The Vibe no sound at all

[Anonymous]

Hi !
I’ve recently purchased the Vibe kit from musikding , had a lot of fun building it but the only problem i’ve faced from the beginning is that it makes no sound at all , not even a faint hiss .
Bypass works , but the effect seems dead .
So I’ve been reading all I could on this forum about troubleshooting the Vibe pedal and I tried so many things like reflowing any suspicious solder pads , verifying D1 polarity , measuring the voltage across all the transistors , verifying the resistors values , conneting both ground pads …
I found mistakes along the way and fixed them but nothing seems to change the fact that it still does not produce any sound , excepte when I strum very hard I can extract a little cracking noise from the pedal , like an underbiased fuzz pedal .
While tinkering around I’ve found out that poking my finger around IC1 and IC3 solder pads made it produce a very muffled and weak tremolo’d signal .
So maybe it could be IC1 or 3 fault ?
Here’s the voltage reading for IC1 :
1 – 76 mV
2 – 1,4 V
3 – 0,9 V
4 – 0,1 mV
5 – 76 mV
6 – 1,4 V
7 – 9 V
8 – 3,5 mV

And the reading for IC3 :
1 – 0 to 20 mV
2 – 3,6 to 5,5 V
3 – 3,5 to 5,5 V
4 – 0 V
5 – 0 to 40 mV
6 – 0,6 to 8,5 V
7 – 9 V
8 – 2 mV

I hope the oscilating values are a normal thing , they are linked to the speed knob from what I observed .

And last but not least, all the transistors read exactly the same :
Drain – 240 mV
Source – 238 mV
Gate – 0,71 to 0,68 V

Here’s a picture of my board ( Don’t judge the solder blob on top , I’ve had some mishaps with the speed potentiometer but it works )

R10 and R17 are mounted that way because I was planning to do the half/full mod … when it will finally work .

[Anonymous]

Sould I mention I built the pedal using the wrong version instruction but I checked any parts values that may have changed and fixed two resistors .
R16 had to be removed and R31 was the wrong value , since then I think it burned in an infortunate short circuit caused by a contact with the housing during a reading , but still when it  was not burned the pedal made no sound .

[Anonymous]

Q1 through Q4 are backwards. The curved sides should match that of the image silkscreened on the board. Unless they’re weird ones.

No judgement. Most of us have done something like that. I’ve done it on three separate occasions when I don’t have that visual indicator.
Just make sure that solder at the top doesn’t short. If it works it works, I’m just overly cautious.

I was also going to ask why R10 and 17 were mounted that way before I read the post again. That’s a good idea. Think I might try it.

[Chuck]

If Q1 – Q4 are 2N5952s they are backward, if you’ve got matched 2N5457s they are correct.  Did you do any trimmer adjustments?  Both The Vibe and the Dr Phybes have a sweet spot – either side of the sweet spot they just don’t do anything.

Chuck

[Cybercow]

I can barely make out that you’ve used 2N5457 JFETs. And while they are correctly oriented for this build, did you use 4 matched JFETs? That is crucial. Also, the trimmer is VERY sensitive and has only a very small arc of rotation that will get the effect working. That trimmer MUST be moved in extremely small increments during the setup when tweaking it.

[Anonymous]

The Jfets are what came with the kit so I assume they are matched .

They are 5457 so I mounted them bachwards on purpose .

The problem here is that the pedal is totally mute , from what I have read the trimmer affects the phasing but if not correctly set the pedal will at least pass the dry signal .

Or am I mistaken ?

[Playsforfun]

You are not mistaken about that. But: Check the input jack wiring. The blue wire should go to the tip. Do you need a stereo jack? Instead of ignoring solder blobs, clean them up and make sure no slag is making a solder bridge anywhere. A toothpick can be a useful tool. Also cheap glue brushes work great to clean up solder splash. I see some questionable areas including the out pads. Lastly, but should have been first is to provide clear pics of BOTH sides of the board and ALL connections.

[Anonymous]

I checked that blob with continuity tester and everything’s right , no bridge whatsoever . I had to do it because I damaged the solder pads when removing the pot that was directly soldered to the board at that time , so I scraped the traces and extended the wiring .

I don’t need a stereo jack but that’s what came in the kit so I used it , the blue wire is connected to tip .

I spent a good hour tracing the dry signal path using the schematic , everything looks in order , all the resistances and traces are right .
I really think that IC1 is busted since that’s the first active component the dry signal passes thru before branching out to the phasing stages .

Don’t mind the bundle of cables connected to the switch below , they are not connected , just in place for the half full mod .

[Playsforfun]

Felix, I am not any electronics authority but here are a few opinions that may help. I checked the resistors and capacitors that I could see, and they all look to be correct. Your soldering looks good too. Small clean-ups, afterward, might be helpful (or at least a good habit). R32 can be ignored since the LED pads won’t be used. ‘The  blob’ is necessary if you indeed broke the trace between speed pot pad 2 and R24. In this case I would make sure that connection is beautiful and permanent as long as there is no chance of a short to the ground plane below.  A tiny piece of cut off lead soldered very carefully between the two works well. Tweezers will be necessary. But I would choose the back side to do it on because it is unscarred back there, with less chance of unwanted short circuits when completed. If you choose that, then clean up the front to eliminate problems with possible exposed ground plane shorts. There are some components I can’t see well enough to identify. I read your post about R31 change-out. The latest build doc BOM says 10 ohms but the finished board shows a 47 ohm resistor used. Either way it is a small amount and works to adjust the 9volts down a slight bit, from what I can tell, before it goes to each transistor as ‘VB’. On your board the R31 color bands are chipped and shaded, but I suspect is still a wrong value. You would have to de-solder and pull up a leg to measure properly. I believe your transistor voltages to be way off. As for chipped resistors, I’ve had problems before with their metal shell touching something else metal and causing crackling and mutes. Make sure that doesn’t happen to you here. You’ve done a great job so the fix will be easy once found. Side note: make a troubleshooting probe to save yourself a lot of time. If you are anything like me you will continue to make mistakes. It’s normal. But in some cases we can prepare for it. Hope some of this helps.

[Author]

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