Dick Byrd advised against that transformer - too many modifications required to accommodate the increased voltage.
Thanks for that information. I remember when the the ETO Alpha 70 and 77 amplifiers were new !
There was a commercial version of these amplifiers mfg. for low VHF-TV (2-6) translators in late 1960s / early 1970s. I had a chance to buy (cheap) one of those as surplus 35 years ago, lost opportunity.
Did Dick make any comments about the S-1 or S-3 replacement models?