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Midi Merge "expansion" for MB64


Pablop
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Hello everybody

In order to work more comfortably, without the need of plugging and unplugging cables I would need a setup like this:

00.jpg

But what if I include the Midi merger in the MB64 to simplify things and get this?

01.jpg

I understand that would already allow me to get rid of the power section in the Midi Merger PCB.

The question is:

Are there any other components that could be removed?

I guess it'd be possible to do that in the OUT section of the merger and/or in the IN section of the Core, but I'm not quite sure of what could be simplified.

Thank you in advance,

Pablop

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How about:

/--> Keyboard ---> MB64 ---> Computer --\

|                                                        |

\-----------------------------------------/

MIDI Thru should be on, for the keyboard and MB64, and not the PC.

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Keyboard doesn't have a merge (or thru, or in-to-out) function, so I wouldn't be able to send sysex or any from the computer to the MB64... Not many keyboards support that function.

That's why I need it this way, otherwise, I'll be connecting and disconnecting all the time. What's more, if I want to use cubase for sequencing, I cannot record my keyboard on Cubase and feed the MB64 with already recorded automation at once..

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Keyboard doesn't have a merge (or thru, or in-to-out) function, so I wouldn't be able to send sysex or any from the computer to the MB64... Not many keyboards support that function.

You sure? I've never seen a master keyboard that doesn't do that. It might be called "Local=on/off". Anyway, if that's the case, you can just do as you drew.

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I think, that using the MIDI merger is the best choice in such a case - I know many keyboards (not master keyboards) w/o integrated merger as well.

Note that I'm planning to release a PIC16F88 variant of the merger project soon. It's just for completeness, because this PIC is smaller than PIC18F452 or PIC16F87x and powerful enough (it comes with an integrated USART). But it will require a PIC burner to flash the firmware - if you don't own a PIC burner, then PIC18F452 with MIOS bootloader is the better choice.

Best Regards, Thorsten.

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You sure? I've never seen a master keyboard that doesn't do that. It might be called "Local=on/off". Anyway, if that's the case, you can just do as you drew.

A local on/off function is not what I need. That lets you control or not the sound engine built in the device with the keyboard of it. What I need is the ability to send to the MB64 both msgs. from the Controller and the PC at the same time, so, somewhere there must be a merger. Some controllers, but a few of those which I know, let you merge the thru (notes coming from outside (PC in this case)) with those coming from inside (Controller Keyboard in this case). (sorry if I'm explaining obvious things, I'm just trying to make mysef clear). Mine doesn't have that option.

Regarding whether to go with the 16f or 18f version, I already have a spare PIC18F452, and I wouldn't have any trouble in using it. I have a JDM programmer, and didn't have any problem with it and the 18f452. Maybe I prefer keeping things this way.

Now, I know that the first picture will work in doing what I need, whether the Merger is built as a separate unit or put it in the same case as MB64 (second picture). But my point is,

In order to connect the MIDI Out of the merger to the midi in of the Core,

Do I need to have all the components, or maybe there are some components that could be not used (eg. the optoisolator), or some part of the circuitry bypassed?

Thanx

PD: At this point I'm beginning to think the most practical idea could be to use the circuits and PCBs as given, but I'd like to learn a little out of this... Thanx again

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Yes, you can leave out the optocoupler part of the core module and the 220 Ohm resistors of the merger MIDI Out in this special case without danger so long both PICs are supplied by the same voltage source. The Tx output of the PIC used for the merger has to be connected to the Rx input of the second PIC

An more clever method: you could easily re-use the optocoupler circuit of the core module for the merger circuit. Just break the track which is routed to the Rx pin. One side (the Rx pin of the core module) has to be directly connected to the Tx pin of the Merger circuit, and the other side (optocoupler part of the core module) can be directly connected to the Rx pin of the Merger circuit.

It's like if you would "insert" the merger Tx/Rx pins between optocoupler and Rx pin of the core module.

Best Regards, Thorsten.

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A local on/off function is not what I need. That lets you control or not the sound engine built in the device with the keyboard of it....

(sorry if I'm explaining obvious things, I'm just trying to make mysef clear)

Yes you are, but that's no problem. I do understand what you're trying to do, so I'll repeat myself in more detail as it seems I wasn't clear enough. MIDI master keyboards don't have an internal sound engine. Perhaps it's for this reason, that on some master keyboards, the midi thru/merge function is called local on/off. Yes, I know that is not the correct terminology, but I thought that I should advise you that some master boards use this incorrect terminology, so that you can check it.

Mine doesn't have that option.

For a synth that might be a little unusual, but for a dedicated master keyboard it is extremely unusual (because they should be designed for the type of thing you're trying to do). Have you checked the manual and the sysex implementation?

Do I need to have all the components, or maybe there are some components that could be not used (eg. the optoisolator), or some part of the circuitry bypassed?

You can skip the opto but it won't hurt to leave it there :) In fact, you could just use J11 to connect them...

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Well, my keyboard is a low-profile electric piano. Nice touch, nice weight, 88 notes, but very basic in its MIDI functions (It doesn't even have a thru port).The manual is, let's say, 10 pages long! He!  ;)

Thanks for the answers, both Stryd and Thorsten, I will study it later, it's 4am. now.

Cya around

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