Dig Dug

[JakeFuzz]

Is it still clicking overall though, not necessarily when it gets to pot 8?

Looking at the schematic the only thing I can think of that would cause the step 8 LED to stay on is if the resistance value of the pot is too low or more likely there is something wrong with either the value or the connection at R19. Check R19 to make sure it is not very large and that one of the sides of R19 is connected to ground (use the continuity tester on your DMM).

I suspect this because if R19 is too large (infinity if it is not connected to ground) the voltage divider doesn't produce the correct division ratio and the LED always see's a large enough voltage to stay fully lit. Same story if the pot value is too low just the other way around.

[insomniac2295]

Is it still clicking overall though, not necessarily when it gets to pot 8?

Looking at the schematic the only thing I can think of that would cause the step 8 LED to stay on is if the resistance value of the pot is too low or more likely there is something wrong with either the value or the connection at R19. Check R19 to make sure it is not very large and that one of the sides of R19 is connected to ground (use the continuity tester on your DMM).

I suspect this because if R19 is too large (infinity if it is not connected to ground) the voltage divider doesn't produce the correct division ratio and the LED always see's a large enough voltage to stay fully lit. Same story if the pot value is too low just the other way around.

Haven't worked on this project in a while, but something just occurred to me:

Could it be possible that this problem is being caused by the fact that I used high brightness 5mm LEDs instead of the 3mm LEDs used in other builds of this pedal?

[jkokura]

yes, it could be that.

LEDs, because they are diodes, have different forward voltages depending on the size and colour. If you're using one of a different size, type and colour could result in atypical function. In theory. It could also work just fine.

Jacob

[insomniac2295]

yes, it could be that.

LEDs, because they are diodes, have different forward voltages depending on the size and colour. If you're using one of a different size, type and colour could result in atypical function. In theory. It could also work just fine.

Jacob

Hmmmm.... i am using 4 different color high brightness 5mm LEDs. Any suggestions for a new resistor value for the LEDs? Or at least a starting point?

[JakeFuzz]

yes, it could be that.

LEDs, because they are diodes, have different forward voltages depending on the size and colour. If you're using one of a different size, type and colour could result in atypical function. In theory. It could also work just fine.

Jacob

Hmmmm.... i am using 4 different color high brightness 5mm LEDs. Any suggestions for a new resistor value for the LEDs? Or at least a starting point?

The first thing I would do is remove the vactrol you have in there and replace it with sockets. Then I would put in an LED so you can visually monitor what is going on when you get to step 8. Remember the intensity of light from this LED directly changes your wah signal. From there you can see if it is more dim than the other steps and make the appropriate changes.

[insomniac2295]

yes, it could be that.

LEDs, because they are diodes, have different forward voltages depending on the size and colour. If you're using one of a different size, type and colour could result in atypical function. In theory. It could also work just fine.

Jacob

This is a great idea! I just did this little test and came to the conclusion that the 4th and 8th step of the sequence are brighter than the rest. It just so happens that they are both red LEDs. Now, help a newbie out- If the 4th and 8th step in the sequence light up brighter, that means that i should increase the resistance on those two steps of the sequence on the pot board?
Hmmmm.... i am using 4 different color high brightness 5mm LEDs. Any suggestions for a new resistor value for the LEDs? Or at least a starting point?

The first thing I would do is remove the vactrol you have in there and replace it with sockets. Then I would put in an LED so you can visually monitor what is going on when you get to step 8. Remember the intensity of light from this LED directly changes your wah signal. From there you can see if it is more dim than the other steps and make the appropriate changes.

[jkokura]

Depends on the LED and resistor.

What I would do is setup a bread board. Run your 9V along the + rail, and then your 4 LEDs between the - rail for the negative lead and any 4 strips with the positives. I would then start at whatever the value of resistor is called for in the dig dug and put one in between the + rail and each of the LED + leads. Once that's done, check out the relative brightnesses. I bet those reds will be brighter. Start raising the limiting resistor by a few k at a time until you have equal brightness all the way along. Lower or raise any other colours you need to, and you'll have your answer.

Jacob

[LaceSensor]

anyone build one of these that actually sounds like a wah pedal yet?
Mine does a good seek trem impression to be honest.

[LaceSensor]

Hi

Ive now socketed the Vactrol and tried

vtl 5c9
vtl 5c3
NSL - 32

and all perform the same

Anyone know how to make it wah and not trem?

Thanks