It seems like the interweb answer is yes and no. In guitar and amp circuits, regarding resistors, is power (watts) additive in both series and parallel? In guitar and amp circuits, does Ohms law E=IR equally apply as does P=I^2R? If you use E=IR the answer appears to be no if voltage remains constant. If you use P=I^2R, the answer appears to be yes if amperage remains constant. The question stems from trying to build a 10% power switch using https://robrobinette.com/AB763_Modifications.htm#10%_Power_In_External_Box I wish to use two 3ohm 100W and two 4ohm 100W resistors in series to make a 6ohm and 8ohm 200W 10% power switch, suitable for a 4ohm output 10% power switch for a dual showman, twin reverb, or similar 4 power tube fender amp.