DG Stomp Mod - Hum Removal (56k - Be prepared to wait!)

Discussion in 'The Sevenstring.org Workbench' started by Randy, Apr 26, 2013.

  1. Randy

    Randy Ooh, Degrasse Tyson-son Super Moderator

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    Posted previously, I scored a DG Stomp from the local music store.

    As I found out with tweaking and reading, I found that the DG-Stomp is notoriously noisy at medium-high gain. This isn't much of an issue for me, because I'm using the DG for playing jazz standards at home but it'd be nice to eliminate some of that extra noise.

    Thankfully, Soundside has a pretty popular lesson on how to remove a lot or all of the hum coming from your DG Stomp. Original article posted here: Soundside - Multimedia Solutions

    I decided to give this a shot and include some pictures, as well as a few alterations.

    WARNING! Any time you open up the inside of an electrical device, you have to be very careful. Obviously be sure that it's unplugged and all residual electricity has dissipated. As a rule of thumb, I make sure to discharge and static electricity I might be carrying into a nearby fixture (in my case, my desk) before fooling around too much.

    This mod is carried out at your own risk, if you so choose to proceed. I do not guarantee your results.

    On with the pics!

    The subject:
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    1.) Flip over the unit and remove the six screws holding on the rear cover

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    2.) Remove the back cover. I had the best luck prying from the right and straight up. If you pry at an angle, it gets stuck.

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    3.) Let's take a look at the graphic from the original article.

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    4.) Working with this as a guide, remove all three screws retaining the board to the chassis. This is so that we can get underneath it for the next few steps.

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    5.) Remove the screws holding the components against the chassic.

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    6.) Remove the nuts holding the input/outputs to the chassis:

    [​IMG]

    7.) Carefully pull the board back, and watch not to unplug any of the ribbon connectors underneath. You can pivot the board backward to free up access to the inside of the chassis, if necessary.

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    8.) Based on the Soundside graphic, we want to make the cleanest connection between the metal chassis and the input, outputs and headphone output. To accomplish this, I decided to clear some of the paint from the face surrounding those output jacks.

    To isolate where I cleared the finish, I used some electrical tape as a mask. Make sure you put some behind the holes so that you don't get paint/filings in the chassis:

    [​IMG]

    9.) In my case, I used a stainless steel wire brush to clean away the finish. You can also use brass or sandpaper. Either way, be careful (as usual)

    EDIT: This step wasn't in the original directions, so it's optional. I could've done a cleaner job keeping the paint removal exclusively "underneath" the circular shape of the washer, but this unit is scratched up pretty heavily and plus, looks on this don't matter to me. YMMV:

    [​IMG]

    10.) Along with making great contact with the chassis on some points, we also need to restrict contact on others; in particular, the expression pedal jack, digital output, MIDI in and out, and A/C (power) components.

    You'll want to pay extra attention to the MIDI and digital out components because they have a metal facing that presses right against the chassis, normally.

    [​IMG]

    11.) Make sure you have a good bit of room to get in.

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    12.) For this step, I used electrical tape to limit the number of places the "no-no" components contact the chassis and limit them from grounding out on it.

    On the graphic, they mention removing the screw on the far side right side (when viewed from the outside; so on this inside view, it's the far left) and I decided to expand on this idea and cover that area as well.

    [​IMG]

    13.) Next, we just push the components back through their openings carefully (unpictured).

    The original graphic mentions leaving a couple screws off two of the places where the board attaches to the chassis and putting adhesive in between. Here's a look at what they're talking about:

    [​IMG]

    14.) Apply a couple small pieces of tape to these tabs. I used electrical tape here, as well.

    [​IMG]

    15.) The last important step is to mostly reassemble the pedal, using just one screw at the top of the board and reattaching the nuts to the input/output jacks.

    As mentioned in the tutorial/graphic, you leave pretty much all the screws that run from the back into the components out.

    The jacks are soldered pretty well to the board, which is in turn pretty well fixed to the chassis, so it's not a big deal to leave the nut off of the expression pedal jack (as described by the graphic). I decided, for conscious sake, I still wanted something to tighten down the jack; so I used a nylon nut (non-conductive) to hold it in place.

    [​IMG]

    16.) Lastly, replace the bottom plate on the pedal and reattach the six screws on the bottom.

    You're done!

    I experienced a very noticeable reduction in hum and it was really easy to do.

    One optional step (which I might do later on, when I can track some down) is to replace ALL of the removed screws with their nylon equivalents; that way you get don't have conductivity and grounding at those points, but you'll still have a factory "solid" mounting. I'm not sure how necessary it is, because everything feels really solidly held in place as is but, hey, it's an option.
     
    Draceius likes this.

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