverb in/out in the back, then the reverb control would act as a master allowing you to get some pretty good distortion at low volumes , later on someone actually started making a device called the "ice cube" that did the same thing.
Found this on the web..(below)..seems I'm not the only one who remembers it:
The original Ice Cube was a little ice cube shaped device that plugged into the
reverb input and output on Fender amps. It merely connected the input and
output jacks, there may have been a resistor in there. This converted the
reverb circuit into a cheesy harsh sounding overdrive. You can get the same
effect with a wire w/ 2 RCA jacks. There was a later version that allowed you
to switch between reverb and overdrive, and may have had some controls.
Of course I know your looking for more volume initially but this is something you might want to try just for grins.... :)
Oh..I should mention, I haven't done that in decades but it does work, as a precaution tho-before making the connection ? Turn your volume down or your amp off- if memory serves it could make a loud enough noise to damage your speaker when connecting it.
AH!! I actually found one on Ebay>>
Ice Cube II[/u][/color]That "buy it now price" looks like a ^ rip-off to me unless you just bid low..but as I said it's easy to make one with a single wire.
I actually for some odd reason bought one of the later cubes but started getting back into Distortion boxes , it looked like this one>>
Sustain coupler[/u][/color]But believe me ..the prices were nothin like that back then (lol) ..so simple to make.
At the moment I'm in the same boat with you with my Marshall VS-8040 (less than 40 watts clean I think) wanting to get a louder clean sound with it but there doesn't seem to be a speaker situation or mod that I know of for it, so I usually just end up mic-ing it.
