Problems with ampeg scrambler clone?

[Dirtydrowningman]

Hey guys bringing up a dead post here. But maybe some new info since a topic like this was posted years ago. Can't get effect to engage when clicked on. Just clean sound. Texture knob won't do anything and the blend seems to work as a volume Transistors are 2n5306 for q1 q3 and q4
Q2 is bc169b. All 4 ecb pinout. No bridges on solder side. I am also using diodes 1n4148 I also took the breakout board out and hand soldered it as the diagram shows. So far this is the only build that has given be a problem. I have tried using mspa13 and 2n3904 as replacements. Does anyone see somthing I don't? Thanks in advance.

[Marcos - Munky]

First of all, welcome! Now, let's go:

1- you're missing 3 diodes. Where are D3, D4 and D5?
2- please tell me you didn't soldered the wires on the texture pot on the pot's eyelets. Very bad practice that can kill your pot...

The Scrambler is basically a clean booster and a octaver circuit, which output can be taken from the booster, the octaver and a mix of both. Blend pot working as a volume shows your booster is working ok but the octaver part is killing the signal somewhere, and that's why the texture pot don't do anything. Start by adding those missing diodes and test the pedal again.

Also, do you know how to do an audio probe test? It may be necessary to troubleshoot this one, maybe not. But knowing how to do it will help you a lot along the pedal building way.

[PRR]

> missing 3 diodes

The build doc says these are on factory plan but not on factory-built units. They may not be needed.
http://www.tonepad.com/project.asp?id=16

Yes, DC voltages and audio tracing. After BRIGHT light and magnifier to study your joints.

[Dirtydrowningman]

Hey thanks for the welcome and the replies. As pointed out by pbr the diodes missing are optional. But putting them in I guess wont hurt. Thank you for the info. Good to know the boost part is working. In the pic it does look like I used the eyelets but I didnt. I used the lug hole.

I have never used test probe but I'm sure my girlfriends dad has one and can show me how to use.

[iainpunk]

the ampeg scrambler i used to have didn't have those diodes, but there were factory units in the first weeks of the production run that do have them. the sound allegedly doesn't change b

audio probe: i strongly recommend building one yourself.

its the first tool i grab for debugging. and 95% of the time, it points me to the problem i should address to make it work. if there is sound before a certain point in the circuit but not after, you know what that point is the culprit.

cheers, Iain

[Dirtydrowningman]

Thanks man. Definitely going to be making one of these.