MATRIXSYNTH

Rebel Technology Stoicheia Dual Euclidean Sequencer

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Perfect Circuit Audio (RSS)

"Στοιχεῖα is a dual Euclidean Sequencer that algorithmically generates rhythmic sequences from an input trigger signal.

The name (Στοιχεῖα, Stoicheia, or Elements) comes from the title of Euclid’s book Elements in which the algorithm was first described.

Operation

Each sequence is controlled by a column of three knobs and a switch. The input parameters to the algorithm are sequence length and fills.

The length of the sequence, measured in clocks or beats, is controlled by the second knob from the top. The range goes from 1 (fully counter clockwise) to 16 (fully clockwise), with 8 in the centre position.

The number of fills, or on-beats, is set by the third knob. In fully counter-clockwise position, this is set to 1. Centre position will set every other beat ‘on’, or 50% . Fully clockwise sets every beat ‘on’, in other words: the number of fills are equal to the sequence length.

The top knob adjusts which beat the sequence starts on – and hence resets to. In its centre position, the sequence will start on its first step. The start position can be changed by turning the top knob left or right: this will have the effect of rotating the sequence left or right, respectively.

Trigger Mode

With its switch in the centre position, the sequence is turned off. To turn it on (Trigger Mode), push the switch up. In trigger mode, the sequence will switch its output high when receiving a clock signal rising edge (low to high transition), provided the next beat in the sequence is ‘on’. When the clock signal falling edge is received (high to low transition), the output will be switched back to low (0v). This means that the output trigger signals have the same pulse width as the input clock. So if the clocks are generated with very short pulses, the output triggers will be equally short. As a consequence, a pulse width modulation on the input clock signal will be passed on through the sequencer.

Alternating Mode

Pushing the switch down from its centre (off) position puts the sequence into Alternating Mode. In alternating mode, the output goes high on the first ‘on’ beat, and remains high until the next ‘on’ beat. In other words, the output toggles on every ‘on’ beat in the sequence. The up and down transitions occur on the rising edge of the input clock.

Reset

The centre jack can be used to connect a reset trigger. When a reset is received, both sequences restart at their first position. This takes into consideration the rotation setting: If sequence A and B have different rotations, they will remain offset in respect to each other. Reset can also be manually triggered by pushing the centre switch momentarily upwards.

Chained Mode

The centre switch can be pushed down, which enables Chained mode. When chained, the two sequences are repeated one after the other, instead of concurrently. This is very useful to build up more complex patterns. In chained mode, the output of the combined sequence is available at both output jacks. On startup, the first sequence will play through to its determined length. It will then stop, and the second sequence will play through to the end, at which point the first one starts up again. For example, setting the first sequence to length 12, and the second to length 4, will result in a combined 16-step sequence. A reset signal in Chained mode brings the combined sequence to the start of the first pattern. Rotation works as in regular mode. Chained mode can also be used to create sequences longer than 16 steps.

Hacking

Στοιχεῖα is driven by a micro controller which interfaces modular signal levels through discrete transistor networks. It functions by responding to incoming trigger signals using the MCU’s built in hardware interrupts. The step sequences are pre-calculated in the main processor loop and updated when the knobs are turned, which means that the interrupts can be processed very efficiently. This leads to a very low on/off latency.

Efficient design, solid code and good use of hardware interrupts means that Stoicheia can process clock signals well into audible frequencies.

The circuit board has a 6-pin header which brings out the serial and reset pins of the MCU. It mates with an FTDI USB TTL Serial Cable. It is compatible with 3.3v and 5v TTL levels.

The MCU is an AVR ATMega168. It is loaded with the Arduino Bootloader, and can be programmed as an Arduino Diecimila. The firmware is dependent only on avr-gcc, and on Arduino/Wiring for the optional serial debug interface."

Rebel Technology Klasmata Sequencer EURO Module

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Perfect Circuit Audio (RSS)

"The Klasmata module by Rebel Technology contains one half of the Stoichea module but with additional voltage control of two parameters and 32 steps sequence length. Just like the Stoicheia it creates rhythmical, very musical structures from an incoming clock. Perfectly suited to trigger drum voices or just for creative sequencing.

The upper control sets the start point of a sequence and also the reset point. In mid position the sequence starts at the "one". Turning the pot makes the sequence shift forwards or backwards. The control below sets the sequence length, from 1 to 16 steps. The middle control determines the number of fills i.e. how many notes from a sequence will be played.

The sequence length and the number of fills can be modulated by control voltages, the according attenautors are the two bottom controls.

The switch is used for manual stopping and resetting the sequence, on the other hand it influences the behavoiur of the sequence:

In middle position the sequence is off.
In upper position the trigger mode is activated. The sequence will switch its output high when receiving a clock signal rising edge (low to high transition), provided the next beat in the sequence is ‘on’. When the clock signal falling edge is received (high to low transition), the output will be switched back to low (0v). This means that the output trigger signals have the same pulse width as the input clock.
In bottom position you activate the alternating mode. The output goes high on the first ‘on’ beat, and remains high until the next ‘on’ beat. In other words, the output toggles on every ‘on’ beat in the sequence. The up and down transitions occur on the rising edge of the input clock.
The top jack "|<-" is used to reset the sequence to step one. Below you´ll find the socket "γ" , that´s the gate sequence output. The sockets 3 and 4 are the two CV inputs (see above) and the socket at the very bottom is the clock input.
The module is protected against reverse polarity. It needs +5V to operate"

Sound Charts for Minimoog - ELP Trilogy & Emerson's Fat Bass

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Note the listing is for a PDF scan of the sound charts and not the original. Posting this for the information and two patches below.

"This is a meticulously scanned pdf file of an original, out of print, 1974 publication of sound charts for the Moog Minimoog Synthesizer.

It is 30 pages, and contains sound charts to program classic, vintage Moog sounds.

Even if you are not fortunate enough to own the actual vintage instrument (got $3,000?), thanks to modern VST plugins from Arturia, Steinberg, GForce, and others, you can enjoy that classic analogue sound.

Using these sound sheets to program, you can have these amazing sounds that have been gathering dust since the 70’s, and since this is out of print, you can have something that not everyone else has.
It will even help you learn about synthesis technique and custom sound programming.
You will soon be able to dial up any sound you hear or can imagine.

The sounds in this collection cover a wide range of styles:
Orchestral - Piccolo, Flute, Recorder, Clarinet, Oboe, Bassoon, Trumpet, Horn, Trombone, Tuba, etc.
Progressive Rock – Emerson Lake and Palmer, Rick Wakeman, etc.
Dance, Hip Hop & House - Drum Roll, Bass Drum, Fat Bass, Jet Plane, Exploding Bomb, Siren, Whistlers, etc.

Plus, it includes a Tutorial on routing an instrument through the Minimoog, and blank patch charts for your own custom sounds"

1978 ARP AVATAR STOLEN FROM THE GODS GUITAR SYNTHESIZER 2-PAGE PRINT AD

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"When joined ad measures approx. 16"X10.5" inches."

Oberheim SEM Pro Analog Synthesizer With Modular Patch Panel SN 0772

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Interesting that the auction mentions Marion Systems which was Tom Oberheim's last synth company.

"Marion Systems SEM-Pro synthesizer expander module, signed by Tom Oberheim. This is the version with built in MIDI to CV convertor and the full modular patch panel."

There is no mention of Marion Systems on http://tomoberheim.com, but it would be interesting if his previous Marion Systems was the parent company.