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.

Monday, June 6, 2016

Keeley 4-Knob Compressor

The Keeley 4-Knob Compressor is a modified Ross Compressor and is highly regarded in the stompbox world. It's only down side is the use of the obsolete CA3080 chip. These can be hard to find and a little pricy. However if you're unable to find one, or unwilling to pay for one, use the LM13700 chip (which is 2 3080s in one) and this conversion daughter board. The schematic can be found here. If you have a hard time getting 150k pots, use a 250k pot with a 390k resistor in parallel (between lugs 1 and 3).


81 comments:

  1. Yaayyy! Another keeley!!
    What happen to "recent comments" fiture of this blog? It seems no longer working.
    Anyway, you are awesome as usual brother!

    ReplyDelete
    Replies
    1. Yeah the code for that widget seems to be broken. *shrug*

      Delete
    2. one more, if I have to replace that B150Ks, what would you suggest?

      Delete
    3. Read the last sentence of the post

      Delete
    4. ah... how could I missed that last sentence... my bad

      Delete
  2. can i use this compressor with my active bass?

    ReplyDelete
  3. Verified! sustain is great) nice tapping :3

    ReplyDelete
  4. Great to see this one is verified. My build is 90% and still ongoing. Anyway, i replace the 150p ceramic with 100p and 47p in parrarel. Hope it would be fine

    ReplyDelete
  5. Just realize that the ATTACK on the perfboard is different to the pcb version. Which one should I stick with?

    ReplyDelete
  6. Hello! The solder side wiring pattern seems to be different from that of parts side around level pot connection point.For instance, 10nf cap connected to No3pin of 3080 is missing.Which should I stick with?

    ReplyDelete
    Replies
    1. yea yea, I just realized it. perhaps this was the reason why my build didnt produce any sound..

      Delete
    2. Bericau,
      After my previous post, I figured out the issued solder-side also works.I have just confirmed it Sounds, not boxed yet though.Move the 10nFCap to below 15k resistor, and 1uF should be placed on the left side of the 15k connected to the ground via the hole on the left of 1M resistor.Minus pin to the ground.

      Delete
    3. Oh man, I must have had a massive brain fart. haha! It's fixed now and is consistent between the parts layout and the solder side. Sorry about that!

      Delete
    4. @shimaneko, from what I read, you only move the components and don't change the way they are connected, am I right?
      so my problem is likely bad component(s)..

      Delete
  7. UPDATE
    my build is now working, but I really get fuzzier sound as I roll the SUSTAIN pot up.
    for consideration, I use 100pF for the yellow cap instead of 150pF.
    any suggestion to fix my build?
    help me, anybody

    ReplyDelete
  8. most update
    my build is now perfectly working
    the problem was that my new strat's pickups were too close to string which made my gain was too loud
    done this one
    awesome like usual!

    ReplyDelete
  9. Could you please do the one with blend/ratio mod?
    Thank you very much bro

    ReplyDelete
    Replies
    1. use a blender. I'm about to try it though...

      Delete
  10. just curious, if the output gain is too loud, will changing the 10k resistor solve the problem?

    ReplyDelete
    Replies
    1. Yeah increasing that resistor would lower the output, but so would turning down the level pot ;)

      Delete

  11. I finished my foot today , big pedal this , in place of the potentiometer 150k put a de200K with a 680K resistor between pin 1 and 3 , it was great

    ReplyDelete
  12. It's working but I don't have compression :/ Sustain works, Clipping works and Level works, but the Attack pot doesn't work. Any Idea? I put my multimeter in the 1 and 3 lug and gives me 150k, so I assume it's working outside de circuit.

    ReplyDelete
  13. No encuentro el diodo 5817, reemplazo?

    ReplyDelete
  14. I got sound with the cable not plugged when i plug it i got no sound any ideas?

    ReplyDelete
  15. Hi, this compressor is like keeley bassist?

    ReplyDelete
    Replies
    1. No. The Bassist is based around a THAT chip I believe. This is just a modified Ross Compressor.

      Delete
  16. What type of capacitor is big 1uF to clip 3?

    ReplyDelete
    Replies
    1. It's a box film type capacitor. I get them from Tayda.

      Delete
    2. With respect to the 1uf non-polar capacitor, could I replace it with a polarized 1uf electrolytic capacitor or what replacement options would it have? regards

      Delete
  17. Hi, can anybody help me?
    If I have sound signal at pins 2 and 3 of the IC which are the inputs of CA3080 then I should have had sound signal at pin 6 too, which is the out put of this IC right? And if there's no any sound at pin 6 then probably my CA3080 is bad, isn't it?

    ReplyDelete
    Replies
    1. and I have something around 8V at pin 6

      Delete
    2. Yeah I'd say either your chip is bad or you've got a short that's letting voltage from pin 7 bleed in.

      Delete
    3. I've checked It one more time, now I have 2.4 V at pin 6 and 0.1 V at pin 5 which is the amplifier bias, but right before 27k I have smth around 8 V, can't remember exactly now. But that's interesting, before 27k there are let's say 8V and right after 27k which connects to pin 5 I have 0.1. seems like the IC sucks all the current :D

      Delete
    4. p.s at pin 7 I have 9V as it's supposed to be

      Delete
    5. So, I've changed the CA3080, With the first one, I had no sound at all, with the second one a have a mega fuzz-distortion pedal ))). It's even more distorted than may Box of Rock.

      So.. again a bad IC or I have something wrong in my circuit?

      Thanks.

      Delete
    6. Have you checked the rest of the build for faults? Run an audio probe through it any?

      Delete
    7. I have the same problem. Have you solved it?

      Delete
    8. Same here mega loud distortion pedal

      Delete
  18. This comment has been removed by the author.

    ReplyDelete
  19. This comment has been removed by the author.

    ReplyDelete
  20. This is a really great pedal compressor. Thank you again, David. You, sir, are a legend! =)

    One thing I noticed in my build is that clipping control changes the tonality a bit - the lower it's set the less low end I get at the output (with overall output level matched). Is it normal for this ciruit?

    ReplyDelete
    Replies
    1. Not sure. I haven't built it. You'd have to compare it to a demo.

      Delete
    2. it does like it supposed to be. so I believe that's normal

      Delete
  21. I am the only one who got a lot of RF interference in this project even shielding the enclosure?

    ReplyDelete
  22. Is there something that could be done to the uneven sustain I´m getting. Release is like in steps and not smooth at all. I tried matching the transistors (2n5088 hfe 470 +-5) but that did not help much. Also used 5% caps and 1% resistors. Anything else I could try?

    ReplyDelete
  23. Hi guys, I have tried to build it two times and hadn't got any sound what so ever. Double checked everything. Could it be because of the used ic bought from aliexpress. It's CA3080E. Any suggestion what should i try to test? Thanks a lot. Paul

    ReplyDelete
  24. Everything woks ok, but im getting a little of highs loss, ive checked and rechecked values, is that normal? ive read that some comps make a bit of loss on the high end but on demos of this pedal desnt happen, any workaround?

    ReplyDelete
  25. I had the distorted sound, then I change the IC and now I have low output. Can someone help me?

    ReplyDelete
    Replies
    1. Debug IC. I had the same problem.

      CA3080 or LM3080

      1. NC
      2. 4.6
      3. 4.6
      4. 0.0
      5. 0.7
      6. 2.7
      7. 9.0
      8. NC

      Delete
  26. Works for me!! great effect. cheers!

    ReplyDelete
  27. Can i sub 1uf box caps for 1 uf tantalums? Thanks!

    ReplyDelete
  28. Hi guys, Is this verified? I have tried to build it two times and hadn't got compressor sound what so ever. They were like distortion sounds. Can somebody give me a hand?

    ReplyDelete
    Replies
    1. It is verified. It's very sensitive to the chip. If you're using a Chinese knock off chip it's not going to go well. Best to find a good RCA or Harris chip or use an LM13700 with the converter board.

      Delete
    2. I am very grateful, thank you. I was using CA3080EZ made by INTERSIL. Total of 7 of OP - AMP was tried from China and Japan, but everything was the same result. I'm looking for RCA or Harris chip, and I'm going to try it. Thanks!

      Delete
    3. I verified with the 'LM13700 to CA3080 Conversion Board' by NJM13600.
      It's a great sound. Many thanks.

      Delete
  29. Is there any chance to mod it to Compressor Plus? I mean to add single/humbucker switch ;)

    ReplyDelete
  30. Is there any modification of this pedal but for bass?

    ReplyDelete
  31. Hi. My circuit works, however, I can not understand compression or attack. Checking the values ​​on the IC pins, I found:
    pin 1: 0
    pine 2: 3.61
    pin 3: 3.61
    4: 0 pin
    pine 5: 2.23
    pin 6: 2.22
    pine 7: 8.46
    pin 8: 0
    The curious thing is that just after the diode (1n4007), the voltage dropped to 8.46v. Is that the problem?

    ReplyDelete
  32. Hello friends!
    Can you tell me what type of capacitors are the ones we should use in this project?

    ReplyDelete
  33. Hola, no entiendo como debe ir la conexión del potenciómetro "LEVEL", la conexion dice del pin 1 y 3, por favor explicarme cómo iría conectado el potenciometro en LEVEL

    ReplyDelete
  34. Hi people.

    I finished mine. It seems perfect, but I noticed somethings weird. If someone could help...

    First of all: I used LM3080N, 2n3904, metal fim resistors, ceramic, polyester and eletrolitic (polarized) capacitors.

    Highs -- I get more highs than when bypassed. Where/what change to fix it? Any idea?

    Saturation? -- Rolling up sustain, near of 95-97%, I get a kind of "explosion" and the sound is cutted off; and if clipping is full up (or down... right now I can't check), I lost the sound, staying just noises and a much lower signal.

    Attack -- I don't know, but I can't notice difference rolling attack pot...

    But the project is really cool! Thanks a lot!!

    ReplyDelete
  35. Built this using LM3080 and it works fine. The only issue I have is where can you get 150k linear pots? I've use 100k pots, however not sure whether 150k pots would be better.

    ReplyDelete
  36. Okay solved ... I read the last sentence of the post. :)

    ReplyDelete
  37. This comment has been removed by the author.

    ReplyDelete
  38. Its working and 100% verified! Jun fr Philippines! Tnx guyz

    ReplyDelete
  39. Donde esta la salida de señal... NO la veo... Solo veo el In... and out??

    ReplyDelete
  40. Apakah saya bisa menggunakan ic 13600

    ReplyDelete
  41. This comment has been removed by the author.

    ReplyDelete