[sdiy] MIDI notes filter which is also a MIDI converter for Junos ?

[Ingo Debus]

Am 29.12.2013 um 08:14 schrieb rsdio at sounds.wa.com:

> It doesn't seem possible for your circuit to output the full 5mA while only receiving 5mA on input,

I'd say it depends on how often output data are sent. Dave's circuit can draw current continuously from pin 4 of its MIDI in jack. But output current is only required when the output is low. Current peaks can be delivered by the filtering cap C1.


> unless your CPU is micropower (MSP-430) or you thin out the MIDI stream so that fewer bits are transmitted than received.

Sorry, you've lost me now.
Do you mean the transmitting device can deliver more current while sending data? Dave's circuit is powered from pin 4 (return path is pin 2 aka ground of course), and on the transmitting device this pin should be tied to Vcc via a resistor.


BTW, in addition to D4 I would add another protection diode to ground, and probably a small series resistor between the MIDI in jack and the diodes. Maybe a pair of protection diodes at the MIDI out too. You never know what people connect to the jacks.

Ingo