Apart from a few early DIY solid state amps, the mainstay in my system have been the EAR 509 amplifiers. Since they have been doing the job of pushing around the ESLs for years so well it is only recently I thought about trying to build what I thought would be the ultimate amplifier to drive the Acoustats hence the 813 PP amplifier described here.
Over the years, I’ve found parallels in life’s journey and the development of the stereo – it’s design and realisation have certain significance. So after 20 years with the same speaker and now being driven by this monster of an amp, it dawned that the journey for this path was essentially at an end. Development would only refine the basic sound and tragically I realised, this was not the sound I’d been pursuing however good it sounded now. After 20 years, we’d grown apart.
Part of that realisation was having some 15″ Tannoy Monitor Gold speakers lying about for 18 months. A casual listen to them on an open baffle made me realise that maybe I should go on another journey – that of higher efficiency speakers and lower power amplifiers. This will enable more fun to be had exploring amplifiers and also open up the stereo to be more than a 1 person experience.
Over the years, I tried plenty of other designs for the 813 amp, E-linear, pure pentode, schade feedback but I could never get them stable, quiet or both but in 2018, had another go here.