Re: GS PSU-1

I remember the EU effectively banning it in 2010, and I personally didn't like building them, so I tried all kinds of alternatives that would meet with EU rules, as well as international standards approval (the PSU1 has an IEC CB safety certificate that cost me a fortune in 2005 to comply).

Only last year I discovered why the PSU1 works as it does. Who designed it? Well, me of course. So why so long in understanding? All I can say is that nobody else does either.

Every product in the range uses some form of capacitor coupling in avoidance of the dastardly servo (I hate DC servos), and it had taken me a lifetime to comprehend of these capacitors being "ephemeral in-circuit power supplies." There's an article on Rod Elliott's website that almost grasps it, but Rod thinks I over-think everything, so is a bit dismissive.

So, these in-circuit "ephemeral supplies" put some half wave signal rectification on ground returns, and they flow back around the power supply (the PSU1 in this case). These currents add to transformer harmonics, and those transformer harmonics cause diode phase angle lag or lead or both. And you get a regenerative distortion that you can't measure, but you can hear.

It just so happens that with a very close wired laminated transformer, rectifier and capacitive input filter, that these harmonics are far reduced in their effect, and that's what a PSU1 is.

Back in 2010, I'd extended it all out on my workbench to try alternatives, and all failed subjectively (to my ears). As each section was put back to where it was, things improved, and once all back together, the sound quality of the product being powered was back to normal.

So, I found the only loophole there was (more than one voltage at the same time) and the PSU1 was street legal again. And eventually I got John building them so I didn't have to.