Electronic Drum Synthesizer

The circuit consists of two twin-T oscillators set below the oscillation threshold. To initiate oscillation, a touch on the Touch Pad is required. The schematic diagram illustrates the circuit, where different touch patterns on the pads can create a variety of effects. Prior to oscillation, the two 25k potentiometers are adjusted to a specific point. A drum roll effect can be produced by swiftly moving a finger across adjacent ground and drum pads. This circuit is a modification of the Hartley oscillator, enhanced with additional components. It utilizes a small audio transformer, type LT700, with a center-tapped primary impedance of 1 kΩ. Incorporating a touch switch adds sophistication to the circuit, and having separate touch pads for the on and off functions enhances safety, preventing unintended actions. This is a single op-amp tone control circuit, which is a hybrid of low-pass, high-pass, and one-pole circuits featuring both attenuation and gain. This design is cost-effective due to its minimal component requirement. Additionally, a metronome circuit with a mechanical sound character is also included, which adds an elegant and enjoyable element to the project. Furthermore, a frequency-selective frequency multiplier can be constructed using a Phase-Locked Loop (PLL) system by integrating a frequency divider within the feedback loop between the phase detector input and the Voltage-Controlled Oscillator (VCO) output.

The circuit design incorporates two twin-T oscillators that operate just below their oscillation threshold, allowing for dynamic interaction through a touch-sensitive interface. The use of a Touch Pad enables users to engage with the circuit, triggering oscillation and various sound effects based on touch patterns. The adjustment of the two 25k potentiometers is critical to achieving the desired operational state before initiating oscillation. The ability to produce a drum roll effect through rapid finger movements across designated pads enhances the user experience and showcases the circuit's interactive capabilities.

The modification of the Hartley oscillator introduces a small audio transformer, specifically the LT700 type, which is integral to the circuit's functionality. This transformer features a center-tapped primary with a 1 kΩ impedance, facilitating efficient signal processing and amplification. The inclusion of a touch switch not only enhances the circuit's aesthetic appeal but also improves user safety by providing distinct on and off touch pads, thereby preventing accidental activation of opposite functions.

The single op-amp tone control circuit exemplifies versatility, as it combines low-pass, high-pass, and one-pole filtering characteristics, allowing for precise audio manipulation with minimal components. This design approach maintains cost-effectiveness while delivering quality sound control.

Additionally, the mechanical sound character of the metronome circuit adds a unique auditory element, making it an appealing feature for users seeking an elegant and enjoyable experience. The integration of a frequency-selective frequency multiplier using a PLL system further expands the circuit's capabilities. By incorporating a frequency divider in the feedback loop between the phase detector and VCO, the circuit can achieve precise frequency synthesis, enhancing its functionality for various applications.The circuit below consists of two twin-T  oscillators set to a point below oscillation. To set the circuit into oscillation, we can touch the Touch Pad. Here is the schematic diagram of the circuit: By touching the pads in different ways and a whole range of effects are available will produce different effects. Before oscillation, the two 25k po ts are adjusted to a point. We can produce a drum roll by shifting a finger rapidly across adjacent ground and drum pads. [Source: talkingelectronics. com] This is a circuit which is a modification of Hartley oscillator with the addition of several components. This circuit uses a small audio transformer, type LT700. The primary of this transformer is center tapped with an impedance of 1Kohms at Continue reading †’. Providing a touch switch can be a cool way to make your circuit looks sophisticated. Moreover, providing separate touch pad for on  and off  function improve the safety, since touching one function doesn`t trigger opposite action to what we expect Continue reading †’.

This is single op-amp tone control circuit. This circuit is a hybrid low-pass, high pass and one-pole circuits with attenuation and gain. This circuit is the solution for limits cost because it requires a minimum component. Here is the circuit Continue reading †’. This is a metronome circuit that has mechanical sound character. The metronome that has mechanical sound character will make our life more fun and it would be elegant and cool. Here is the circuit : This circuit uses two two Continue reading †’. A frequency-selective frequency multiplier can be construct with a PLL system by inserting frequency divider inside the feedback between the phase detector input and the VCO output.

Figure below shows the schematic diagram of low-frequency synthesizer with a programmable three Continue reading †’. 🔗 External reference