When gear is properly powered, it will save your pedals and your wallet from unnecessary damage. When I get power questions, it’s usually not in the form of “what power supply should I buy?”. More often, it’s something like “my pedal doesn’t sound right” or “this pedal died as soon as I plugged it in.” About 85% of the time, power is the root cause of malfunction or poor performance. Most commonly, the wrong voltage was supplied to the pedal or the pedal draws more current than the power supply can handle. Pedals will function and sound as the builder intended when they are properly matched with a quality power source.
What is the right power source for my pedals?
Most but not all pedals are 9 volt, center tip negative. In some instances such as the Digitech Whammy, a 9v source will not work; so the manufacturer provides an appropriate power adapter. Using the manufacturer’s provided supply eliminates the risk of powering your pedal incorrectly. If you’re unsure about the required or acceptable voltages, try this handy database by Andreas at Stinkfoot. If you can’t find your pedal there, I’m sure the support page from the builder will have this info as well.
Another consideration is how many mA your pedal is draws. This is the amount of electrical current that your pedal will “pull” or “draw” from the power supply. A simple dirt box like the LPB-1 may only draw .5 mA. However digital delays are notoriously power hungry, drawing as much as 174 mA for the DD-20. If you’re unsure, you can consult the power database (linked above) or measure it yourself using this handy guide.
PSA or wall wart rated appropriately for your pedal will work fine though it does introduce some noise into the mix due to the artifacts introduced during AC to DC conversion. This solution works fine for one or two pedals but it is somewhat limiting and just plain cumbersome to power a board this way.
Which brings us to the Visual Sound 1-Spot. A lot of folks use the 1-Spot to power as many as 8 pedals without any real problems. However, it depends largely on what pedals are on their board. Some pedals introduce a substantial bit of noise (I’m looking at you EHX Holy Grail). This doesn’t mean that the Holy Grail is a bad pedal or that the 1-Spot is a bad power source. BUT it is not an isolated supply and this commonly causes ground loop issues. This is especially true when powering pedals that are in front of the amp and in the effects loop with the same daisy chain. The good news is that it is a very inexpensive way to power up your gear.
Isolated power supplies such as the Pedal Power 2 or 4X4 from the Voodoo Labs product line can solve most of the above problems but comes at a relatively steep price, around $169 for the PP2. You can read up on the specs but it offers multiple voltages and clean power isolated power. There are a ton of other options as well; check out Cioks and The Gig Rig.
The Common Mistakes: The mA specs provided in your pedal or power supply manual are averages, not peak. These averages are accurate in a testing environment without external factors such as extreme heat or cold. Its critically important to understand the role that heat specifically, plays in powering your pedals. When your pedals get hot, the components in the pedal work less efficiently which in turn, requires more power. In that same heat, your power supply also works less efficiently, generating less power than in normal conditions. So even though all your specs are sufficiently matched, your pedal is now requiring more power to work correctly and your supply is providing less power than designed . Something is going to give.
When it comes to mA, figure for worst case scenarios. If a pedal requires 175 mA, you can safely power it with a supply capable of providing 300 mA. This will not cause damage to the pedal since the pedal will only draw what it needs. In the heat situation described above, the pedal gets hot and draws more power. If your power supply can provide more, you’re in good shape.
When it comes to voltage, go with the specs. When it comes to mA, it’s good to over compensate. If you think of voltage as the current pushed to the pedal and amperage as current pulled by the pedal, you can see that too much voltage is very bad for the pedal but the extra mA available is safe because your pedal will only pull what it needs.
Mark the voltage on the power cables coming from your power supply. Several power supplies have multiple output voltages. By marking them you can be sure that you don’t plug a 9v pedal into a 12 or 18v output from your supply. In almost every instance, you’ll cook the pedal.
So what’s right for you? Thats up to your specific pedal needs, your budget, and most importantly your ears. Eric Johnson has famously said that he can hear the differences between Duracell and Energizer batteries. If you can hear the difference, then picking a power supply should be no problem.
Long story short; KNOW, don’t guess what your power needs are (even in hot and cold conditions). Find a power source that meets those needs. This will protect your gear and ensure that it sounds its best.