This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Wednesday, August 30, 2017

Colorsound Tremolo

Haven't done a tremolo in a while, so let's remedy that with the original 4-transistor Colorsound Tremolo (the re-issue is the 3-transistor version). Originals used 2SC945 transistors (BCE pinout), but I've laid this out for more common NPN transistors with CBE pinout. You might want to use a C100k pot for the Speed control. Here's the schematic for reference.


13 comments:

  1. I've done it on PCB and it works ! You can tag it verified...
    But when I add the LED it doesn't pulse (only a dimmed light) and there's no more effect. Any idea on how to add this nice feature ?
    Another question : the speed pot could have a wider range, from very slow to ultra-speedy. How can I achieve that ?

    ReplyDelete
  2. I forgot to mention that the depth pot is effective only on the first 1/4 of rotation.

    ReplyDelete
    Replies
    1. Try increasing the value of the speed pot and lower the value depth pot. Not sure about the LED. Maybe check the Tagboard blog post with this same circuit.

      Delete
  3. Thanks for the tips. And for the layout of course !

    ReplyDelete
    Replies
    1. Stumbled across some info on the LED. Just connect the + side of the LED to the collectors of Q2-3. The connect - side to the footswitch as you would normally. I'll update the layout with a pad for doing that shortly.

      Delete
  4. verified!! really nice, but I have the same problem with the LED as eve-the-frog!
    excellent website thanks for the projects

    ReplyDelete
  5. I've built this on pcb and on vero - all I get is clean output, no tremolo effect. The LED pulses just fine. I'm confused.

    ReplyDelete
  6. For anyone wondering about the LED (I got everything working and took some time to experiment). You have to add a resistance between the LED and ground. I got these results with a C100k speed pot:
    * Little to no resistance (~<1k) will ground the pulsating signal resulting in no effect.
    * Low resistance (3.3-5.7k) will result in a dead zone on the speed control.
    * Too much (>10k) and the led will be too dim.

    I got it working with ~7.6k (33k and 10k on parallel). But still, the Super Bright LED I put gets as dim as a regular one. So I'll modify it sometime. Maybe some transistor would be a better choice for powering the LED.

    ReplyDelete
    Replies
    1. Update: I added another 2N5088 for the led to work. Base to the LED+ on the board, Emitter to the Anode of the LED and Collector to +9v. Works great. Also changed the 100k depth pot for a B25K for a way better working range.

      Delete
    2. need to add some resistance between the emitter and the ground?

      Delete
  7. I could use a Darlington (MPSA13/TIP120) for Q2+Q3 right?

    ReplyDelete
    Replies
    1. You could try it, but the typical HFE of an MPSA13 is 5000, while the combined HFE of 2, 2N5088s would be 160,000.

      Delete