First of all, the Mark series was built to perform live with which means played loud and the Mark IV is no different. One reason the middle channel gets a bad name is that the first and third channels are so so great. If you play at home at low volume, ch. 2 is not really all that fun when you have 1 & 3 available.
But, if you perform live, ch. 2 is where you'll live if you play classic rock & roll because it is the tone that is in 90% of the tunes. Ch. 1 & 3 don't need or want a boost pedal but ch. 2 likes to get boosted when needed and will take the boost like a champ. I have the amp set at full power, pentode, simul-class and I like to keep the channels Master volume up at around 8 and the Master volume low at around 2-3, I've never had it above 3 ever, the amp is that loud!!!
But, if you perform live, ch. 2 is where you'll live if you play classic rock & roll because it is the tone that is in 90% of the tunes. Ch. 1 & 3 don't need or want a boost pedal but ch. 2 likes to get boosted when needed and will take the boost like a champ. I have the amp set at full power, pentode, simul-class and I like to keep the channels Master volume up at around 8 and the Master volume low at around 2-3, I've never had it above 3 ever, the amp is that loud!!!