Leap 42.3 broken AVR toolchain after update

After a recent update the AVR Toolchain did nor longer work. It turned out that some links are missing. You can repair that easily. Login as root and then goto:

cd /opt/cross/avr

Now set the limks:

ln -s /usr/avr/sys-root/include include
ln -s /usr/avr/sys-root/lib lib
ln -s /usr/avr/sys-root/man man
ln -s /usr/avr/sys-root/share share
The toolchain should work again.

Microphone Preamplifier

Microphone Preamplifier

Microphone Preamplifier

I needed a microphone preamplifier for my Shakuhachi 2 Synth project. So i build one. The schematic follows the circuitry given in the data sheet of the SSM2019. Nothing fancy. A optional volume indicator is added. I didn’t bother with phantom power. I already have a external unit and didn’t want to go into the trouble designing something. It is on my list for future versions.

Specs and features
Simple microphone preamplifier
Optional volume indicator
Runs on +/-15V and +/-12V

The documentation for download can be found in my website.

Microphone Preamplifier schematic

Microphone Preamplifier schematic

The schematic follows the circuitry given in the data sheet of the SSM2019. Nothing fancy. A optional volume indicator is added.

Microphone Preamplifier populated PCB

Microphone Preamplifier populated PCB

Microphone Preamplifier back

Microphone Preamplifier back

Scaled Voltage Reference 1V and 83,3mV steps

Scaled Voltage Reference

Scaled Voltage Reference

This module provides high precision CV outputs in 1V (octaves) and 83,3mV (halves) steps. The 1V output goes from 0 to 8V. The 83,3mV steps goes from -5 to plus 5 steps (halves). This module is thought for all who are missing octave switches in some modules. Especially in VCO. With this module you can switch octaves and halves as well.
Specs and features
High precision output 0-8V in 1V steps (octaves)
High precision output in 83,3mV steps, +/- 5 steps (Halves)
Runs on +/-15V and +/-12V

The documentation for download can be found in my website.

Scaled Voltage Reference schematic

Scaled Voltage Reference schematic

The precision voltage is derived from the REF102. The negative voltage is provided with the INA105. It is crucial to match the resistors in the voltage dividers as good as you can. The outputs of the voltage dividers are buffered to avoid loading of the dividers. The resistors around the OpAmps must be matched as well. The one volt and the 83,3mV steps are added together with IC4A. The three outputs are individual buffered.

Scaled Voltage Reference populated PCB

Scaled Voltage Reference populated PCB

Scaled Voltage Reference back

Scaled Voltage Reference back

Buffered Multiple

Buffered Multiple

Buffered Multiple

This is an useful and often needed utility module. It comes in handy when you need to distribute signals which must be decoupled. The input signal is buffered and decoupled with means of individual operational amplifiers. One input drives 5 individual outputs. The signaling of the PSU rails is optional. I use at least one of this modules in every case to see if something went wrong with the PSU.

Specs and features
Three buffered multiple 1 in, 5 out
Optional PSU signaling
Runs on +/-15V and +/-12V

The documentation for download can be found in my website.

Buffered Multiple schematic

Buffered Multiple schematic

Straight forward design. The input signal is buffered with five independent buffers and split in five decoupled outputs.

Buffered Multiple populated PCB

Buffered Multiple populated PCB

Buffered Multiple front

Buffered Multiple front

Logic Module

Logic Module front

Logic Module front

I needed a module to combine gate and/or trigger events for steering sequencers, ADSR and other gear. So I build one. This one here has and, or, ex-or and neg logic gates. The states of the inputs and output are signaled with LED. The inputs takes audio as input as well. This makes for some interesting patches. The minimum input level can be set to your needs.

The documentation for download can be found in my website.

Logic Module schematic p. 01

Logic Module schematic p. 02

Logic Module schematic p. 02

Logic Module populated PCB

Logic Module populated PCB

Logic Module back view

Logic Module back view

Clock Divider 2-8

Clock Divider 2-8 front view

Clock Divider 2-8 front view

This clock divider divides the incoming clock signal down to /2, /3, …. /8. The output is a 5V positive pulse. The length of the incoming pulse is kept. The trigger is on the rising edge of the incoming signal. The reset input can be used for syncing with other clocks. All outputs are buffered and brought out parallel with LED signaling the pulse.

The documentation for download can be found in my website.

Clock Divider 2-8 schematic

Clock Divider 2-8 schematic

Most work is done by the microprocessor. The micro takes care of the input and output timing. All outputs are independently buffered. The clock is made visible with LED.

Clock Divider 2-8 back view

Clock Divider 2-8 back view

BPM Generator

BPM Generator module back

BPM Generator module back

The BPM Generator give you +5V pulses output with 20ms length, from 40 to 240 beats per minute. Controlled by a microprocessor. The BPM are displayed with three 7 segment LED. The speed is adjusted with an rotary encoder.

The documentation for download can be found in my website.

BPM Generator module schematic main

BPM Generator module schematic main

Most work is done by the microprocessor. The micro takes care of the output timing and the multiplexing off the display. All four outputs are independently buffered.

BPM Generator module schematic display

BPM Generator module schematic display

BPM Generator module front

BPM Generator module front

Modulation Sequencer

Modulation Sequencer populated PCB

Modulation Sequencer populated PCB

This is a small easy to use and easy to build sequencer. The sequence is adjustable from 2 to 8 steps. The output range is switchable from 0..1V to 0..5V. So you can cover 1 or 5 octaves. The sequencer is clocked from an external source. The clock range goes from very slow (LFO) to way above the audio range. When used in the audio range you can realize quite interesting envelope patterns. With the reset input you can start and reset the sequence. This is useful for creating a gated repeating pattern. Many more applications are possible.

Specs and features
2..8 steps
Switchable output 0..1V, 0..5V
Clock input
Reset input
Positive and negative output
Runs on +/-15V and +/-12V (with minor changes)
Power consumption below 10mA each rail

The documentation for download can be found in my website.

Modulation Sequencer schematic

Modulation Sequencer schematic

The sequencer is build around the decimal counter 4017. The clock and reset input needs at least 1/2 off the positive supply voltage to trigger. Therefore the inputs are amplified (IC5C, IC5D, IC1) so you can run the sequencer with lower input voltages. The input circuitry also protects against negative input voltages which are not allowed for the 4017. With the rotary switch you can select the length of the sequence. The rotary switch selects the output which is feed to the reset input of the 4017. The outputs are buffered with the transistors Q1 ..Q8. The emitters are connected to potentiometers which adjust the output voltage. The transistors are driving the LED for the step display as well. The output is buffered with the operational amplifier IC5B. IC5A provides the negative output.

Modulation Sequencer back view

Modulation Sequencer back view

Modulation Sequencer front

Modulation Sequencer front

36dB VCF LP/HP

36dB VCF LP/HP populated PCB

36dB VCF LP/HP populated PCB

I just wanted to know how a 36dB VCF sounds like. So i build one. This one is basically derived from my 24dB VCF LP/HP which i build for my Next Generation Formant project. I just added two more filter stages and the compensation circuitry from my Moog Ladder filter to compensate for the volume loss when Q is turned up. I have brought out all 6 filter stage outputs. Depending on your wiring you can use a switch to select between the outputs or/and bring all outputs out in parallel. The LP/HP switching is done with electronic switches on the PCB to avoid the problems (hum, noise…) of the wiring with a mechanical switch.

Specs and features
36dB voltage controlled low pass and high pass filter
Switchable output 6dB, 12dB, 18dB, 24dB, 30dB, 36dB
Volume loss compensation with high Q
10Vpp signal level
Voltage controllable Q
Voltage controlled lin and log timbre modulation
Positive and negative ENV control with sign changer
Runs on +/-15V and +/-12V (with minor resistor changes)
Power consumption below mA each rail
Volume indicator (optional)

The documentation for download can be found in my website.

36dB VCF LP/HP schematic page one

36dB VCF LP/HP schematic page one

Straight forward design. Six state variable filter cells are connected together in series, The output of each filter cell is brought out. There are a lot descriptions of those state variable filters out there. I feel no need to add another one. The resonance (Q) is voltage controlled with means of the OTA IC16OTA2 in the upper right corner (page 1). To compensate the volume loss when the resonance (Q) is turned up a second OTA (IC16OTA1) is used. This two OTA shares the same Iabc source. The amplification of this second OTA is increased when Q is going high and add volume to the output signal (See page 2 of the schematic).

36dB VCF LP/HP schematic page two

36dB VCF LP/HP schematic page two

36dB VCF LP/HP module back view

36dB VCF LP/HP module back view

36dB VCF LP/HP module front

36dB VCF LP/HP module front

NGF AC/DC Mixer: flat Version

NGF AC/DC Mixer front

NGF AC/DC Mixer front

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.
Most noticeable change is moving to a “flat” design. The depth of the module is significantly reduced and most important no more potentiometer wiring is needed!

The documentation for download can be found in my website.

NGF AC/DC Mixer schematic

NGF AC/DC Mixer schematic

Straight forward design. The mixer is completely DC coupled. So you can use it for CV mixing as well as audio mixing. IC1A sums the four inputs. P5 is used to adjust the overall signal level. The level indicator is build around IC2. A precision full wave rectifier followed by two comparators to indicate the high an low level

NGF AC/DC Mixer side view

NGF AC/DC Mixer side view

NGF AC/DC Mixer populated PCB

NGF AC/DC Mixer populated PCB