I have a Rivera KR100 that I love very much, but somehow I've managed to put off a retube for it for uh...
My abilities to procrastinate are legendary. (Though I did have other tube amps on hand for most of the procrastination)
Tell me what to buy forthwith, so I can do it ASAP. 4 EL34s 5 pre tubes, pretty standard config.
V1 preamp tube:
Preamp tubes are good until they're not; just play them until they burn out, since V1 is really the only one that effects your tone. The rest are just gain stages.