Small tune with samples from babyBotte shoeBox fraktalSynth

I sampled two fraktalSynth sounds and added drums, bass, percussion, some riffs and TADAAAA!

It contains some mistakes because I was mixing it live on the MC 909 (which by the way have to get some synth porn pictures of it)

Here! Criticism accepted (Because I moderate the comments :)


google sites apparently has limited bandwidth so I made an account on rapidshare. If you stumble to any problems please drop me a note!

so, go here:

Shoebox fractalSynth

This is how fractalSynth looks like:

And this is how it sounds (a little tape delay added)

I had once stumbled upon Catweazle's fractal synth. In the circuit benders forum it seemed that the project had come to a halt. But recently I realized that it was going on elsewhere.! Here.
Also, the files can be found in the forum or in
There are two schematics and lots of mp3 samples if you want to hear how it sounds.

I decided against building a PCB in eagle and then etching, soldering, etc. and went for the perfboard. It is a very simple schematic and I pulled through it with relative ease. Just remember to leave a little space around the MicroChip so as to put the simple filter and the voltage stabilizer (a simple 7805 with two capacitors, nothing special).

The schematic mentioned 10K pots but since they are used as simple voltage dividers you can go (as I did) up to 100k with no apparent malfunction. I used a lot of female pin headers on the board (as you can see) and connected the pots and buttons with male pin headers. This is rather flimsy as a connection. You might not be able to go live with such a thing but, it is quick and easy.

The underside of the perfboard is all connected with solder. A difficult to correct method but again, it is quick and I can't wait :)

I used a cardboard box because it was the only thing I could find around me at the time. I had some aluminum panels lying around but I would make noise and the kids would wake up. I have mentioned again the problem I have, making panels for my stuff.

Now I have a noisemaker in a shoeBox :)

I added a simple voltage stabiliser with a 7805 and two electrolytic capacitors and fed the voltage to the chip.

The pots were mounted on the cardboard (a tedious and dangerous job because the cardboard was thin and there is always the risk of ripping it appart.) and soldered with wire and pin headers.

Some special attention was given to the 7-segment LED that connects to the chip. I used 150 Ohm resistors instead of 200 Ohm mentioned in the schematic. The difference is not a big issue. (It would be if 10 Ohms where used for example). The resistors where directly soldered on the led pins because I wanted no other things than the led on the top side of its board in case I wanted to glue it on the cardboard.

So it looked like this:

The whole thing was put in the box after determining which pin of the led went to which pin on the chip. This made the wiring a bit of a rat's nest.

So the final "product" was firmly closed to hide the ugliness of it's interior.

The first tests were a reality.. And it WORKED!!!!!

The next step was to figure how it was working.!!

A big thanks should go here to Catweazle (you can find him in forum) for releasing the source code as well as the schematics. I put a programming header on the board so as to try some things myself.

The next thing is to put the shoeBox fractalSynth through my MC 909 and make a tune out of it !!

Dissecting SY 77

I had an SY-77 lying around in my old house so I decided to take it appart just to look how it is built and what is made of. It wheighs around 15 kg and it is a very solid built. You have to unscrew at least 14 screws just to remove the underside panel which reveals the electronic guts of the instrument. There are two main boards visible. Both have countless DIP chips and some surface mount giants. Of course, it is well over me to make out what each of the chips actually do so I was just staring at them in awe.

The SY was the flagship of Yamaha back in the 90s. It had 32 voices, 16 of them where AFM (an advanced kind of DX's FM synthesis with more algorithms between the operators and the ability to feedback an operator with it's signal) and the other 16 were AWM (a PCM like sample playback synthesis method). Each voice signal could have two resonant filters and the output of the AWM voices could be used as input to an FM operator. This, if you didn't know what you were doing, was usually a noisy mess. I didn't but the guys that programmed the presets did because it has some wonderful mininoog style sounds that became very expressive with the velocity/channel aftertouch, semi weighted keyboard the SY features.

Moreover, in its FM synthesis, a different envelope (both pitch and amplitude) could be assigned to each of the FM operators so you could program some evolving sounds. Its envelopes featured repeat points and so on.
The SY also featured an on board sequencer which I didn't really like (It was the time of cubase on atari ST). But my SY grew older, some keys grew sticky, some sliders were in need of repair and it gave way to the VST stuff. The floppy drive died a horrible-sticky death (there is a rubber band that used to turn the disk but it just disintegrated in my hands leaving a sticky, tar-like residue. I cleaned it with acetone but I need to find a replacement now).

I put it back in its case, waiting for the time to move to a bigger house where it will take the place it deserves. A master controller maybe? Or maybe not?

For more pictures and closeups of the ICs you can always look here
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QY Synth porn pt 2

This is the bottom of the main PCB. Is it bendable?!? ;)

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Some synth porn

Dissecting the QY 70. Nice piece of gear. Would really like to know what are those chips anyway! (filters/roms maybe ?) The big one in the middle must have the OS.

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A dsPIC33 breakout box.

Made this in order to test the samples I (again) got from microchip... (coolest guys in the world.. If I ever make something sellable in huge numbers with a microcontroller, it will surely be a PIC :).

I include the brd file of eagle so you can make it yourself (it is tested that it works). If you want you can print the bottom layer on a laser printer and then iron the paper on the back side of the board so you can have the pinouts printed on the top side..

files as always here
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AVR Synth part 5 (final)

The connections are simple now.

It got a little wiry but it plays alright.. The following sample is a single note (until the end where I start to improvise :)
The loop is made by the envelope only (decay time)

The original site of JAREK ZIEMBICKI is here
There is this other guy named krüe who modified a little the hardware (used an atmega 32 instead of atmega16 and a 16MHz osc instead of 8MHz) and added a lots of features. Source code included! here

A note. I found that the code on Jarek's site didn't work with my atmega16 so I got the hex file off here where they also sell ready made boards.

My sample is here
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AVR Synth part 4

The switch multiplexer.. lots of diodes

and cables
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AVR Synth part 3

midi interface (a little deviation from schematics here since I didn't have a P900 or 4N25 optocoupler at hand and used a 6N138/9)
The (typical) power supply. 5v with 7805
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AVR Synth Part 2

This is the Digital to analog converter. It uses lots of 1% resistors. The schematic mentioned that for the most significant parts, 0.1% resistors should be used but I didn't use such. It really has no effect on sound (at least for me that I didn't expect anything special).

Again, a little attention to the schematic, can save you from a lot of bugs later...
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AVR Synth Part 1

I decided to make JAREK ZIEMBICKI's AVRSYN. But there were only the schematics and no board layout so I had to make my own. So I started laying it out on eagle but I got on a deadlock due to the fact that I didn't want to make a double sided board. I would etch it myself and double sided boards are a BIG pain in the but (vias and such, alignment etc). So I made it on a perfboard. But before that, I decided that it should be made into discrete modules. One for the microchip, one for the D2A (an R2R resistor ladder type) , one for the midi interface, one for the power supply and one for the switch multiplexer.

Here is the main part. I put pin headers to wherever it would connect to another module and got myself a lot of ribbon cable. The AVR is a really simple design. Only the layout makes it complicated. It can be made by anyone (Even I made one!!!).

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Serious Programmer

At least more serious than the one I had before.. The pickit2 from microchip (I felt guilty for all the free samples I got so I bought the original, but there are clones on, you guessed it, e-bay!!!). It can program a much wider range of chips, namely the 16Fxxx and 18Fxxx and also the 24Fxxx, dsPIC30Fxxx and dsPIC33Fxxx (and the PIC32 but I never got to try it) . The good thing on these chips is that the dsPIC33 have Digital to Analog conversion on board at 16bit and can go to more than 110KHz sampling rates. MUST-TRY!!!!
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