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, May 4, 2016

Keeley Katana

The Katana is a highly regarded clean boost pedal that can give a nice clean boost or push your tube amp into breakup. The circuit itself is fairly simple, but achieves extra headroom thanks to the internal voltage doubler. For this you can use a ICL7660 or MAX1044. You may want to socket the two 4.7k resistors or replace them with 10k trimpots. The drain of both transistors need to be around 9 volts. On original units, the switch is a push/pull on the pot (which is why it's mounted to the side of the enclosure), but a regular toggle can be used. If the switch wiring doesn't make sense, reference the General Layout Notes tab for switch numbering. It should be possible to fit this in a 1590A if you're not claustrophobic. Here's the schematic for reference.


  1. can you please make this one whit 555 ??
    i promises no break your b4lls anymore ;)

  2. Another keeley, awesome!
    Is it possible to replace 5817 with 4148?

  3. Works great! Now I have to get it to the box... And next Cornish G-2.

  4. i have an issue regarding to the humming noise of this pedal, i don't know where it came from..

    1. Did you box it up or just test it? If it's not boxed you could be getting the hum because the board isn't shielded from outside interference.

    2. the MAX1044 runs at in boost mode so it could potentially still be the source of noise. That's why I just stick to ICL7660SCPA, because I know they work perfectly.

    3. I replaced the 4,7k resistors with 10k trimmpots to bias the drain voltage to 9v but still getting noise. It's boxed. Tried to adjust the trimmpots to where the noise is low, but then there is no boost and the sound is getting dark and fizzy. Also when i get noise low and turn the switch, there is noise on the other switch position. So i'm not able to adjust the trimpots to get the effect without noise in both switch positions at the same time. Any ideas? Sorry for bad english. Thanks in advance.

    4. Have you tried increasing the value of the power filtering cap? It's the 47uF cap just below the charge pump. Increase that to 220 or so and see if that helps reduce the noise.

    5. I tried, but it didn't reduce the noise, not even a bit. Wondering were it is coming from.

  5. Why not using a trimpot instead resistor? I build my katana and the boost is incredible but i have adjust the bias :( New version with mountin pot and trimmers please!

  6. Please help me with my build!
    Problem: low output (yes i did the offboard wiring)
    1 9,14V
    2 4,46V
    3 0
    4 0,14
    5 0,3
    6 4,73
    7 4,16
    8 9,14

    Q1 and Q2:
    G 17,53
    s 0,04
    d 0,01

    1. Sorry but i wrote wrong Q readings: D 17,53 S 0,04 G 0,01