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Hi, My first inquiry on this forum. I highly appreciate the build quality of these PCBs and the fantastic community around this forum. I am relatively new in pedal building, my main hobby is to service, mod, build and restore tube amps. But building pedals is a real fun ! Here are my concerns :
- I have bought a Dr Phybes kit from MUSIKDING here in Europe (I am French) and, looking at the illustration on the build document (page 3, “WIRING” drawing), I am wondering if P1 is not shown wired backwards : the P1 holes on the PCB show a little “1” digit on the upper left, and indeed connected to nothing just like schematic page 2 , but the SPEED pot is shown with its pin Nr 3 wired in this hole ! What is correct ?
- Do you think I am right to believe that if I connect the middle pin of the foot-switch center section (which connects the two-color LED) to pin 3 of P1, I will BOTH have a color change (green ON, red BYPASS), but I will ALSO have the RATE LED MOD (in any position) blinking with the LFO speed ? Just like the APOLLO TREMOLO (which incidentally was the first GuitarPCB project that I assembled) ?
Keep on the good vibes !
Chris
A good eye! It is strange that so many of us have looked at that diagram for years and never noticed that the diagram had the pot wired wrong! Barry will correct the diagram. In the meantime, just follow the board for the correct placement of the #1 pot lug.
Sadly, you cannot use the bi-color LED to perform both functions. The LED is a common anode LED. The wiring diagram for the RATE LED mod shows that the anode of the LED faces toward the CLR and the +9V power source. Only a single cathode wire connects to lug 3 of the Rate pot.
Thanks for your answer, Wilkie1, but I still have some concerns around P1 and the LEDs.
First, on the schematics P1 is used as a variable resistor, with lug 1 unconnected. This is confirmed on the PCB, pad for the lug#1 goes… nowhere. Then, why bother to install the red (pink ?) wire on the WIRING picture ? We can save a wire & two solder points.
Secondly it is a mystery to me how the RATE LED can work : once you have fed the anode from 9V through the 3.3k CLR, the LED expects its cathode to be grounded to close the circuit. How can connecting this cathode to the pin 3 of P1 (and pin 6 of IC3) provide such a low resistance path to 0 V ? (BTW on the RATE LED pic, the pots lugs are connected the right way). To the opposite, I feel like this will inject (9V less LED Vdrop) into IC3…
Nevertheless IF THIS WORKS, then the proposed bicolor LED has lots of similarities with the RATE LED mod, as both are fed from 9V with a 3.3 Kohms CLR.
In consequence it should perform exactly the same if I connect either S4 or S6 to pin 3 of P1, through the foot switch,by connecting the green wire of the foot switch (WIRING figure) to pin 3 of P1, instead of S5 (using one half of the bicolor LED at a time).
But again I do not understand how RATE LED cathode goes to ground via the P1 #3 lug…
Chris
Hi Christian. It does indeed work. Many people have built it, including myself.
You’re right, pin #1 of P1 is unused. It does NOT need to be connected.
And Rate LED mod works because the cathode side is connected to the more negative potential between those two rate indicator LED & CLR points. And will not inject any loading onto IC3. A bi-color LED will NOT readily work for the Rate LED indicator.
Sorry gentlemen : I am stubborn ! Therefore, I did the bicolor / rate LED mod… and it works perfectly !
The return path of the bicolor LED cathodes I connected to the footswitch normally, but the middle contact of the footswitch goes to lug #3 of the pot (instead of 0V). As the footswitch selects either red or green cathode, the LED now blinks the selected color at the rate of the LFO. Simple and easy mod !
While I was it it, I also added a “depth” pot with simply changes a bit the mixing between dry and wet signal (between R17 & R18). I lowered these resistors to 82 k, and inserted a 100 k linear pot (that is the only value I had available). Works far better than the “R30” mod which I had tried before.
Next mod will be a switched jack socket allowing to insert a 100K expression pedal that I have, will replace the speed pot and allow foot control of the speed. A stereo jack allows the use of a shielded cable to the expression pedal, as only two lugs are needed on P1.
We are always happy to receive new mod ideas. Please submit a sketch of your mods and I’m sure Barry will review for verification before posting to the forum community.
Well I will try to explain what I have done. I am new to this forum, hope I can attach files. First a view of my build :
(Wow, what a big picture ! Wish I knew how to downsize it…)
I usually do waterslides on a light “cream” painted box, but this time was different : I initially wanted to integrate the board into a CRY BABY pedal, so I purchased a second hand one on the net. It was so cool that I no longer wanted to butcher it ! So came the idea of building it in a regular 125B box, and install a jack for an optional remote expression pedal (which I already have). I took a used box, it had unwanted holes from a previous project, so I chose to print the front plate on a grey plastic foil of a metal color, thick enough to mask the holes. “FLAPAFLAP instruments” is my imaginary musical company, just for fun. I do not sell pedals, but I build some for my friends, they have to pay the parts and if they are happy they still can buy me a bottle of good wine.
Now for the mods, here is a PNG of the modified schematic :
I also built the other mods : 45/90, and the C7 mod.
I have not yet installed the socket for the remote expression pedal because I wait delivery of the suitable jack with switched contact & compact size.
That’ it folks !
Chris “Warteko”
REMOTE SPEED CONTROL via expression pedal
Just to inform that I finally got a stereo jack socket, installed it and it works beautifully to vary the speed from an expression pedal. Therefore I did not have to butcher my beautiful Cry Baby.
Chris “Warteko”
Just noticed your comment about picture size. I just load the picture I am going to use into Microsoft Office Picture Manager on my PC and then click on “EDIT’ > “RESIZE” > “Predefined width x height” > then “Web Large” or “Web Small” and then import it into a web picture hosting site. From there I can post the picture on the GuitarPCB website.
If you have an Apple product, I can’t help you. But my daughter, an artist and art teacher, probably knows how.
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