Monday, 5 July 2010

DOD 250


17 comments:

  1. Finished this tonight and... 1M seems to be too much. Checked some schematics from the web, and 4 of the first that google's picture search returned, used 500K linear instead of 1M. I'll be changing that tomorrow. The first 500K of that 1M does nothing. Last 50K or so turns this in to really cold and dry distortion.

    Another thing that got me puzzled.. I could only source LM741CN opamps, and they all sound just terrible. Tried LM301 and it warms the sound up a bit, but it's still not-so-good distortion with drive pot all the way up. In other words, i can't seem to get this to sound like the one in the youtube demos. Or is this supposed to be more of a distortion than boost/overdrive? I guess i should try TL071, but i don't have those at hand. I do have NE5534P's and those go on the circuit for testing tomorrow too.

    Any pointers are welcome...

    I have similar issues with MXR Distortion+ at the moment. Although i think that can also be solved with LM301 and C500K pot. :)

    ReplyDelete
  2. I know that the blue thing and the big white thing are both electrolytic capacitors, but whenever I look up "electrolytic 4u7" or "electrolytic 10u" I can't get any results. Can you help me out with this?

    ReplyDelete
    Replies
    1. That's 4,7 microfarad and 10 microfarad. Sometimes these are marked 4u7 or 4,7u. Or to be exactly correct, 4µ7 and 10µ.

      Check out these:
      http://www.taydaelectronics.com/capacitors/electrolytic-capacitors/4-7uf-35v-105c-radial-electrolytic-capacitor-5x11mm.html
      http://www.musikding.de/Passive-parts/Capacitors/Electrolytic/Electrolytic-caps-axial/Low-voltage/10uF-25V-axial::1974.html

      Here's value conversion chart:
      http://www.justradios.com/uFnFpF.html

      P.S. I can't remember what i did with mine, but i got it working perfectly...

      +m

      Delete
  3. How would one go about adding a "Gate" function to this circuit?

    ReplyDelete
  4. I have no idea why I've never tried this pedal before. Miro recommended it to me and I believed him. Boy am I glad I did, my Orange OR50 just sings with this thing in front of it. Thanks!

    ReplyDelete
  5. This is simply amazing design. Everyone i know who have played with any version (original, reissue or YJM308) have been completely sold. I've heard two comments stating that "there's really no need for a tone pot". I think MXR D+ gives this a bad rep (as even the old ones suck when compared to this)...

    From mild dirty booster to full on distortion with characteristic natural compression happening in there. Plus this really shines on any tube amp. Just remember to use 1N4148 for clippers, C500K pot for gain and B100K pot for level.

    My favourite OD.
    +m

    ReplyDelete
  6. I tired some simple mods with this. Ge/Si clipping, upping the input cap etc. 1N4148 was the best clipping diode for me and more bass just turns into flubby nonsense, not worth it if you use high gain settings. So, I left it stock. It's very bright though which has worked for me spot on until now. Now I decided I want to set up my amp brighter to let the single coil cleans shine but that just makes the distortion with the DOD on just waaaay too shrill for my tastes. I think I'll try to darken this a bit and maybe use a switch to dial it back to original. Any thoughts on how to approach this? I probably need it to cut a lot of treble, I use a growly mid-heavy sound with the shrill high frequencies dialed out. Just fat, lower mid growly no bullshit tone reminiscent of a Les Paul running through a boosted Jubilee or someting like that. Try other opamps? Add a low pass filter? Add a tone stack of some sorts maybe?

    ReplyDelete
    Replies
    1. Nooooooo! Heresy!

      You should probably check out the Overdrive II (not the 855 one, but the original). Just go with 1N4148s and tweak the output level to your liking. That's basically the same circuit with TS-style active tone control after 250-like main gain stage.
      +m

      Delete
  7. I know I know! I'm a bit conservative with these things too but desperate times call for desperate measures. I'll definitely keep the ODII in mind. Thanks again!

    ReplyDelete
  8. Started blind shooting with the existing one. I'm actually having great success putting a cap in parallel with the diodes. It doesn't change the main tonal qualities that much and the cut is not very drastic so you can use huge ass values. I tried everything I have between 470pf and 22n. 10n and 22n actually sound wonderful. It's STILL BRIGHT which is amazing but I'm not hearing the icepicky frequencies I did before. Also the clipping is still pretty sharp and focused. Gotta keep trying. The annoying thing is that I can't do a proper test home and as a family man getting to our rehearsal bunker is a bit tricky. Dang it.

    ReplyDelete
  9. Nah, it's a dead end. When the amp is too bright, it's just too bright. The DOD is best served stock.

    ReplyDelete
  10. I used the B500K for drive as Miro said he saw in the schemes for this, and I like it much better. It still gets pretty nutty on the gain at only 500K, but he's absolutely correct that the last little portion with 1 meg is terrible sounding.

    ReplyDelete
  11. Just curious, what version is this? I built it and its on my board, sounds great with an lf351! Now I'm considering building the grey spec one, it looks quite different with the addition of a 1meg and and a 120pf cap and only one 1N cap, as well as pot values. Anybody compare this one to the grey spec one? I'm happy with this build...but curious!

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

    ReplyDelete
  13. By the way, IC's DO make a big difference in this circuit! A TL081 sounded crap, TLO71 much better but the LF351 was just right.

    ReplyDelete
  14. I think the volume pot on this should be 100K A, not 10K. Every DOD 250 schematic I've seen shows 100K. I like two germanium diodes and a 4148 + a BAT41 for the clipping. All 4148's seem to thin out the tone too much.

    ReplyDelete