What did I do wrong in LTSpice

[mkiijam]

I simulated a op amp based little guitar pedal for fun and then build it. I had tons of problems with the AC coupling I was doing and DC building up on the caps. A lot of which I solved by adding resistor to various places. But my question is: the issues didn't show up in spice. I was just using generic op amp models, should I make the op amps and the caps more realistic or something?

[langwadt]

you have to show what you did, no one can guess what you did. It sounds like you randomly added resistors in random places without understanding why, that is probably not the best way to go out it

[SiliconWizard]

How can we know if you don't post your LTSpice schematic, and your simulation parameters?

What do you mean by "generic opamp models"? Which did you use? LTSpice has a ton of models for real opamps, and even if there isn't exactly the one you're gonna use, just pick something similar.
I don't know what their "generic opamp" does, but apart from having probably ideal characteristics, one thing that will be missing are internal diode clamps on inputs, which may make a big difference if you're not biasing the opamp properly (were you using a single supply?)

[Ian.M]

LTspice UniversalOpamp models default to 500Meg input resistance.  In most circuits that keeps the input bias current under a few tens of nA.   Most real OPAMPs not specifically sold  as ultra-low input bias current ones have significantly higher and often asymmetric input bias currents.  You also have to consider board surface leakage.  The general rule is both inputs must have a DC path to either the output or to ground for an OPAMP to function, and in high impedance or high accuracy circuits, ideally the equivalent resistance to ground as seen by each input should be equal so the offsets caused by the input bias current flowing through the resistances feeding the inputs tend to cancel out.

[mkiijam]

LTspice UniversalOpamp models default to 500Meg input resistance.  In most circuits that keeps the input bias current under a few tens of nA.   Most real OPAMPs not specifically sold  as ultra-low input bias current ones have significantly higher and often asymmetric input bias currents.  You also have to consider board surface leakage.  The general rule is both inputs must have a DC path to either the output or to ground for an OPAMP to function, and in high impedance or high accuracy circuits, ideally the equivalent resistance to ground as seen by each input should be equal so the offsets caused by the input bias current flowing through the resistances feeding the inputs tend to cancel out.

Thank you so much.