popping bass noise/slow motorboating because of polar caps

[preciousmolina666]

i got this weird noise on my non-inverting opamp gain of 10,i  begin to add 200ohm series in power supply section, and the pop noise noise beging to slow down, and tried to change 100uf to 1000uf in power supply section, and the pop begin to slow more but still there, and found out the the prob is in my input dc blocking, the polar electrolytic 1uf, i tried to reverse it (guitar to negative side of caps) and the prob is gone, why is that? i thought (guitar-positive side electrolytic) or is there something wrong in my project?

[thermionix]

You didn't say what it is, but for a negative ground pedal with a polarized input cap, yeah the negative side of the cap is usually toward the input.

[duck_arse]

if your pedal has a pull-down resistor on the input cap, which end negative point to becomes rather obvious.

[antonis]

Replace it with a non-polarized one...

[preciousmolina666]

You didn't say what it is, but for a negative ground pedal with a polarized input cap, yeah the negative side of the cap is usually toward the input.

i always see on opamp schematic

if your pedal has a pull-down resistor on the input cap, which end negative point to becomes rather obvious.

i see, because i never had an issue with this before, thanks

Replace it with a non-polarized one...

i want to know why,im afraid if thers a fault in my components because i never had this problem before

[thermionix]

Sorry, but I thought you fixed the problem when you reversed the cap...?

[anotherjim]

Nobody mentioned "leakage current".

The op-amp input is "biased" to about half supply reference voltage, about 4.5v in a 9v pedal. This is done by connection the input via a high value resistor.
A guitar output is "ground referenced" because the pickup coils and control potentiometers are connected to ground. There is a relatively low resistance between the guitar output signal and ground.
There is, therefore 4.5v between the op-amp input and the guitar.
If no input capacitors is fitted, the op-amp input will be grounded by the guitar, forcing your non-inverting amp output pin to swing as close to the 0v supply as it can.
With the input capacitor, this capacitor will charge initially to 4.5v. Then the amp will be correctly biased. Used this way, to separate two different reference levels , the capacitor is called "DC blocking".

If a polarised capacitors is used, it must be correctly polarised. This would be the positive of the cap to the 4.5v amp input and the negative to the ground referenced guitar.

All electrolytic capacitors can pass a small amount of DC current. It is called the "leakage current". With the correct polarity voltage across them, the leakage current is very small, pico-amps. However, if connected to reverse polarity, the leakage current will be much larger, milli-amps. In reverse, these capacitors behave as though they had a resistor connected across them and its a bad resistor at that. The op-amp input now sees ground through the leakage and it's output level will change accordingly.