DIY Klon pedal clone high pitch noise

[blink3388]

Hi Guys,

Tried putting together a Klon pedal clone as way to dip my toe into diy pedals.

It turns on however when both active or in bypass there's a high pitch noise from an unknown origin.

Did some research and found it could be the the 7660 chip, bought a batch of Max 1044 chips as replacements as they are supposed to be better and have swapped it out three times and still have the same problem.

Tried with the pedal box open, closed, from a plug and also from a battery incase outside noise could be part of the issue.

One of the germanium diodes (1N34A) had a chip in it although I didn't expect this to be the problem as the noise persists when in bypass or active I have also bought a batch of these and replaced both of the diodes. I have removed any excess solder and seems pretty clean but I am inexperienced and don't know what to try next!

Youtube video demonstrating the issue here:

Any help would be appreciated.

Thanks!

[Kevin Mitchell]

You should definitely check your wiring. Recheck and check again. Assuming the pedal is true bypass - you shouldn't have any noise from the effect when in bypass.

This being your first pedal - send a photo of your layout so we can verify the orientation of the parts.

It could also be a separate issue not relevant to the pedal.

[thermionix]

Assuming the pedal is true bypass -

The original Klons and many klone kits are not true bypass.  U1A is always in the signal path.  That hopefully narrows the problem down.

Blink, where did you get your ICs, both the TL072s and the MAX1044s?

[italianguy63]

The demo shows the noise.. but, does it work otherwise?  i.e. pass signal?

MC

[bluebunny]

Where did you get the board?  Can you take pictures, please?  (Top and bottom.)  Are pins 1 and 8 of the 1044/7660 connected?

[blink3388]

Kevin Mitchell
Q. You should definitely check your wiring. Recheck and check again
A. I've checked a few times but who knows, could be like "where's Wally" i'll check again for problems.

Q. This being your first pedal - send a photo of your layout so we can verify the orientation of the parts
A. Attached pictures of the front of board, back of board and the diagram for reference.

thermionix
Q. Blink, where did you get your ICs, both the TL072s and the MAX1044s
A. Parts originally from an ebay kit, replacement MAX1044 chips from an ebay seller as well. Links below.

Klon DIY Kit
https://www.ebay.co.uk/itm/DIY-Overdrive-Guitar-Pedal-All-Kits-For-Kon-Centaur-Overdrive-Effect-Pedal/113250808878?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3D8cbbf884095b4e3f801a419c0eb31154%26pid%3D100675%26rk%3D10%26rkt%3D15%26sd%3D112967945748%26itm%3D113250808878&_trksid=p2481888.c100675.m4236&_trkparms=pageci%3Ab4321bcb-1b05-11e9-9f9a-74dbd18098b7%7Cparentrq%3A60594f281680aa486437228cffede57a%7Ciid%3A1

MAX1044
https://www.ebay.co.uk/itm/5PCS-MAX1044-IC-Voltage-Converter-DIP-8-MAX1044EPA/182253607141?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3D7c5a04ba3356463faac5e43e2601eec3%26pid%3D100675%26rk%3D10%26rkt%3D15%26sd%3D113250808878%26itm%3D182253607141&_trksid=p2481888.c100675.m4236&_trkparms=pageci%3Af4da3c5e-1b05-11e9-aa35-74dbd180dcb7%7Cparentrq%3A605af70a1680abd98fc635daffeb7e58%7Ciid%3A1

italianguy63
Q. The demo shows the noise.. but, does it work otherwise?  i.e. pass signal?
A. Yes I get guitar sound when in bypass or when active. When active the tone sounds good and the gain, treble and volume all work. Just has the high pitch tone over it.

bluebunny
Q. Where did you get the board?
A. Ebay seller, links further up this reply in the answers to thermionix.

Q. Can you take pictures, please?  (Top and bottom.)
A. Pictures attached to this reply

Q. Are pins 1 and 8 of the 1044/7660 connected?
A. They look like some of the cleaner solder jobs on the board

[italianguy63]

One of those 1uF electros should be a tantulum.... maybe somebody here can identify which one.  But, I don't think that would cause this.

I am also unsure if this is charge-pump whine... doesn't sound right.. But, I have been wrong in the past (plenty)!

Use up those Max1044's and switch to TC1044S or ICL7660S in the future.  Better chips/same price.  .02.

I verified the cap orientations... OK

Otherwise??

MC

[EBK]

I think I see a couple of stray solder blobs, and that is a lot of extra flux residue.  Perhaps clean that up with some alcohol.  You may have a short somewhere but can't see it in that goo.

[rankot]

It sounds like a 10kHz squeal from 1044. You shall check with multimeter if pins 1 and 8 are shorted. If they are not, they should be.

If it still squeals, try to buy LT1054 and use it instead. It works at 25kHz internally. Those LTC1044 you bought from e-bay could be counterfeits.

There are three 1u caps in the lower row, 2nd and 3rd shall be tantalum, but that is not so important. I have few of similar circuits with normal electrolytic and they're fine. But datasheet suggest 10u for those caps, not 1u.

[bluebunny]

Q. Are pins 1 and 8 of the 1044/7660 connected?
A. They look like some of the cleaner solder jobs on the board

I meant to each other.    It's what Ranko just asked you to check (although the folded picture and the eBay listing seem to indicate they are).

[blink3388]

There were suggestions to replace the 1044 from italianguy63 to TC1044S or ICL7660S and a suggestion from rankot to try LT1054. I've just picked one of the suggestions at random and bought some LT1054 from ebay but happy to buy all three to try if anyone thinks it's worth it?

I did a continuity test between pin 1 and 8 from the soldered side and the chip side and I get continuity.

I've tried touching up the solder on all the pins on the board which hasn't helped.

I'm picking up some isopropyl alcohol from a friend tomorrow morning to clean up the board.

Now I've found that if I poke pin 7 with my finger or hold a piece of solder and poke it the sound stops, so I guess i'm grounding pin 7 when I do this? Looking at the chips schematic I can see that pin 7 is OSC and has this to say about it:

Oscillator Control Input. Connecting an external capacitor reduces the oscillator frequency. Minimize stray capacitance at this pin.

Don't really know what this means but it sounds like it's supposed to reduce a frequency (maybe the one i'm hearing?) but it doesn't seem to go anywhere from what I can see.

[rankot]

Pin 7 is Osc pin, it is used for external oscillation control capacitor. When you touch it, you ground it and oscillations stop. Probably this IC is fake (rebranded 7660A which doesn't use pin1) or malfunction.

[blink3388]

Ok thanks Rankot, i'll try the LT1054 when it arrives and i'll update the forum post!

[italianguy63]

Rankot.. I don't use the LT1054.. is it OK with pin 1 and 8 shorted?  i.e. same pinout?

MC

[blink3388]

Rankot.. I don't use the LT1054.. is it OK with pin 1 and 8 shorted?  i.e. same pinout?

Looks like it mostly is apart from pin 1 has a different name so don't know if it's a different function. I'll grab some of the chips you suggested as well just incase.

[rankot]

LT1054's pin 1 can be safely connected to V+.

[italianguy63]

Hold up... You have to view the spec sheets to get the whole picture.

Many c-pumps get a frequency boost from connecting pin 1 to 8.

I think that is internal for the LT1054.  Trying to verify for you as I am unfamiliar with it.

Save your money for a bit... 

MC

Rankot is smarter than me! 

[italianguy63]

There you go.. all good.

[pinkjimiphoton]

i have built this kit from this vendor and can confirm the kit is good, works properly when correctly assembled.

people don't realize it, but often FLUX is conductive enough to cause parasitic oscillations like this.

it DOES sound like charge pump whine.. and there's a lot of bogus CP's out there now, i've found i dunno how many of them all whine the same, despite different silkscreening. counterfeit shit sucks.

i would check the soldering ON THE POTS THEMSELVES, as a tiny bridge of solder or even flux between pins on the gain pot in particular <remember, a klon is a treble booster> can also cause oscillations.

temporarily connect the cases of all three pots with a jumper and connect that to ground to see if the issue goes away. high gain circuits can oscillate if the pot casings aren't grounded.

clean up the soldering. you did fairly well for a beginner, so kudos!!
you need  denatured alcohol to clean the flux up with, i dunno if isopropyl will work well enough.

also check to make sure there are no bridges between caps... that can cause this to squeal too.

i doubt the type of caps will matter at all. i've built these with chicklets, polys and ceramics, and to my ear <and most of my customers> the ceramics sound the best.. cheap, consistent, and tiny with wayyyyyy better specs than old school ceramics had < i really like the little monolythics>

good luck !

[EBK]

I use 91% isopropyl (the more expensive kind, readily available in stores though) to clean flux.  Works fine.