Friday 29 January 2016

5-knob Compressor

Drew this one up some time ago and thought i'd post it up. It's basically Mark's layout for Keeley 4-knob style compressor with slight tweaks and more notably, an addition of mix/blend/ratio knob. As some of you already know, the basic CA3080 compressors like Ross, MXR and derivatives reverse the signal polarity and thus, the simple blend circuit additions won't work with it. So here's the Ross compressor with tons of usable mods on it. I've built a number of these already, so consider it verified.

2017/05/08 - One cap was reversed on the layout. Now fixed, but i had to redraw this completely due to lost source files. Anyway. Here's the "V2".


Posted by at 18:09
Tags: , ,

68 comments:

  1. Anonymous29 January 2016 at 19:32

    Do you know if this is similar to the BYOC 5 knob?

    ReplyDelete
  2. mirosol29 January 2016 at 20:12

    Yes i do. No it's not. BYOC's take on parallel comp is closer to Ibanez CPL/CP10/CP5 compressor with added tone and blend controls than any of the ones listed here. Completely different VCA and thus, completely different circuit.
    +m

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    Replies
    1. MrPhil11 September 2020 at 02:46

      Hi, Which blend circuit do you think is better and why in your opinion, the op-amp version or the transistor version, as an UN-biased opinion, so to speak?.
      I also pondered why not put a 10k resistor in Q1 collector (input transistor), and take the out of phase signal from there to mix, adjusting gain where needed!
      Thanks.
      Phil

      Delete
  3. MAO30 January 2016 at 03:08

    Nice! Do the transistors need to be matched?

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    Replies
    1. mirosol30 January 2016 at 07:57

      No, they do not. And any NPN will work just fine.
      +m

      Delete
  4. Anonymous30 January 2016 at 05:23

    going on my list right after the engineers thumb . I love compressors !

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  5. resistance30 January 2016 at 21:53

    Sorry but where's the COMP 1? and thank you !

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  6. Unknown31 January 2016 at 16:19

    Built, thank you for that post it works very well. I'm very happy of the mods. Thanks again.

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  7. horseman1 February 2016 at 16:12

    what does the trimmer do?

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  8. Scheissami28 March 2016 at 09:26

    Sorry for the newb question, but I'm super new to pedal building (and electronics, generally) and I have a question about the layout.

    What's the blue square just left of center? There are a few cuts, with a 2K mark and three blue dots. Sorry, just not familiar with this particular set of symbols.

    Thanks!

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  9. Unknown9 April 2016 at 16:11

    can I use this cOmpressor on my bass? .

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    Replies
    1. mirosol9 April 2016 at 17:20

      Yes. As you can use any compressor that is based on dyna or ross.
      +m

      Delete
    2. Unknown9 April 2016 at 19:00

      thanks

      Delete
    3. MAO11 June 2016 at 05:13

      This comment has been removed by the author.

      Delete
    4. MAO11 June 2016 at 05:37

      Finally getting around to building this.

      Is the 1u cap just below the 2k trimmer drawn backwards?

      Should the + side be connected to the Collector and the (-) side to ground?

      Delete
    5. mirosol13 June 2016 at 06:00

      True. Thanks for heads up. I'll fix the layout as soon as i'm back at my desk
      +m

      Delete
    6. Brian27 December 2016 at 21:02

      Did the layout get updated for this cap orientation? I'm having a hard time debugging this one, it's my first compressor. I tried it both ways, but nothing. Does anyone have any voltages I can compare to? I tried tracing it but so far this one is pretty complicated.

      Delete
    7. MAO27 December 2016 at 21:09

      Hi, doesnt look like the layout has been uodated, the 1u cap just below the trimmer needs to be flipped.

      Do you have an audio probe handy for troubleshooting?

      Delete
    8. Brian27 December 2016 at 21:21

      Thanks, yes the layout hasn't been updated, the cap needs to be flipped. I found my problem, I had a small solder bridge. Working great now! Thanks for the response.

      Delete
    9. mirosol4 May 2017 at 19:57

      No, the cap isn't fixed. It's a long story, but last summer i lost all of my data due to currupted disk controller. Home and mirrored backup drives were both rendered unreadable. So i do not hold the source files anymore and to fix any of my layouts would mean to redraw them completely. I might do some of those at one point, but this hasn't been a high priority.
      +m

      Delete
    10. mirosol8 May 2017 at 21:08

      It is fixed now. As noted on the update.
      +m

      Delete
  10. Unknown4 July 2016 at 15:03

    What does the trimpot control?

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    1. mirosol4 May 2017 at 19:59

      Noise balance between the inputs. Nothing to be conserned about when using this circuit with a guitar or a bass. You won't notice any difference turning it with guitar/bass signal levels.
      +m

      Delete
  11. MAO7 July 2016 at 18:34

    I built a slightly modified version of this one(added the BYOC tone control).

    I'm getting an uneven compression, when I strum a chord and let it ring out, the volume seems to increase in waves.

    The controls all appear to be working, but the compression is not smooth.

    Would that indicate a bad CA3080?

    What else could cause this unevenness?

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    Replies
    1. MAO8 July 2016 at 06:42

      I boxed it and swapped out Q5, the waviness seems to be gone now.

      Delete
  12. MAO9 July 2016 at 06:11

    Thanks again mirosol!!!

    I've been playing this pedal all night through the headphone jack of my practice amp and wow! Really quiet and the blend control is definitely the money!

    There were times I literally wasn't sure the pedal was still working, until I turned it off!

    Couple observations/suggestions:
    1. Did I mention the Blend control is the money?
    2. There may be something to using matched sets for Q1,Q2 and Q3,Q4 as well as using higher gain transistors for the Q1 and Q5 buffers. I went with matched MPSA18 for Q1&2, matched 2n3904 for Q3&4 and 2n5089 for Q5 (Mark Hammer suggestions I think?) The pedal sounded cleaner and had more punch than the random set of 2n5088s I also tried. (It's possible I was fooled by the slight increase in volume the MPSA18s and 2n5089 seemed to provide, but it sounded better so I stuck with the matched sets)
    3. TL072 sounded better than the NE5532, I did not notice any improvement in noise levels with the 5532. The TL072 sounded a bit warmer to me.
    4. I added the BYOC 5 Knob Compressor tone control, highly recommended if/when using the neck humbucker. Country players will probably like it too.
    5. For me, the Attack control seems like it's going to be a set-and-forget control. I had converted the clip control to a trimmer to keep the pedal at 5-knobs. It might have been more useful to keep the clip control on the outside (especially if using with multiple instruments/pickup styles, Les Paul/Strat/Bass etc or using after a boost or dirt pedal) and change the Attack control to a on/off/on switch selecting 3 presets. 150k, shorted and something in between like 30k-40k giving the two extremes of the original 150k attack pot and something in between-to taste. (Another Mark Hammer suggestion referring to the original Ross design)

    I may just go with a 6 knob version on the next one :0)

    Finally, for everyone who has built the Keeley 4-knob and like it, you really ought to give this enhanced version a try.

    (I'll most likely be posting the converted layout I used with the added tone control in the Forum)

    ReplyDelete
  13. MAO13 July 2016 at 06:53

    I'd like to give just the dry signal a boost so when the Compression control is at noon, both the dry and compressed signal levels are about the same at both extremes of the Ratio control.

    As it is now, the compressed signal is much louder than the dry signal with the Comp control at noon. Also, with the Ratio control full CCW and the Volume Control full up, the dry signal is just at unity, I'd like to give the dry signal a slight boost with those settings.

    To increase the Dry gain, Would it be better to lower the value of the 100k resistor feeding pin 2 of IC2 or increase the value of the 130k resistor?

    I'm guessing the latter to keep the input impedance of the inverting op amp the same at 100k.

    Thanks

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    Replies
    1. mirosol4 May 2017 at 20:07

      That should suffice. 220K would nearly double the clean level.
      +m

      Delete
  14. Unknown4 May 2017 at 10:14

    What's the chance of getting the schematic for this guy? I would like to create a pcb using the LM13700. I would really appreciate it.

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    Replies
    1. mirosol5 May 2017 at 06:10

      Zero. This being due to the fact that one doesn't exist. Take Ross, read up on Keeley mods and use the blend section from here:
      http://www.diystompboxes.com/smfforum/index.php?topic=40292.msg288800#msg288800

      If you fab them, i'd want a few :)

      (edit - posted a wrong link from my clipboard, sorry - now the link is what it was supposed to be)
      +m

      Delete
  15. Harleking Effects3 July 2017 at 11:59

    So glad I re-checked this, I didn't care for the compressor at all since it always had a bit of distortion, and volume drop, but after reversing the cap it's now my favorite comp!

    ReplyDelete
  16. iiimonfire4 December 2017 at 14:36

    I just recently finished building this, and while debugging I was experimenting with different transistors (I have 2N3904 and 2N5088's on-hand), and found that removing Q3 made the circuit work as expected. Any reason why that may be? Or is it a "if it ain't broke" situation?

    ReplyDelete
  17. BarryW30 April 2018 at 14:24

    This comment has been removed by the author.

    ReplyDelete
  18. Andrew McMann24 May 2018 at 19:37

    Just finished this one up. Its acting semi strange. The blend knob mutes the circuit when it is fully ccw, and the transistor in the bottom left gets super hot. Any suggestions where to troubleshoot this one?

    ReplyDelete
  19. Andrew McMann24 May 2018 at 20:17

    Actually, forget about my comment on the resistor. Turns out that is dependent on the position of the attack knob. However, still getting silence at ccw on the blend knob

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    Replies
    1. mirosol25 May 2018 at 05:46

      Seems like your splitter part of the circuit isn't working right. Probe it to see where the splitted signal dies.

      From the first transistor's emitter there are two caps coming out. Other for the compressor circuit and the other for the split. The 470n taking the signal to IC2 is the split. Check the voltages on the that IC and see if there is signal present on pins 1 and 7. You should have ground on pin 4, supply voltage on pin 8 and all the rest should read around refence voltage (4,5V +/- 10%).

      For the heating transistor, there may be something else wrong with yours too...
      +m
      +m

      Delete
    2. Andrew McMann25 May 2018 at 16:05

      Whew.

      That was a battle. I would fix one thing and then another problem would pop up. In the end, I think my problem came down to the 100 k resistor and the 130k. The signal was fine until it hit those. I think I found one or two places that I had missed when soldering and then there were some bridges that appeared out of nowhere that I fixed. There were just too many freaking parts to heep track of it all, haha. That is definitely the longest time Ive ever spent troubleshooting a pedal, but I didnt want to gove up on it cause it took so long.

      Its all working wonderfully now and sounds wonderful. I have a 100k resistor in there for a bit of a boost. and it has a great sparkle to it. thanks for the fast support!

      Delete
    3. mirosol25 May 2018 at 21:36

      Good to hear you got it running!

      Satisfying thing, don't you think? Get it sounding right after a long debug session...
      +m

      Delete
  20. Unknown30 May 2018 at 11:52

    @Michael Oriente id really like to see that altered layout of your with the tone control. oh and nice comments and suggestions!
    Thank you for another miracle posted on tue forum!! Ill start building this now :)

    ReplyDelete
    Replies
    1. MAO30 May 2018 at 13:18

      Hey Jim,

      Here it is, I used a LM13700 rather than the CA3080.

      http://guitar-fx-layouts.42897.x6.nabble.com/5-knob-compressor-LM13700-version-w-optional-Tone-control-tp36601.html

      Delete
    2. Unknown30 May 2018 at 23:26

      Hey Mao,

      Thanks for the hint although i just stocked some 3080. But i read smthng about the enclosure there on your link.
      Doesnt this fit in a 1590B?

      Delete
  21. Unknown10 June 2018 at 18:34

    This comment has been removed by the author.

    ReplyDelete
  22. Unknown11 June 2018 at 21:29

    This comment has been removed by the author.

    ReplyDelete
  23. Unknown9 October 2018 at 13:53

    Just finished mine today on a 125B. Turns out the board's too large for 1590B. Such a nice effect thought!! Thanks so much, it's working like a charm!!!

    ReplyDelete
    Replies
    1. Unknown29 November 2018 at 12:02

      Here's my demo of it:
      https://www.youtube.com/watch?v=QzvBXsvX2ag

      Delete
  24. Watata1 October 2019 at 09:58

    Hey guys, is there a BOM for this somewhere? I want to order the whole thing from tayda, should I just go through the components one by one?

    ReplyDelete
  25. The Aplikator2 December 2019 at 20:34

    Where can i find the schematic?

    ReplyDelete
    Replies
    1. mirosol3 December 2019 at 13:54

      Nowhere. As noted on a comment above, there isn't one.
      +m

      Delete
  26. Rambling Composer27 March 2020 at 20:15

    Struggling to get this one working. Any info regarding voltages I should expect to see at the transistors?

    ReplyDelete
    Replies
    1. Rambling Composer27 March 2020 at 21:06

      The clean side works, but as I turn the blend knob I get nothing out of the compressor side. Unless... I crank the clip knob and strum REALLY hard...then it will suddenly come through blisteringly loud and super compressed, then suddenly turn back off.

      Delete
    2. MAO27 March 2020 at 21:52

      Check the orientation of the transistors, also is the 3080 from a known source?

      You should be able to find the transistor voltages in the Keeley 4 knob thread.

      http://tagboardeffects.blogspot.com/2012/07/keeley-4-knob-compressor.html

      Delete
  27. MrPhil31 August 2020 at 03:17

    Great So where do I find the schematic?

    ReplyDelete
    Replies
    1. klaus_leo5 September 2020 at 04:57

      This comment has been removed by the author.

      Delete
    2. klaus_leo5 September 2020 at 04:59

      I built this. I used the Keely schematic and link to the Ross mods above and drew this out: https://drive.google.com/file/d/1XaLmzOsF0PonE3bMNnQU0FHxRa7JzRz6/view?usp=sharing

      Delete
  28. klaus_leo5 September 2020 at 05:03

    I recently built this pedal and love what it does for my tone, but the noise I'm getting with it is a lot more than I expected. It sounds like eggs frying, especially when the sustain (comp) knob is turned anywhere past 1/4 of the way. My first thought is a noisy capacitor or transistor. Has anyone else experienced this?

    ReplyDelete
  29. Gurkan16 November 2020 at 20:35

    Hi, all the pots has got 2 wires except the blend. The remaining lug will be empty, right?

    ReplyDelete
    Replies
    1. IvIark16 November 2020 at 21:05

      Yes. They're just being used as variable resistors and so only 2 of the lugs are required. There are some advantages to connecting the unused lug to the middle lug and personally I'd do that but it's not absolutely necessary.

      Delete
    2. Gurkan1 December 2020 at 02:04

      Goodness gracious. I connected everything and it worked the first time. Thanks very much

      Delete
  30. pgorey1 February 2021 at 17:56

    Thank you for all the work ya'll are doing here and the troubleshooting you've helped with. I just finished building this one and have no output. Led and bypass work. I was looking at the board and comparing to the layout and jumper / cut layout specifically and noticed that the jumper / cuts page shows a 2-row jumper on the bottom right that is not reflected on the component layout page. That jumper is required right? I'm not the best at following the circuit but I built an audio probe and circled each point I had audio and it appears to end at IC2 pin 2? I have a redlined version of the component layout page to note where the audio is heard off the probe if there's a way for me to upload.

    ReplyDelete
    Replies
    1. MAO2 February 2021 at 00:19

      This comment has been removed by the author.

      Delete
    2. MAO2 February 2021 at 13:50

      Hey pgorey,
      I'll be glad to help you figure this out. Start a thread over in the debugging section of the forums.

      http://guitar-fx-layouts.42897.x6.nabble.com/Debugging-f23986.html

      In the meantime, check for audio at IC2 pin 1.

      Delete
    3. pgorey3 February 2021 at 11:11

      Thank you! Just created a profile / registered so I can add to the forum. Solder iron is hot and I just fixed my audio probe (aligator clip broke off recently). I'm ready to troubleshoot!

      Delete
  31. Matt4 May 2021 at 07:32

    Hey guys, I've put this together and just have (I think) a relatively small issue to fix. The trimmer inside is set to the mid-point. Also, FYI I used 100k in place of the 56k and 200k instead of the 130k trimmer. I also used electrolytic, not tantalums, although I don't think this is the cause of the problem.

    The clean/unaffected signal is very quiet when I turn the blend knob CCW. Also, the compressed signal is only present when I turn the comp knob up full, and it is not very compressed. In my opinion it seems like the input signal is being attenuated early in the chain before its splits into the clean and compressed signal.

    The transistor and IC voltages are all ok. I have compared them to numbers I found on other similar pedal pages (Ross, 4-knob comp). Any help would be appreciated

    ReplyDelete
  32. JOÃO26 June 2021 at 01:24

    Boa noite. Como faço para colocar somente o controle de Blend no Dynacomp?
    Grato.

    ReplyDelete

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