Well, My buddy has had his Hot rod deville 4x10 for about a year, and recently he's told me he cannot hear the same dynamic change on it when he coil taps/uses the voicing switch on his new guitar. He refuses to get a new amp, as he is some crazy perfectionist who believes he will never get ultimate tone unless he builds his own amp. I think he could use a tube change though... What do you think would be the best tubes to drive the Deville (or at least make the overdrive channel he abuses sound better)?