Belker 5.5 x 2.1mm Jack Reverse Polarity Converter Cable for Guitar Piano Pedals Keyboard Max. Support 3A 3000mA

I use this for a vintage DOD chorus pedal. Works perfectly what can I say? Without this I’ve would have been unable to use it.

This reverses the polarity of any 5.5x2.1mm round-tip power cable. It is a necessity if you also purchase the Belker Universal 5V DC Power Cable USB set since that is only tip-positive. Using this adapter cable along with that universal set allows it to work with tip-negative devices. I am grateful that this is available! I'm disgusted by the electronics industry that it's necessary! The industry should abandon all USB-A to Round-Tip power cables. We all have hundreds of USB-A to microUSB or miniUSB cables lying around so that if one cable breaks or gets lost it's no big deal. But since the industry refuses to standardize on anything other than having a USB-A connector on one end of their cables, this Belker Polarity Reversing Cable is great to have on hand!

worked as expected. Purchased for a Roland JDXI keyboard which has a negative tip, which is unusual. I purchased this with a Universal USB-C to 3V 4.5V 5V 6V 7.5V 9V 12V Multi-Voltage Adapter DC Cable，PD Trigger Cable with DC-DC Step Down Module, 8 Connector Tips, for Tablets, Led Light, Lamps, Routers Brand: YTADNETH for 6volts for the JDXI This unit only had a positive tip.

Suggestion for those who don’t speak electricity: double check the specs/manual on your device before ordering to see if you need a polarity converter cable. Google searching your devise's name/model # + AC polarity should do the trick too. Learned this the hard way when I tried to use this set on my Brother P-Touch D400 label maker. Seems Brother uses the less common center-negative configuration in their AC adapters on some of their devises. Ordered the polarity converter for another $6 bucks and all is right with the world. (While you’re at it, double check all the devices you want to use to make sure the specs and included attachments line up to what you need.) I'm docking this 1 Star on three counts - 1. The laughably microscopic instructions and teeny-tiny key. Fortunately the adapter is intuitive enough that you “probably” don’t need instructions ... but that’s just a guess. I don't actually know because I can’t actually read them. Like seriously guys, really? It wouldn't take more than few extra centimeters/inches and font points to save your customers eyes. I'm pretty sure your margins can take the hit. Same with the tiny voltage-dial key. It’s like it was make for a Smurf’s hands or something. It's cute ... but so very, very small and so very, very easy to lose. (Even if you’re not a gifted loser-of-thingies. See photo for suggested work-around as misplacing this sucker pretty much renders the entire set-up useless). Please make it bigger on your next model or at least give the key home on the attachment dock. 3. No converter cable. If I had done my homework the first time I probably would have gone with a different set. Overall though it’s a handy, versatile product and a quite a good value. Well Done Belker!

I ordered this one for the colored tip so I could always tell what it was. The one I received was blue colored, not yellow, but still serves the same purpose.