I have a similiar amp - a Peavey Bravo that has 3 preamp tubes, 2
EL 84's for the output, approx 20 watt output, but with a 12" speaker. I also use this at church, but it was too loud, and the high gain channel was too saturated. I used a 12 AT7 in the the second position and it cleaned that channel up quite a bit. If I were you, I would try just one 5721 in each position, two may cut it back too much. I also put in a speaker I had that happened to be less efficient. If you want a clean sound at a higher volume than what you are presently getting, you will need to change the speaker, or use an extension cab, with maybe a 12". Changing from one type of output tube to another may yield a little less distortion, or a tiny bit more headroom, but it will be very subtle if even noticeable at all. Any headroom gained by a more powerful tube may go to waste, however, if the output transformer is already reaching its saturation point. If a heftier output tube were capable of delivering an extra watt or 2, that would not be enough to be noticeable. You would have to DOUBLE the output power to gain 3 db (6 db is considered to be "twice as loud") and quadruple the output to gain 6db and be "twice as loud". Now speakers vary a LOT in their efficiency, typically 94 to 101 db/watt at 1 meter for 12", the one rated at 101 would be TWICE as loud as as the 94. This means that your 20 watter with a speaker rated at 100-101db would be as loud as an 80 watt amp with a speaker rated at 94 ( not accounting for speaker saturation...) Anyway, I don't know what the rating would be for the Emminence 10" in yer PV, probably in the middle somewhere, but a real efficient speaker like
a Celestion Vintage 30 would yield a lot more sonic output, allowing you to leave the volume turned down into the cleaner range of the amp...
EL 84's ROCK tho, don't they! Good luck my brother.
