# No clipping on Kliche Mini



## apierz (Oct 12, 2022)

I've got a Kliche mini that isn't clipping. As I turn the gain knob I get changes in volume and it sounds like it is mixing two channels, but they are both clean, even with the gain turned all the way up. I get sound when the pedal is on and when it's off and the treble knob and volume pot seem to be working.

The issue seems similar to the one in this thread:





						Kliché Mini - Low Gain, Very Loud
					

Hi kids. I have an issue with my Kliché Mini. The gain adjustment does not add a lot of overdrive sound but the pedal is stupid loud. Also, this is the 2nd I've built and the first one works as expected. Everything seems to be in place. I don't see any bleeds or unwanted connections in the...




					forum.pedalpcb.com
				




so I've tried the advice there.

1. Tested for continuity using these charts and got continuity on all of them:







2. Did my best to verify all component values.
3. Changed out the TL072 ICs
4. Tested forward voltage on GE diodes: (.323 and .313)

I've also tried an audio probe but since I get signal all the way through I'm not sure how to pin down the problem. Here's some pictures of the board, any advice would be appreciated.


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## Dirty_Boogie (Oct 12, 2022)

I'd start by cleaning the board.  Blow off both the top and bottom with a can of compressed air.  Then use a toothbrush and some isopropyl alcohol to clean the solder side.  The look for any solder issues, like solder bridges.  After that, the detailed troubleshooting can begin.

Are these solder bridges?




Is that a hair or a strand of wire across the TL072?


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## apierz (Oct 12, 2022)

I don’t think those were causing shorts. In either event, they aren’t present anymore but still there still isn’t any clipping.


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## fig (Oct 13, 2022)

Did you use the footswitch board? Pin 4 of the FS taps directly at the clipping diodes, so I'd check that out.


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## apierz (Oct 14, 2022)

fig said:


> Did you use the footswitch board? Pin 4 of the FS taps directly at the clipping diodes, so I'd check that out.


Thank you for the suggestion. Yes, I did use the included footswitch board. I tested continuity on each wire between the main board and the footswitch board and got a tone on the DMM for each of them so it looks like the footswitch is properly connected at least.


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## swyse (Oct 14, 2022)

I tried to assist in the other post with the similar issue, but I ran out of ideas. I'm not sure what the issue could be. I notice you used the same exact diodes, so my only suggestion is trying different diodes even though yours test good. I personally would just tack some schottkys to the bottom of the pcb to test quickly because I hate desoldering, especially fragile parts.


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## benny_profane (Oct 14, 2022)

Can you probe the circuit both before and after the diodes and report the difference?


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## fig (Oct 14, 2022)

1N36s?


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## MichaelW (Oct 14, 2022)

Wait, are you saying you get no clipping at all? Or no diode clipping? The OpAmp should clipping and giving you overdrive sound, the diodes just add a little flavoring on top.  (albeit very mythical and mystical flavoring).

If your getting nothing but clean gain then there's something else going on besides the diodes.


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## apierz (Oct 15, 2022)

Yeah it seems like nothing is happening on the “gain” side of the mix and turning the drive knob counterclockwise makes it louder which is leading me to think the problem is at least partially in or more of the op-amps. Wouldn’t be the first time I wrecked an IC.

I needed more TL072s for something else so when they arrive I’ll be able to swap out the ones I have with parts from a different batch.

If that doesn’t make a difference I can start probing through the gain section to see if I can figure out where it’s going wrong. I should have some other Ge and schotky diodes I can also try to swap in if necessary so hopefully I can report back in a few days.

Thanks again for looking at this.


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## fig (Oct 15, 2022)

You _could_ swap the TL072s (IC1 with IC2) and see if that makes a difference..or if you have any other dual op-amps you can try one. 

Edit: See below. 👇


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## benny_profane (Oct 15, 2022)

I wouldn’t recommend replacing parts without evidence. Probe before and after the gain stage as well as the diodes. Compare the results. That will tell you where the issue is if it’s one of those.


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## music6000 (Oct 15, 2022)

What are the voltages on the Opamps:



If C8 - 390pf & C14 - 820pF are wrong you will kill the Gain also!


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## Coda (Oct 15, 2022)

Make sure your dual-gang pot is SUPER insulated. My Klon did the same thing as yours for a year before I was able to get it to work properly. I ended up essentially wrapping the entire dual-gang pot in electrical tape…


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## music6000 (Oct 17, 2022)

apierz said:


> Yeah it seems like nothing is happening on the “gain” side of the mix and turning the drive knob counterclockwise makes it louder which is leading me to think the problem is at least partially in or more of the op-amps. Wouldn’t be the first time I wrecked an IC.
> 
> I needed more TL072s for something else so when they arrive I’ll be able to swap out the ones I have with parts from a different batch.
> 
> ...


You need to respond or we can't help you!
You viewed this yesterday since requests to you were asked?!


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## apierz (Oct 17, 2022)

music6000 said:


> You need to respond or we can't help you!
> You viewed this yesterday since requests to you were asked?!



I haven’t had a chance to work on it yet. I’ll probably be able to do the recommended testing on it later today.


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## apierz (Oct 17, 2022)

Here are the voltages I recorded off the ICs starting from the one closest to the jacks and going down towards the footswitch. Pins are numbered starting with top left and going counterclockwise.

IC1:

1. 8.89
2. 4.66
3. .004
4. 4.03
5. 8.38
6. 3.98
7. 5.49
8. 8.88

IC2:

1. 4.45
2. 4.47
3. 4.46
4. 8.40
5. 4.46
6. 4.46
7. 4.48
8. 15.86

IC3:

1. 4.47
2. 4.47
3. 3.52
4. 0.001
5. 4.47
6. 4.47
7. 4.47
8. 8.88

When I tried the audio probe on the diodes I don't notice any clipping. I also tried insulating the dual gang pot with silicon tape but that didn't make a difference. When I measured C8 I got  440pF and C14 770pF.


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## music6000 (Oct 17, 2022)

IC2 - 4 should be -8.40V
Can you remove IC2 & test for continuity between pins 1 & 2, 2 & 3, 3 & 4, 4 & 5, 5 & 6, 6 & 7, 7 & 8, 8 & 1 .


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## apierz (Oct 17, 2022)

music6000 said:


> IC2 - 4 should be -8.40V
> Can you remove IC2 & test for continuity between pins 1 & 2, 2 & 3, 3 & 4, 4 & 5, 5 & 6, 6 & 7, 7 & 8, 8 & 1 .


You are right, I misreported pin 4 on IC 2 and missed the minus sign. It is reading as -8.40v. 

Continuity test results on IC2:

1&2: no
2&3: no
3&4: no
4&5: no
5&6: no
6&7: no
7&8: no
8&1: no

I did the other TL072 as well:

1&2: yes
2&3: no
3&4: no
4&5: no
5&6: no
6&7: no
7&8: no
8&1: no


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## music6000 (Oct 17, 2022)

apierz said:


> You are right, I misreported pin 4 on IC 2 and missed the minus sign. It is reading as -8.40v.
> 
> Continuity test results on IC2:
> 
> ...


What you are experiencing happened to another Member who used the same looking red striped diodes.
I don't know if it was resolved.
Did you test the forward voltage on these Diodes, it should be around 0.27v to 0.35v for Germanium?


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## apierz (Oct 12, 2022)

I've got a Kliche mini that isn't clipping. As I turn the gain knob I get changes in volume and it sounds like it is mixing two channels, but they are both clean, even with the gain turned all the way up. I get sound when the pedal is on and when it's off and the treble knob and volume pot seem to be working.

The issue seems similar to the one in this thread:





						Kliché Mini - Low Gain, Very Loud
					

Hi kids. I have an issue with my Kliché Mini. The gain adjustment does not add a lot of overdrive sound but the pedal is stupid loud. Also, this is the 2nd I've built and the first one works as expected. Everything seems to be in place. I don't see any bleeds or unwanted connections in the...




					forum.pedalpcb.com
				




so I've tried the advice there.

1. Tested for continuity using these charts and got continuity on all of them:







2. Did my best to verify all component values.
3. Changed out the TL072 ICs
4. Tested forward voltage on GE diodes: (.323 and .313)

I've also tried an audio probe but since I get signal all the way through I'm not sure how to pin down the problem. Here's some pictures of the board, any advice would be appreciated.


----------



## apierz (Oct 17, 2022)

music6000 said:


> What you are experiencing happened to another Member who used the same looking red striped diodes.
> I don't know if it was resolved.
> Did you test the forward voltage on these Diodes, it should be around 0.27v to 0.35v for Germanium?


I got forward voltage of .32 and .31.


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## music6000 (Oct 17, 2022)

apierz said:


> I got forward voltage of .32 and .31.


You may have a bad Gain Pot, you wouldn't be the First
You said that it gets Louder when its CCW, doesn't seem right?


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## apierz (Oct 17, 2022)

You may have a bad Gain Pot, you wouldn't be the First


music6000 said:


> You said that it gets Louder when its CCW, doesn't seem right?



From what I understand of how the circuit works it blends in the clipped signal with a clean signal with the dual gang gain pot controlling the ratio. The more CCW the pot the more clean signal and the more CW the pot the more clipped signal. So this is what I would expect if there was an issue in the pot with the clipped signal path leading the pedal to be at its loudest where the clean signal is maxed and getting quieter as the clean signal is blended out but none, or a weak signal, is mixed in. So I think you may be right about the gain pot being the source of trouble.

Here's what I get when I measure the resistance values on that pot:

Fully CW:

top:
1->3: 35k
2->3: 2k

bottom:
1->3: 1.5k
2->3: 2k

Fully CCW:

top:
1->3: 101k
2->3: 101k

bottom:
1->3: 1.5k
2->3: 1.5k


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