There is a lot of debate among players with regard to output power on guitar amp and specifically Marshall style amps. 50W or 100W? Which one sounds better? Is 100W too loud? Is 50W loud enough? This is my perspective on this issue. For me, less is not more. More is more. When you get down to the details of the matter, a 100W amp is only 3dB louder than a 50W amp so the volume is not really a determining factor. What IS a determining factor is TONE! Having played the El Guapo and Bakersfield extensively over the past few months, I can attest that there is just the slightest difference in volume between the 100W and 50W mode. However, what you will notice immediately is how the 100W mode fills out the room and helps to tighten up the low end and gives the amp more overall headroom. That low end punch is huge contributor to what people are describing when they use words like “kerang” when a huge power chord is hit. It’s just one of the most musically inspiring sounds a guitarist can make and is something that everyone needs to experience in their playing!
Having 100W of power available does not mean that you HAVE to use all of it or that you can’t turn the amp down. You certainly can, however it’s nice to have it available when you need it. Think of a 100W amp like a Ferrari. A Ferrari can go 60MPH on the highway with everyone else but not everyone else on the highway can go 200MPH! So it you need more power for playing super clean and high volumes or you just want the low-end punch that comes from running a raging 100W amp into one of our Dual Ported Cabinets you can go wrong with a 100W amp.
That being said, if I’m designing a 100W amp, there’s no reason NOT to put a half power switch on the back of the amp. The only reason I can find to not do it is just slavish devotion to economy. With the 50W/100W switch, the player now has the option to decide for themselves which tone they prefer and can switch it as needed depending on the room or the gig.