lewm,
The EA-230 (great amp, btw) was the last Berning amplifier to use a linear power supply, so hearing switching noise from it would be impossible. Every amp and preamp thereafter used SMPSs (we're talking the 1980's here, just to give you an idea of how advanced the man's thinking is). I've used various Berning amps over the years, and the ZH270 is still one of the finest sounding amplifiers I've heard.
The EA-230 (great amp, btw) was the last Berning amplifier to use a linear power supply, so hearing switching noise from it would be impossible. Every amp and preamp thereafter used SMPSs (we're talking the 1980's here, just to give you an idea of how advanced the man's thinking is). I've used various Berning amps over the years, and the ZH270 is still one of the finest sounding amplifiers I've heard.