Korg SDD 2000 to 3000 mod

Discussion in 'Effects, Pedals, Strings & Things' started by Jackie Treehorn, Apr 5, 2015.

  1. Jackie Treehorn

    Jackie Treehorn Member

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    There was a really nice Korg SDD 2000 at a local music store I was able to pick up for $100. Just playing around with it, I was really blown away by the sound quality. It's bright but still soft on top, warm, and has incredible dynamics. I had to adjust the compander a bit to get a bit of distortion out of the decays. A lot of that was due to not being able to get the levels right for guitar level.

    When set for guitar to get a hot signal, it was very low output, whereas to get it loud, it was very low impedance. I did try a few mods to fix the problem, but seemed to not be able to get the gain and high impedance at the same time. So, I figured I was only in $100, what if I could take it apart and reconfigure the preamp/buffer as in the SDD3000?

    Well, it works! It took a couple jumpers on the bottom of the board, and I kept the level control as it appears in the sdd2000, which is between the two stages where the attenuator is on the 3000. I did that primarily because I didn't have ( nor did radioshack) a 100k linear pot that would fit the chassis.

    I also stuck a couple diodes on the bottom of the board that are in the sdd3000 but not the 2000. Didn't cut any traces, so it's reversible.

    It worked out pretty well, I may cut a bit of level at the output jack, which involved changing 3 more resistors.

    Next will be a true bypass mod and perhaps turning down the modulation a touch since it's a bit of a jump between 0 and 1.

    Of course there are some other features the 3000 has and I will definitely buy the next one I find for $100, but I'm pretty pleased with this 2000.

    Here are the manuals...

    Owner’s

    Service
     
    Last edited: May 31, 2018
  2. mike_lawyer

    mike_lawyer Member

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    I'm really interested in your conversion. Could you post pictures of what you did? It would be nice to have the extra presets that the Korg SDD-2000 has with the additional preamp feature of the 3000.
     
  3. theanalogdream

    theanalogdream Supporting Member

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    Ditto^ Post pics! Sounds clips/video if you have em would be cool too!
     
  4. Black_Label

    Black_Label Member

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    Cool thread. Pics and videos would rule!
     
  5. Jackie Treehorn

    Jackie Treehorn Member

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    I can post some pictures, probably tomorrow evening. I just recapped the power supply, so I took some more shots before closing it up. I don't have many before the mods shots, though.
     
  6. Jackie Treehorn

    Jackie Treehorn Member

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    Ok, this is sort of a before pic. There are a couple of abandoned mods here from when I was trying to just adjust the stock preamp.

    [​IMG]

    Here is after putting the sdd3000 preamp on it...

    [​IMG]

    Things to note r119 on the sdd2000 is changed to 2.2M
    R118 is changed to 5.6k
    R117 is changed to a 0.1uf capacitor
    C81 is changed to a 4.7, I actually used a 2.2 WiMA here.
    C82 is removed and left empty to break the connection to the inverting input.
    Remove d31 and d30. I retained these to use as the clipping diodes in the sdd3000 preamp
    R115 and c83 are removed and a jumper is put where c83 was.
    R116 is changed to 560k BUT one needs to leave a little length on the end of the resistor facing the opamp since we need to use that point as a new input. A jumper will be attached from the blank hole from C82 facing the 0.1 coupling cap to this point on r116.

    I think that's it for the first stage. I will post a clip of the 2 jumpers on the bottom of the board in a bit.

    Here's another look...

    [​IMG]

    R112 is changed to 100k, on the sdd3000 this is the level pot, but I'm retaining the level pot before this stage, as in the sdd2000. Again, leave the ungrounded end on this resistor a bit long under the board, as we will jump to it to use the inverting input.
    Remove r114 and replace with the diodes removed above.
    Replace r113 with a 3.3k

    Another shot...

    [​IMG]

    There's another red cap there next to the plug that is swapped to a 4.7uf (2.2 in my case), it's c78.

    Oh, and you need to remove the chip, install a socket, and then put a TL072 in it. All the resistors that are curved over, not flat, are the ones I changed in the pictures.

    Here is the underside of the board with the jumpers and extra diodes.

    [​IMG]

    That one jumper there is curved because it needs to cross a trace beneath it at 90 degrees to avoid capacitive coupling of the output to the input.

    I think that's most of it.

    I'm going to record some clips at some point...

    There's one resistor I put on the wiper of the level pot, this is the 3.3k R6 on the sdd3000 service manual schematic.

    [​IMG]
     
  7. mike_lawyer

    mike_lawyer Member

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    I already have an SDD-3KP preamp pedal, so I'm not really interested in monkeying around with the preamp. If there are mods that can be made to make the delay itself sound close to the SDD-3000, I'm definitely interested.
     
  8. Jackie Treehorn

    Jackie Treehorn Member

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    Well, the delay sound is pretty fantastic as it is. The stock sdd2000 has the sound it just doesn't like to work into the front end of the amp. There's something to the input level where if you get it hot enough with a bit of modulation, the delay's get this soupy upper harmonics, ambient thing happening. I haven't heard that characteristic in other delays.
     
  9. louis

    louis Supporting Member

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    Hey Jackie !..............hope all is well!

    I took my 2000 to my tech with your mod and after costing me $282 ouch !
    think it cost me a little more cause this was new for them and they had to fight a bit to get
    it right but it was worthed !...............A few owners at the store told me that they might do this mod
    on their own 2000's ,......so we all beacme believer's !!.....Haha !!.........Thank you Sir !!
     
  10. Jackie Treehorn

    Jackie Treehorn Member

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    Awesome! I posted all that and I kind of figured I was talking to myself by the crickets. Hope you like it!
     
  11. Bartimaeus

    Bartimaeus Member

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    Well that isn't very punk, is it?
  12. louis

    louis Supporting Member

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    Well I must say that I didn't bring this unit to some nerds !!.....they are awesome tech's and nut gear heads
    and have a lot of vintage gear that they keep for themselves and when I took my 2000 with your thread and pictures,
    they said what a cool project !!.............the owner who also have a few 3000' and 2000's really heard the difference
    and improvement in the width and quality of the tone and said he would do it to all of his units and will
    probably offer this to all of his customers ,............and it's all because of you !!
    Your mod is now in Montreal !!

    Too bad your thread is not in the new Rack Space !

    Thank's by the way !!...haha !


    Lou
     
    Last edited: Dec 11, 2016
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  13. Jackie Treehorn

    Jackie Treehorn Member

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    Montreal must know delays, then! If you happen to get some feedback from these folks on a comparison between the 3000 and modded 2000, please share. Glad to hear that people like the mod!
     
  14. louis

    louis Supporting Member

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    Will do for sure !!

    Do you think Brian could transfer your Thread in the Rack Space area ?
     
  15. earwax

    earwax Member

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    I think I need to go to Montreal to find one of these modded racks :drool
     
  16. Space Jazzer

    Space Jazzer Member

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  17. louis

    louis Supporting Member

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    My guess is that any good tech near you could do it .
     
    Last edited: Dec 12, 2016
  18. Hallogallo

    Hallogallo Member

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    [​IMG]
     
  19. 59 Restorer

    59 Restorer Supporting Member

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    I have had a couple of these recently. The one I currently have seems to brighter and the modulation is VERY prominent.
    Has anyone been able to darken up the delays and dial back the mod?
    I can't put the depth or rate Of the mod past 1 for either if the delay is in the 350- 400+millisecond range.

    There are a lot of trimmers under the hood and even I know better than to start messing without some direction.
     

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