I owned the 509's with Quad 63's many years ago and as expected thet were magic. I was told the 509's were designed for Quads. In the course of selling them, I bumped into a real 509 fan who told me how much better the amps could be with some updates of the old materials. Since I was moving in another direction, I never took the time to update my 509's but he was talking about changing all the point to point wiring, tube sockets and some internal components as well as a total cleaning and detox etc. Since the 509's are one of the "cult" amps with the Quads, it would be a shame to give up on them when they could be better than new. I have never heard anyone make a serious case that ANYTHING is better with Quads than these old amps. I'm sure someone with more tech chops than I would love to tell you about the glory of these old amps made new. I have had great luck with Chris at Parts ConXection and tube projects for greatly improved sonics. Good luck.
Amplification for stacked quads?
Hello I have a pair of wonderful stacked ESL 57. Right now I am running them with a pair of EAR 509MKII monoblocks (100WPC) but I am considering Berning's ZH-230 (30 WPC) and the integrated Jadis DA-60 (60WPC). Has anyone had experience with stacked quads? Any recommendations in general? And how about the amps I mention here? Many thanks.