[sdiy] Who apart from me things the whole MIDI board needs replacing ?

Roman Sowa modular at go2.pl
Thu Jan 27 11:59:34 CET 2022


100nF between cable shield (pin 2) and device GND is now in MIDI DIN 
hardware specs, I guess for 8 years or so. Can't recall a word 
"obligatory" in there, but it probably is.

Roman

W dniu 2022-01-26 o 16:30, rburnett at richieburnett.co.uk pisze:
> That's a good point.
> 
> Often you can solve problems like this by connecting the shield to 
> ground via a 100nF capacitor and 1Meg resistor in parallel (at one or 
> both ends.)  The impedance of the parallel combination is low for 
> high-frequency signals (and most noise that has come through the air 
> before coupling onto your cable is high-frequency in nature,) and 
> conversely the impedance is nice and high for low-frequency signals 
> (like 50Hz "hum" currents due to earth loops,) so not much current flows 
> at these low frequencies.  The 1Meg resistor prevents static build up 
> across the 100nF capacitor, so it at least tries to keep them with the 
> same DC potential if one of the bits of kit is "floating" relative to 
> the other.
> 
> -Richie,
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