Well, I only have a few boards left of my PSU-2448mk2 kit.... less than a dozen left. So if you need them, place your order early before I run out of stock.
I'm debating whether to just do another run of the 2448mk2, or upgrade my PSU design.
The most common request to my PSU boards is adding a 4th voltage rail. People want another +5V or +12V to use.... maybe they want to power some relays, or add some digital logic, or whatever.
Of course, one can easily hang a 7805 or 7812 or 317 regulator on the V+ output and you get your 4th voltage but it's not as elegant as having all parts on a single PSU board. Also, I don't want to use a 7805 or 7812 or even another 317 regulator for the 4th voltage rail to bring down the voltage to +12 or worse, +5V low.
That's going to be a lot of wasted energy and will result in high heat dissipation in the regulators and therefore, requiring the use of big or heavy heatsinks. Plus, it will also increase the ambient temperature inside your rack case with all that heat generated.
So the next Fivefish PSU version will have a 4th voltage rail and will be using switching regulators instead of linear regulators (but only for that 4th voltage rail).
The nice thing is the 4th voltage rail can be configured for +5, +9 or +12V output. They'll be running at 80% efficiency, requires no heatsink, and will generate no heat. Yes, no HEAT.
It will also be using a high switching frequency beyond the audio range.
At first I was worried about switching noise screwing everything up but I've tested this PSU configuration in a mic pre and it's audio-friendly. Not all switching PSU are bad! That's an old myth.
Also, I'm calling my 4th voltage rail my "digital psu output" and the 4th voltage rail will be electrically isolated from the rest of the linear +/-V, 48V section. I'm thinking the typical function of this 4th voltage rail will be for powering digital circuits or powering small relays, or just lighting up some LEDs.
The digital psu output will even have it's own Ground line. Of course, you can tie the Ground line of the digital output to the GND line of the linear regulators. But it's up to you. I'll just provide a jumper on the board if you want to do that.