I don’t think the crossings of pins would create voltage starving so much as have the singles fighting each other and being in phase and out of phase all over the place and thats what would create the glitchy sounds. A straight voltage starve on the supply pin would , well I’m not really sure, but for starters it might mis-bias the internals and have gating type effects while also having more dropout on fuller sounds.

Not sure what you mean about checking the data output – how would I go about this?

And the voltage starving thing, is that what’s happening already within the chip when the pins are “crossed” to create some of the glitchy sounds?

By having the 555 counter controlling the 4017 which steps out a sequence, then the 4066 doing your switching you can automate the patterns of switching on your drum machine.

If I were you I’d check first if the data output from the chip is a straight soundfile by inputing it to an amp, through a cap of course, and that would give you the basis of how the system works.It would make sense then as the sounds are modulating each other as opposed to straight mixing. That said, given it is the case, then putting a resistor on the end of each signal would mix them and a pot accros them would define the area between modulation, of sorts, and mixing.

Another thing, which may or may not work, is starving the chip on its voltage input. It’s most probably, if it can be done, a very small span of voltage, that send the outputs into territory where they just work. Too much voltage starving and the chip won’t have enough current to operate and would most likely shut down but there may be an area that yeilds interesting results.

I like the idea of the Floppy drive input. Then you can use the controller you make for other circuit bending tasks.