Klone volume gain problem

[AntKnee]

I just built two Centaurs, the ones with the charge pump, based on the sunking schematic...

One works great, but doesn't seem to have as much gain as my "Bare Bones" version. That may be normal since the bare bones version clips more... I don't know.

The other is doing strange switching and gain things. When the pedal is off, is sounds like the gain is still engaged, until I turn the gain all the way up, then it sounds clean and bypassed. When the pedal is on, the gain doesn't seem to reach full potential and even with it turned all the way down, still sounds like it is engaged.

[IvIark]

Post all your IC voltages and see if that gives a clue

[AntKnee]

Sorry it took a while to reply.
Here are the voltages for the first of two that I built. This one works fine, but doesn't seem to be putting out as much gain as it should. I hope I got these reading correctly. First time I tried this.
IC1:
1. 4.53
2. 4.53
3. 1.23
4. 0.00
5. 4.42
6. 4.53
7. 4.59
8. 9.05

IC2:
1. 4.60
2. 4.53
3. 4.47
4. -8.48
5. 4.47
6. 4.53
7. 4.45
8. 17.14

IC3:
1. 9.05
2. 3.93
3. 0.00
4. -4.79
5. -8.48
6. 4.48
7. 3.80
8. 9.05

[IvIark]

Most look good to me, but pin 3 of IC1 looks a little suspect, I'd expect it to be at least a couple of volts higher.  That's right at the input, so check for soldering and shorts from the input wire.  10K resistor > 100n cap > lug 3 of IC1 and importantly the 1M resistor from pin 3 to vref

[AntKnee]

I swapped out the footswitch on the one that was acting strange with the controls when the pedal was off and that seems to have fixed that issue. Thats what I get for getting cheap footswitches from Tayda.

Strange, I have built two, and they are both reading nearly the same on all pins, even pin 3 of IC1, reading at 1.23/1.25.

I used TL072s and ICL7660SPCA. I used 1N277 for D1 and D2, used 1N5817 for D4 and D5.

Even with the gain turned all the way down, I still get a lot of gain when the pedal is on. Shouldn't it be more transparent with the gain all the way down?

Compared to my bare bones build, the bare bones has more gain, more low end, and is very clean when gain is off. What gives? Do they just sound different?

[AntKnee]

Still have a problem with the gain turned down. I still hear gain, it is not clean. I am new to building, and don't know much about reading a schematic, but I have been giving it my best try. I'm using an audio probe to work through the circuit trying to find where the gain begins. I have been at this all weekend and can't figure out where it is coming from. Anything going into/out of IC1 is clean, and anything going into/out of IC2 has gain/distortion. I have the gain all the way down. I don't know if that should be there or not, or if I should be checking elsewhere.

Any guidance or suggestions are very welcome.
Thanks

[AntKnee]

Though I don't really know what to look for, I'm not fining any of the obvious problems with this. The fact that I have the same problem with two of these tells me that maybe they just sound this way.

So, would someone who has built this please answer this question...
With the gain all the way off, this pedal is supposed to be clean, regardless of the volume level, right?

[AntKnee]

I just figured out, while building the new Madbean Sunking, that I used .68uF caps instead of .068uF caps. I'll switch them out as soon as I order the right ones. Would this be the problem?

[induction]

Yup. That could be it. Bigger caps let more signal through. You might be overdriving the op-amp.

[vvv]

Sounds so familiar. Wherever you read many people are reporting IC1 pin 3 voltage being 1.XV and gain not working right. I´m getting to think there might be something wrong with the layout or something. Personally I´m in the middle of building my third Centaur, the first two had just the same symptoms and were checked component by component and were correctly build. Anyway, there are people who got them working right so there is something strange. I don´t know if there has been updates to the schematic/layout and the later versions don´t work or something like that?