VS1103b MIDI Synthesizer

I published a guide on this a while back, but it was disorganized and scruffy, so here is a tip-top new version with proper photos, diagrams, and a full write-up.

The VS1103b, manufactured by VSLI Technology, is a single-chip MIDI/ADPCM/WAV audio decoder and ADPCM encoder that can handle upto three simultaneous audio streams. It can also act as a MIDI synthesizer.

It is this MIDI synthesizer capability that we are interested in. Make no mistake - the quality of the MIDI voices isn't stunning, but it has a charm to it that reminds me of the FM synthesis found on old Soundblaster cards of yesteryear. The VS1103b MIDI synthesizer mode conforms to the General MIDI standard - 15 melodic channels and 1 percussion channel.

The only problem with this chip however is that it is a very small 48 pin surface-mount package. Fortunately, SparkFun make a break-out board for this chip that has a 20 pin DIP package - much more suitable for DIY electronics.

Here is a video of the VS1103b synthesizer in operation, playing a full multichannel track with drums :

Step 1 Parts list

Passive components
(1x) Dual-gang 10K potentiometer (preferably logarithmic but linear is OK)
(2x) 120R resistors
(3x) 220R resistors
(1x) 1.2K resistor (1K would probably be OK)
(4x) 10K resistors
(1x) 22K resistor
(1x) 100nF ceramic capacitor
(1x) 1uF electrolytic capacitor

Optoelectronics
(1x) 6N139 optoisolator (6N138 is pin-compatible substitute)
(2x) LEDs of your choice

Semiconductors
(1x) 7805 voltage regulator
(1x) BC549 transistor (or pretty much any NPN transistor)
(1x) 74LS00 quad 2-input NAND gate
(1x) SparkFun VS1103B break-out board

Hardware
(2x) 5-pin 180º chassis mount DIN sockets
(1/2x) Audio connector(s) of your choice - I used a stereo 1/4 inch jack socket
(1x) DC power socket and matching power supply (anything between 9V and 12V is fine)
(1x) SPST toggle switch
(1x) Control knob for potentiometer
(1x) Project enclosure
(2x) LED bezels
(4x) Self-adhesive PCB pillars
(2x) 10 pin header strips with matching sockets* (2.5mm pin pitch)
(1x) 8 pin DIP socket
(1x) 14 pin DIP socket
Stripboard (60 holes x 24 tracks)
Stranded-core wire

Comments

[Abbaheart]

I have seen the metric unit K for kilo but not R. Like I would see it written as 1K resister. What do you mean by the 120R? Does that mean that is just 120 Ohms? Also I would like to know if A 6n139 OPTOCOUPLER DARL OUT 8-DIP would work. I could not find an optoisolator

Thanks For posting this. I spent $80 on something that did not work on windows 7 64 bit. A midi interface. The fact that it does not need a computer is outstanding. I am really good at electronics so this should be a peace of cake.

Oh and it does not matter if it is perfect. I just need something to play on and practice. Not only that but it is just for fun. Thanks again for posting this.

[Harrymatic]

Yes, the R is just an alternative symbol for Ohms. Optocoupler and optoisolator are interchangeable terms, so the part you have quoted is absolutely fine.

[justinbailey]

Toe Jam & Earl theme! Sweet!

[Harrymatic]

Hats off to you for recognizing it! The TJ&E games had such good music - so funky.

[killerbunny4life]

Can you explain to me how exactly this is a synthesizer?

[Harrymatic]

While VSLI are not specific in the way the instruments are produced, it is most likely a 'rompler' in the sense it just plays back prerecorded samples from ROM.

Wikipedia describes sample-based synthesis as, "One of the easiest synthesis systems is to record a real instrument as a digitized waveform, and then play back its recordings at different speeds to produce different tones. This is the technique used in "sampling". Most samplers designate a part of the sample for each component of the ADSR envelope, and then repeat that section while changing the volume for that segment of the envelope."

As sample-based synthesis is a subset of synthesis in general, I would therefore consider this to be a synthesizer.

[killerbunny4life]

Thanks!

[blinkyblinky]

Wonderful. As well as beautiful.