Little Smart Super Sound Works : Deconstruction
A Brief History of the Super Sound Works
The Little Smart Super Sound Works is a product of VTech Holdings Ltd. It was first introduced to the public in 1998, and products in this category of VTech kids learning toys usually had a 3 year lifespan before being discontinued. In 1998 it retailed for $39.99. VTech owns several factories in China, and the Sound Works was manufactured there. I, however, was not in my research able to find out which factory specifically. In the days that the Sound Works was being sold it was very popular and highly rated by parents.
History of the Sample-Based Synthesizer
The Little Smart Super Sound Works is at its heart a sample-based synthesizer. Sample-based synthesizers operate by storing samples in memory and then playing them back at the desired pitch and volume. A sample-based synthesizer might have different samples for the different parts of the sound envelope for a particular instrument. This might include the attack, sustain, and release portions. Complex multi-sampling technology can combine multiple samples to be used at regular pitch intervals to better represent the natural timbral differences of acoustic instruments at different octaves. With multi-sampling one could record a sample for every note at multiple volumes to best describe the natural timbre of an acoustic instrument, and some of the best sample-based synthesizers do just that.
Sample-based synthesizers are digital instruments as they hold their samples in memory. The first of such synthesizers was the Computer Music Melodian first available in 1976. The primary advantage of the sample-based synthesizer is that it does not require nearly as much processing power and complex electronics as say additive or subtractive synthesizers. All that is required is memory storage and a way to recall that memory and pitch shift it accordingly. This makes the sample-based synthesizer cheaper to produce and the perfect choice for a child's toy like the Super Sound Works.
Theoretical Model
The theoretical model for the Super Sound Works is fairly simple. There is a control unit which selects the sounds that will be played back from the memory unit. The keyboard on the unit does two things: triggers the sound and selects the pitch. Once triggered, the sample is pitch-shifted by the control unit and then sent to the filtering stage. The filtering stage is an optional stage that is activated with push button controls on the front of the unit.
This filtering stage consists of two low frequency oscillators, a delay circuit, and left to right panning. The two low frequency oscillators are linked to the amplitude of the sample and the pitch of the sample. This allows for some basic application of tremolo and vibrato.
After filtering the sound is amplified and then sent to the speakers.
Tools List
- Multi-Purpose screwdriver with 10 various bits for screws.
- Small needle-nose pliers
- Two different Torx screwdrivers
- A full metric allen wrench set
- Various other imperial allen wrenches
- Toothpicks
Deconstruction Log
On the backside of the Super Sound Works there were 12 screws that needed to be removed before I could remove the main back panel. This panel came off easily, and with the exception of two wires to connect to the batteries, there were no other electronics attached to the back panel. If needed these wires could simply be cut as there is an external AC power adapter plug on the back of the unit.
Upon opening the unit, I could immediately see a variety of components on the inside. There was a primary circuit board which contained all the controlling chips and memory unit. Wired to this main control board was the left and right speakers, two smaller keyboard controllers, an on\off switch board, keypads for the drum buttons, a board for the AC power plug. Hidden underneath these components was the volume\tempo control keys, special effect keys, play\pause keys, and the main sound selection board.
The keyboard seems to be two identical keyboards of one octave placed right next to each other rather than one large two octave keyboard. This makes sense as far as simplifying the construction of the device. The keyboards contained one board with LEDs to light up the keys as they are pressed, and another board with a rubber cover that is pressed to activate the keys when it is pressed. This rubber cover and the board below it are the actual keys. The plastic “keys” on the outside of the unit do nothing but push these rubber buttons below them.
The speakers are identical and are connected to the main circuit board with two wires each. It would be no problem looking from the construction of these speakers to instead attach a stereo headphone jack to output to a large speaker system rather than using the internal speakers.
Individual input keys for things like volume, play, pause, effects are all activated in the same way. There is a plastic key on the front of the unit with a small rubber conductive surface on the back and a board behind it that allows the key press to close a circuit thus activating the key.
To access the primary circuit board required me to detach half of the boards connected to front plate. Communication between the sample selection board and the main circuit board was achieved through a plastic card-like cable that simply folded over the receiving edge of the main circuit board and was clamped down with a removable plastic attachment. After disconnecting most of the boards from the front panel I was able to fold back the main circuit board in order to get a look at it. Manufacturing used a lot of hot glue all over the Super Sound Works to make things stay in place. A lot of this hot glue seems like it was used to keep things out of the way while assembly was taking place. It does not add much structure, but instead keeps things in place. On the main circuit board I found the primary control chip, a chip-based amplifier, and a variety of transistors, resistors, and capacitors. I was not able to determine specifically what the various transistors, resistors, and capacitors accomplish in the model of how the Super Sound Works operates as my understanding of circuitry is not great enough to be able to decode a circuit board by looking at it.
Further disassembly of the Super Sound Works was not really possible to achieve without removing solder and beginning to rewire things. At this phase of the project I felt this was not something I could easily get back together with any real confidence that I would not completely break it in the process, so I stopped at this level of deconstruction. However, this level of deconstruction has definitely given me ideas of where I can go for Project Two.
Research on Parts
While most of the parts of the Super Sound works were made just for it. I was able to identify a couple of items on the main circuit board. Unfortunately I was not able to see what the central processor of the unit is. I was however able to find documentation for several of the transistors: the C9012, C9013, and s8050. I was also quite luckily able to identify the amplifier used on the board. It is a KA2209.