I have both , several 50w and 100w Plexis ( yes I collect them):
50W more midrange, more Distortion early in volume knob, fuller sound, softer feel, great for leads, singing quality "WOWIWAH"
100W more 'scooped', stays cleaner longer in volume knob, hard attack, more fizz on top, great for...
THESE VERY RARE TUBES are the missing link for the true EVH tone,
same tubes he used in his Legendary 12 series Plexi Marshall SuperLead.
See pics below of Eddie's amp.
They do not sound and react like 'normal' EL34s
FULL MATCHING QUAD with MATCHING DATE CODES (label RCA) +1 Spare ! ( spare is...