Waddle Box Problems

[Alexander Maier]

Hello,

today I received my kit for the Waddle Box (DOD FX25 Clone). The documentation was very good and I build the parts together. When I tested the Waddle Box I can only hear a constant noise. I have looked at all and I think everything is build together as it should be. All parts are on the right place. The D1, D2, D100 was inserted as the ring on the diode goes to the quatratic hole.

What can be the problem?

Thanks

Alexander

 

[zgrav]

Not the basket bin! : ^ ) My suggestion is to put is aside for now and build another pedal that interests you. Sometimes you can come back to a project with fresh eyes and find a problem that you could not find before. And it may turn out to be something very simple.

 

[Alexander Maier]

My suggestion is to put is aside for now and build another pedal that interests you.

This I have done It was a Schalltechnik04 Pumpernickel Compressor - Great pedal - and it works fine

 

[zgrav]

Did you drill the case holes? The LEDs look nice!

 

[StephanCOH]

This I have done It was a Schalltechnik04 Pumpernickel Compressor - Great pedal - and it works fine

Wanting to build a Pumpernickel for quite some time now. Did you drill the enclosure yourself?

 

[Alexander Maier]

Wanting to build a Pumpernickel for quite some time now. Did you drill the enclosure yourself?

No, I didn't drill the enclosure myself - it was my son . Not really difficult, but you have to drill slowly, carefully and accurately with a pillar drilling machine.

 

[Alexander Maier]

I have seen that the listed 22k resistors are delivered as 22.6k resistors. I think this is the problem that I didn't get 4,5V round of IC1.

 

[Robert]

As long as they were both the same value that shouldn't have made much of a difference. I've seen the resistors in a Vref voltage divider range anywhere from 4.7K up to 1M each.

BTW that compressor build looks fantastic.

 

[Alexander Maier]

Me once more I have change IC1 and also put the diagram into LTSpice to get some values. The currently measured values on IC1 and IC2 are close to the expected values from LTSpice.

 

[zgrav]

You have done a great job recording the voltages in your circuit. Do you have an audio probe? They are easy to make and will let you listen to your input at different points on your circuit board. It is just an audio cable that plugs into an amplified speaker, with the ground attached to your circuit board ground, and the lead wire goes through a capacitor to block any DC voltage going to your speaker. You can find examples if you do a google search. With an audio probe, you start by putting a signal into the PCB and touching the probe to the input jack to hear it there, then to the input on the PCB to make sure it reaches the board, then on the other side of the first capacitor the sound goes through, etc. When a board is not working as expected, you will find the spot where things are wrong.

 

[Alexander Maier]

I don't have experience with an audio probe. But I have found something like a cable with a capacitor. Shorty used some spare parts

I connected my notebook on the input jack running a web radio to get a "constant signal". The I connected the ground cable to the enclosure. Now I bypassed the pedal with the switch connect the hot cable to the hot pin on the input jack. I hear a the full sound from my speaker.

Now I activate the pedal. Attached the hot cable to the hot pin on the input jack. I hear a very low slightly modulated signal from my speaker. This it the same low slightly modulated signal on the output jack of the pedal and on some IC pin's. -> Should this be correct?

 

[zgrav]

try not putting sound in the input and using your probe to see if you still get noise in the circuit starting at the input and going through toward the output.

 

[zgrav]

also -- since you are getting noise coming into your signal path even at the input, I suggest trying a different wall wart for power and see it it makes a difference. I had one instance where the wall wart I used to test an effect went bad and became noisy.

 

[Alexander Maier]

also -- since you are getting noise coming into your signal path even at the input, I suggest trying a different wall wart for power and see it it makes a difference. I had one instance where the wall wart I used to test an effect went bad and became noisy.

I didn't get a "noise" at the input of the signal path. I am getting a very, very quiet signal when I activate the pedal in comparison when the pedal is in bypass mode. Even on the output, input and one some pins inside. The signal is slightly modulated, but that makes sence. The waddle box should modulate (envelope filter) the signal.

 

[zgrav]

thanks for the clarification. so the level of the signal within the effect is very quiet compared to the bypass. use the audio probe and start at your footswitch where the signal comes in from the input jack, and compare it to the ppare of the footswitch where it goes to the pcb when it is switched on. The sound level should be the same there. Is it? If the sound is lower going to your PCB than it is coming in from the jack to the footswitch, I would disconnect the wire going to the pcb and see if that makes a difference when you test the sound at the footswitch. If the sound level is low coming out of your footswitch even if it is not connected to your PCB, you might have a bad footswitch. You can connect the wire from the input jack to the "in" pad on the pcb to take the switch out of the circuit and see if that makes a difference in what you hear. If the sound only gets lower level when the wire is connected to the PCB, use your audio probe and the circuit diagram to see if you find different sound levels where the signal goes into different parts. test the points where sound goes into each IC and out of each IC.

 

[zgrav]

another way to get a good feel for using the audio probe is to use one of your effect pedals that works OK to explore different parts of the audio path and compare it to the circuit diagram for that project. in general, your incoming audio should be at about the same level going into an effect until it reaches either a pot (or trim control) or an IC or transistor.

 

[Alexander Maier]

So I now had some time to "play". I "disabled" the footswitch by wiring the cables together. Then I used my audio probe cable.

• Input jack - Sound ok.
• After C1 - Sound ok.
• After R1 - Sound ok.
• Pin 3 of IC1.1 - Sound ok.
• Pin 1 of IC1.1 - Sound pulsating and little less signal
• Before R6 - Sound equal to Pin 1 of IC1.1
• Pin 3 of IC 2.1 - No Sound (not correct, very very low signal)
• Pin 5 of IC 1.2 - No Sound (not correct, very very low signal)

So I changed IC1 to two other new IC's. -> The same.
So I pulled out IC1 and bridged Pin3 to Pin1 -> The same.

The only idea I have is to rebuild the kit with new parts. -> So time for the trash bin!

 

[zgrav]

Sometimes it helps to build another one and get it working. If you do, I would keep this one and compare it to your working one to see where the differences are inside the circuit so you can fix it and have two of them, or pass one along to a friend.

If you wanted to keep looking at your project, from what you posted above, it would be worth figuring out why you have OK sound before R6, but then you don't have OK sounds at pin 3 of IC 2.1 See if the sound is OK on the other side of R6. If the sound on the other side of R6 is different from what you get at pin 3, of IC 2.1, then something is wrong in that part of the circuit because the "back side" of R6 should have a direct connection to pin 3 of IC 2.1

 

[Alexander Maier]

I gave the project some time. First of all I pulled out the ics, soldered out all cable and all capacitors. Then I measured the connection between all parts according to the diagram. Seams there is all ok. Then I measured all resistors. And - I first was happy - all 22k resistors had a value about 11-14k. Did I found the problem. I soldered out all these 6 wrong resistors. That was R9, R10, R11, R16, R17, R102. After them I measured the resistors outside the board. All values are 22k. That was why I first was happy. So I decided to pull all parts back to the board. Then I measured these 6 resistors (from the side of the soldering) and the values are between 11-14k.

Why ??? I don't understand this

 

[zgrav]

The resistors on a board can have multiple paths that connect through other components. So when you are measuring each side of a resistor on a PCB there can be multiple paths through other resistors on the PCB, so your the resistance you measure will be lower than just the value of that one resistor.