Motivation

I have build my first synthesizer end off the 70’s out of a kit which was based on the schematics from Elektor, a German DIY electronics magazine. This synthesizer was called “Elektor Formant”. This was way before the Internet gave us access to so many resources. Nearly everything has to be ordered via mail order. Or bought in shops if you was lucky enough to life nearby. The only resources then were some magazines or rare books. While life went on the building stopped. The synthesizer was stored away in a closet.

Some five years ago I started to restore my original Elektor Formant and got it working. Over the last years I build a lot of more modules from other sources first on strip-board and now on PCB. Mostly my own designs inspired by many fellow SDIY builders. I have done some bigger projects like Shakuhachi to Synthesizer which enables the Shakuhachi player to steer the synthesizer from the flute, or a 24 Band Vocoder.

Now it is time for another bigger project. Over the years I heavily modified my original Elektor Formant to enhance the performance, usability and add new features. This was done partly on the original Elektor Formant PCB or with additional circuitry on strip board. The additional functions leads to more knobs and plugs on the front panels. That means new face plates. And so on.

Finally I decided to build a complete new analog synthesizer to put all features and enhancements in it. All analog with PCB’s and today (end 2016) available parts, staying as close as possible to the original Elektor Formant. Here are the corner points:

In the course of this project I will describe all changes that I made to the original Elektor Formant as well. Those will show up in the Elektor Formant Mods section on my website.

Sitelist

Current state

NGF Current state

NGF - Modules (First book)

NGF VCO Core 1

NGF VCO Core one

NGF VCO Core 1

Top

Current state: Published

NGF VCO Core one is for those lucky people which have some spare uA726 left or want to sacrifice on original Elektor Formant VCO. This VCO contains all changes and extensions i added over the years to the original Elektor Formant VCO in one PCB. I left out the waveshaper section here for a more flexible design. The waveshapers will be part of another PCB. Anybody who wants to build this implementation should be aware that i use some obsolete parts here (uA726 and 74LS13). They are still accessible but it will take some research, afford and money to get hold of them. I removed the need for the +5V current supply, added an octave switch, FM lin, stabilized all internal control voltages, sync in and the improvements suggested in the second Format book. The signal level is raised to 10Vpp to get a better SNR throughout the system.

NGF VCO Core 2

NGF VCO Core two

NGF VCO Core 2

Top

Current state: Version 1.0.1 (Stand alone Version) tested and working.

Current state: Version 1.1.0 (NGF Version) published

NGF VCO Core 2 is my second implementation of the original Elektor Formant VCO with today (2017 March) available parts. I kept the heated exponential converter and the Schmitt Trigger to stay as close as possible to the original. The uA726 is replaced with LM3046 and the 7413 with 4093. All internal control voltages are stabilized. I removed the need for the +5V current supply, added an octave switch, FM lin and sync in. A new feature is the LFO switch.The signal level is raised to 10Vpp to get a better SNR throughout the system.

NGF E Waveshaper

NGF E Waveshaper

NGF E Waveshaper

Top

Current state: Version 0.9.5 (Stand alone Version) published.

Current state: Version 1.1.0 (NGF E Version) published

The waveshaper provides the same waveforms as the original Elektor Formant. But the circuitry is changed to make use of better performing implementation and up to date OpAmps. The signal level is increased to 10Vpp for better SNR. Wiring options are added as well.

VCO E

VCO E

Top

Current state: Done - Next: To be published

This is a combination of VCO Core two and the waveshaper behind one faceplate. Build for my mobile Next Generation Formant (NGF).

VCF 12dB Multimode

VCF 12dB Multimode

VCF 12dB Multimode

Top

Current state: Version 0.9.0. PCB stuffed and tested working - Next: To be published

Current state: Version 1.0.1. (NGF Version) published - Next: ---

This is my implementation of the original Elektor Formant 12dB Multimode Filter. It uses today (April 2017) available parts. LM13700 are used instead of the 3080. The FET buffers are replaced with OpAmps. I added some useful features i added over the years to the original. Voltage controlled feedback (Q), linear timbre modulation, external inputs, level control indicator, wiring options for internal or external CV and advanced ENV handling for HP/LP use. All internal wiring options are kept.

VCF 24dB HP/LP

VCF 24dB HP/LP

24dB LP / HP

Top

Current state: Version 0.9.0 PCB Published

This is my implementation of the original Elektor Formant 24dB HP/LP Filter. It uses today (Nov. 2016) available parts. LM13700 are used instead of the 3080. I added some useful features i added over the years to the original. Voltage controlled feedback (Q), linear timbre modulation, external inputs, level control indicator, wiring options for internal or external CV and advanced ENV handling for HP/LP use. All internal wiring options are kept. The HP/LP switch is replaced with DG914 switches to avoid the problems with to long cables for switching.

VCA

NGF-E Project: VCA

VCA

Top

Current state: Done.

My Implementation of the Elektor Formant VCA. The internal structure of the original VCA is kept. It uses today (Aug. 2017) available parts. LM13700 ar used instead of the 3080. Better OpAmps and higher signal level gives better SNR and overall performance. A level indicator is added. Internal wiring options are kept.

NGF-E ADSR

NGF ADSR

NGF ADSR

Top

Current state: Version 2.0.1 published - Next: ---

My implementation of the Elektor Formant ADSR. The original has had problems when used with sequencers. This is corrected. The output level was a bit an the low side. It never reached 5V. This is corrected as well. I added a switch to change the duration of the envelope between fast, middle and slow for better performance. Other additions are single shot switch, internal/external gate wiring option and a optional correction of the output level.

NGF ADSR with Controller

NGF ADSR with Controller

NGF ADSR with Controller

Top

Current state: Version 1.0.0 published - Next: ---

My Implementation of the Elektor Formant ADSR with the ADSR controller of the second book on one PCB.

Mix Out (COM)

NGF-E Project: Mix Out (COM)

Mix Out (COM)

Top

Current state:Version 1.0.1 published - Next: ---

This module is the replacement for the Elektor Formant COM Module. All functions are kept, but the circuitry is different. Some additional inputs are added for mixing which proved useful over the years. A level indicator is added as well.

LFO

NGF-E Project: LFO

LFO

Top

Current state: Version 1.1.0 published

This implementation follows closely the original with some minor changes. It provides triangle, ramp up, ramp down and square wave output (-5V to +5V)

Noise

Noise

Noise

Top

Current state: Version 1.0.1 Published

This is the noise module for my Next Generation Formant project. It is a combination of two original Elektor Formant modules. The Noise module from Elektor Formant book one and the Coloured Noise (CNC) module from book two. It provides a white noise output, a fixed coloured noise output, a variable coloured noise output "red" "blue" and a random voltage output.

PSU

PSU Basic LM350

PSU

Top

Current state: Using Basic PSU with LM350

No special site planned. Just take two Basic PSU350 and daisy chain them and you are done.

Scanner Keyboard

Links and Picture

Top

Current state: Working protototype

I have build a working prototype of a scanner keyboard using the original Elektor Formant keyboard with Kimber Allen contacts. Needs more work.

Keyboard electronic

Links and Picture

Top

Current state: Working protototype

I have build a working prototype of a scanner keyboard using the original Elektor Formant keyboard with Kimber Allen contacts. Needs more work

Keyboard Interface

Keyboard Interface

Top

Current state: To be published

I added a intern/extern option to the original Elektor Formant implementation for use with a sequencer.

Housing

NGF Housing

NGF Housing

Top

Current state: published

First step of the Next Generation Formant Project was the housing and the PSU. I want my Elektor Formant based clone to be portable. Therefore I ordered a custom made 19’’ flightcase, build to my specifications. The enclosure holds four rows of modules in Eurorack format. As PSU two of my basic PSU with LM350 are used.

NGF - Modules (second book)

Digital Noise

Digital Noise

Digital Noise

Top

Current state: ---

I did not build the original digital noise of book two. Instead you can use the digital noise from my Vocoder Project. I prefer the analog one though.

Coloured Noise

Noise

NGF E Noise

Top

Current state: Version 1.0.1 published (Noise Module)

No extra implementation planned. See NGF Noise.

RFM

RFM

RFM

Top

Current state: published - Next: ---

My implementation of the RFM Module follows closely the original Elektor Formant RFM with minor changes.

Dual Ringmodulator

Dual Ringmodulator

Dual Ringmodulator

Top

Current state: Version 1.0.1 Published

I was a bit hesitant doing this module because it uses the now obsolete LM1496 balanced modulator-demodulator. But you can still source them and I have some in my stock. So I decided to make a PCB and module for my Next Generation Formant project. I started with the original Elektor Formant schematic published in "Formant Erweiterungen" p35ff. I left out the microphone and envelope follower part because I already have such modules. I have added input buffers and raised the signal level to my 10Vpp used throughout my system. I was able to put two ringmodulator on a 50x100mm PCB.

Phase shifter

Links and Picture

Top

Current state: ---

I owned one and it did not convince me. The Elektor Formant Phaser used the now obsolete BF245C. No future plans in the moment.

ADSR Controller

ADSR with controller

ADSR with controller

Top

Current state: Published (NGF ADSR with controller).

No extra implementation planned. See NGF ADSR with controller.

VC-LFO

Links and Picture

Top

Current state: ---

No extra implementation planned. The NGF VCO Core 2 is capable of going down to the LFO range.

LF-VCO

Links and Picture

Top

Current state: ---

No extra implementation planned. The NGF VCO Core 2 is capable of going down to the LFO range.

Envelope Follower

Envelope Follower

Envelope Follower

Top

Current state: V. 1.1.0 published

My implementation of a envelope follower was done for my Shakuhachi to Synth project. It did not follow the Elektor Formant implementation.

Dual Sample and hold

Dual Sample and hold

Dual Sample and Hold

Top

Current state: V. 1.2.0 published

Storing analog signals is a often used function in analog synthesizers. This sample and hold implementation follows closely the original Elektor Formant version of Book 2 "Formant Erweiterungen" p84ff. Because I use the LM13700 here as replacement for the CA3080 I have build a dual sample and hold version. The PCB size is reduced from 100x160mm for a single version to 50x70mm for the dual version.

Waveform Processor

Elektor Wave Processor

Elektor Wave Processor

Top

Current state: published

My implementation of the Waveform Processor Module follows closely the original Elektor Formant Waveform Processor with minor changes. A small but very versatile module. It is derived from the original Elektor Formant book "Formant Erweiterungen" p87 ff. Some resistor values are changed to handle the 10Vpp signal level of my system. You can shape the input signal in many ways. You can clip the signal. You can fold the signal. You can emphasize the third harmonic. You can unsymmetrical emphasize the clipped and unclipped signal. You can reverse the input signal. The clipping level is voltage controlled.

Mixer

Mixer

Mixer

Top

Current state: published

I wanted to have a DC coupled mixer capable of mixing control voltages. It did not follow the Elektor Formant implementation.

440CPS

440CPS

440CPS

Top

Current state: published

The original Elektor Formant implementation needed regularly recalibration. This is a very different implementation using a microprocessor.