My First Kingslayer Build-Uh perro, no Trabajo!

[Ekimneets]

I thought I did a pretty good job until I hooked it up. There is a very pronounced hum that does not vary with the pots on the pedal only the volume on the amplifier. LED lights up and it's fine on bypass.

My first suspect is that I cooked the build. I've noticed a tendency to dwell on a pad . I'm going to literally could 2-3 1000 for each solder connection. My second suspect is my soldering itself. It is where I need to improve the most. Failing that, am I populating the board incorrectly, are my diodes backwards, etc?

You may not be able to see it, but the backside of the pots are covered in double-sided tape. Those dust caps from small bear/mammoth are nice but they take up a lot of room.

[jimilee]

Do you have bypass?


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[Ekimneets]

Yes, bypass works fine.

[somnif]

Could be a ground issue, try connecting the grounds of both jacks to the power ground with alligator clips or similar as a test.

Also, what sort of power supply are you testing with? If its a wall wart, does it produce similar hum with other circuits?

[Ekimneets]

 So the home is less with common ground but still there.

Tried it with the battery and measured 8.54 V I noticed the LED would not light up but there's no change in the sound it still is fine on bypass and on the effects night there's nothing.

Next I try to wall wart  end it measured 9.54 V the LED with light and there was no change in the sound .

Then I tried the benchtop power supply which version 8.91 V and once again no change the sound whatsoever .

[jimilee]

There are several solder joints that look almost empty. Each joint should look like a silvery Hershey's kiss. They should flow through the pad.Reflow and add where needed, then let's see where we are. If we go one step at a time instead of guessing, it will save a lot of time and effort.


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[Ekimneets]

I will hunt those down and reflow them. I tend do glob solder, so I guess I'm a little gun shy. I just happen to be getting a digital microscope today. Sounds like a match made in heaven. Thanks for your help.

-Mike

[Ekimneets]

Jimilee, you are seriously observant. I only saw this stuff through the microscope. I reflowed all I found. Thx.

[reddesert]

via Imgflip Meme Generator

One step to take in debugging is to measure the DC voltage relative to ground at some convenient test points.  Most people measure at each pin of all the transistors and ICs.  Correct voltages will be tabulated in Madbean's excellent build documents. You don't have to worry about being off by small amounts (less than a tenth of a volt), but if a voltage is off by a lot, it usually indicates and helps locate a problem. Often the problem is not with the IC but with components around it, for example an op-amp that isn't getting supply voltage, or if a component in its feedback loop is not soldered.

Measuring the DC voltages helps trace the flow of DC levels through the circuit. After that, the next step is to trace the audio signal path. The audio signal is an AC voltage superimposed on top of the DC voltages. Most people use an "audio probe" to follow the signal through the schematic. The audio probe is basically half of an old guitar cable with a capacitor that blocks DC, and you plug it into an amp to listen for the signal as you touch points in the circuit. It is easy to make and everyone should have one - instructions can be googled from various websites.  The audio probe will typically help you find where a signal disappears, localizing the problem.

[jimilee]

Jimilee, you are seriously observant. I only saw this stuff through the microscope. I reflowed all I found. Thx.

When my troubleshooting becomes troublesome, I will take a picture of the the solder and look at it enlarged. It helps.


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[Ekimneets]

 Thank you both for being so gracious and helpful.

I will take your info run with it .

🎛 Mike

[Ekimneets]

Before taking the next step and measuring voltages, I bit the bullet and removed the pots to look at the soldering underneath. I found a few that were suspect and reflowed them, put the pots back on and guess what?

Bingo! It works now.

I started really slowing down and concentrating on my soldering and I'm also checking them under the microscope after every 2 or 3 times. I'm sure it's overkill, but I'm a belt and suspenders kinda guy.

Thanks for all your help.

-Mike

[jimilee]

Nicely done! Enjoy it.


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