@brd
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The traces are the lines in the schematic connecting the components, they can be signal or power. They run traces on both sides because they can’t cross. They are not drawn like the schematic because that would waste space on the board. Hope that helps.
Sounds like what happens when you connect the power supply to an active pedal. You will get a pop and a delay before signal is passed. Check voltage on the board with the switch in bypass.
Go bright and crank up the fog machine, you’ll get a stage light show off of your pedal board. Best reason to use the bi-color led’s
Using the schematic and the readings that you have already supplied I think your Va, Vb, and Vc reading are fine.
Long explanation:
Va should be the same as your Q1 drain voltage, which was 7.4v. The expected value given by Barry was 7.27v. That is close enough.
Vb should be half of Va because of the voltage divider R29 and R30, which it is.
Vc should equal to your collector voltage on Q2 and Q3, which it is, and it is close enough to the expected voltage of 5.05v
What doesn’t look correct is your base voltage (middle pin) on Q2. Barry’s number is 3.75v you are at 1.48v.
Recheck that voltage measurement and be sure you have the Decay pot turned fully counter clockwise.
Also, Just using a little math, you have a diode D3 that should be dropping at least .25v so you should expect your voltage at pin 1 of IC2 to be at least .25v higher than your base voltage on Q2. Your readings are nearly identical, that doesn’t seem correct either.
Just to be sure, Are Q2 and Q3 BC550’s?
There is a small pass through next to R23, that is suspiciously close to pin 1 of IC2. Check your work there to see if you may have bridged that by accident.
Thanks for the tip, I wish I had that information a few years ago. However, talent and patience are the missing ingredients here. Below is a photo of my first and last pedals, clearly showing no improvement in my art or my ADHD.
Big O
I have been around this forum for a while, long enough to know you are one of the most prolific build posters here. Your graphics and finish are second to none. I can make them work but I can’t make them pretty. I built my “Omega” petal a while ago, but there is a breadboard on my desk now with some half baked idea that just might make it into a box. Hopefully something will inspire you again.
Ralf,
I would say the first version might work. I have the equivalent of Barry’s Tone TwEQ circuit installed in my semi-hollow guitar as a pre-amp for the piezo, although I’m using 2 jacks and a modified Paramix board to mix the signals on the floor. Note, my piezo pickup just doesn’t play well with some effects, so try it before you modify the guitar. Mojo is hard to predict.
Awesome project, good luck,
Elio,
Raising the values of the input and output caps will pass more bass frequencies, but c7 and c9 may also need to be adjusted too. You may need to experiment with values to find your sweet spot, so if you decide to try to adapt the pedal I suggest using sockets to spare the board from repeated de-soldering. No worries about letting the smoke out.
-Best
In regards to pin identification, short answers is yes, I think you have the pins numbered correctly in the picture. However flipping the board over requires too much extra thought for me, I use the legs of the IC for checking voltages. From the top of the board, number 1 is the pin to the left of the little indent on then count down then over and up the other side.
As far as the wiring for the jacks, there is a “T” printed on the board to identify the pad that is connected to the Tip on the jack.
Now as far as the signal. You should check for output from both the send and the out jack. remembering the gain and mix pots should only affect the signal at the out jack.
Best
If your definition of DOA is that the LED doesn’t light up. The S4/S5/S6 pads are connections that should go to the foot switch to activate the LED. Without a switch or jumper there the LED will not illuminate. If you want the LED to be on whenever the board is connected to power, a jumper between S4 and S5 should do the trick.
Hope that helps
Be sure you made both ground connections and check your trimmer adjustment? Not really a thought just guesses.
Okay it’s a little early yet but I didn’t see any notes in the new build doc regarding the trimmer and adjustment. For that you should start around mid-sweep on the trimmer and make very small adjustments to find that spot.
Another basic question is, are you using a known good power supply?
The troubleshooting could be getting more technical from here. Do you have a Digital Volt Ohm meter?
It is nice to have an audio probe to be able to trace the signal path. I think it’s one of the best tools to isolate issues. By being able to verify a good audio signal at the input to the board you have a quick way to know which direction to go with testing (usually). It can also help locate problems on the board by following the audio path on the circuit.
For safety and simplicity, I use a 9v battery powered amp for bench testing. If I need an audio probe, I can clip it to the output jack on the build and test away using the amp to listen.
You can do some damage with a probe so be aware of what you touch with it.
If you build the tap tempo board with a voltage regulator, so you don’t have to tap VB from the delay board, ( see build notes ) I think it can work with just a patch cable.
You could de-solder the leg of R9 that connects to R22 and lift it from the delay board. ( sorry I don’t have a board to verify which leg that is ) Then connect a wire from that leg of R9 to the tip lug of your new switching jack. This will be your send to the tap tempo.
Then connect a wire from the ring lug of your switching jack to the pad on the delay board where you lifted R9. You will then have a switch that will separate R22 and the Time pot on the delay board from the circuit when you plug in your patch cable and connect them when the patch cable is out.
On the tap tempo side, just connect the tip lug of your input jack to the board.
If you use an external power supply that is daisy chained to both boards, I don’t think there will be any ground issues. I am unsure what would happen without a common ground.
I hope I explained that well enough.
