Pedal Power Fiasco

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Drop Daddies Rehearsal at Annex 2013-03-15 The night before my St Patrick’s Day gig with the Drop Daddies, we were setting up at a rehearsal space for a last minute practice.  I powered up my gear, and none of my pedals were working!

After a bit of trial and error, it was clear that my ancient SKB PS-25 pedalboard power supply had finally keeled over.  I never use batteries, but fortunately a couple of the pedals had old 9V batteries still in them, so it was enough to scrape by for the rehearsal.

Pedals want DC negative-polarityThe following morning, just a few hours before the gig, I went through my box of old guitar gear to try to find a replacement 9V DC negative-tip power supply.

Hey, here’s the power supply for my Digitech Jamman Delay which I’m not currently using in my live rig.   It says 9V, 1.3A.  Strange, it doesn’t show a polarity, but it’s a power supply for a guitar pedal, and the plug barrel fits, so it must be good, right?  What could possibly go wrong?

Zap!I plugged it in, powered up, and…  I’m not sure if I actually heard a pop, zap, or boom.  Maybe I just imagined the smell of electrical burning…

It was with a sense of dread that I unplugged the power cables, and tried the pedals on battery. No lights, no sound- nothing.  They were all fried.

So, there I was, with just hours before the gig was to start, with a miserable collection of dead pedals.  Fortunately, our bass player Ryan, had a Tube Screamer, Fulltone Full Drive 2, and Fulltone Fat-Boost in his old guitar gear bag.  I loaded em up with batteries and velcroed em down.  It all sounded different, and felt unfamiliar under my feet, but I made it through the gig ok.

Digitech Jamman Delay Power SupplyI didn’t figure out until later that this Digitech power supply, part # PS0913B-120-B, is actually 9V AC, not 9V DC.   Ok, I’m an idiot for not realizing that the lack of polarity indicator was a clue.  And I only realized just now while looking at this picture, that the tilde next to the 9V must indicate AC.

But honestly, shame on Digitech for selling a pedal with a power supply that says 9V, has a standard pedal barrel connector, but is actually AC, not DC.  They should at least make the connector different so it won’t fit a standard pedal jack!

In the week following the gig, I took apart and fixed my pedals- blown diodes in my Speed Racer overdrive were about the worst of it.  No big deal.

Vox Ice 9 PCBMy VOX Ice 9 was a more difficult nut to crack, since it uses a PCB with tiny surface mount components.  Using the microscope and a multimeter at the office, we were able to identify that both the 2SC4617 transistor (Q5) in the power section, and the 4558DR opamp (U1) in the overdrive section were fried.  You can actually see the PCB is blackened around Q5 (top-center in the picture)- maybe I did smell smoke after all!  I ordered parts, and thanks to my boss Charlie’s mad skillz soldering under the microscope, we were able to repair it.

Korg 9V DC Power SupplyMeanwhile, I stuck a big label on that Digitech power supply “9V AC – NOT FOR PEDALS”, and I repurposed an old Korg 9V DC 500mA power supply for the pedalboard.  It has been working ok, but I’m getting some hum from the boost.  I could get a Voodoo Labs Pedal Power Plus but it’s a bit pricey.  On the cheaper side, there’s always the Visual Sound One Spot, but it gets mixed reviews.  I’ve also been thinking of building a new DIY pedalboard, but actually, I am pretty envious of Ryan’s awesome pro pedalboard- the SKB PS45.

Update 5/22/2013: I figured out why the boost was humming- I hooked up a multimeter to that Korg power supply, and turns out that it’s really putting out 13V, not 9V. What is up with these power supply labels?!

Our next Drop Daddies gig is tomorrow night, and we’re heading back to the Annex for a rehearsal tonight.  Note to self, pack some 9V batteries, just in case Smile