SOLVED Kentauride No Sound

[joelorigo]

I have an Effects Layouts Kentauride that I have finished but there is so sound in either bypass or effects. This is the first time I've had this specific issue; could someone tell me what is the first thing to do? (Photos included)

Bellow are links to the project and the build doc.

KENTAURIDE – Effects Layouts

http://effectslayouts.com/wp-content/uploads/2021/12/Kentauride-build-doc-v2.pdf

 

[jimilee]

Did you check the pin outs of the transistors? Looking at the data sheet, if I’m seeing it right, they need to be moved down and flipped 180 degrees. Check me on that.

 

[joelorigo]

The transistors in the photos in the original post are 2SC1815. That orientation looks right to me.

Today I pulled those out, just to see if there was something wonky with them, and inserted 2N3904. I did orient them down and flip 180 degrees.

 

[jhaneyzz]

90% of the time I have an issue like this it turns out I have the guitar plugged into the OUTPUT jack and the amp plugged into the INPUT jack.
the other 10% of the time it is a soldering issue or something is grounding out.

 

[joelorigo]

I WISH it was me getting the in and out mixed up. If fact I've made sure several times that I'm plugging the cables in correctly

 

[jhaneyzz]

I WISH it was me getting the in and out mixed up. If fact I've made sure several times that I'm plugging the cables in correctly

Then you definitely need to buy a new guitar, you're welcome...

 

[joelorigo]

But I bought one 2 weeks ago

Well if I have to…

 

[jhaneyzz]

The next step should be tracing the signal with an audio probe. Absolutely the best way to track down "no signal" issues.

If you don't have one, they are super easy to build.

Misc > Audio Probe : DIY Fever – Building my own guitars, amps and pedals

[DIY Fever] Audio Probe - very simple contraption that helps with debugging audio circuits

diy-fever.com

 

[joelorigo]

Yep, I have one I built just like that, and I have a pedal that has a loop function so I'll give it a go.

 

[joelorigo]

Doing the audio probe now. Get signal at the T of the IN pad on the PCB. Yay!

Do not get any signal on R1. Get only a crackle sound on C1 and one side of R2 (Section of the schematic included). Have we already found a problem?

Also, I forgot to ask, what do the voltages I posted earlier tell us?

 

[joelorigo]

Just giving this a bump, sorry for being pushy.

 

[jimilee]

Doing the audio probe now. Get signal at the T of the IN pad on the PCB. Yay!

Do not get any signal on R1. Get only a crackle sound on C1 and one side of R2 (Section of the schematic included). Have we already found a problem?

Also, I forgot to ask, what do the voltages I posted earlier tell us?

Do you get any continuity, with your DMM, between the in pad and R1?

 

[joelorigo]

Not with the "T" IN pad, but yes with the "S" IN pad, on both sides of the resistor.

 

[jimilee]

Not with the "T" IN pad, but yes with the "S" IN pad, on both sides of the resistor.

The S pad is your ground pad, so somewhere you have a short to ground.

 

[jhaneyzz]

Not with the "T" IN pad, but yes with the "S" IN pad, on both sides of the resistor.

Wait, you are getting signal to the In pad, but getting continuity between Sleeve and In pad as well?

 

[jhaneyzz]

The S pad is your ground pad, so somewhere you have a short to ground.

What he said...

 

[joelorigo]

Thanks, that feels like some progress!
What should I do now?

 

[jhaneyzz]

You say you get crackly sound at C1, put your audio probe there and wiggle stuff around until you find the culprit.

I would suspect the in jack wires first.

 

[joelorigo]

I don't know, doing that, I'm not hearing anything. What do you mean about the in jack wires?

 

[joelorigo]

Um, does it mean anything that I also get continuity between ground and both sides of D3 & D4, or is that just more of the same short to ground issue?

 

[jhaneyzz]

Um, does it mean anything that I also get continuity between ground and both sides of D3 & D4, or is that just more of the same short to ground issue?

Probably the same short.

What do you mean about the in jack wires?

Two things

We have a ground bridge somewhere

1. solder connections on the jack
2. Input pad
3. solder bridge between input positive and input ground
4. Solder bridge between output positive and output ground

We have a Crackly sound

1. Bad solder joint somewhere
2. Broken Trace
3. Lifted pad (have you unsoldered anything?)

to trouble shoot this, put the audio probe wherever it is where you get the crackly sound then start wiggling wires and components until you find the culprit.