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Friday, 25 April 2014

Son of Screamer

OK we already have this here essentially with the Lovepedal Eternity, but this was a request and using the Eternity as a template meant it took 2 minutes to do.  This is Jack Orman's circuit which pre-dates the Eternity and so the design that Sean was "inspired" by.  Anyway I suppose it's nice to keep filling the library so we have everything,

Not verified in this guise, but it is really of course :o)




and an 18V charge pump version as requested



at

65 comments:

  1. Zombie1126 April 2014 at 10:54

    This was my request! Thanks a bunch! I like this one much better than the lovepedal, i'll be building it after the weekend :)

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    Replies
    1. Geezer27 April 2014 at 11:31

      Zombie....can you describe what differences you hear and like between the "Son" and the LPE, and while you're at it, what diffs over the classic screamer circuit?

      TIA....Geezer

      Delete
    2. Zombie1127 April 2014 at 20:52

      Less gain and a totally different tone control in the Lovepedal Eternity, more of a treble boost and it already sounds very trebly (the eternity burst is said to have more gain)

      The "Son" is basicly a tubescreamer with the input and output stripped out. So it's a tubescreamer with the real tubescreamer sound that is very simple to build. I also like this better because I understand what all the values do alot better in the standard circuit. Read "The technology of the tubescreamer" if you want to learn more :)

      Delete
    3. Zombie1129 April 2014 at 15:30

      Also the clipping here is a little bit different. If you want the standard tubescreamer clipping jumper D1 or D2 and substitute the remaining 1N34A with a 1N914

      Delete
  2. Luke1 May 2014 at 02:37

    I went through with the formality of building it. It works. I put the diodes on an on off on spdt with the other side being a pair of mosfets with gat and drain connected running anti parallel. On that side of the switch I'm getting a high pitched squeal on most settings. Did I fry the mosfets? They are 2n7000. I like the character of the clipping but I don't know why it's squealing. This is my first time using mosfets as clippers. Anyway I'd say the layout is as good as verified.

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  3. Luke1 May 2014 at 03:39

    The mosfets only squeal when gain is turned above 3/4 and through about the middle half of the tone rotation. I wonder if it is just the proximity of input and output wires? I had the same problem with a high gain pedal. I changed the input and output wires to shielded wire and no more squeal

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    Replies
    1. IvIark1 May 2014 at 08:38

      Yes input and output wire separation and shielding them could help and so worth trying. Also you could have damaged the mosfets which are easily damaged by static.

      Thanks for verifying!

      Delete
  4. Travis11 May 2014 at 19:49

    Hey Mark could you do an 18v version of this using the 7660S? I just got some from MKLEC and want to try an 18v OD

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  5. Travis11 May 2014 at 20:50

    Wow! Mark you are seriously the best!

    Thanks bud!

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  6. Travis18 May 2014 at 07:51

    I finally got around to boxing up the 18v version and it seems to work great. It's late so I can't test it properly, but there's definitely no whine or noise problems, which is a first for me with charge pumps

    Just checking it out quickly at low volume, it sounds nice too

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  7. Travis18 May 2014 at 18:51

    I got to test my build at high volume today and it sounds great! Thanks for the layout Mark

    http://i825.photobucket.com/albums/zz176/Dub-T-123/B60157FA-06CB-43DC-B865-7CA4C6F32B9D_zpszqux0jcv.jpg
    http://i825.photobucket.com/albums/zz176/Dub-T-123/1FEF7D5F-E59D-4EA5-B905-6DBC570A87DD_zpsvnssejrb.jpg

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  8. Zombie1126 May 2014 at 18:41

    Lol i've requested this but I cannot get it to work correctly for the life of me. I've built it two times now and it's the same problem both times: the tone knob.

    It's reacting in a very strange way, making very strange noises as it's turned and also controlling how much distortion comes into the circuit. I've knifed the tracks a million times, checked the layout, reflowed solder, seems to be right. No idea what to do. First time a circuit has given me this much trouble

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  9. Zombie1126 May 2014 at 19:35

    http://nl.tinypic.com/view.php?pic=nxvwhx&s=8#.U4OJQXJ_ths

    If anyone would like to take a look that would be great

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    Replies
    1. Zombie1126 May 2014 at 19:39

      The 1M and the 47p are missing but this shouldn't be a problem since it's a pulldown resistor and the circuit will function without the 47p

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    2. IvIark26 May 2014 at 19:56

      Are you sure the cut is complete between the 220R and 10K?

      Delete
    3. Zombie1126 May 2014 at 20:13

      yeah it's there. Checked with multimeter and there's no link

      Delete
    4. Zombie1127 May 2014 at 12:22

      I'm just gonna let it lie, do some other builds and I'll do it another time with extreme patience and multimetering caus it's driving me crazy right now. Thanks for the help!

      Delete
    5. IvIark18 July 2014 at 21:20

      A bit of a late answer :o)

      A cut was misplace on 3rd row from bottom instead of the 2nd. Put a cut under the ground link on the 2nd from bottom row (or anywhere else between the 220n cap and 4K7 resistor) and that should sort it.

      Delete
    6. Zombie1123 July 2014 at 21:18

      Damnnnnnnnnn thanks! I thought I was crazy after building it twice

      Delete
  10. Piltdown Man23 July 2014 at 12:50

    I tried the 18v version last night 'cos I've been dying to try any 18v project and I am getting signal but no distortion. Volume and tone work (though I have the wiring backwards on the tone) I tried a JRC4558 first then a NE5532. I figured I'd wait and look at it tonight since I could've be staring right at the problem and not noticing it last night. Also is the ICL7660CPAZ okay to use? I notice most call for the 7660S.

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    1. IvIark23 July 2014 at 13:06

      Post your voltages and see if that gives any clues. No you probably don't want to use the standard 7660, its oscillator is a low enough frequency that it can cause audible whining.

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    2. Piltdown Man23 July 2014 at 13:19

      All I have at the moment is the 7660CPAZ. I didn't realize there was a big difference. I'll look at it tonight. Thanks

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    3. Piltdown Man23 July 2014 at 17:56

      I will just wait until the ICL7660S order comes in. ($3.80 for 10 on ebay)

      Delete
  11. Travis23 July 2014 at 14:23

    I was wondering if the tone control was supposed to act like that!

    How embarrassing. I've never really used a screamer before, and it sounded pretty decent so I thought that was it. I'll add the cut when I'm home from work :)

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  12. Travis24 July 2014 at 04:02

    Alright so I was excited at first but ultimately regretted boxing this up and was going to use the enclosure for something else..

    Just added the cut and now this is the best drive I've ever built, possibly the best I've used. There's almost no added noise even with all knobs dimed. That's amazing to me. The sound is very natural and just good. Great sustain.. Just awesome

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  13. Travis24 July 2014 at 04:07

    By the way I've built like almost no overdrive pedals haha so take that into consideration. I crank my amp and like fuzz pedals :O

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  14. Zombie1125 July 2014 at 16:20

    What diodes did you use travis? Did you go for the 2x 1n34 and 1x 1n914 combo? just curious

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  15. Travis25 July 2014 at 16:30

    I made it exactly as per the layout. I got some 1N34A from MKLEC that are about the size of a regular silicon diode and used those

    I did use tantalum for the 220ns because the internet told me so :P probly doesn't really make a difference

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  16. Zombie1129 July 2014 at 23:35

    OK! Finally got it built (the charge pump version) Built it with 2x 1n4001 and a 1n914 for some nice assymetric clipping. Swapped the 4,7k / 0,047uf combo for a 2,7k / 0.1uf combo for improved bass response and some more gain on tap. I'm looking forward to boxing it up and seeing how it holds up against my other TS clones! Thanks again for the layout IvIark!

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  17. Unknown9 March 2015 at 00:24

    I only have 1uf polarized electros, should the negative pin be in the top or bottom hole?

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    1. Unknown9 March 2015 at 01:30

      Negative goes to Vol 3 as per the schematic. (Google Son Of Screamer Schematic and you'll see the 1U cap at the end of the schematic just before the volume control)

      Delete
  18. fred27 June 2015 at 04:22

    hi, which capacitor I need change to use this pedal with bass?

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    1. Zach27 June 2015 at 06:09

      to me it looks like all you really NEED to change to is upping the input cap. that should allow more bass into the circuit. if you don't like the response from the gain pot, you can always alter the resistors in the feedback of the resistors and/or caps.

      Delete
    2. fred28 June 2015 at 19:56

      for bass guitar? , I see online tube screamer 808 some guys change one cap to get or don't lost low end. but i don't know which capacitor is here in this diagram.

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    3. Zach28 June 2015 at 20:40

      the input cap is first cap after the input wire, which is 47nF, which is fairly small. this lowers the amount of bass that enters the effect. if you raise the cap to something higher you will let more bass into the effect, thereby retaining the low end. the output cap is already 1uF which should be more then enough and not need to be changed.

      Delete
    4. fred28 June 2015 at 21:25

      thanks brother, I really appreciate your help.

      Delete
    5. Zach28 June 2015 at 22:52

      any time buddy. i've got a real bass tubescreamer and it's ok. i got it when it first came out, before i was building effects. it sounded great when i played it in the store, but when i got it home, i can never get what i really want out of it with all my gear, so she just collects dust now.

      i would socket the input cap and start trying different ones till you get something you like. i hope you get something you like out of this, btw.

      Delete
  19. fred28 June 2015 at 19:55

    This comment has been removed by the author.

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  20. Skajaquada18 December 2015 at 14:56

    Hey guys. Just built the 18v version of this, and had some problems (drive was doing nothing, vol and tone worked perfect). I was using an old layout posted that misplaced a cut, so I figured that was my problem. Made the proper cut, and my drive control still wasn't working. But while handling the bare board on my testing pedal, the drive signal was cutting in and out. On a suspicion, I jumped pins 7 and 8 on the 7660, and lo and behold, my drive control works perfect now. Any thoughts on this?

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  21. Unknown19 August 2016 at 06:07

    I breadboarded the circuit as described in the geofex "Technology of the Tube Screamer" article and had a similar problem to one of the earlier posters - the pedal "works" in that I get a signal out, and the tone and level controls work, but I get very little distortion. Right now it just sounds like a weak boost pedal. Anyone else run into a similar problem?

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  22. Unknown19 August 2016 at 06:08

    Woah, just read the post directly above mine. I'll try jumpering 7 and 8 on the op-amp as well.

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  23. Unknown19 August 2016 at 06:22

    I noticed that on the muzique site there's a new circuit diagram that looks pretty much like the one on geofex, but it has the clipping diodes in opposite order. That shouldn't matter though right?

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    Replies
    1. Ciaran Haslett19 August 2016 at 12:30

      No that won't matter. Don't jumper pins 7 and 8 either. The 4k7 and and 47k (along with drive pot) sets the gain of the opamp. Are you sure your values are correct?

      Delete
    2. Unknown20 August 2016 at 01:28

      Yeah, the 4k7 and 47k resistors are correct (checked with my multimeter). Checked the pot too and it seems fine. I don't feel like there's any clipping going on. Any suggestions on how to troubleshoot this?

      Delete
    3. Unknown20 August 2016 at 01:31

      FWIW the 500k boost pot seems to have a very subtle effect, i.e. turned down all the way vs. up all the way I notice a small change in distortion but the signal still sounds basically clean. Earlier I noticed that if I left one side of the 500k pot unconnected I got a subtle octave effect and some distortion, but that doesn't seem to be the case any more. Guess it's back to double checking every connection.

      Delete
  24. Unknown20 August 2016 at 03:25

    I figured it out. The cap in the drive circuit going from the 4700 ohm resistor to 4.5V+ was off by 2 orders of magnitude. Replaced it with the correct cap and now the circuit sounds great! Thanks, Ciaran, for taking the time to answer my question.

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  25. Unknown1 February 2017 at 03:00

    Hi guys. Looking forward to building this one. Can you advise on what charge pump to use? Also, is the charge pump the top IC in the diagram?

    Cheers. Matt

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  26. Kelli Overbey27 May 2017 at 07:05

    Hi guys, I have a super beginner question here... I want to put a toggle in to be able to select either symmetrical or asymmetrical clipping. I believe I should remove all 3 diodes and then have wires going from the same row as the drive 1 lead and the same row as the lower leg of the 47pf ceramic cap... is that correct?

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    1. mirosol27 May 2017 at 08:51

      Take all three diodes out and move the 47p to where D3 was (between pins 1 and 2 of course). Then take the switch wires from rows 3 and 4 on the left hand side.

      Also, i'd recommend using different type of diodes for the symmetrical mode. Simply sym/asym has too slight difference IMO. Try 1N4001s, BAT41s or red LEDs for the symmetrical. Also, you could use three position on-off-on swith to get a third option, diode lift. In that mode it would be only the opamp doing the clipping.

      But. These are just suggestions. Do not take me as an authority on tone :)

      One more thing. If you get squeels (like most do with simimlar circuits) try to lower the value of 470K at IC pin 3. Lowering it will take the input impedance down, but the squeel will seize.
      +m

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    2. Kelli Overbey27 May 2017 at 14:27

      Thanks!

      Delete
  27. Jcows29 June 2017 at 03:28

    Built a couple of these (I always build in pairs) and they are good. The tone control however isnt working correctly the last 5 percent or so makes it rather bright. Tone does little in the middle and works fine for cutting highs all the way down or ccw. Is the taper wrong?

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  28. mirosol29 June 2017 at 05:52

    That's mostly a feature. W-taper evens it a bit, but tone maxed is what one would expect. Original Tubescreamer utilizes W-taper and the sweep is better.
    +m

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    1. Jcows7 August 2017 at 01:05

      Hmm would there be any easy remedy to fix the sweep a little? Possibly just even bypass the circuit board tone and doing a passive tone cut with a cap? Also i added a 17v charge pump and it seemed to make no difference so I swapped it for a Lpb1 boost circuit for added volume. Shouldn't the charge pump give tons of headroom?

      Delete
    2. mirosol7 August 2017 at 08:54

      You could try tweaking a custom taper. http://www.geofex.com/Article_Folders/potsecrets/potscret.htm

      But i think it would still be way easier to get a W-taper pot and replace the linear with that.

      For the voltage; this type of circuit sounds exactly the same when fed anything between 5V to 18V. Most discrete FET circuits get more headroom with higer voltage, which is not the case with a tubescreamer. So your behaviour is a feature.
      +m

      Delete
  29. Anonymous29 September 2017 at 21:32

    Hi everybody, I built one of these but somethings wrong with the Drive pot. When I turn it all the way to the bottom I get squealing and extreme distortion. I have no idea how to fix this.

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  30. ManicStrat211231 December 2019 at 19:33

    Could someone show me what a 10uf cap in parallel with the biasing resistors with the negative leg going to ground would look like on this layout?? Thanks in advance

    ReplyDelete
  31. superferrite12 June 2020 at 04:59

    Hi guys!
    Sooo I built this for bass, increasing the input cap to 1uf with no other mods.
    The output is absurdly low, waaay below unity when vol is maxxed.
    Where should i start checking?

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    Replies
    1. IvIark13 June 2020 at 00:49

      This should have plenty of volume so if you're not getting enough there must be a problem with your build or a problem with a component.

      Have you ever used an audio probe? You really need to go through the circuit from the beginning and see exactly where you're losing the signal, which will make finding the problem much easier.

      Have a read of this, and then you can follow the circuit here

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    2. ManicStrat211213 June 2020 at 19:57

      had the exact same problem. Output way low. Also hardly any gain with the gain knob maxed. (I know this circuit is low gain, but this is almost an un-noticeable amount.) how is the gain on yours superferrite?

      Delete
  32. m.miyagawa20 February 2022 at 08:13

    Hi there, I know it has been a while since you posted it but I double checked the Jack Orman schematic and some values were off. With fixed values there is no oscilation or squealing whatsoever (at least from what I could test).

    I posted the layout here
    https://www.reddit.com/r/diypedals/comments/sww8tj/son_of_screamer_squealing_fix_vero_board_schematic/

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  33. Fredrik Fencke28 March 2023 at 01:25

    Is there a simple mod to get less gain at the minimum setting? If it lowers the overall available gain, that's fine.

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    1. Elijah-Baley28 March 2023 at 09:00

      You can get less gain at minimum setting decreasing the 47k resistor.

      For less overall gain you could use a 250k pot for the Drive, instead of the 500k.

      Delete
    2. Fredrik Fencke28 March 2023 at 20:10

      Great, thank you! I'll socket that one and try a couple of different values.

      Delete