as far as I understand the power supply project, it's about how a professional engineer turns a project into reality.
Yes, and no. It's how a professional engineer develops a hobby project for their own enjoyment, based on many whims that change often.
And iirc one of the design goals was through-hole, because you wanted a kit, right?
Correct, that's what I originally wanted.
Shouldn't you have checked the cost of pre-soldered SMD vs. self-assembled through-hole before you choose all parts according to their availability in through-hole casings?
I already know that a through-hole kit wouldn't save much, if anything, and may in fact be limiting the design in various ways.
I did it because I
wanted a through-hole kit, not because it was the best or lowest cost option.
I became kind of infatuated with the kit idea at the time.
I now possibly changing my mind. That's allowed
And before you've gone through two revisions of a board for these through-hole components? You've already invested a lot in the through-hole kit, time and money, and I can't really understand why you make such a drastic change in your design, so late in the game.
Drastic?
It actually won't cost me a cent, because I have to re-spin the board anyway. All it will cost me is a day or two tops to lay out a new SMD version of the board, no biggie. My existing boards and proto parts can still be used to build up functional units, so no waste.
And what's bugging me even more, why didn't you check the cost before you went through all that work? You're a very experienced engineer, which you've proven over the years again and again in your blogs and especially in your power supply series. And that's why I just can't comprehend this sudden and drastic change. I'd expected that you would've checked this up front and can't really believe that you didn't. Especially because you so often talk about production cost and what possible cost factors are and then all your (recent) blogs about the cost for kitting something up vs. shipping it pre-soldered.
You don't get it. It's not about getting something "right" up front, as there is no "best" or right solution for these types of personal projects. It's about having fun on a personal pet project and seeing where it goes and very often changing your mind on a lot of things. I wanted a kit because I thought that would be kind of cool, like I've done many times in the past, not because I methodically went through the sums and deemed that was the best option.
A "drastic" change would be changing the architecture completely or functionality in some big way. Just changing from through-hole to SMD is fairly trivial and actually costs nothing.
I didn't suddenly realise today that "OMG, I can't believe that an SMD assembled board will likely cost the same as a through-hole kit". I knew that was likely.
Just some discussion with the assembler today was the catalyst to get me to re-think my infatuation with the kit idea.
The project has morphed and changed in many ways, and in many ways you haven't seen on the blog. And those changes are often done on whims, simply because I want to, not because it's the "best", cheapest, simplest, or whatever option.
Dave.