This question is directed towards Psycho Bass Guy. Would the GEC TT21 which is supposed to be a equivalent to a KT88 also work in place of 6146 tubes in an Ampeg SVT? It has a higher plate voltage than a KT88 and has the top anode cap as well. Or would the required modifications be as much or more work than converting from 6146's to 6550's. I was just curious as my dream amp would be a vintage 1969-1970 svt with its original 6146's.