Boss SD-1 project

Discussion in 'Burnt Fingers DIY Effects' started by JuneauMike, Apr 21, 2021.

  1. JuneauMike

    JuneauMike Poster Extraordinaire

    Posts:
    6,978
    Joined:
    May 5, 2015
    Location:
    Alaska
    I bought the Boss SD-1 PCB from General Guitar Gadgets as a fun build project. I don't have much experience building pedals so aside from a few IC buffer circuits and a couple of bypass loopers, this is my introduction to pedal building.

    I'm not sure how this will go but I've identified what I think are good candidates for modification within the GGG circuit and I'm socketing those locations. Last night I soldered the permanent resistors to the board and socketed all the resistors that I may experiment with. I'll do the same for the diodes and capacitors next. I missed a 1.5 M resistor at the start of the circuit because that's an unusual value that I don't have, then it dawned on me that it's just a pulldown resistor so I'm going to drop a 1M in it tonight and be done with it (dumb).

    sd1circuit.jpg

    sd1.jpg

    I'm kinda following Brian Wampler's excellent article on the SD-1 and really playing around with it.

    I'm not really sure what op amp I'm going to use here. I don't have the stock one but I do have a few options at home. It's going to be socketed so I'll play around with those as well.

    This is a weird build since the GGG SD-1 board is shoehorned into their Tube Screamer PCB. Few of the values printed on the PCB are in fact what the circuit calls for and there are several components that aren't added to the final build.
     
    Urshurak776 and TeleTex82 like this.
  2. chris m.

    chris m. Poster Extraordinaire

    Posts:
    8,991
    Joined:
    Mar 25, 2003
    Location:
    Santa Barbara, California
    Very smart to use sockets. Unsoldering components, especially op-amps, can be pretty tricky.
     
    JuneauMike likes this.
  3. DADGAD

    DADGAD Friend of Leo's

    Age:
    67
    Posts:
    2,709
    Joined:
    Mar 18, 2003
    Location:
    SoCal
    Building pedals can be addictive. GGG makes great kits and I have built a few from them.

    Any 8 pin dual opamp should work fine. Socket it and swap chips until you find something you like. :)

    The SD-1 is my desert island overdrive. I have two old ones that are made in Japan.
     
    TwoBear and JuneauMike like this.
  4. JuneauMike

    JuneauMike Poster Extraordinaire

    Posts:
    6,978
    Joined:
    May 5, 2015
    Location:
    Alaska
    What little I have learned about the SD-1 so far seems to reinforce that the mojo is not in the opamp chips so there's a whole range of low noise dual ICs that will work. I think I'm going to start with a NE5532 and I'll try a TL072. I don't have an OPA2134 or a OPA2604 but I could order them if I'm really curious.

    The magic seems to come from the clipping diodes and how the filtering sections voice it. The ubiquitous C6 mod in my case would be C13. I've got several different diode combinations that I'm looking forward to trying too.

    Beyond the IC and the transistors I'm going to build it bone stock and get it working before I start playing around with components. So wish me luck.
     
    Urshurak776 likes this.
  5. Lowerleftcoast

    Lowerleftcoast Friend of Leo's

    Posts:
    3,683
    Joined:
    Dec 30, 2019
    Location:
    california
    I doubt you will notice much of a difference in IC choice. My go to are usually TL072.

    Several different *clipping* diodes/LEDs/transistors (used as diodes) are good to have in your stash to help voice the distortion. It is good to have diodes with different forward voltages. Putting them in series has an additive effect for forward voltage. Here is a short list of helpful values. There are many many others:
    Bat42
    Bat41
    1N914 or 1N4148
    1N4001
    2N7000 (transistor)
    LED (red mostly)
     
  6. JuneauMike

    JuneauMike Poster Extraordinaire

    Posts:
    6,978
    Joined:
    May 5, 2015
    Location:
    Alaska
    Yeah, I got this thing off of Amazon for cheap. It's been endlessly fun so far. It's perfect to interrogate the diodes that I have. It also does capacitors, ICs, transistors and resistors.

    tester.jpg
     
    TwoBear and ponce like this.
  7. JuneauMike

    JuneauMike Poster Extraordinaire

    Posts:
    6,978
    Joined:
    May 5, 2015
    Location:
    Alaska
    Ok, so that's it. I think I'll run the wiring next and maybe populate it this weekend before I put it on my test bed. Man, that's a lot of sockets. Not sure if this is the right way to do it, but generally if the sockets would line up with the PCB holes I would cut to length and just snip off the middle sockets. Probably should drill those out so it's unambiguous, but eh. I didn't.

    pins.jpg

    ggg.jpg
     
    TeleTex82 likes this.
  8. JuneauMike

    JuneauMike Poster Extraordinaire

    Posts:
    6,978
    Joined:
    May 5, 2015
    Location:
    Alaska
    I have a technical question here. The schematic calls for a 20k W-taper pot for the tone. I don't have one of those. Is that critical? or could I use another 20k pot? Looks like Wampler recommends a linear taper pot there, so I'd guess it would be fine going without the W-taper.

    I see Tayda had them all along, unfortunately I didn't know what an EQ pot was when I placed my last order.
     
  9. JuneauMike

    JuneauMike Poster Extraordinaire

    Posts:
    6,978
    Joined:
    May 5, 2015
    Location:
    Alaska
    Going through my collection I've got
    BAT46
    1N34A equivalents (Small Bear)
    1N914
    1N4148
    Assorted LEDs
    1N4001
    1N4007

    Probably some others as well. I've been on a buying spree lately. This stuff is so cheap, I seem to keep adding things to my cart until my thumb is sore. Then when it arrives, I completely forget why I bought it. LOL.
     
    TwoBear and Lowerleftcoast like this.
  10. pi

    pi Tele-Meister

    Posts:
    278
    Joined:
    Sep 30, 2003
    Location:
    bay area, CA
    You can use a linear pot. It will give you the same range of tones, the difference is that it might sweep through that change differently as you turn the pot.
     
    JuneauMike likes this.
  11. JuneauMike

    JuneauMike Poster Extraordinaire

    Posts:
    6,978
    Joined:
    May 5, 2015
    Location:
    Alaska
    Thanks for posting. Yeah it seems like a 20k pot with a center detent (the W-tapers I've seen seem to have that) would either be really sensitive or not appear to do much. Wampler recommends a 5k, which I can't imagine right now.
     
  12. chris m.

    chris m. Poster Extraordinaire

    Posts:
    8,991
    Joined:
    Mar 25, 2003
    Location:
    Santa Barbara, California
    I wish I had a better ability to "see" a schematic and translate it into an actual wiring scheme. In theory then I could breadboard just about anything. I guess the way one learns to do it is start with converting very simple schematics into wiring schemes until you can work your way up to something like this:

    upload_2021-4-22_11-56-25.png

    And then work your way up to something like this:

    upload_2021-4-22_11-57-14.png
     
    JuneauMike likes this.
  13. JuneauMike

    JuneauMike Poster Extraordinaire

    Posts:
    6,978
    Joined:
    May 5, 2015
    Location:
    Alaska
    Yep, I'm doing it in reverse. I built a 5F11 before I built anything else. The first time I did it paint-by-numbers and it turned out pretty crappy. Rebuilt it and now it's my favorite amp.

    I think building pedals is going to be a real eye-opener when it comes to voicing circuits. A lot of the components in the SD-1 seem to serve to manipulate specific ranges of frequencies. So yeah, very cool.

    https://www.electrosmash.com/klon-centaur-analysis
    This guy really helps me begin to visualize a schematic better than I would be able to on my own. I'm still pretty illiterate when it comes to electronics though, long road.
     
  14. Urshurak776

    Urshurak776 Tele-Afflicted

    Posts:
    1,134
    Joined:
    Jul 2, 2004
    Location:
    Charlotte
    I have been thinking of this one as my next project. I was looking at PedalPCB: https://www.pedalpcb.com/product/uberdrive/

    $8 versus the $14 at GGG. Any reason why you went with them over any of the others (PedalPCB, Aion, guitarpcb, etc. ?) I have never tried one of the GGG, so just wondering.
     
  15. TwoBear

    TwoBear Tele-Holic

    Posts:
    984
    Joined:
    Mar 31, 2020
    Location:
    oc. CA.
    yeah it used to be on Tayda, That if you ordered ‘out of order’ you could end up with more than what you wanted. I don’t know if they’ve changed it, But you think you’re done and you look more closely and you find out you’ve ordered 10 K resistors three different times.
     
    JuneauMike likes this.
  16. chris m.

    chris m. Poster Extraordinaire

    Posts:
    8,991
    Joined:
    Mar 25, 2003
    Location:
    Santa Barbara, California
    Building a Way HugeLlama and an autowah from GGG kits made me realize what a bargain non boutique pedals are. Economies of scale make a big difference....
     
    TwoBear likes this.
  17. jamesepowell

    jamesepowell Tele-Holic

    Posts:
    803
    Joined:
    Jun 12, 2019
    Location:
    Los Angeles
    Don't forget this

    download.jpg
     
    TwoBear, Greg70 and JuneauMike like this.
  18. TwoBear

    TwoBear Tele-Holic

    Posts:
    984
    Joined:
    Mar 31, 2020
    Location:
    oc. CA.
    Go on EL 34 world Hoffman amps and look for signal flow in an amplifier circuit. AC and DC existing in the same paths, cool stuff, easy to see and follow the different colored arrows.

    Edit-I just reread this and it looks like I am being condescending or something which I am one hundred percent not doing I was just trying to convey how I was sort of knocked out the first time I saw it.
     
    Last edited: Apr 22, 2021
    JuneauMike and CapnCrunch like this.
  19. CapnCrunch

    CapnCrunch Friend of Leo's

    Posts:
    3,918
    Joined:
    Jan 7, 2011
    Location:
    Washington, USA
    Dang it @JuneauMike. I don't need another DIY hobby, but you are tempting me here.
     
    TwoBear and JuneauMike like this.
  20. CapnCrunch

    CapnCrunch Friend of Leo's

    Posts:
    3,918
    Joined:
    Jan 7, 2011
    Location:
    Washington, USA
    EL 34 World and The Amp Garage were two of my favorite sources when I was really into amp building. Great stuff and lots of knowledge shared there.
     
    TwoBear likes this.
IMPORTANT: Treat everyone here with respect, no matter how difficult!
No sex, drug, political, religion or hate discussion permitted here.