hey guys, I was looking at the Reeves Custom 12 and I noticed that it has two el84s but only uses one 12ax7 for the preamp and has a full t/m/b tone stack. Almost all the amps I've seen has more than one preamp tube. How does that work? Are there any disadvantages/advantages tonally and functionally to using only one preamp tube verses more? I do understand one tube is used for the phase inverter. Is that all you need to make a preamp section? Just curious how it worked and was hoping someone can explain to me simply, if there is a simple answer. Tried looking it up but couldn't find any answers. I did come across someone mentioning an amp had to be utilizing solid state components if it only has 1 preamp tube. Not sure if that's true or not. Thanks!