Obsidius Preamp not working

B

BouncyBear

New member
Hi all, im new to pedal building and when i turn on the obsidious preamp pedal it has no sound i was testing it with aligator clips and the leds i was using stopped working when i turned the blend knob so i tryed another one and this one again stopped working. the pedal has sound when de activated and when activated there is nothing but when i turn the nobs and everything up to full you can hear a tiny buzz. i am very new to pedal building and am stuck and was wondering if i can get some help
here are some photos
 

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obsidius.png

Quite hard to see what's going on. Better lighting will help us all, but maybe for starters check that the wire with arrow pointing to it isn't shorting against anything.
 
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Had the same feeling like @mybud with the connection from the LED.
But this will not be the problem with the sound.
First: Check every single component, if it's the right value. When everything is alright go to the next step.
Second: Reflow every single solder joint, cause some of yours looks like cold solder joints.
Third: use some isopropyl alcohol and clean your board.

Lastly: Which J201 do you use? There are many fake J201 for sale. To be on the safe side, use some SMD J201.
I would also always use a 3 pin sockets for the JFET. That makes the life easier for repair work.
 
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No, R100 is the current limiting resistor for the LED.

Here’s a possible approach to try:

Touch up any suspect solder joints. Do a visual check and confirm all other component values are correct while you’re at it.

The joints should be shiny and look like little volcanoes, with solder visible on both sides of the board; IOW, evidence of a solid connection.

The risk of soldering haphazardly may be damage to a trace (no disrespect @TillMack).

Before jumping to conclusions (again no disrespect @BouncyBear 😉) that the 201s may be fake, consider making an audio probe (search the forum for info) which helps to establish more clearly where the problem lies.
 
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BouncyBear said:
so i touched up the solder joints now i have a alarm sound when i turn on the pedal i have a very high frequency hum could it be from the transistors
Click to expand...
It may be that your JFETs are fake. Do have a look at the audio probe option. Again, that might help determine the integrity of the transistors.
 
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