Add USB-C Jack to USB Device

Question

I have some inexpensive audio equipment that I am willing to experiment on. Trying to cut down on cables and I would like everything to be USB-C. I have a small midi keyboard and a small audio interface that both use USB-B. Is there any USB-C female to USB-B cable I could buy? I would even be willing to desolder the USB-B jack and replace it with a USB-C jack as long as I can figure out the wiring.

I tried looking online, but I didn't see anyone selling USB-C jacks or a USB-C female to USB-B adapter. I did see some USB-C male to USB-B adapters, but that defeats the purpose since I want to be able to connect everything with a USB-C male to male cable. Any suggestions?

Answer 1

Formally the task of adapting an old USB Type-B device into Type-C environment is solved by using a Type-B to Type-C "legacy cable assembly". This is an official way, as per USB specifications. All it takes is a single cable, and the Type-C end will have all necessary attributes of representing a Type-C device.

However, you want to introduce yet another adapter, Type-B plug to Type-C receptacle. And then to use another, standard C-C cable. It certainly can be accomplished, by wiring a Type-C receptacle to a USB Type-B plug, and having just two pull-down 5.1k resistors on CC1 and CC2 pins.

There are two problems with this approach:

1. This adapter+cable arrangement introduces yet another connector, and every connector usually introduces imperfections into USB transmission line. For MIDI or Audio devices (which typically are full-speed devices, slow 12Mbps), this is likely not an issue, but for HS devices it might cause flaky behavior.

2. Likely most important obstacle in the adapter approach is that the USB industry didn't see a need in Type-B plug for attachment to a PCB. All produced Type-B plugs are designed for cables. It is very inconvenient to attach these standard Type-B plugs to any PCB to make a good adapter.

I would guess this is why no one is making the "B-plug-to-C-receptacle" adapters in industrial quantities.

Answer 2

You didn't mention what USB standard the equipment is using. If it's very old at all, it's likely using USB 2.0. USB-C was designed for USB 3.1 and beyond. It is backwards compatible, in that, you could get an adapter to plug a USB-A/B device into a USB-C port, but the opposite is not true; hence the lack of USB-C female to USB-B male cables.

USB 2.0 A/B cords used 4 (sometimes 5) wires (image courtesy of Wikipedia). Micro and mini cords are the same pins in a smaller form factor.

On the other hand, USB-C has ... a lot ... more pins (image courtesy of Wikipedia).

But notice, it still has the standard V+, GND, and Data+/- lines, so you could make your own cables by splicing a USB-C extension cord like this from amazon and a standard USB A/B cable to fit into your device, but it is not guaranteed to work correctly. Of course, this cable would be like an extended port coming out of your device - not ideal.

If your devices use USB 3.0, then they have the updated "Super Speed" ports which do have pore pins as well (image courtesy of Wikipedia).

As you mentioned, USB 3.0 B - C male-male cables do exist (on Amazon). You could theoretically cut off the USB-C male end and splice in a USB-C female end from the above extension cord. Again, it's not guaranteed to work.

If you want to add a true USB-C port, you could get a breakout like this and solder jumpers from the correct pads on the breakout to the pads where your current USB port is soldered to the board (after you remove it), or to a cut and stripped USB-B wire going into your current USB port.