Hey guys, so I've been dabbing in pedal building for a while now and with some success. But dear god this circuit has left me scratching my head and I decided to ask for help... I got the layout from here.
Now, let me explain what's wrong with it. I've never built a circuit with LFO and this was my first time but it seems to be working. The LED flashes when I strum strings and it seems to be fine. But the problem is, there is barely any signal coming through. I had to turn up the amp quite a bit to realize that there is some raspy, buzzy fuzz coming but it's all very dirty, noisy and without any delay. Things I have done so far... I have double checked all the cuts, components and it looks like I didn't miss or misplace anything. Then, of course, I cut the tracks with a knife. Also, reflow all the solder. I did find a couple of mistakes with the Volume and Blend pot wiring but fixing it didn't bring the circuit to life, didn't even change anything, really. The pots seem to react with the way the LED lashes/glows but the Volume pot seems to do nothing at all... I have tried a few different PT2399, the LM386 and 78L05 and it was just the same. Now, for the voltage readings. I had all the pots fully CW and the fuzz switch ON: PT2399 1. 4.94 9. 2.47 2. 2.46 10. 2.47 3. 0 11. 2.47 4. 0 12. 2.45 5. ~1.7 13. 2.47 6. 2.3 14. 2.49 7. 1.4 15. 2.47 8. 1.44 16. 2.47 LM386N 1. 1.38 5. 7.58 2. 0.02 6. 8.3 3. 0 7. 4.16 4. 0 8. 1.38 L78L05 I. 8.3 G. 0 O. 4.95 PICTURE GALLERY HERE
aka Dead Eye
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Hey!
Maybe asking the obvious, but have you taped the LDR and the led together? If you test it outside the box, and the LDR is picking up any other light besides the LED, it might have that effect? I have built the same layout from this site and all was working perfectly. |
Thanks for the reply! No I haven't taped the LED as I was testing with different colours. What I did was I put an non drilled empty enclosure over the circuit to stop the light from coming in when testing it. I don't think this is the problem though but I'll try taping it later anyway and see what it does as I'm pretty desperate now.
aka Dead Eye
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from the back of your board, i can see that at pin1 of pt2399, it seems like you have an other connection under the chip. is that right? or you've just desoldered something and that's why a see that.
(also why are you soldering the small 2x5 board on your pots that way?isn't it more difficult to solder? i have my soldering side facing outside so that i can solder my wires with clear view. ) |
Ah I see what you mean. I think it's just excess solder there but I'll check if the link is in the right place under the pt2399. I really don't know why I oriented the 2x5 boards that way. Maybe so the wires can look a bit neater, anyways, it wasn't much of a problem to solder.
aka Dead Eye
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I'm sorry, I'm not really good at this stuff yet, but did check all of your components, and didn't see anything out of place.
I did learn that you can replace a polarized cap with a non polarized, like in the top right.. I usually make mistakes in the wiring, that's why I always use the same colors. Always. Blue for output and black for ground. Do you do the same? Cause in that case I would say that the wires to lugs 1 and 2 of the volume pot are switched. Or was that what you meant i nyour comment about the vollume/blend wiring? (if anything it bumps your question ;) ) |
Hey. The polar cap at the top right is actually a tantalum. And the volume wiring colours are off because I had it wired wrong earlier but then fixed it (ground and output). I checked the solder next to pt2399 lug 1 is just excess solder. So after checking the board the 20th time, I am absolutely certain that there is no mistake anywhere.
Today I'll go through it with an audio probe and check resistance values on the pots. I'm thinking, maybe by squeezing them into the 2x5 vero, I damaged the pots somehow. Or it might just be a microscopic solder bridge somewhere that I just cannot seem to find. I've been stuck on this for far too long and and if any of this doesn't help, I'm making a new one...
aka Dead Eye
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