103 lines
3.8 KiB
Plaintext
103 lines
3.8 KiB
Plaintext
The following text explains how to build a MIDI interface for the
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Sound Blaster. The circuit is my own design, but works just like
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the commercialy available interfaces that retails for $60-$90.
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Here is the list of parts necessary:
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Qty. Part
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1 Sharp PC900 or HP 6N138 opto-isolator
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1 DB15P (15 pin 'D' connector, male. like joystick connector)
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3 220 ohm resistors (2 for input, 1 for EACH output you need)
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1 3 conductor shielded cable (length is up to you)
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2 Female 5 pin DIN connector (1 for input, 1 for each output you need)
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1 PC board with pre-drilled holes (about 2" x 2" from Radio Shack)
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A few short lengths of hook-up wire
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All of these parts, except the first 2, are available from Radio Shack.
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Construction techniques are completely up to you, if you want to go
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ultra-cheap, you don't even need a PC board or enclosure, and you could
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use a MIDI cable you already have by cutting it in the middle. I used
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a PC900 out of a non-working organ and cut the end off of a joystick I
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didn't need and built the whole thing for about $4.00. Buying all the
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parts new, and using an enclosure with built-in MIDI jacks may cost
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about $20 or so.
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Here is a diagram of the DB15P connector (looking at the solder side).
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1 5 8
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o o o o o o o o
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o o o o o o o
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9 12 15
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Here is the 5 pin FEMALE DIN plug (solder side).
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2
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5 o 4
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o o
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3 o o 1
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This is the circuit for the MIDI INPUT.
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+-----> To pin 5 of 'D' connector
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To pin 15 of 'D' connector <---+ | +-------+-----> To pin 9 of 'D' con.
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| | | |
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| 6 |5 |4 \
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+---------------+ / 220 ohm
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| PC900 | \ resistor
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| or | /
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| HP 6N138 | |
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+---------------+ +------> To pin 6 of PC 900
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|1 |2 |3
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| | |
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\ | +-----> No connection
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220 ohm / |
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resistor \ |
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/ +-----> To pin 5 of DIN connector
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To pin 4 of DIN connector <----+
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Don't overlook the two 220 ohm resistors.
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Also, for cables longer than a few feet, connect pin 2 of the DIN to pin
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5 of the 'D' connector.
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The output circuit is much simpler.
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220 ohm resistor
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To pin 12 of 'D' connector <---------/\/\/\/\/---------> To pin 5 of DIN con.
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To pin 15 of 'D' connector <---------------------------> To pin 4 of DIN con.
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Also, for cables longer than a few feet, connect pin 2 of the DIN to pin
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5 of the 'D' connector.
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This circuit has been built and tested by me, using Voyetra's SPJr, and
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a cheap-o Casio keyboard. The input and output do work as shown here, but I
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don't have any other MIDI devices to use to test using more than 1 output
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device. Theoretically, it should work fine, but it has not been tested.
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The chances of hurting anything by trying is slim and none.
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This circuit DOES work, but I make no guarantees, nor will I be
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held responsible for any damages you may cause from your use of
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this information.
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If you have any questions, or would like to buy one already built for you,
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I can be contacted on:
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The Lighthouse BBS (207) 255-3700 (username is Ronald Davis)
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The Music Studio BBS (708) 351-0288 (username is Volstagg)
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