MIDI Out to multiple MIDI Ins

[freddy]

Guys,
 
I can't seem to find (I always struggle with Google about using proper keywords) a way how to connect MIDI output (current loop, not TTL-level) to multiple inputs - MIDI standard permits that - without using additional hardware (that is without converting MIDI in to TTL and using the TTL level to drive multiple MIDI out circuits creathing a multi-Thru device). Should the connection be chained:
 

MIDI Out +    -----    ----------    ----------    ---- MIDI Out -
                  |    |        |    |        |    |
                IN1+  IN1-    IN2+  IN2-    IN3+  IN3-

 
or connected in parallel:
 

        OUT+  OUT-
          |     |
          +-------------+-------------
          |     |       |            |
          |     +-------|-----+------|-----
          |     |       |     |      |    |
        IN1+   IN1-   IN2+  IN2-   IN3+  IN3-

 
 
(Sorry about the ASCII, no mood to open Paint-like tool).
 
Thanks,
freddy

Edited March 2, 2013 by freddy

[TK.]

Hi Freddy,

 

you need a dedicated driver for each pin which drives the optocoupler of a MIDI IN (in fact: the inbuilt LED of an optocoupler).

A 74HCT541 could be used for such a purpose - it would allow you to drive up to 8 MIDI INs

 

Best Regards, Thorsten.

[freddy]

TK,

 

thanks for the reply'

 

Hi Freddy,

 

you need a dedicated driver for each pin which drives the optocoupler of a MIDI IN (in fact: the inbuilt LED of an optocoupler).

A 74HCT541 could be used for such a purpose - it would allow you to drive up to 8 MIDI INs

 

Hmm, that sounds like the configuration I was trying to avoid - converting the current loop to TTL and driving separate MIDI output circuit (ehm, basically a single resistor). The idea was to build a small portable Bassline Synth using 4 BassBoy modules and using Core 8 with SCS to configure the them - each module requires 5 DOUT pins (4 for selecting MIDI channel and one to select module operation mode). Looks like a 6th DOUT pin will simply be used by TTL MIDI output and the Through function will be done by software by using MIDI Router app bits and pieces. Makes sense - thanks again!

 

Cheers,

freddy

[TK.]

You can't use a DOUT pin to output MIDI data.

My proposal for such a setup would be, to connect a TTL based MIDI Output (e.g. J4B.SD) with the Rx pins of the BassBoys in parallel.

The grounds have to be connected as well (e.g. via J4B.Vs)

 

Now each synth will receive the same MIDI data, but you are able to differ between the synth by using different MIDI channels.

If SysEx data is transmitted as well, then I hope that BassBoy supports a Device ID?

 

Best Regards, Thorsten.

[freddy]

You can't use a DOUT pin to output MIDI data.

My proposal for such a setup would be, to connect a TTL based MIDI Output (e.g. J4B.SD) with the Rx pins of the BassBoys in parallel.

The grounds have to be connected as well (e.g. via J4B.Vs)

Hmm, sounds reasonable, I missed the DOUT point. Okay, I'll pass the (appropriate) MIDI data to the synths via J4B via SW, I already found an appropriate solder point with TTL MIDI in on the device.

 

Now each synth will receive the same MIDI data, but you are able to differ between the synth by using different MIDI channels.

If SysEx data is transmitted as well, then I hope that BassBoy supports a Device ID?

Looks like BB doesn't support Syx at all, since passing the MIDI data is done by SW I'll probably implement a kind of filter no to bother the poor BB more than needed.

Thanks again,

freddy