'THE VALVE' 3/100 Handmade Boutique 100/50 Watt 3 Channel Head in Black 4 x 12 cabinet not included What new, original features does the 3/100 Head offer? The 3/100 Head offers an array of unique features, first among which is the boost control for solos. The amp features two master volume controls, one for rhythm and one for solo, so the guitarist is free to choose from a total of 3 channels and 6 volume settings. The real bonus here is that the solo function boosts the ouput level and the gain at the same time.