Had a pre-revoicing MA50H for about 6 months now. Volumes are usually kept somewhere between 1.5 and 4, which is probably louder than "bedroom" and quieter than "stage."
These are my settings
CLEAN
Treble, mids, and Bass all at 3/10. Guess I find the OD channel to be too dark compared to a traditional marshall and I raise the presence to fix it, but have to dial down the clean channel to avoid ice-pickyness. But rehearsing and recording with a straight 412 in relatively confined places may have something to do with it
or putting a JJ tube in V2.
Sounds great overdriven with a clean boost out in front. Maybe even better than the OD channel.
OD
Used to use treble at 10, mids at 9, and bass at 3.
Now, after reading about how the marshall style treble and bass controls affect the upper and lower mids, I've changed to
treble at 8, mids at 7, and bass at .5 to 1.5
Gain at 3-4, crunch balance somewhere between 5 and 10 based on the style of music.
If I engage the boost, I think I get a decent 80s hot rodded sound.
The boost makes the tone brighter to my ears, so I can't really use it for high gain metal stuff. For high gain, I just set the crunch balance to 10 on OD and use a clean boost of some kind in front of the amp, with an eq (danelectro fish and chips - $30 US) in the loop to massage the mids and low end.
MASTER Section
Presence at 6 or 7.
Resonance 0-6 based on amp volume. I tried going from 0-10 today and found that I didn't really care what it was set at - the effect is subtle
Reverb at 6.
If I were gonna mod it (I'd rather not) I'd add/ change a bright cap or something to the OD channel and fix the boost so its more like a dark high gain 3rd channel.
Oh an I gave the "OD pedal in the fx loop trick" a try today. granted I was using a digitech RP multifx version of a TS and a few other OD pedals, but I didnt notice any difference on very very low pedal gain settings (2/100, or low enough to add a faint amt of distortion). Granted I don't really hear any unflattering fizz normally unless I have the volume below say 1.5 or the gain and crunch balance up to like 9 or 10. But in the second case I think most pre-amps over-over-saturate at extreme settings - its why amp makers keep adding more and more tubes for high gain users.
With a bit more OD pedal gain, it definitely got more textured and gritty and lost some of the high end fizzle that overdriven Marshalls tend to have (I'm thinking bright fizzly Page live vs middy Billy Gibbons Fandango OD). I like OD in the fx, def makes the mids more pronounced/ aggressive, like an amp thats being pushed hard.