After a while I realized that I was getting different results when the effect was in bypass than when it was ON. I've removed the LED from the circuit and now it sounds better. Take a look at the test I've done:
No led, no resistor
D G S
min 6.78 0.73 1.55
max 3.88 0.72 0
Led + 4.3k resistor
D G S
min 5.30 0.53 0.90
max 3.78 0.54 0
Led, no resistor
D G S
min 1.88 0.15 0
max 1.88 0.15 0
I don't know if these results are ok or not. To be honest, I wasn't expecting the led to change that way the transistor behavoiur. I would like to have the led but...It's working better without it.
I've removed a couple things: the led resistor from the pcb and the hot wire that comes from the pcb to the led's anode. I've tried connecting the led right into the 9V from the battery but same results.
The pedal is working well, but without led :S The problem comes when you connect the led to the circuit and then the voltages drop.
First of I would contact the guys that made the PCB because there's a lot that doesn't make sense. The LED should not be sucking power away from the pedal circuit to the point that it changes the sound, cause that tells me that the LED is somehow in part of the signal flow which it shouldn't be.
Secondly I only see 1 jack, assuming the input jack, which appears to be a mono jack, what is the output jack, mono or stereo? If you're using a battery are you using a DC jack too and what kind? Typically if you're running a battery you want the battery off when nothing is plugged into it, so you would use a stereo jack that switches the battery when a cable is plugged in and DC jack with 3 lugs (2 power, 1 ground).
Also, I would take a look as the soldering on the jack, it doesn't look good to me.
the anode is a black wire that goes to pin 8. The cathode goes straight to the pcb, but now I have removed it (it's the red wire that you can see around the switch). In the pcb is where you install the resistor for the led as well.
The battery it's pretty much new. I've only used it for testing porpuses.
Hi rocket88. You're totally right about the soldering in the input jack. I know it looks awful, but I've done and undone this soldering a couple times and I always get that ugly result. I've tested a few times and the continuity is good. Anyway I'll try one last time.
About the DC jack and stuff...Yeah, I'm aware of how it works. I'm using a battery till I put the pedal in the enclosure, but I'm not going to add a battery clip so my two jacks are mono.
Lastly, maybe it is doing what it should do...The thing is, are you getting drops in the voltages when the pedal is engaged?
Many thanks to you all, this web site it's absolutely great :)
Solved. Apparently my batteries weren't as good as they should be. They made the pedals work and gave a good reading tough...but I don't know .
I realized that there were something wrong with them when I tried with a new 9V battery over some brand pedals and got same voltages in bypass/engaged. With this same battery I tried in my SHO and got almost the same voltages, just around 0.30v difference between them. After a while I understood that it was because of the resitor+capacitor that I had for power filtering. In order to solve this I put the led before the filtering and the rest of the circuit after the filtering. Right now it's working perfectly.
Too much time for such a tiny and simple pedal, thanks guys!