FONITRONIK

Older Synth Suff

2011-06-06T02:29:00.000-07:00

Now that i am on the blog again i decided to post some pics of my older Synth-DIY projects. These are mainly some cabinets containing modular stuff. Enjoy.

My 1st cabinet, built in 2005:

When i started with with electronics in 2005 i bought myself a realy cheap soldering iron, and the first project i built was the Psycho LFO from Ken Stone. I did not want to spend too much money, just in case i would not get the designs working (as an absolute beginner), so i stuck with Ken Stones CGS and Tom gambles EFM projects, which have been affordable for me.
So this 1st cabinet is filled mainly with modules from those PCBs (from left to right, top to bottom):

EFM RXCV midi2CV converter
CGS Psycho LFO
EFM dual VCO 3D
CGS Wavemuliplier
dual CGS DC Mixer
EFM dual VCA 6B
EFM dual ADSR 2A
EFM VC LFO 5A
dual CGS real vintage Ringmod/ Multiples
fonitronik passive Attenuators Module
fonitronik digiFX I Modul
Polivoks VCF clone
dual MFOS 12db Statevariable VCF

Breakdown Filter redux

2011-06-06T02:25:00.000-07:00

The Breakdown Filter Module finally made it into a new housing. This is a 10U mixer rack case. i made a 4U panel for the breakdown filter together with my simple divider, an attenuverting mixer, and the PSU.

As you can see there is plenty of room for more modules... We will see what comes next.

Red Dimension Chorus (DIM-C Clone)

2011-06-06T02:20:00.000-07:00

This is my version of the DIM-C aka Lush deluxe Chorus. It is a MN3202 based stereo chorus. I left off the preset settings, and added a blue LED indicating the internal LFO control voltage.

it is realy nice and warm sounding, however, i think i will have to tweak the depth control and the LFO range selection...

Ace Tone Rhythm Ace FR-3

2010-05-10T00:32:00.000-07:00

This is an old Preset Drummachine from the late 60ies. I completely dismantled the unit and thoroughly cleaned it. Now it shines like a new penny!?

This unit has been sold as Roland TR-33 in 1972. It is used LC based technology. I hope to add master trigger in and out soon (even a MIDI clock in). May be there will be a breakout box for single trigger in and out later).

Attenuverting Mixers

2010-04-27T03:49:00.000-07:00

The Fonitronik Attenuverting Mixers are coming...

VCPS-8 Sequencer

2010-03-29T01:33:00.000-07:00

This is the 1U version of my VCPS8 Module: a 8-step sequencer with voltage controlled patterns. An 8-bit ADC is controlling the stages of a 4017 based sequencer, however the ADC data can alway be overwritten by manual seetings.

Breakdown Filter

2009-12-03T14:02:00.000-08:00

this is another project i am currently working on. you know this VST fx 'breakdown' filter? this is the analogue version of it, or at least an early stage of a prototype.

what is it? what does it do? it is eight (8!) analogue voltage controlled filters, each providing cut-off, resonance, mode (lowpass, bandpass, highpass) and pan control. for each filter there is an attenuator for external CV.
a mainboard serves as I/O: incoming audio gets subsequently switched to the eight filters. the steps are controlled by an external LFO or manual step. an additional external CV is routed to all filters.
so you have a different filter for each step - audio stepping through multimode filters...
i am currently working on a new I/O board, since the current one uses just switches to distribute the audio. that causes 'clicks' when stepping from one filter to the next. the new board will use AR generators to control 8 VCAs. we will see...

Jim Patchell's Vocal Filter

2009-12-01T15:30:00.000-08:00

this s the fully featured vocal filter i built from jim patchells layout. it provides 3 channels of VC shapers for the control voltages, VCFs and VCAs. the audio signal gets fed into all three filter (each filter providing LP and BP at the same time). the 6 outputs of the filters go to the 6 VCAs, which fed the summing stage.

the trick are the control voltage shapers. they modify the incoming control voltages with 4 breakpoints (voltage controllable) to attenuate certain frequencies. with carefully trimming you could use the unit as vowel filter, speaking i.e. 'A' - 'O' - 'U'...

the unit really needed this big cabinet, since the PCB is really huge... however, i like this monster. it sounds really good as resonator!

1st post - Attenuverting Mixer

2009-12-01T14:53:00.000-08:00

so i thought it would be good to first post a picture of what i am working on right now.

it s an 4-channel attennuverting mixer. each channel attenuates the input signal from inverted gain 1 to zero to non-inverted gain 1. each input is normalled to +5V, each single out is normalled to the summing stage. this way one could use 2 channels for mixing audio and simultanious use the 2 spare channels for attenuvertion. the summing stage is switchable from DC coupled (LEDs indicate the positive and negative excursions of the signal) and AC coupled (audio signal will be centered to zero volt).

this mixer is for common control voltage and audio. it is not 100% unity-gain, so it will not be suitable for 1V/oct keyboard control voltages.

it will draw approx. 20mA on the negative, and 30mA on the positive rail. it can be powered from -12V/+12V or -15V/+15V. it followes the 'eurorack' form factor.