[sdiy] USB/MIDI ground isolation?

[Neil Johnson]

Hi,

Manuel Odendahl wrote: 
> Am I missing something here?

Yes, you didn't quote the right part.  Here:

>  That doesn't apply to devices that don't have 5 pin DIN MIDI connectors; for 
example, 
> a synth with a USB/MIDI connector instead if a 5 pin DIN MIDI In connector. 

So, the question is about synth boxes that have a USB connection to a PC rather than a MIDI connection and pretend to be a MIDI device, for example one of those Roland Sound Canvas boxes.  In these low-cost consumer models I think it highly likely that the PC ground, via USB, finds its way to the audio out jack, leading to ground loops and a strong likelihood of hum.

Cheers,
Neil
--
http://www.njohnson.co.uk