Klon centaur clone kit, making loud squealing noise

[Phil4321]

I finished this a klon clone pedal kit from bit box (https://www.bitsbox.co.uk/index.php?main_page=product_info&cPath=280_281&products_id=2038)

The link contains a list of all the parts in the kit, however, I had a couple of resistors and a capacitor left over

having put it all together following this diagram for a true bypass version


I am getting signal when the pedal is being bypassed so I know the input/outputs are working, however when I turn the pedal on all I get is a high pitched whine. the diodes and the integrated circuits are all in the correct orientation.

The led doesn't light up, this makes me believe that it is a power issue but as this is my first pedal build and first time doing electronics in a while I am not sure and it could be anything

Here are the IC values:

IC1-tl072
1:5.8   5:8.95
2:5.8   6:8.33
3:2.79 7:5.82
4:0.00 8:5.9

IC2-tl072
1:15.38 5:16.04
2:6.05   6:15.4
3:5.82   7:14.36
4:0.00   8:5.82

IC3-icl7660spca
1:8.95  5:8.95
2:1.89  6:4.58
3:0.00  7:6.30
4:-6.95 8:-6.91

Thanks for any help

Phil

[idy]

That's a pretty big first build...
I'm thinking you aren't numbering the pins correctly on the ICs: you know you count them clockwise?

You should be seeing 0 volts on pin 4 and "power supply" volts on pin 8. Those pins are "caty corner" on the chip.

Then you should see "mid" voltage on the other 6 pins. In the Klon each opamp has a different "mid" and "supply" voltage. Properly biased opamps hang out like that, although a low impedence meter will drag the "mid" voltage down a bit.
Confirm the pin numbers, check for solder bridges on the ICs (and everywhere else!)

[Phil4321]

Thanks for your reply,

I agree that is probably isn't the best first pedal to try and build but I've got this far 

I am confused as to what you are saying about the numbering of IC pins as resources I have found say anti clockwise? I am looking at the IC with the legs facing down (if that makes sense?)

https://www.youtube.com/watch?v=ss3nEWGDkiY like in this video

i will try reseating the ICs and see if that helps

[slashandburn]

Hey, welcome to the madhouse. Maybe I'm having a "probably shouldn't be drinking on a Tuesday" kinda moment, but if the 7660 chip is the charge pump and you're not getting more than 9v out of  it, how can IC2 be getting ~16v?  Something ain't right!

If it wasn't for that detail, my usual troubleshooting routine when something works in bypass but not when engaged (with no obvious shorts or other mistakes) is to check I haven't mixed up my in an out Jack wiring to the switch (schoolboy error but it still catches most of us out) and then reach for the audio probe.

Hope you get it running. I like those Tagboard layouts but big cramped stripboard/Veroboard is a nightmare even for seasoned hack amateurs. A lot of potential for shorts and other avoidable errors.   

Photos of each side of the board would really help your cause here.

Edit: anti clockwise is correct for iC number (as far as I'm aware) if they're orientated as per the video you linked you're good in term of the IC, further backed up by your pin four (ground) reading O v on the opamps.   Shorts, bad solder joints, bad pots. A misplaced link/cut are more.likely what you're looking for.

[Phil4321]

I do agree that the voltages are wrong, this is what leads me to believe its a power issue. but as I am not to well versed in this I'm not sure where to look to find this out. I have since reseated the ICs and checked for crosses and made sure the cuts are cut, same issues still apply

Here are some lovely images of my terrible soldering:

[idy]

Yes, sorry, anti-clockwise viewed from above.

Usually we clip the leads that protrude from the solder joint...

Turn the power off and measure with a meter to make sure that all adjacent rows are not bridged and also that the "cuts" (you probably used a drill bit) are really cut and not connected still.

Sockets for ICs are a good idea...

[Slowpoke101]

Double check the link going to pin 5 of IC3.



You appear to have it going to pin 6 which may help to explain some of problem.

[Phil4321]

Having moved that link to the correct pin it now works, however, there is still a bit of a buzzing issue with the pedal, how would I go about identifying which part o the circuit is causing this?

[bluebunny]

Buzzing, like "bzzzzz"?  Is your circuit boxed-up yet?  If not, it could be picking up all kinds of airborne crud.

[Phil4321]

Edit: yes its making a BZZZZ sound

No, it is not boxed up yet, I am still waiting on some project boxes to arrive.

It also likes to make a very loud screech when the footswitch is toggled, would I be right in assuming this is related?

do you think this issue will resolve itself once it is boxed?

Also, the LED is not lighting up. having measure it with my multimeter it has 9v running across it so not sure why. it has a 1K resistor on the positive leg

Thanks for all your help so far guys

[bluebunny]

It may not fix everything, but boxing it will certainly help with noise.

If you're really measuring 9V across your LED then it's become a DED.      Can't really see why, though.  Your board in that area looks OK.  (But do trim your wires as previously noted.  Also run a knife between the tracks to make sure you've got no shorts.)  BTW, you don't need an additional resistor the other side of the LED - the 4K7 on the board is your CLR.

[Phil4321]

So the foot switch noise was because of the LED being broken as once I changed it, it stopped.

After cleaning the stripboard the bzz was reduced to generic overdrive levels of noise.

All that is left now is for the project box to arrive so it can be finished!

Thanks for all the help and advice

Im sure ill be back as I also have a delay pedal to finish and want to build phasers, reverbs ect!

[bluebunny]

Of course you'll be back.  This is the Hotel California of hobbies.   

And in any case, we'll be wanting pictures of the finished article.  It's the law.   

[antonis]

boxing it will certainly help with noise.

Especially with mosquitos "BZZZZZ" origin...