Can Someone Tell Me What's Going on With My Pedalboard?

Chris Schlotzhauer · From: Colleyville, Tx. USA

I recently got a new Pedaltrain board for the few pedals I use. The last board I had was cheap and all of the pedals were powered by individual power supplies crammed into a plug strip.
I wanted to clean this up and get a power supply and board. The picture below is the setup. I love the power supply and the compact setup of this board. However, recently it has intermittently given out this med/high pitched hum when amp and board are powered up. At first I though certain stages would cause it, thinking maybe the lighting or grounding was bad. The other night I setup, powered up, and no noise. Then as I was getting up, I knocked over my throne, and it fell over on the pedalboard (not very hard). The hum started and I was jiggling cables, inputs, etc. It would not stop so I had to do the gig with every pedal bypassed except the verb pedal.

Has anyone had experience with this? I'm no expert on pedals, boards, signal paths, etc.....thanks

Bryan Daste · From: Portland, Oregon, USA

I'd try patching into the pedals one-by-one to see if you can isolate the problem. If it happens with all the pedals, it's most likely a cable problem. Try switching back to the individual power supplies and see if it goes away.
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David Nugent · From: Gum Spring, Va.

My money is on the Strymon pedal. The T-Rex units will not handle the power demand (voice of experience)of Strymon pedals. My two pedals emitted a high pitch squeal when powered up (also a clicking sound as if they were turning on and off), changed supplies, problem solved. Try eliminating the "Lex' pedal from the chain to determine if that is the culprit.

Len Amaral · From: Rehoboth,MA 02769

Make sure the dip switches on the fuel tank didn't get moved.

Brett Lanier · From: Madison, TN

Yeah, the Fuel Tank is not the best choice if you're using digital pedals that draw a lot of milliamperage. All eight 9 volt plugs share 500ma, and you're using about half of that with one Strymon pedal.

I used to hear that high pitched hum in my rig when I was using a 1 spot with too many pedals, and like you it came and went with little rhyme or reason. Fwiw, one time a sound man figured out that it was 6.8k. So if you're ever in a scenario where that sound is coming back through the system just have the sound person pull out 6.8 or 7k from your channel and it should help a lot.

ajm · From: Los Angeles

Try plugging in the pedals one at a time.
Do any of them cause the problem?

Try plugging them all in EXCEPT for the Strymon.
Problem or no?

Plug them all in.
Problem or no?

If you have the capability, both with the problem and without, measure the voltage feeding the pedals.
What is it without the problem?
With?

ajm · From: Los Angeles

By the way, as a general FYI, here is some data on some popular power supply units with approximate prices.

Dunlop Brick: NON-isolated outputs (I was surprised): $120
Voodoo Labs Pedal Power II Plus: 8x9v isolated: $170
Voodoo Labs Pedal Power Iso 5: 4x9v isolated (one 12v), one 18v isolated: $110
TRex:
Chameleon: Isolated outs: $150
Classic: 8x9v, Non-isolated: $200
Juicy Lucy:5x isolated outs, BUT they are 12v: $200
Junior: 5x9v isolated: $100
BBE Supa Charger: 8x isolated outs: $150
One Spot: Single 9v out: $35
Pedal Pad (MKS) Power Pad II: 8X 9v outs, no info on isolated or not, $90. Note: Doesn't seem to be carried by a lot of dealers, FWIW.

ajm · From: Los Angeles

Here is what I was able to dig out of the interwebs. Warning: It may not be good news for you.

Zoom MS-70CDR:
2xAA batteries (typically 3.6vdc @ 600-1000ma)
or Zoom AC adapter AD-16, 9.6vdc center negative 500ma

EHX POG2:
9.6vdc center negative 180ma

Strymon Lex:
9vdc center negative 250ma

Tube Screamer:
9vdc battery (probably 10ma) or
9vdc center negative adapter

TREX Fuel Tank Classic:
8x9vdc outputs, grounds non isolated, 500ma TOTAL
Additionally FYI:
12vdc isolated ground 500ma
12vac isolated ground 500ma

My gut conclusion:
It is real difficult to figure out what pedals *really* need for current as opposed to what their documentation says. However, you appear to have three real current hogs in the Zoom, EHX and Strymon. Any two of those might be pushing the limits of the TREX supply. All three would most likely put it over its limits. The Tube Screamer is not a concern as it consumes almost nothing.

As you plug in more of your pedals and get close to the current that the TREX can supply, the voltage may start to drop, causing one or more of the pedals to do weird things. That is why I suggested measuring the voltage to see what is happening.

Someone will probably suggest using the 12vdc output on the TREX to supply one of the "big three". I would not, since it is 12vdc and your pedals spec 9vdc. If they want to do it with THEIR pedals, then best of luck to 'em.

My guess is that the TREX ultimately may not work for you.

Chris Schlotzhauer · From: Colleyville, Tx. USA

Wow.....great info here...I really appreciate it.

I never looked into the power consumption specs when I bought the TREX. I just bought it and it wasn't cheap!

So ajm...so are you saying any of those power supplies you listed have the ma capacity to drive my pedals?
What should I be looking for in output?

ajm · From: Los Angeles

Chris: I would not jump into another supply without doing some research. I don't know if any of the others would work or not.

I did a check on all of the supplies that I have listed. From what I can determine, the ONLY one that MIGHT work would be the TREX Chameleon. I wouldn't bet the mortgage on it, though.

You could try a One Spot. It is a "wall wart" style wise, but it should supply about double what you need for current for all of your pedals combined. I have never used one. I read about a couple of users having problems with them and their clones when they first came out, but that was well over 10 years ago. Since then I have only read good things, including a few major magazine reviews. Most everyone I have heard commenting about them likes them. And they are relatively cheap.

From what I read the problem you may be having is fairly common. These newer pedals are packing more and more in a smaller space, but it still takes power to run them, more than a simple old 9vdc adapter to replace a battery.

Try some of the "experiments" that we listed and let us know what you find. I'm starting to think that going back to an outlet strip and wall warts may be the best and easiest and a guaranteed solution. With some cable ties and a couple of screws you should be able to put together a fairly rugged and secure set up.

Chris Schlotzhauer · From: Colleyville, Tx. USA

Thanks buddy....I will try that!

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