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Posted by Parham (from: 217.66.202.17) on April 21, 2001 at 14:17:08:
In Reply to: Re: MAKING A MIDI CABLE posted by ???????? on January 30, 2001 at 11:23:28:
: : Please send me some information about MAKING A MIDI
: : CABLE
: How to build a MIDI interface for a Sound Blaster/Sound Blaster Pro:
: Probably works with almost any soundcard
: The Sound Blaster MIDI port uses two pins from the 15 pin
: joystick port. These normally would be redundant +5 volt and
: ground lines. In the Sound Blaster, there are called MIDI TXD
: (Transmit eXternal Data) and MIDI RXD (Receive eXternal Data).
: The signals to and from the Sound Blaster are TTL logic signals.
: MIDI uses a current loop interface, so the job of the interface
: box is to convert between TTL level signals and the MIDI current
: loop. : If you want to use the MIDI interface and the Sound Blaster
: joystick interface simultaneously, you can make a simple adapter
: by connecting one male and 2 female 15 pin connectors to a short
: length of ribbon cable. : SBMIDI1.PCX is a PCX format graphic file of the schematic diagram
: of the MIDI connector circuitry. You can use Windows Paintbrush
: to view and print the schematic. : For simplicity, the schematics show the MIDI input and output
: circuits separately, but they share the +5 volt and ground lines.
: (Pins 8 and 5 on the Sound Blaster). The interface uses 4 wire
: shielded cable to connect the computer to the interface box and
: two 2 wire shielded cables to connect the interface box to the
: input and output ports on the MIDI instrument. : The MIDI input port only can connect to one instrument, but the
: MIDI Out from the computer could go to up to 5 MIDI instruments.
: The schematic diagram only shows one complete MIDI output line.
: You can connect up to 4 additional MIDI outputs by adding a
: 220 resistor (from the +5 volt pin to pin 4 on the MIDI cable)
: and a 220 resistor (from the buffer output to pin 5 of the
: MIDI plug) for each output. You should also add a 220pf
: capacitor between each additional MIDI line and ground. :
: Construction:
: Start with using half of a dual 20 pin IC board, using the first
: six pins for the optocoupler and the last fourteen pins for the
: hex buffer. Then remove portions of some of the copper lines
: on the circuit board with an X-Acto knife, as is shown in the
: schematic below. Cut each trace on
: both ends first, then remove the copper between the cuts.
:
: RED = Remove BLUE = Marked as remove, but doesn't seem to be needed
: Now Turn over, left to right...
: BLUE = Link wires GREEN = Small components :
: Looking at the diagram, I now believe the links from IC2 pin 2 to IC1 pin 3, and IC2 pin 2 to pin 4, to be incorrect. The links IC2 pin 5 to pin 9 and IC2 pin 9 to pin 11 are only required if you intend to use the corresponding outputs - pins 6 and 8. This also explains the additional track cutting
: Now on to component installation! Be sure to use rosin core
: solder and a low wattage soldering iron. Solder the 20 pin
: socket to the center of the board, being careful not to bridge
: solder between connections. Then install the other components
: in the locations shown in the above schematic. Note that the ringed
: end of diode D1 needs to connect to pin1 of the optocoupler.
: Be sure to run hookup wires from the ground pin on the optocoupler
: (Pin 4) to the ground pin of the hex buffer (Pin 7) and between
: pins 11 and 12 on the hex buffer. The remaining hookup wires
: are optional for additional MIDI outputs. Notice that both a
: resistor and a capacitor must be connected in the same hole for
: each MIDI Out. Then connect the 4 conductor shielded cable to
: pins 5,8,12 and 15 of the 15 pin plug. Connect the shield to
: the metal case of the plug. Connect the other end of the 4 wire
: cable to the corresponding locations shown in the above
: schematic. Tie the cable shield to the large mounting hole in
: the circuit card and connect one end of each of the two connector
: shielded cables to pins 4 and 5 of the MIDI plugs. Connect the
: shield in the MIDI plugs to pin 2. Mark one cable "MIDI IN" and
: the other cable "MIDI OUT". Connect the other end of the cables
: tot he corresponding locations on the circuit card. Tie the
: shields to mounting holes in the circuit card and connect all
: three shields together with a hookup wire. Check the card and
: cables to ensure that all connections are correct, file small
: notches in the cover of the aluminum box for the cables, and
: wrap a piece of heavy paper around the circuit card to prevent
: shorting. Your next step is to plug the 15 pin connector into
: the Sound Blaster and the MIDI In and Out to the MIDI jacks on
: your MIDI instrument. :
: Testing:
: A MIDI port requires software to function. You can test the
: input portion of the MIDI interface with the FM Organ program
: bundled with the Sound Blaster. With "MIDI Mode" selected,
: MIDI Note-On messages will play sounds from the Sound Blaster
: card, but only those notes valid for the musical key you have
: selected. For example, if you select the key of C, only the
: white keys will sound. To test the MIDI Out portion of the
: interface, you can use any MIDI sequencer that supports
: Sound Blaster. All of Voyetra's sequencers, Cakewalk, and
: Trax are examples of some that are available. When you go
: shopping for a sequencer, make sure you specify that you have
: a Sound Blaster. The Sound Blaster MIDI interface is NOT
: Roland MPU-401 compatible! But that's not a major drawback
: anymore - Most companies are now supporting the Sound Blaster,
: but some have separate versions - One for SB, one for Roland.
: There are some ShareWare/DemoWare sequencers available on
: the Creative Labs BBS. You can reach them by modem at the
: number given at the end of this file. :
: Parts List:
: Resistors: (¼ watt, 1%, metal film) - not that critical, really
: R4,R5 220
: R1 270
: R2 1K
: R3 4.7K
: Capacitors:
: C1,C2 220pF ceramic
: Diodes:
: D1 1N914 or 1N4148
: Integrated Circuits:
: IC1 4N35 Optocoupler
: IC2 7407 Hex Buffer
: IC Sockets:
: (IC1) 8 pin
: (IC2) 14 pin
: Other Components:
: 1 Dual IC board, Radio Shack part #276-159
: 1 15 pin male DB-style connector, solder cup
: 1 Hood for 15 pin DB connector
: 2 5 pin DIN plugs, 180ø
: 1 Aluminum project box, approx. 3"x2"x2"
: 2' of 4 conductor shielded cable
: 8' of 2 conductor shielded cable
: Other info:
: Creative Labs, Inc. BBS:
: Node 1 & 2 : (408)428-6660 1200/2400
: Node 3 : (408)428-6662 9600/14400 v32/v32bis/CSP
: Node 4 : (408)428-6664 9600/14400 v32/v32bis/HST
: Available on the BBS is a library of MIDI files (.MID) as well
: as several ShareWare/DemoWare MIDI applications. : Note: Please do NOT call the Technical Support department of
: Creative Labs for help on this - With this file, you have
: just as much information as they do! If you don't want to
: deal with it, just buy the cable - It costs $24.95 + S&H
: direct from Creative Labs. The sales number is (408)428-6600. : Good luck!
: Information presented from files obtained via the UK Creative BBS (now defunct), with suitable reformatting into HTML. All information presented is understood to be in the public domain and intended for distribution.
: No responsibility accepted for damage or injury resulting from the use of this information - if in doubt, buy it, don't build it! All trademarks acknowledged, particularly CREATIVE, SOUND BLASTER etc. For Creative's web site, go to www.soundblaster.com ... www.creative.com is incorrect, but will offer a courtesy redirection.
: A junkroom internet production, built entirely with freeware, cover CD and other legitimate but unpurchased software under Windows 3.1.
: Webford 2.01 was used for some parts of the production, and to clean up the conversion of spaces to by Netscape Composter... I mean Composer... no I don't! This site could look a lot cleaner if I used more advanced code and the background is more of a liability than it's worth.
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