At this point I think I have added all the stuff and done all the modifications I had in mind for LittleSixteen V3. Thus it is about time to refine the power circuit. I am not particularly keen at this kind of thing but luckily fellow Edoardo, who already helped a lot with Rämixx500, joined this project too, and talked me into the following circuit:

This still relies on the original +9VDC power supply alone with the TSR-2450 regulating that to +5V providing up to 2A. We went heavy with the filtering since switching regulators might introduce high-frequency noise. We also added a TVS diode that will cut overvoltage/ESD transients on the +9VDC rail while also providing protection against reverse polarity, which is important to have since the C16 uses a center-negative barrel connector that is relatively unusual these days and people might be tempted to plug a center-positive one into it

Fitting everything in the already crammed connectors zone (it might not look like that at first, but you'll realize if you take a look at the underside...) wasn't exactly easy, but I managed to do it:

You can rest assured that the voltages you are going to feed your LittleSixteen with will be much cleaner than those in an original C16! Your 8501 and TED will be delighted :).