MTP Series MIDI-to-Parallel Converters
Frequently Asked Questions

How many outputs can be on at once?
As many as there are note outputs on the unit. All MTP units are fully polyphonic.

Is there a delay between the MIDI signal and the note output when several notes are on?
No, the MTP units use a fast real-time processor which switches the outputs as fast as the MIDI notes can be sent.

Can I change the note mapping after I get the unit?
MTP-1 to MTP-6: No, this is fixed during manufacture. However, a new processor chip can be supplied with a different mapping if required.
MTP-7 and above: Yes, by playing it a special MIDI file whilst in its configuration mode. An free on-line service allows you to create the file.

Do I need a smoothed power supply?
Only the low-power logic supply needs to be smoothed. The output loads can be supplied from an unsmoothed supply.

Are the output stages 'pull-up' or 'pull-down'?
The outputs are open-collector. They 'float' when the note is off and pull down to near ground when the output is on.

Do I need freewheel diodes on the outputs?
No, these are already built in and are rated up to full current for each output.

How would I drive high power loads with an MTP unit?
Any output could be used to drive a relay which can then handle as much power as required.

Can I use the MTP outputs to control 5V logic?
All units: Yes, with some simple level-shifting circuitry on the outputs. Please contact j-Omega Electronics for further details.
MTP-7 and above: You can remove any output driver chip and plug a DIL header in its place to access logic-level signals directly.

Can I mix different types of MTP unit together in a 'chain' system?
All MTP units from MTP-1 to MTP-6 are compatible with each other. The MIDI cable can be plugged into any of the units.
MTP units from MTP-7 and above do not use the chain system, but have a MIDI-through output which can be connected to any other unit.

How do I control registers or moving figures?
It's usually easiest to use a few MIDI notes at one end of the scale which are out of the playable range.
For the MTP-7 and above, these can be on a separate MIDI channel to the normal notes to make music arrangement easier.

Can an MTP unit be used to generate MIDI signals from a keyboard?
No, the MTP units are MIDI-to-parallel. To scan a keyboard needs a parallel-to-MIDI function.

What device do I need to provide the MIDI data?
Any MIDI-compatible output device, typically a PC (with sound card), disk player or electronic keyboard.

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