First pedal ever works . . . but the output is low

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portugalwillie
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Post by portugalwillie »

so, built my first pedal ever after a lot of soldering/installing pickups, switches, and all kinds of stuff on a guitar.

I used this veroboard layout, which has been confirmed: Image

I couldn't find those exact transistors so I used a BC547BG and 2N3904TF

so, after mild success i was excited then built a booster with this (also verified) veroboard layout:
Image

exact same problem. Being new to this, I think it's a power issue but I really can't back that up with a shred of evidence. I'm also using a 4k7 resistor on the LEDs but I don't think that's significant.

soooo, what gives?

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PokeyPete
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Post by PokeyPete »

On your first example, I assume that you used the 2n3904 where the original called for a 2n3904.
That would mean that you swapped a BC547 for the BC182L. You are aware that the pin out for
these two transistors are different, right?

You don't state any "swaps" on the second circuit so no idea what is causing your issue.
Just be aware that the pot is audio tapered, and make sure you pay attention to which way you
wire it....you could be turning it 'down' when you think you're turning it 'up'.
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Lucifer
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Post by Lucifer »

You could also look at the track cuts to make sure that they are clean, with no slivers bridging the cuts.

I notice that there is a cut under C4 on the first layout (the Meathead). If this were missed it would feed DC to the pot and you'd probably get some crackling noise when you turn it.

However, there don't seem to be any 'hidden' track cuts on the second layout, so it could just be slivers bridging the cuts (as mentioned above), solder bridges between tracks, or dodgy solder joints.

I've found that veroboard can oxidise, making it difficult to get good soldered joints, so I now always give mine a light sanding before putting any components on it. This would probably remove any slivers too.
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