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



48 comments:

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

    ReplyDelete
    Replies
    1. 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. 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. 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. 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.

    ReplyDelete
  3. 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

    ReplyDelete
    Replies
    1. 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. 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

    ReplyDelete
  5. Wow! Mark you are seriously the best!

    Thanks bud!

    ReplyDelete
  6. 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

    ReplyDelete
  7. 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

    ReplyDelete
    Replies
    1. Very cool, thanks for the pics

      Delete
  8. 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

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

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

    ReplyDelete
    Replies
    1. 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

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

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

      Delete
    4. 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. 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. Damnnnnnnnnn thanks! I thought I was crazy after building it twice

      Delete
  10. 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.

    ReplyDelete
    Replies
    1. 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.

      Delete
    2. 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

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

      Delete
  11. 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 :)

    ReplyDelete
  12. 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

    ReplyDelete
  13. 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

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

    ReplyDelete
  15. 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

    ReplyDelete
  16. 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!

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

    ReplyDelete
    Replies
    1. 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. hi, which capacitor I need change to use this pedal with bass?

    ReplyDelete
    Replies
    1. 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. 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.

      Delete
    3. 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. thanks brother, I really appreciate your help.

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

    ReplyDelete
  20. 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?

    ReplyDelete
  21. 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?

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

    ReplyDelete
  23. 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?

    ReplyDelete
    Replies
    1. 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. 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. 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. 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.

    ReplyDelete