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, April 1, 2015

ColorSound OverDriver

The OverDriver is a dynamic transparent drive that works great with a tube amp. It's essentially a massive clean booster that pushes the amp to overdriven tones. Original units from '69-'70 didn't have a master volume control, but modern versions do and it's a good addition to the circuit. (If for some reason you don't want the master volume, the Volume 3 pad becomes the Out pad.)

I've upped the power filter cap to 47µ and added polarity protection and a pulldown resistor. The original BC transistors used had BCE pinouts, but I've laid the effect out for the more common CBE pinout. Also, the BC169 transistors used for Q1 and 2 will probably be pretty difficult to source, so socket and try out some alternatives (2N3904, 2N5088, etc). Might be a tight squeeze horizontally, but it should fit in a 1590B enclosure.




Here's my build. Haven't boxed it up yet, but I tested it and it seems to work. I used 2N2222s for Q1-2 and a BC550 for Q3, though I plan to try out some different ones. Also, you may want to try a lower value for the gain pot. There's a serious drop in gain once you start turning it down. Since the first stage is based on the Fuzz Face, maybe try a B1 or 2k pot. Reverse log might not be a bad idea either.



12 comments:

  1. I made this, it works very well, I made a video comparing some transistors, thanks for the layout !!!

    https://youtu.be/ROnE0rKJ0Zo

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    1. any chance you could take the video off of private i'd love to hear the different transistors

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  2. hi, in my country "BC's" is more common. I get a lot of them out of trash. (has another "word" for a electronic trash in English?)

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  3. Hi. I want to build the Solasound power booster pedal. I saw that the electronic sketch is relatively the same like the overdrive version.
    Then. Can i use the present layout to build the power booster pedal? In this case what must i change? 
    Thank you very much.
    Gerald from Belgium

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    1. I think the only difference between the Power Booster and the Overdriver was the Power Booster ran on 18v instead of 9v. So just throw in a voltage doubler daughter board and you should be good to go.

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  4. Built and working!
    The B1k pot for the gain is a great improvement.
    Used BC549 for Q1, BC148 for Q2, and 2n3904 for Q3. The 2n904 is a must try for sure.
    Also tried Germanium in Q3 with great results.

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  5. A 555 charge pump would work as a voltage doubler ? thanks!

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  6. hi i'm not getting unity gain what could i change to bring up the level a-lot I'm wanting to use it as a clean boost type pedal this is my second one as i made a strip board kit from bits-box. which i used the same way till it died on me so decided to do a PCB layout as i've discovered my definite hate for Stripboard. I'm not super up on electronics just enough to solder some boards like doing legos so any help would be welcome.

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    1. hi got the volume thing fixed but treble and bass appear to do nothing. any ideas?

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  7. Built it and it sounds amazing ! I used a B5k for gain (might swap in a C1k instead, the taper of the pot is weird...but it sound great with gain dimed, sooo...) and tested out a few transistors, settled for 2n2222 in Q1 and Q2 and 2n3904 in Q3. I also added a charge pump with a SPDT to go from 9v to 18v, as it is the main difference between the Overdriver and the Power Boost (that Gilmour used).
    Again, amazing circuit, thanks for laying it out, awesome blog !

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