Hello - I have an '83 Marshall JCM 800 model 4010 (which is the combo version of the 2204) that I use as a head. It's almost identical to the 2204 except that it has a capacitor across the middle tone pot. Apparently Marshall did this to revoice the heads as a combo. I'm not sure exactly what it's removing, but the amp does sound a bit darker/thicker with it. In fact in it's current form I actually prefer having the stock brite caps in place. The cap on the mid pot is a 4n7 cap - so that's 4700pF. I removed it to hear what it sounds like in "head" form and it was a little bright for me...I definitely prefer having a capacitor there. I always get confused about how going up/down in value affects tone. If I'd like to still keep a cap on the mid pot but have it split the difference between the current sound and the sound with no cap what value should I use? Is it as simple as trying something around 2400pF to get right between 0 and 4700? Thanks.