electrisizer said:
thanks for helping me out!
they are 35v 33uf.
i think its a heat related problem because it happend to the caps on the lower EQ board. i have some air holes in the top of the case, so the upper EQ board has some air. the ICs run pretty hot in that build... its on 24v. perhaps ill lower the voltage a bit too.
yes, it seems is heat related, or you got a bad batch of 35v 33uf caps, it can happen also.
I don't recognize the brand of those caps you used in the build, they could be of lower quality, or they could be already in bad shape inside when used. Sometimes electrolytic caps spend decades in shelfs, so shelf life is an important issue.
Thats why I only buy electrolytic caps from a supplier that has a big rotation of stock like farnel or mouser. I only use good brands, like Panasonic or Nichicon.
I never had any of those electrolytic caps fail from use in a circuit built by me.
Do as I suggested, replace with a cap rated for an higher maximum voltage, that way the cap will be more robust to the circuit voltage and heat up less (less stress on the cap), I advive on 50V or 100V caps
Also buy Panasonic caps that are rated for 105 degrees, that way you also make sure you the caps are more robust to heat
I'm sure your caps are maximum 85degress
Any of this will solve your problem:
http://uk.farnell.com/panasonic-electronic-components/eeufc1h330/cap-alu-elec-33uf-50v-rad/dp/9692401
http://uk.farnell.com/panasonic-electronic-components/eca1jhg330/cap-alu-elec-33uf-63v-rad/dp/9693025
http://uk.farnell.com/panasonic-electronic-components/eca2ahg330/cap-alu-elec-33uf-100v-rad/dp/9694609