Midi Solutions MIDI Power Adapter
The Power Adapter provides power to MIDI Solutions products in instances when it is not available or where a large number of MIDI Solutions products are being chained in series. It's possible to power up to 20 MIDI Solutions products from the Power Adapter's single MIDI Thru output. The Power Adapter has an optically isolated MIDI In, a MIDI Thru, and a power connection for a 9V wall adapter (a 9VAC wall adapter is included with North American orders, international customers can use any 9V wall adapter with standard 2.1 mm barrel connector, AC or DC, any polarity, minimum 50 mA rating).
The Power Adapter can also be used in a transmitter/receiver configuration to send MIDI over long distances. They have tested the operation over 4000 ft. of average 2-conductor audio cable, however individual results will vary depending on factors like the type of cable used, electromagnetic noise present, etc. For a good explanation of what to consider when sending MIDI over long distances, see Richmond Sound Design's FAQ on MIDI Cable Length. It may be possible to use only one Power Adapter at the transmitting end, however in this case results are dependent not only on the cable length, but also on the type of MIDI input that the signal is being sent to. Since MIDI inputs from various manufacturers are designed differently, for best results it is recommended that two Power Adapters be used - one at the transmitting end and another at the receiving end.