Thanks so far, Steven...
I don't understand very well what you mean by :
I never dared to build as small as that, since kicking them in always moves them a feet
But yes, the challenge is to enter all
the stuff of a standard stompbox in a 1590A : you need to study the size and relative position of the elements; that's the main task, in fact.
On this forum, there is many talented 1590A specialists (with graphic artwork way more sophisticated than my "plexi" method), but usually the units are not standalone and require external supply, compulsory to save space for more complex circuits, like phasers, flangers... Most of them being designed for a pedalboard use.
I like very much this pedalboard-friendly box format, but as I do not use pedalboard, a standalone unit was unavoidable for me, an the idea to power it by the A23 battery is a very good idea, moreover coming from one of you from this forum (sorry, I do not remember the name !). And it works well !
I am planning to build in this "1590A-standalone-compact-complete" style an IC-based overdrive, and a non-photocell tremolo. Wait and see...