[sdiy] Midi opto isolation

[John Luciani]

On Jan 1, 2008 1:09 PM, Sean Ellis <tensiontype at hotmail.com> wrote:
> Over the years I have picked up some modules that have trouble with complex
> midi signals. I'm considering ways to fix them like improving the midi
> inputs stage but I'm curious, why have the signal isolated? Surely using the
> isolation lowers the quality of the signal with very little benefit, is it
> really needed?

The isolation prevents the different ground levels between midi devices
from affecting the quality of the signal. Another benefit is that a fault
in one device will not cascade to other devices.

With an opto that has high enough rise and fall times you shouldn't
see any measurable effect on the signal quality.

(* jcl *)


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