super psycho

Description: The schematic of the updated power filtering on the R2 PCBs. One of each of the 100n capacitors could be replaced with 10n, or even 220pF to improve the spread of response times to spikes. The Super Psycho Modulation Source is a fairly simple circuit with a lot of repetition. The circuit consists of several distinct blocks. The first are the oscillators, each based on a section of a 40106 hex Schmitt inverter and their associated components. The switch allows extra capacitance to be added, reducing the speed of the oscillator to a lower range. The same switch allows the capacitor to be bypassed to the negative rail via a protection resistor, disabling the oscillator, and setting its output to near 0 volts. The 1M pots specified allow the upper frequency range to extend over a large portion of the audio spectrum, and in the lower frequency position, to extend from sub-audio to low audio frequencies. Two of the oscillators are equipped with voltage followers that follow the roughly triangular shape of the wave present on the oscillator capacitors. The 100k and 470k resistors on the output, when coupled to the virtual ground summing node of the following mixer, via the switch, correct the amplitude and offset of the triangle wave. The next block is a traditional op-amp inverting mixer stage. Signals from the six oscillators are mixed through 470k resistors, the overall gain controlled by a 100k pot in the feedback path of the op-amp. What is interesting here is that in order to keep the output signal of the mixer positive without the need for an additional inverting stage, the chip used to build the six oscillators is powered from the negative rail, its positive power pin connected to 0V and its earth pin connected to -15V. Take special note of this, because it is an unusual way to power a digital chip, and inadvertent poking with a logic probe powered from the positive rail could cause issues. The final stage is a simple glide circuit consisting of a potentiometer, a capacitor, and a unity gain voltage follower. The switch allows easy switching in and out of a preadjusted glide setting. It can be omitted, and a link soldered in its place on the circuit board. The component overlay for the VER2.1 PCB is available for printing at 300dpi. Due to a manufacturing error, the overlay on one version of these PCBs has become cluttered. There is also a basic emitter follower LED driver on this version of the PCB. LA = LED anode. LK = LED cathode. LD = LED drive. Connect LD to the output jack to monitor the output of the module, or omit the components if not needed. Before assembly, check the board for etching faults, looking for shorts between tracks or open circuits due to over-etching. Sand the edges of the board if necessary to remove any splinters or rough edges. Once the board is confirmed to be free of faults, assembly can proceed starting with the resistors, followed by the IC sockets, and then the taller components. Care should be taken with the orientation of polarized components such as electrolytics, LEDs, transistors, and ICs. The board is arranged to allow each oscillator connection to run through a 0.1-inch pitch plug and header if desired. When inserting ICs into their sockets, care must be taken to avoid bending any pins. The notch on the chip should align with the notch marked on the PCB overlay. When switching the oscillators with triangular outputs off, it is advisable to switch their outputs to square wave to prevent an offset voltage from being introduced into the mixed output.

The circuit schematic of the updated power filtering on the R2 PCBs incorporates several significant features aimed at enhancing performance and usability. The initial stage involves the oscillators, which utilize a 40106 hex Schmitt inverter. This configuration allows for the generation of diverse waveforms, with the option to modify capacitive values to influence the response characteristics. By substituting one of the 100nF capacitors with either a 10nF or 220pF capacitor, the circuit can achieve a broader range of response times to voltage spikes, thereby improving stability.

The oscillators are designed with a switch that enables the user to add extra capacitance, effectively lowering the oscillator speed to target specific audio frequency ranges. This switch also facilitates the bypassing of the capacitor to the negative rail through a protection resistor, which disables the oscillator and sets the output to approximately 0 volts, offering flexibility in modulation control.

A notable aspect of the design is the inclusion of voltage followers connected to two of the oscillators, which help to maintain the triangular waveform shape present on the oscillator capacitors. The output stage employs 100k and 470k resistors to adjust the amplitude and offset of the triangle wave before it is mixed in the subsequent op-amp inverting mixer stage. This mixer combines signals from six oscillators, with the overall gain being adjustable via a 100k potentiometer in the feedback path.

An unconventional power configuration is employed for the oscillators, where the chip is powered from the negative rail, with the positive power pin connected to 0V and the ground pin connected to -15V. This unique setup ensures that the output signal remains positive without necessitating an additional inverting stage, although it requires caution when probing with logic tools to prevent potential damage.

The glide circuit at the final stage consists of a potentiometer, a capacitor, and a unity gain voltage follower, with a switch for toggling between glide settings. The design allows for straightforward assembly, with detailed instructions emphasizing the importance of checking for etching faults before proceeding. The board layout supports modular connections for oscillators, enhancing the circuit's adaptability for various applications in audio synthesis and modulation.The schematic of the updated power filtering on the R2 PCBs. One of each of the 100n capacitors could be replaced with 10n, or even 220pF to improve the spread of response times to spikes. The Super Psycho Modulation Source is a fairly simple circuit with a lot of repetition. The circuit consists of several distinct blocks. The first are the oscil lators, each based on a section of a 40106 hex schmitt inverter and their associated components. The switch allows extra capacitance to be added, reducing the speed of the oscillator to a lower range. The same switch allows the capacitor to be bypassed to the negative rail via a protection resistor, disabling the oscillator, and setting its output to near 0 volts.

The 1M pots specified allow the upper frequency range to extend over a large portion of the audio spectrum, and in the lower frequency position, to extend from sub-audio to low audio frequencies. Two of the oscillators are equipped with voltage followers that follow the the roughly triangular shape of the wave present on the oscillator capacitors.

The 100k and 470k resistors on the output, when coupled to the virtual ground summing node of the following mixer, via the switch, correct the amplitude and offset of the triangle wave. The next block is a traditional op amp inverting mixer stage. Signals from the six oscillators are mixed through 470k resistors, the overall gain controlled by a 100k pot in the feedback path of the op amp.

What is interesting here is that in order to keep the output signal of the mixer positive without the need for an additional inverting stage, the chip used to build the six oscillators is powered from the negative rail, it`s positive power pin connected to 0V and its earth pin connected to -15V. Take special note of this, because it is an unusual way to power a digital chip, and inadvertent poking with a logic probe powered from the positive rail could cause you grief!

The final stage is a simple glide circuit consisting of a potentiometer, a capacitor and unity gain voltage follower. The switch is to allow easy switching in and out of a preadjusted glide setting. It can be omitted, and a link soldered in its place on the circuit board. The component overlay for the VER2. 1 PCB. Click here for an enlarged, printable version. Print at 300dpi. Due to a manufacturing error, the overlay on one version of these PCBs has become cluttered. Print this out to assist with assembly. There is also a basic emitter follower LED driver on this version of the PCB. LA = LED anode. LK = LED cathode. LD = LED drive. Connect LD to the output jack so you can monitor the output of the module, or simply don`t install the components if you don`t need it.

Click here for old version of overlay. Before you start assembly, check the board for etching faults. Look for any shorts between tracks, or open circuits due to over etching. Take this opportunity to sand the edges of the board if needed, removing any splinters or rough edges. Most likely you will find no faults. When you are happy with the printed circuit board, construction can proceed as normal, starting with the resistors first, followed by the IC sockets if used, then moving onto the taller components.

Take particular care with the orientation of the polarized components, the electrolytics, LEDs, transistors and ICs. Most likely the LEDs will be panel mounted. I have arranged the board so that connections each oscillator can be run through a 0. 1 inch pitch plug and header if desired. When inserting the ICs in their sockets, take care not to accidentally bend any of the pins under the chip.

Also, make sure the notch on the chip is aligned with the notch marked on the PCB overlay. When switching the oscillators with triangular outputs off, it is best to switch their outputs to square wave, as otherwise an offset voltage will be introduced into the mixed output. If you have separate digital and analog p