Neovibe almost complete, but with quirk. DC power supply help (please)...

[jessetrbo]

I've populated a Neovibe board purchased from GGG using R.G's files as instructions.  I've done a considerable amount of searching in various stages of the build to guide me through the ambitious project and was quite happy when I powered it up--IT WORKED.  Not only did it work, it sounded great to my ears.

Cut to the chase:  I'm powering the circuit with an EHX 24v DC power supply.  I omitted the diode bridge.  I didn't ground the DC jack.  Here's the thing:  If I have the power supply already plugged into the wall and insert the barrel of said power supply into the DC jack, it sparks (at the point of insertion)!  

I'm pretty tired after returning from SXSW.  Maybe I'm overlooking something obvious...  I did some cursory searching and found a thread in which R.G. mentions that one of the large filter caps can be removed (along with diode bridge) when using DC.  So I did an experiment and removed both, and voila--no sparking.  The 'Vibe still works and doesn't sound extra noisy, but I'm concerned about filtering.  I soldered in two filter 100uf caps (rated at 35 v), and again sparks fly when inserting the DC power supply.   I figured that the 1000uF caps were storing a decent charge that would then become discharged as I plugged the jack in... I also figured that if I used smaller filter caps, this would not be a problem.

Thoughts?  I'm opening my self up to be humbled.  I usually don't plug in the power supply first, then into the pedal second, but it obviously happened once.  And sparks are not  consistent with my DIY aesthetic.  I have not deviated from the project file in any other way (than already listed).    The DC jack that I'm using is plastic...I will post any further information as necessary...  (Thanks).

Here's links to the project file, and thread mentioned above:
http://www.generalguitargadgets.com/index.php?option=com_content&task=view&id=121&Itemid=26
http://www.diystompboxes.com/smfforum/index.php?topic=87294.0

[jessetrbo]

Has anyone else who uses DC to power their Neovibe experienced this??

--Jesse Trbovich

[thedefog]

Sounds like you're just temporarily bridging it when plugging it in. I wouldn't worry over it.

BTW, what band are you in?

[jessetrbo]

Kurt Vile and the Violators.

(Jesse)

[yeeshkul]

You need just something like 220-470uF to the ground at the input if you feed it with DC. That cap doesn't have to be there at all, but it helps to smooth the DC voltage that can vary due to the cable resistance, so it is a good habit to put one in. I do it myself. And yes i am using 24VDC for Neovibe. No sparks.
Also, you may wanna stick one 100n/50V ceramic cap across the 7815 output (this one won't help with sparks, just will help to keep 7815 well behaved).

[yeeshkul]

I'm sorry, by saying input i mean DC input, not signal input.

[thedefog]

Kurt Vile and the Violators.

(Jesse)

Fellow Philly musicians! We should play a show together Jesse, we'd match up well.

www.thedefog.com