Klon Centaur No Sound

[willwaush]

Hi guys. I am having some troubles with my Klon Centaur Silver edition build and I hope that someone helps me out. I get no sound out of the pedal, only some weird oscillations, it does't changes it if it's engaged or not because it's not true bypass.

This are my IC's measured voltages:

(from 9.18 POWER SUPPLY)

IC1 (TL072ACP)
1) 8,48
2) 7,48
3) 7,79
4) 7,27
5) 7,45
6) 8,60
7) 0


IC2 (JRC4558D, i hadn't another TL072 and I just placed in another dual opamp)
1) 6,80
2) 7,25
3) 7,18
4) -7,50
5) 7,24
6) 7,26
7) 7,50
8) 9,51**

IC3 (7660S)
1) 9,17
2) 4,79
3) 0      
4) -3,71  
5) -7,45
6) 5,20
7) 4,64
8) 9,17


**No double voltage (?)


Some Pictures:
https://www.dropbox.com/s/14mys7m7lhcjnck/20161113_200205.jpg?dl=0

https://www.dropbox.com/s/oh8h2ea28a4alft/20161113_200227.jpg?dl=0



The veroboard drawing that i followed:
http://tagboardeffects.blogspot.it/2014/07/klon-centaur-silver-edition.html

[Marbles]

It looks like youre missing the 390pf cap in the upper right corner?

[willwaush]

Thanks for pointing it out Marbles! I actually missed all the ceramic caps

Anyways, now I placed them in.. but it only gives me a low crackling guitar sound in the buffered stage, and a tiny tiny tiny overdriven tone (I assume) when ON.. but I can't quite tell as It's too low volume.

Anyways I will repeat the voltage measurings... is there a possibility that i "burned" some of the ICs due to this caps missing?


Thanks a lot!!

[willwaush]

Source is still 9.18 V

IC1
8.46
8.49
7.26
7.73
7.21
7.24
8.59
9.17

IC2
5.80 to 6.08
7.9
7.18
-7.90
7.19
7.22
5.60 to 5.90
9.73 (increased after placing the ceramics, but not yet doubled)

IC3
9.17
4.76
0        
-3,56
-7
5.19
4.64
9.17

[Marbles]

Could it be a solder bridge? In the picture of the bottom just below your fingers? I'd think somewhere around the 390k resistor on the bottom left. Maybe it's the angle from the picture, but it looks like a bridge

[willwaush]

Thanks again Marbles, actually now I am far from home, but as soon as I come back I will definitely check.
Anyways, I zoomed the pic and it quite looks an optical effect more than a solder bridge unfortunately.

I will report back soon!

thanks again

[Marbles]

Yeah, sorry man, I can help in the sense that 2 pairs of eyes are better to spot an error than 1.
The question if something could be fried or if the volrtages are correct are above me :D
Like what pins should have 0 cause of ground instead of the values you're posting.

I'm sure someone else wiser than me will chime in.

[Marbles]

Your voltages do look off compared to what should be normal.

Because there are multiple klon builds, that are not that different, I'm going to guess the voltages should be the same. I would check the comment sections of the other Klons too. A lot of people have posted voltages there.
To copy and paste the voltages IvIark posted that you should get:

IC1
1 +4.43V
2 +4.44V
3 +3.45V
4 0V
5 +4.43V
6 +4.43V
7 +4.41V
8 +8.87V


IC2
1 +4.6V
2 +4.43V
3 +4.43V
4 -8.44V
5 +4.42V
6 +4.43V
7 +4.26V
8 +15.92V


IC3
1 +8.84V
2 +4.52V
3 0V
4 -4.13V
5 -8.42V
6 +3.97V
7 +5.29V
8 +8.82V



Yours do seem to be way off. Especially IC1 seems off. I don't know how that influences IC2, but I would check around and before IC1 first.

[willwaush]

My dear, not a single solder bridge, but it actually turned out that instead of 10K pots I accidentally used 100K. I will swap them as soon as possible and will come back with another report!

I don't know if this will fix the issues because over the 4th pin of IC1 there should be 0 volts, and there aren't. Also I noticed that for the first seconds of working, the IC2 doubles his voltage over the 8th pin, but soon after it drops down. Don't know why..

[Ciaran Haslett]

IC 1 doesn't have a ground reference.  Check the link under Pin 4.  It looks like it isn't soldered in on your pic.  If there are no other issues that will at least fix the wonky readings on that IC.

[willwaush]

Measurings after fixing the pin4 bridge problem (thanks for spotting it!):

IC1

4,52
4,52
1,27
0
4,27
4,30
1,49
9,16


IC2
4,51
4,51
4,45
-6,94
4,45
4,51
4,51
9,41 (starts at 16 V, but if you keep measuring, it falls down to 9,40 V)

IC3
9,16
4,73
0
-3,46
-6,82
5,20
4,64
9,16

Be aware that I still didn't replace the wrong pots, but I assume that they don't influence those measurings.

UPDATE: the pedal with the correct pin 4 bridge now works, but i feel like it has low gain.. at max gain it doesn't feels like max at all! and there is still that double voltage Pin 8 problem on the IC2... when i plug in the 9V it starts at 16V, but then it tends to slowly decay and stabilize around 9,4V

[willwaush]

Hi guys. After solving the 4th pin problem the pedal did work, even if not quite as I wanted because of the 100k wrong pots I assume.

Now i placed in the correct 10k pots, but the pedal isn't working anymore. In buffered mode it's working properly, but when on there is no sound out of it. To hear it I have to cranck my amp up and it seems like the tone knob isn't affecting the sound anymore as well as the gain knob. The only one working it's Output, but it reaches its max in the middle of the sweep.

What can I do apart from throwing this in the garbage?

PS: the only thing that changed it's the voltage on IC1 pin 7... it's grown up to 4,4V and it doesn't seem regular. I even tried to revert to the 100K pots, but the situation it's stille the same.

[Ciaran Haslett]

Don't get too annoyed at yourself lad.  We've all had nightmare builds.  I think it's audio probe time.  Follow the schematic posted with the layout you followed and probe for your guitar signal.  When you come to a point where it disappears, goes really quiet etc you can have a look in that area for any problems...shorts, bad solder, placement, value etc.  A probe helps to focus in tiny sections rather than the complete build.

A quick Google search on audio probes will get you going.

And maybe recheck all your wiring.  Something may have broken while you were changing pots.  Continuity test with a DMM will make quick work of that.

Good luck

[PMowdes]

Ciaran Haslett wrote

Don't get too annoyed at yourself lad.  We've all had nightmare builds.  I think it's audio probe time.  Follow the schematic posted with the layout you followed and probe for your guitar signal.  When you come to a point where it disappears, goes really quiet etc you can have a look in that area for any problems...shorts, bad solder, placement, value etc.  A probe helps to focus in tiny sections rather than the complete build.

A quick Google search on audio probes will get you going.

And maybe recheck all your wiring.  Something may have broken while you were changing pots.  Continuity test with a DMM will make quick work of that.

Good luck

Just to add to Cairan's post i'd definitely get an audio probe sorted, not only is it really useful but it also gives you a better understanding of schematics and how they relate to the vero layouts.  

I took the easy route and brought one of these kits, my "it doesn't f'ing work and i have no clue why" pile is significantly smaller as a result

http://shop.pedalparts.co.uk/Ultra_Tester/p847124_15700704.aspx

[Marbles]

Could you check the 1u cap next to the gain 1-3 wire and the bridge above it? I can't see clearly if the cap is 2 or 3 rows large. The bridge above it looks like a double bridge instead of single?
It's hard to tell what goes on on that side.
We'll get it to work in the end :)


EDIT: Nvmnd, I compared it to the bottom of the board and it seems to be placed correctly.

[willwaush]

Guys, thanks for the suggestion. I will definitely get in to the "audio probe" thing as soon as I can. I understood that it's very useful for every build that I will try to make.

Anyways, in the meantime, looking closely at the schematics, I discovered that I placed the extreme bottom right 1uF cap the wrong way. It is tantalium, and I placed it with + on GND

After resoldering it the correct way, i cut all the Output pot wires, took another 10k stock pot and wired it with alligator clips. What I noticed is that the effect now works like a charm. I assume that he "old" 10k pot was broken, as it also is working if I place it with alligator clips, but i have to make pressure on its tree to make it work.

Anyways, as soon as I can i will solder all the thing that I left and get back here with a final report if it works. Otherwise I will just wait for my audio probe!


I wanted really to thank you for the support, you guys are amazing! Thanks


PS: in case this could help someone... after placing the 1uF cap the right way, I finally managed to get the double voltage on the IC. I still don't understand how it's possible that the pedal worked even before correcting this problem and the wrong pots! Really strange

PPS: thanks Marbles for double checking again and again for me! Btw as you said it's placed correctly!

[Marbles]

Yeah I can see that now. I was zooming in on my phone (long busride) and from the top side it seemed to be fishy. When I compared it later with the bottom (which is playing tricks in my head reversed, plus I think you added an extra column?) I saw they were placed correctly.

Did not consider the tantalium caps. I am too safe in these things I think, and always use MKT or greenies when these caps are mentioned.

Great you got it working! Guess the first things to check are thet hings we do different from the layout :)

Let me know how it sounds when you finish it (which sounds like it is). I have put it off for too long and shoud get started on it someday :)