i understand where you are coming from you want your amp to growl but at a level that your wife/neighbors can tolerate. it is simply not that easy as prr stated. i thought i had found a way when i discovered the 6G6/G tube which is a power pentode with 2.75watts plate dissipation. it has the same pin out as a 6v6 and i was working on a silvertone se 6v6 amp that was too loud when i cranked it to a nice creamy saturation. i bought a used 6G6/g for maybe 6 or 8 bucks and when i plugged it in i got 2 surprises. 1st , the 6G6 sounded amazing. i mean this thing has killer rock and roll tone when i cranked the amp i was floored. 2nd was that it was not all that lower in volume. yes it was noticeably less volume but still pretty loud. when i took measurments the thing was dissipating 7watts at idle. which was my third surprise. so a tube doesnt just take the current it needs like some devices if the voltage is sufficiently high it will take the current that balances out via ohms law. point is you would have to mod the circuit to send less voltage to the plates/screens or else the circuit is going to squeeze more out of the lower powered tube then it was designed to handle. i figured what the hell. it (6g6) is a little lower in volume and it sounds phenomonal in this circuit, it didnt cost much so if it fries it fries... lol. i am still a newbie so i am finding the boundries of things . i design a circuit, usually cobbling together bits of other circuits with whatever transformers i have acquired and i see what it sounds like. if good then i tweak it a little until its great. if shite i dissasemble it. i am not the guy who builds fender tweed kits i want to figure out what is possible then creat my own personal tone nirvana. but that will take years hopefully.