Help with Aion Maelstrom Bass Drive

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Hydrogened

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I have the maelstrom bass drive from das musikding, it works perfectly on its own or at the start of my signal chain, but when I try adding another pedal before it (Boss GEB7), my signal just becomes a static hum. I suspect it's a grounding issue because when I touch my bass strings the hum gets a bit quieter, but I'm not sure how to resolve it.
 

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I would first make sure that both jacks are correctly in contact with the enclosure, that there is no paint preventing them to touch it.

Then i would use an audio probe and try to find where the signal turns into a static hum, following the shortest path on schematics from IN to OUT.

Once the issue is located, i would check all values, reflow the pads in the aera, check the connections between parts with multimeter in continuity mode, and clean the spaces between soldering pads with the iron.

Misc > Audio Probe : DIY Fever – Building my own guitars, amps and pedals

[DIY Fever] Audio Probe - very simple contraption that helps with debugging audio circuits
diy-fever.com

If it still doesn't work, i'd suggest to do a full debugging process, post a link to schematics and clear pictures of the soldering side, and write all ICs and transistors voltage values, following these steps :

 
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I am using a 3D printed enclosure, so I don't think I have the jacks grounded to it, may that be the problem? But I have also built pedals in the past using 3D printed enclosures and those work fine.

I don't own an audio probe, where would it be possibe to find one?
 
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Hydrogened said:
I don't own an audio probe, where would it be possibe to find one?
Click to expand...
i posted a link to help build the audio probe, it's a very simple thing.
You can build an audio probe with a female jack, 2 wires, and a 100n cap, no need to waste a guitar cable.
Hydrogened said:
I don't think I have the jacks grounded to it, may that be the problem?
Click to expand...
i guess so, especialy if it sounds like a ground issue.
If you have an aluminium enclosure, it could be interesting to try your circuit with both jacks grounded to it.
You can make a test with the aluminium enclosure of an other stompbox.
 
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Hydrogened said:
would it work if I used copper tape to cover the inside of the 3D printed enclosure? I don't have an aluminium one at hand
Click to expand...
you really dont have another stompbox from the industry with a metal enclosure ?

You dont need to put the circuit inside the metal box, you just need to use the jack holes to test if the static hum goes away.

I dont think copper tape on the inside would help much, the idea is to let the current go through the enclosure into the ground, avoiding ground loops.

Maybe that's not your issue, it's just a possibility.

You can still probe the circuit, see if the issue appears somewhere specific.

If you really dont have any aluminium enclosures anywhere, as a last resort, you could try to test your circuit with wires connecting the jacks rings to the GEB7 enclosure, or any other metal enclosure. It's not academic but i guess it's worth a try.
 
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Hydrogened said:
I only have another Boss EQ pedal but I'd strongly prefer not to take it apart

It'll take a couple of days for the components to arrive, I'll build it as soon as possible
Click to expand...
As you wish.

In case you didn't notice, i ve edited my post to suggest to test the circuit using wires to connect the IN and OUT jacks rings (the part that should be in contact with the enclosure), to your other boss enclosure. If the hum is still there, then it's probably not an enclosure issue.

i know musikding always provides lots of wires.
 
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Could also be your DC jack, looks like it's in metal and it's not a good thing according to this thread :

E

Thread 'Grounding Issue With Enclosure'

Hey folks, new to the forum, but no stranger to diy synths and circuit bending, but I’ve got a couple issues with my first batch of pedals.

- bare, separated from their enclosures, all the pedals work as they should; powering up, bypassing, signal processing.
Though when I put em in their enclosures, I get none of that. And the daisy chain I power the rest of my non-diy pedals refuses to power up.
Realize it’s probably simple grounding, but never seen this issue in any other project.

- the dream fuzz is only a clean boost, no gnarly fuzz. Worried I may have flipped the chips, but pin 1...

You can try to insulate the metal part of your DC power jack with plastic tape, or use a plastic DC jack from musikding.

www.musikding.de

DC power jack 2,1mm isolated, 0,55

DC jack, 2,1mm Enclosed frame with switch Mounting diameter: 12mm Length: 18mm
www.musikding.de www.musikding.de
 
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The plastic enclosure should insulate the metal DC jack from the rest of the circuit. Still if it were me I would get rid of any metal DC jack. You’re just asking for trouble if you have a big stash of those.

I’ve built several maelstroms before but never had a problem with them. It does sound like a possible grounding problem but hard to say for sure. Check it with some other pedals may and see if you can confirm it’s the maelstrom that’s the problem. Finding the problem is the name of the game in troubleshooting. Eliminate as many things as possible issues as possible until you find the problem.
 
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