Notes: Advanced generative sequencer featuring mutes per channel and transposition facilities.
Akropoli is an extension and enhancement of our successful Little Melody and High Towers modules, offering the features of both of these modules as well as some of it's own unique features such as mute buttons per channel, manual transpose knob and 1V/oct transpose CV input. Akropoli operates using Frequency Central's proprietary TOOL V2 code, and can count in integers as well as multiples for even more subtle and evolving variations.
Akropoli is a generative sequencer based around clock divisions and a chromatic quantiser, used to create in-the-moment licks and riffs. It is more that the sum of it's parts.
Akropoli's internal operations can be considered as 4 clock dividers patched into a CV mixer via attenuators. The attenuators select notes over a 5 octave range, the clock dividers determine how often those notes are added to the mix. The final output of Akropoli is quantized chromatically for fast set up and continuously pleasing results. Akropoli has an onboard transposition knob, as well as a 1V/oct transposition CV input.
The 4 clock dividers are labelled A, B, C, and D. They all receive clocks from the same source, the divisions may be selected using the presets and the individual division selectors. The clock dividers can be set to count up, down, or to one of a variety of modes that move between counting up and down. For further information on Presets and Modes see the Little Melody User Guide.
Additionally, each clock divider has it's own binary output (either high or low), these 4 outputs can be used to clock/gate/trigger other stuff on other modules to great effect.
Notes: A couple of years back, Frequency Central developed Cosmic Background as a standalone percussion voice. The concept was to bundle all required sub-modules behind one panel, pre-patched, yet also fully modular, with each sub-module having its own inputs and outputs. This proved to be a very popular product, but Frequency Central decided to replace Cosmic Background's noise generator with a VCO (and do a few other tweaks), creating a cute little fully modular synth voice ripe for sequencing - and that's how Dark Star was born!
Dark Star consists of 4 sections:
Voltage Controlled Oscillator based on AS3340 with sawtooth, triangle and pulse waveforms
Voltage Controlled Filter with lowpass and highpass options, Drive control, Sweep control which attenuates amount of Release CV
Release generator with CV input for voltage control of release time. Option for sustain via jumper on rear panel.
Voltage Controlled Amplifier
Together they form a pre-patched super versatile analogue synthesiser voice.
Additionally, each section is fully modular in it's own right, so there are patch points for:
1V/oct CV input
PWM CV input - attenuator doubles as manual pulse width when no external signal is present
Gate input for Release or Sustain/Release
Release CV input for voltage control of Release time
VCF audio input with attenuator, for introducing external audio
VCF CV input with attenuator (1V/oct CV is normalised to this input)
VCA audio input (VCF is normalised to this input)
VCA CV input (Release CV is normalised to this input)
Release CV output
VCO audio output
VCF audio output
VCA audio output
Here are some useful patches to try:
Release CV output to PWM CV input, for swept PWM
VCF OUT to VCF IN, thickens and further overdrives the filtering
VCO OUT to VCF CV input, for fizzy FM of the filter
Use a multiple to patch 1V/oct to Release CV input, lower notes will have longer release, higher notes will have shorter release
5 x 5 active patchbay/matrix mixer/switcher with normal and inverted outputs and attenuators
Notes: Looking Glass is an 5 x 5 active patchbay/matrix mixer/switcher for both audio and control voltages. It features:
5 inputs (1 through to 5), each with attenuators
5 inverted outputs (A through to E) which are 180o out of phase with the inputs
5 normal outputs (A through to E) which are in phase with the inputs
A switch matrix of 25 push on/push off switches and LED status indicators
Any of the 5 inputs can be patched to any of the 5 outputs simply by pressing the corresponding switches. A patched signal will appear at both normal and inverted outputs simultaneously.
A single input can be patched to a single output. A single input can be patched to multiple outputs. Multiple inputs can be patched to a single output. Multiple inputs can be patched to multiple outputs.
The attenuators allow you to reduce the volume of an incoming signal. If you add many inputs to one output you will of course cause clipping (which may or may not be desirable!), the attenuators are your on-board way around this.
Notes: Shapes is a wide ranging and fully analogue oscillator which can perform duties as both auxilliary VCO* as well as VC-LFO. Shapes can be configured to cycle continuously, or to provide one-shot shaped outputs. When set to one-shot mode, Shapes may be used as an ersatz envelope generator.
Using the Time knob, Shapes can cycle from as low as 8 seconds (whale song) to as high as 19500Hz (bat beeps).
Shapes has 3 simultaneous outputs:
sawtooth (+/-5V, 10Vpp)
ramp (+/-5V, 10Vpp)
triangle (+/-5V, 10Vpp)
Additional waveforms may be derived courtesy of the Shape knob. Anticlockwise from 0 achieves progressively logarithmic sawtooths and ramps, whereas clockwise from 0 achieves progressively exponential sawtooths and ramps. The effect of the Shape knob on the triangle waveform is asymmetric, anticlockwise from 0 achieves progressively logarithmic leading edge, whereas clockwise from 0 achieves progressively exponential falling edge. Progressively exponential triangle waveforms can be achieved using the Time CV knob (set Shape knob to 0) providing there is no jack in the Time CV input socket
Time CV input provides wide ranging control of time. It is possible to dial in something approaching 1V/oct over a limited range, although Shapes has not been designed to perform as an accurately tracking VCO. In the audio range, Shapes comes into its own when used as a 'daughter' VCO to an external 'mother' VCO by patching the 'mother' VCO into Shapes' Gate In input socket - some impressive oscillator sync style effects can be achieved.
Gate In can also be used to initiate waveforms in one-shot mode, where a pulse of any length will cause Shapes to complete one cycle.
*Shapes has not been designed to perform as an accurately tracking audio VCO.
Notes: Chris Huggett, chief designer at EDP came up with a novel little circuit for the filter envelope of the Wasp, based around half a CD4013, half a CD4066 and half a LM3900. It was an A/R generator with looping option which would proceed through its whole cycle from only a trigger input. He further developed the circuit for the filter envelope in the Gnat to use just one knob to provide a range of attack envelopes when anti-clockwise (from 12 o'clock), and a range of release envelopes when clockwise (from 12 o'clock). 12 o'clock gives a very short symmetrical blip. As you can build two of these with a CD4013, CD4066 and LM3900, Frequency Central have provided both a two knob version and a one knob version, each has its own place.
Both envelope outputs are 0V to 5V.
All Q and not-Q outputs are 0V to 8V
Upper section cycle times: 23Hz to 20 seconds
Lower section cycle times: 8Hz to 10 seconds
Expandable 4-channel VCA based stereo mixer module - 20HP
Notes: Expandable 4 channel VCA based stereo mixer with tone shaping and FX bus.
Chipset:
For this item, Frequency Central offer a CHIPSET which contains the following:
3 x LM13700
For all other components required, please see the build document.
Features:
4 x input channels, each featuring LEVEL, HIGH, LOW, FX send, PAN, MUTE and CV control of level.
FX send and stereo return + FX phase jumper
Left and Right Eurorack level inputs (2 x 3.5mm sockets)
Left and Right line level outputs (2 x 6.35mm sockets)
Scribble strips!
Strips is also expandable! You can add a second strips, connected to the first via a 16 pin to 16 pin cable. The cable powers the second Strips and gives you 8 channels to play with. The second Strips accesses the first Strips FX bus. When using in expanded configuration, the FX send/return and main outputs for the second Strips are not available. Here's how!
FX phase jumper - because not all FX that you might use in the FX loop are in phase with respect to their input/output. The phase jumper allows you to compensate for this and avoid weird phase cancellations.
8 x 8 active patchbay/matrix mixer/switcher with normal and inverted outputs and micro-attenuators.
Notes: Wonderland is an 8×8 active patchbay/matrix mixer/switcher for both audio and control voltages. It features:
8 inputs (1 through to 8), each with micro-attenuators (which can be set with a small screwdriver)
8 buffered inverted outputs (A through to H) which are 180o out of phase with the inputs
8 buffered normal outputs (A through to H) which are in phase with the inputs
A switch matrix of 64 push on/push off switches
Any of the 8 inputs can be patched to any of the 8 outputs simply by pressing the corresponding switches. A patched signal will appear at both normal and inverted outputs simultaneously.
A single input can be patched to a single output. A single input can be patched to multiple outputs. Multiple inputs can be patched to a single output. Multiple inputs can be patched to multiple outputs.
Each input features a micro-attenuator which can be set with a small screwdriver. This space saving feature allows you to reduce the volume of an incoming signal without having to resort to external attenuators. If you add many inputs to one output you will of course cause clipping (which may or may not be desirable!), the micro-attenuators are your on-board way around this. I find it useful to leave the micro-attenuators set to 50% (which is how they come pre-set at delivery). Of course, their size is a little bit of a compromise, but they are a useful feature nonetheless. Wonderland’s sister module Looking Glass includes full size input attenuators as well as LED status indicators.
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