dgarlans, could you try attaching your multimeter in series between the + battery/power and the left side of the 33R before the reg in mA mode and just see what sort of current you are drawing when 1) nothing is playing and 2) when you are playing hard and getting the sag? It would clinch current draw being a possible offender.
nocentelli, I know these circuits work becuase other people have built them (as well as yourself) but my suspicion is, as I think you might be thinking too, that the cheap clones may only work properly given enough juice, if at all. I knew it was probably too good to be true to get 20 of them for less than 5 pounds from ebay
I do intend to breadboard this layout this week before I commit to soldering. I will also report back
EDIT: Oh yeah almost forgot, also going to add 10R between pins 3 (analog ground) and 4(digital ground) for the PTs to cut down digital noise / lockups. Saw that here, lots of success stories and going to add that into my build too https://www.diystompboxes.com/smfforum/ ... =92872.240
.. and following on from that, the two emitters to pin 4 digital ground, as well as the grounds on the delay pot and 470k to digital ground.