I use the regular 9V DC negative center power adapter, and every so often the connector gets ripped or the internal soldering wears off and in middle of a gig the adapter stops working. It usually happens at the connector (barrel) side (see following fig):

enter image description here

What I had in mind is buy a heavy duty cable and solder it myself to the adapter so it's more durable, plus having an external power cord to the adapter so if I need extended length it's the power cord rather than the adapter cord.


What's the size of the connector in standard (i.e. Boss) 9V DC adapters? Here are some examples, looks like it's the 5.5*2.5, but maybe it's not even in this list.

Please disregard the other side of the connectors in the picture below. All I'm interested to know is the size of the connector (to the left).


enter image description here

  • You might be better soldering straight to the internal socket, and taking a cable out through a small hole you make, so the socket is still available. Open the pedal and hardwire to the socket itelf. that way, basic options are still available
    – Tim
    Oct 21, 2018 at 18:22
  • That's what I'm planning to do, but I need the right connector and I'm not sure what's the size of it. Oct 21, 2018 at 19:30
  • No. I mean solder inside, so the connector isn't involved.
    – Tim
    Oct 21, 2018 at 19:55
  • The Voodoo Lab pedal power manuals will have this info. I’ll come here and quote it later if you haven’t found it before then. It’s not only the outer diameter but also the inner diameter that counts. Oct 21, 2018 at 20:35
  • 1
    You can post it as your own answer if you want. Definitely I think you should keep the question. It’s a pretty good one. Oct 21, 2018 at 21:49

2 Answers 2


As Todd Wilcox referenced in his comment, the standard barrel used in FX is of:

5.5 x 2.1 mm


OK, so it's 5.5 x 2.1 mm.

But don't. When there's a plug-and-socket connection that is vulnerable to getting 'ripped', the answer isn't a heavier plug. That just ensures that when it IS ripped, more damage gets done, probably to the socket.

Mount your pedals on a board, tether the cables so strain will never be placed on the plug/socket interface.

  • It's not the plug that gets damaged, it's the connection to the cable between the barrel and the wire. But you definitely got a point. Oct 21, 2018 at 23:30

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.