This is the 12V Euro version of my NGF dual version. 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. 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.
Specs and features
Quad Ringmodulator
10Vpp input and output
Runs on +/-12V and +/-15V
Power consumption around 70mA each rail
The documentation and the Gerber files for download can be found in my website.
This scanning mixer is derived from the work of Jürgen Haible and Don Tillman with a lot off additions, changes and expansions.. The mixer is able to scan through four inputs with variable depth ans position. Manually and CV controlled. You can overdrive the individual channel nicely to add some overtones per channel. Rate, depth and scan amount are voltage controllable. The mixing level is controlled with sliders and voltage controllable as well. The four channels are summed into an output channel with similar controls.
The scanning mixer comes in two flavours linear and logarithmic. The linear scan gives a more smooth transition between the channels. The logarithmic scan gives a steeper separation between channels. All channels are DC coupled. So you can get interesting slowly moving CV textures when slowly scanning through different LFO outputs. When the depth potentiometer is set to zero you can use this module as simple voltage controlled mixer
Specs and features
Four input channels
DC coupled
Overdrive per channel
Variable scan depth and position
Voltage controlled rate, depth and scan amount
Mixing level voltage controllable
Power consumption below 80mA each rail
The documentation and the Gerber files for download can be found in my website.
There are to much schematic to post here. Please refer to my website. Only pictures here.
This is a 4 x 4 matrix mixer with switches for unipolar/bipolar mode for each column. Unipolar means that the controls work as attenuators. Bipolar means that the controls work as attenuverters. In this mode the amplification is zero in the middle position of the corresponding potentiometer. Turning the knob counterclockwise from the center position the signal is subtracted from the output sum. Turning the knob clockwise from the center position the signal is added to the output sum. The module is DC-coupled and can be used for audio and control voltage mixing.
Specs and features
4×4 Matrix
Switchable unipolar or bipolar mode
Power consumption below 30mA each rail
The documentation and the Gerber files for download can be found in my website.
This is basically a combination of 6 VCA configured as a mixer. The five inputs can be used as individual linear VCA or as input channels to the mixer output. All five input channels and the mixer output are voltage controlled. The control voltage inputs for the input channels are normalized so you can modulate all five channels with the same control voltage or group them to your needs. The sliders controls the amount of the modulation per channel. The inputs are normalized as well. This makes for a nice voltage controlled overdrive when used. A level indicator shows the output signal at the summed output. The summed output is voltage controlled as well. Instead of the here used CA3280 (I am using up some NOS) you can use the new available AS3280.
Specs and features
Five voltage controlled inputs
Five independent VCA
Voltage controlled output
Level indicator
Power consumption around 75mA each rail
The documentation and the Gerber files for download can be found in my website.
On the schematics you can see 6 VCA with linear control current sources. Just as it is done over and over again. Plenty explanations on the web.
It is mostly sufficient to mix only two or three audio or control voltages together to enhance your sound or the sound animation. So this small mixer comes in handy for mixing CV sources and audio sources as well. This version is DC coupled, so you can use it for AC and DC mixing. There is an inverted output added. You can reverse the DC-CV mix with it or experiment with feedback loops in the audio domain.
Specs and features
Three inputs
Inverted and non- inverted output
Runs on +/-12V and +/-15V
Power consumption below 20mA each rail
The documentation and the Gerber files for download (link) can be found in my website.
This is an often used utility module. The mixer comes in handy for mixing CV sources. The mixer is DC coupled, so you can use it for DC and AC mixing. The input impedance is constant 1MOhm. The input signals are amplified by a maximum factor of two. It is possible to offset every input with +/- 5V. The offset is signaled with LED’s for every channel and for the summing output. The outputs are normalized, so you can remove selected channels from the output mix. The summed output has a -6dB switchable attenuator. There is an inverted summed output added as well. The added volume indicator us useful for finding the appropriate signal level.
Specs and features
Three inputs, three outputs
Inverted and non- inverted summed output
2x amplification
+/- 5V offset for every channel
-6dB switch
Volume indicator
Normalized outputs
Runs on +/-12V and +/-15V
Power consumption below 20mA each rail
The documentation and the Gerber files for download can be found in my website.
Control board: Straight forward design. The mixer is completely DC coupled. So you can use it for CV mixing as well as audio mixing. IC1B,C,D buffers the three inputs and and keeps the input impedance constant. P2, P4, P6 sets the amplification from zero to 2X. P1, P3, P5 sets the offset voltage. The LED indicates the offset and signal level.
Main board: IC3B, IC4B, IC6B adds the offset voltage and the signal. IC1C, IC1D, IC1B, IC1B drive the low current LED. IC2A sums the signals and drives the negative output. IC2B drives the positive output.
This is an often needed utility module. The mixer comes in handy for mixing CV sources and audio sources as well. This version is DC coupled, so you can use it for AC and DC mixing. There is an inverted output added. You can reverse the DC-CV mix with it or experiment with feedback loops in the audio domain. The added volume indicator us useful for finding the appropriate signal level. The volume indicator is optional. You can leave it out with no problems for the other functions.
Specs and features
Five inputs
Inverted and non- inverted output
Volume indicator (optional)
Runs on +/-12V and +/-15V
Power consumption below 20mA each rail
The documentation and the Gerber files for download can be found in my website.
Control board: Straight forward design. The mixer is completely DC coupled. So you can use it for CV mixing as well as audio mixing. IC1D sums the five inputs and inverts the signal. P3 is used to adjust the overall signal level. IC1B inverts the signal again. IC1C and IC1A buffers the outputs.
Level indicator: The circuitry around IC2 build an precision full wave rectifier. The output is smoothed with C1. The parts around the BC560C build a constant current source for driving the LED’s. The comparator LM393 (IC1A/B) switches the LED on and off according to the input level.