Hey there. I've built this pedal a few times in the past and haven't had any problems. For some reason I can't get the one I'm working on currently to work. I used an audio probe and found that I don't have sound after the 10K resistor connected to the Q1 collector. I can hear it on the collector side, but not the side connected to power. I've checked and re-checked for cold solder joints and bridges. Any other ideas? My Q3 collector is also reading very low a .407V. By the way my Q3 collector, emitter, and base all read .407V. Not sure why that's happening.
Schematic:
https://www.diystompboxes.com/smfforum/index.php?topic=51626.0
Quote from: esurreal on January 17, 2021, 01:44:54 PM
I don't have sound after the 10K resistor connected to the Q1 collector. I can hear it on the collector side, but not the side connected to power.
Quite normal.. :icon_wink:
(power supply sources exhibit almost zero impedance so they short signal to ground..)
Amplified signal goes from Q1 Collector into Q2 Base and and a new amplified one goes from Q2 Collector into Q3 Base and so on..
Quote from: esurreal on January 17, 2021, 01:44:54 PM
By the way my Q3 collector, emitter, and base all read .407V.
Can we see some pics of your build..??
Quote from: esurreal on January 17, 2021, 01:44:54 PM....my Q3 collector, emitter, and base all read .407V.
Transistor is a dead short.
You think the transistor is bad?
I didn't realize it but the j201 is meant to be placed directly onto the board without twisting the legs around like the original schematic. I now have sound, but it's not fuzzy. It's a dull tone. Almost clean, but a little muddy.
I had a pcb made for this circuit. Here's the board schematic. I can't find any faults.
(https://i.postimg.cc/1gJh4w8s/hfp.jpg) (https://postimg.cc/1gJh4w8s)
Quote from: esurreal on January 17, 2021, 10:41:01 PM
I had a pcb made for this circuit. Here's the board schematic. I can't find any faults.
(https://i.postimg.cc/1gJh4w8s/hfp.jpg) (https://postimg.cc/1gJh4w8s)
Tracks width and clearance(spacing).. :icon_wink:
Quote from: antonis on January 18, 2021, 03:37:59 PM
Quote from: esurreal on January 17, 2021, 10:41:01 PM
I had a pcb made for this circuit. Here's the board schematic. I can't find any faults.
(https://i.postimg.cc/1gJh4w8s/hfp.jpg) (https://postimg.cc/1gJh4w8s)
Tracks width and clearance(spacing).. :icon_wink:
This is the reason I tend to draw circuits "freehand" in Diptrace. I have better luck than with trying to allow the PCB design program to make the initial guess at the board from a schematic.
I was think the same thing when I saw it. Unless I need to really cram stuff into a design, I usually keep 2x the trace width between traces and at least 1x trace width between pads.
Hmm, never used Diptrace, I'll have to look into it. I used Eagle for this. It was my first time using a computer program to make a PCB. I definitely made a few mistakes with component sizes, but I've sorted it out now. I also hand connected all the connections to the components within the program and then had Eagle do an auto route, so it wasn't completely guessing. I'll try re-adjusting the spacing and have another run at it. Fortunately these boards are cheap, so I'm not out much moolah.
Thanks for the suggestions!