I finished this, but sadly, I can’t get it to work. @tamasgal and @Swirv seem to have built theirs using this layout, so I take that it’s been verified independently, so not an issue of the layout.
I seem to get some output only from the highpass. I checked the stripboard cuts before populating, the LM13700 (it works), the supply before powering on, my soldering is rather tidy, and aside from a stupid mistake in plugging in the TL074 backwards (I discarded it just in case), I cannot spot something wrong.
Obviously, I must have done something stupid, so I would appreciate it if I could have a couple of extra pairs of eyes check this. Perhaps someone familiar with the circuit could suggest where to start the troubleshooting with a multimeter or oscilloscope.
