STAX: Their 717 & 727 energisers

Hi Howard, Very briefly, could you tell me if there is any significant improvement in sound between the older SRM 717 and the newer 727 solid state amplifiers. Also, I would be interested if you have any opinions on third party energisers for Stax earspeakers. I’ve seen several mentioned such as KGSS and Rudistor (at a price!) and I’ve often wondered if it’s all just hype?

After extensive listening, virtually no differences of any significance and even those differences were not improvements to my ears. Re the other items you mention, I have no direct personal experience and rather than divert you with well-intentioned buy ultimately worthless speculation, I’d rather not comment.