[sdiy] How to design out "usb noise"?

[Jay Schwichtenberg]

Typically it's the USB power supply that creates the problems. Computers 
are usually pretty bad, you can hear things like disc and video access. 
My solution is to use a hub that has a decent power supply. I have a 
couple that I've found over the years that I've used with my converter 
boxes. It took a couple of tries to find ones that worked.

Another solution is there are USB adapters that just pass the data and 
allow you provide your own power supply. So using a decent 5V linear 
supply might solve the problem. That's providing that the device you're 
plugging into isn't the source of noise in the first place.

Jay S.

On 2/1/2024 2:06 PM, Mike Beauchamp wrote:
> I recently stumbled across this post on reddit of someone showing usb 
> connection causing some serious noise: 
> https://www.reddit.com/r/synthesizers/comments/1aghqsa/how_to_get_rid_of_usb_noise/
>
> Some comments suggest to use DIN MIDI instead of USB MIDI as a 
> solution, but it got me wondering if there's a best practice for 
> implementing MIDI OVER USB output that wouldn't cause this. MIDI spec 
> includes schematics for hardware implementation of DIN MIDI 
> connections as we know, including the use of opto-isolator, but I 
> can't find the equivalent for the USB connection.
>
> A typical USB-B connector has the following pins:
>
> 1. VBUS
> 2. D-
> 3. D+
> 4. GND
> 5. SHIELD
>
> How do you think these connections should be handled inside the synth, 
> assuming a hostile environment where connections are also being made 
> to/from a PC with audio cables, MIDI cables, power adapters to 
> different outlets/circuits, etc.
>
> Mike
>
>
>
>
>
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