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You can't just bung pots in like that to drop the voltage, and the decoupling capacitors need to be directly at the chips.
My 2 cents:
The coupling caps should go between pin 1 and 8 of IC1 and between pin 2 and 4 of IC3.
But that is probably only worth 2 cents, I'm sure there is more to add.
Mike
I knew before I'd ordered there were a few things wrong, this board is just for testing, I will build 2 or 3 of these and then order another revision next week. I have a surplus of pots for sure, I will use the pots to decide what input and output of the 555 would be best. I don't know yet how to change amplification of the tca opamp so I have that at unity gain and i'm using the pots to attenuate the signal. Would it be better to replace those with a voltage divider or regulator?
I thought I could get away with fewer by having them where they were. Must check if the 555 even needs them.
You set the gain of an opamp with the feedback, there are tutorials all over the net.
And you DON'T vary the supply rails to anything with pots.
Pretty well EVERYTHING needs them - electronics works on the bsis that the supply rails are at the same AC potential, that's what the decoupling capacitors do. For a 555 it's absolutely crucial, although less so for the CMOS versions.
I see. I should replace the pots with voltage dividers, I will need to look that up but I'm thinking use high values and have one resistor going to earth with the other to the output, somewhat like a pot but fixed. And I will have to keep the + and - supply the same.