BTW, only the 15ohm versions were the best sounding and only 15ohm used the Rifa capacitors. There was only a few years in production where Rogers, Chartwell, Goodman, Audio Master, Ram used the Rifa caps. Rogers used them in the late 1970’s. Rogers early production LS3/5a speakers are not the best sounding but are the most valuable. Since I am mostly a Rogers LS3/5a collector, I do not know the time period where other manufacturers used the Rifa caps inside their LS3/5a speakers but I have seen it in some of there models. Years ago, Chartwells were highly sought after by Asians and I believe it was because some, not all Chartwells contained the Rifa caps. I was a member of a forum many years ago put together by the son of one of the engineers who designed the BBC LS3/5a and we talked about this issue 25yrs ago of why do some LS3/5a’s sound better than others.