Quad 405 current dumping amp is a very unique design. It has yet to be "truly discovered" as one of the great sounding amps. Had one on extensive loan back in late 70s, like almost a year, to drive legendary Rogers LS 3/5A speakers. Short of the mamoth sized class A DIY built Pass A40, nothing could touch it in sound quality. Since 405 was designed with Quad Electrostatic ( now often reffered to as 57 ) and its impedance characteristics in mind, it can cater to pretty violent current or voltage needs of any load. Sure did help with the LS35/As and their nearly 70 ohm peak impedance - on paper more powerful amps into 8 and 4 ohms clipped driving LS3/5A far earlier than 405 did.
"Normal" impedance characteristics of transformer driven electrostatics, like Float, is some very high value in the bass gradually falling to very low value in top treble. No idea if new QA transformer uses any measure(s) to try to "equalize" this wild impedance characteristic to something more approaching to pure ohmic loads - but if it does not, Quad 405 is a very good match to drive it indeed. It has about the right amount of power to drive Float correctly.
There is quite a lot of info on the modding of the 405 on the web - generally, making an already great sounding by now vintage amp even better. Despite not being a class A amp, 405's particular forte is playing at low levels, where it is clearer than more conventional AB amps and where most of the music, likely to be listened with Float, really happens. That is not to say there is something to be desired in loud passages - on the contrary, 405 will hold its own.
Can't wait to see/hear what the first impressions on Jecklin Float QA, driven by 405 - or anything else, would be !
