Best 7581A listed at

7581A (Uprated sub for 6L6GC) (7581A is a good substitute for 6L6GC, uprated power, smooth sound) - Ampeg VT22 - Fender Bassman 1969 - SunValley VP-3488SE - Fender Vibrolux reverb 1971 - Fender Super Reverb 1970

GE: -- 1 pair $199) 7581A GE NOS original boxes around 1970 1 tube) 55ma branded Amperex 1 tube) 52.5ma branded RCA 1 pair $179) 7581A GE NOS no printing 1970 large getters in white boxes (best value) 1 tube) 55ma glass slightly tilted 1 tube) 57.2ma SINGLE TUBES: ------------ black base: ---------- 1 tube $90) 7581A GE NOS rebranded RCA 1970's (70ma)