not sure if this has been covered yet, so... the old Marshall DSL heads C12 cap mod (disconnecting the 470pf that is across the OD channel gain pot) is cap C19 in the new DSL 40 combo/100 head. sits right behind the pot on the board. I just left in place but lifted one leg of connection so that it is out of circuit. easy to put back if needed really makes a big difference in brightness (harshness to me) of the OD (red) channel if like me u run gain pretty low (and crank the volume) for a more vintage type OD tone. and really matches up the tones of red and green (clean) channels in my opinion. this really depends on your playing style, guitar, speakers, etc. some find this channel too bright but some may like the cut it provides with the cap in place. and if you are cranking up the gain pot it is probably not an issue (because the more the gain pot is turned up the more this capacitor is out of the circuit). this mod also cuts out some hiss noise. a lot of folks hate these DSLs, lot of folks love 'em, but it sounds great to me - with this mod. I can post pics if anyone needs.