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Seattle WA

I recently tried to build a guitar fx pedal from freestompboxes.org And can’t get it to work. I want to know if the direction of the resistors matter. I really want to get this to work, so plz help

Here is the Schematic:

Here is what i built

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Resistors do not have polarity, so does not matter. For troubleshooting, have you measured that your opamp gets valid voltage?
You can also check all the connections with continuity test on multimeter. Also add pic of the bottom side of your build.

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Sea of Souls

Bottom pic please. I would like to see the traces which were supposed to be cut.

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Sweeeeeeden

R1, R2 are wrong value (about 10x too high value). R5 is also wrong value (about 10x too low value). I can't see R7 so can't confirm the value of it.

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Seattle WA

bottom pic
side of R3

The R2 is the correct value, as for R1, it is a 15K, since I don’t have a 12K
R7 is a 10K, you might just not be able to see it, and R5 is an 82k with a 100K soldered on top to make ~182K also FYI R3 is 4 100Ks with a 62K or something like that with some heat shrink tubing on it.

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Sea of Souls
Peter Dodge wrote:

bottom pic
side of R3

The R2 is the correct value, as for R1, it is a 15K, since I don’t have a 12K
R7 is a 10K, you might just not be able to see it, and R5 is an 82k with a 100K soldered on top to make ~182K also FYI R3 is 4 100Ks with a 62K or something like that with some heat shrink tubing on it.

You've mixed up your series- and parallel-resistance calculations. An 82k in parallel with an 100k will equal 45k. They need to be in series to get 182k. R3 is going to be way way lower with 5 resistors in the mix.

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nitro2k01 wrote:

R1, R2 are wrong value (about 10x too high value). R5 is also wrong value (about 10x too low value). I can't see R7 so can't confirm the value of it.

nitro2k01 is correct.

Peter Dodge wrote:

The R2 is the correct value,

R2 in the schematic = 1K.
R2 on your board has resistor code brown, black, orange = 10 x 10^3 = 10 * 1000 = 10K

Peter Dodge wrote:

as for R1, it is a 15K, since I don’t have a 12K

R1 on your board has resistor code brown, green, yellow = 15 x 10^4 = 15 * 10000 = 150K

Peter Dodge wrote:

R5 is an 82k with a 100K soldered on top to make ~182K

By soldering the resistors on top of each other, you have joined them in parallel. The values do not sum together (as is the case with series resistors). These 2 resistors in parallel have an equivalent resistance of ~45K.

Peter Dodge wrote:

R3 is 4 100Ks with a 62K or something like that with some heat shrink tubing on it.

Same issue as R5 above - parallel resistors do not sum together. 4 * 100K + 62K in parallel would give ~17.8K.

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Seattle WA

Oh... oops didn’t know...

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it's good practice to be consistant with the direction of your resistors on the board simply because it looks neater and is easier to read their colour codes if you need to troubleshoot

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Seattle WA

Good to know