How can I power more than one pedal from the same adapter?
I have come to realize that this is a pretty common question, after all. Not everyone are familiar with the world of adapters, daisy chain cables and dedicated power supply units, and some just want to get their three Boss pedals up and running. I therefore decided to let the old power page be a little more advanced, while putting together a real simple guide for the beginner. Er… that’s this page then. So let’s get on with it:
What kind of power?
90% of all guitar pedals use 9 volts DC (direct current), which is the same type of voltage found in the battery you used to run it from. This includes all stompboxes from Boss, Ibanez, DOD, DigiTech (X-series, Hardwire), Maxon… er, the list goes on. Somewhere on the pedal, the power requirements will be specified. Usually it says 9vDC, and if the jack is the same as on Boss pedals (which 90% of all pedals have), there will be a symbol identifying the polarity as well (so + and – ends up in the right place). You’ll see the normal symbol below, indicating that the positive is carried on the outside of the plug, with the center pin being negative.
If the pedal says anything else (like 9vAC or 9v~), it probably has to have its own power supply. Examples of these are DigiTech RP/XP series and Whammy pedals. Likewise, if the symbol is reversed (with the + sign pointing towards the center pin), you may need to keep it separate as well.
Boss PSA – the granddaddy. It has been proven to work flawlessly in almost any situation. Switching type adapters (1spot, Godlyke, EBS AD-9 and countless no-name ”Radio Shack/Maplin/Clas Ohlson” units) are generally more powerful for the same size, but can disturb clock chips in time-based fx pedals (chorus, delay etc). I’d rather have two PSA adapters than one 1-spot, actually…
It does have limitations, though – it can only provide 200mA of the 9vDC needed to power pedals. If your pedals use more than that, it will burn out. That’s why it’s important to calculate how much power you are going to use. But it isn’t as easy as just counting the number of pedals you’re going to power – whenever a manufacturer claims that their adapters can power up to so-and-so many pedals, it’s only an average figure. In reality, one digital delay will use as much power as 8 or 9 overdrive pedals.
To distribute the power from the adapter to more than one pedal, you need a splitter cable (also known as a ”daisy chain”). These are beautifully simple, and you really can’t go wrong with them. They have one female plug where the adapter plugs into, and then two or more male plugs which plugs into the pedals. Simple! The only thing you have to worry about (apart from keeping track of the total current draw, as mentioned earlier) is to keep any unused plugs isolated. Don’t let them touch anything – that could cause a short-circuit, blowing the adapter.
However, finding one that works straight from the adapter can be tricky. For instance, Boss only sells daisy chains to fit the power out jack on their TU-2/NS-2/LS-2 pedals. That type of chain will of course work with the Pedal Power 2 (for powering multiple pedals from a single output – stay below 80mA, though). But you can’t use it with a regular adapter – for that you need a daisy chain that starts with a female plug. Here’s a list of a few that works just fine:
- Maplin (UK) JR94C – cheap and available. If you don’t have a Maplin store in your town, you can order it off their website. Just type in ”JR94C” in the search window, and you’ll find it.
- EBS (Sweden) DC series – readily available here in Sweden, now also with right angle plugs. If your music store doesn’t have it, they’ll be able to order it in within days.
- Visual Sound (US) – comes with right angle plugs for the pedals, and good length between the plugs as well.
There are a heap of others out there as well, so you should have no problem finding one.
Problems and tips
There are a few problems that may come up when powering your pedals this way, and most or all of them will show up as hum/noise or a pedal not working. If you get increased hum or noise, it’s time to investigate further. If a pedal stops working when you plug in the power, or its LEDs lights up, but all you hear is hum, pull the plug immediately and then start investigating. Here are a couple of tips:
* Increased hum or noise can come from trying to power dist/overdrive pedals together with power-hungry pedals like digital delays, chorus pedals etc. If you get noise, try separating them and powering them from two separate adapters. Also, simple designs such as overdrive pedals often use quite small amounts of power, and can therefore be powered with batteries without you having to replace them each week. A battery will always provide cleaner power than a power supply, so if you’re having noise problems with your overdrive pedals, using battery power for them will always remain an option – especially for those times when you really need to keep the noise down (in the studio, for instance). Just remember to unplug the input cable when you’re done (or put the power plug back in the adapter jack – that will also turn the battery off).
* It is generally not a good idea to power pedals that go in front of the amp together with pedals that run in the amp’s effects loop. If you get hum or noise, this may be the cause. Try unplugging either the power from the loop pedals or those pedals from the loop, and see if it clears up. If it does, you need a separate adapter/daisy chain for the loop pedals.
* Make sure you aren’t exceeding the adapter’s capacity. Check the current draw for each of your pedals (the Power List is a good place to start) and add the mA numbers together. The pedals draw full power as soon as they’re plugged in, so there’s no real difference if they’re being used or not. Try to reserve 10% of the adapter’s capacity (i.e. if the adapter can provide 200mA, try not to exceed 180mA) – this will keep it running cooler and prolong its life.
* Do not confuse DC and AC power – most stompboxes work on 9 volts DC (same as a battery), but there are those that require AC voltage. The Whammy (version 1-4) is a classic example, but there are others too. Check the label on the pedal closely – DC voltage is either written out as 9vDC (for instance), or indicated by a straight line (sometimes with a dotted line underneath). AC voltage is either written out as 9vAC (for instance), or indicated by a wavy line (~). Do not mix them up – connecting an AC supply to pedals that require DC may kill them, while trying to power a Whammy with a Boss PSA adapter (9 volts DC) can fry the adapter.
Again, go visit the Power List, where you will find current draw figures and voltage requirements of many common and uncommon pedals. There you will also find an overview of the more popular adapters/power supplies available, and what they can and can’t provide. Whenever you feel ready, visit the techie version of this page for a more in depth explanation. 🙂