USB to 2.1mm DC Booster Cable - 12V (ADA2778)

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This cable is kinda fascinating - it has an integrated boost converter, so you can plug it into any USB port (from a computer, battery pack, etc) and it will give … read more

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I tried this unit and It would not stay on 12V. With the QC3.0 USB the output is monitored and expects to see hand shaking on the D+ and D- to tell it the voltage. No hand shaking means that the USB port reverts to 5V after about 10 seconds.

Hi John,

If you are referring to Qualcomm QC 3.0 products, then it’s worth noting that they are not designed to function with everything. Thanks for letting us know that there is a compatibility issue though.

This product will work just fine with normal computer/laptop USB ports, along with normal 5V USB chargers (including “fast charge” 2+ Amp sockets).


Hello, I am trying to power a Yamaha P125 Keyboard from a power supply 12V 1.5 A 18W and would like to use a USB booster cable or a power supply bank to power it. Can you please suggest a product I could purchase from you to make this happen. The purpose is to power the keyboard for 2-3 hours whilst busking. Thanks very much

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To clarify, The Yamaha Keyboard needs 12V, 1.5 A 18W input… So I would like to find a converter or power bank adaptor to do this task… If it is possible.
Thanks in advance. Dany

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Hi Dany,

Welcome to the forum!

Looks like this cable is only able to output 500-700mA max at 12V, so this won’t be able to power your Yamaha keyboard unfortunately.

Can I please confirm that your Yamaha keyboard accepts power from a 2.1mm barrel jack? If so, what sort of power source do you have available? Are you limited to USB power sources (like a phone battery bank or a laptop) or do you have others available? We can then find an alternative for you.

Sounds like for busking you won’t have a mains power supply available but if you do you could simply power your keyboard from a 12v plug pack with a 2.1mm barrel jack like the following:

Otherwise please provide us some more detail of the power sources you have available and we can find what you need.


Hi Danny,

You’d need to do a bit of soldering, but something like this should do the trick:

Depending on the size of your barrel jack port on your keyboard, you’ll need a jack you can solder to:

You’ll probably also need something to accept power from your USB plug, something like this breakout or butchering a cable would be best:

A small jiffy box would likely also be needed to keep everything retained and safe:

Let me know if you have more questions!

EDIT: Also make sure that your usb charger can supply the required 3.6A, I’d imagine not many could