- Boost Your MP3 Power: 32 Ohm Amplifier Circuit
- Build Your 9V Bass Booster Circuit Diagram
- Build Your 20dB Audio Booster Circuit Diagram
- Symmetrical Class A Preamplifier – Build Your Audio Masterpiece
- Build Your Perfect Symmetrical 4 Channel Amplifier Circuit
- Build Your Ideal Buffer: Class A Circuit Diagram (560Ω)
- Discrete Preamplifier Circuit Diagram
- Build Your Own: Microphone Preamplifier Circuit (2mA)
- Stereo Preamplifier Circuit: Build Your +16dB Bass Boost
- Phono Preamplifier Circuit Diagram: 47K, 6.8K, 47nF Build!
- Modular Preamplifier Switching Center: Build Your Stereo Chain
- Portable Microphone Preamplifier Circuit Diagram – Build Your Own!
- Build Your Own Phono Preamplifier Circuit (18V)
- Amplify Signals: 741 Op-Amp Stethoscope Circuit Diagram
- Turn Speaker into Microphone: Build Your 6-12V Circuit
Modular Preamplifier Switching Center: Build Your Stereo Chain
Description
This unit can represent a crucial addition to the Modular Preamplifier Control Center when multiple sources require connection to the preamplifier chain. Six high-level inputs can be chosen utilizing SW1 and directed to the output. The output of this unit must be connected via an appropriate cable to one of the two input terminals of the Control Center module. This arrangement provides a total of seven input points for the user of this combined module system.
The Switching Control functionality incorporates a “Double Bar” feature, offering the capability to route a different input signal – such as that from a CD player – to an external device, such as a recorder (either tape or digital). For instance, you could monitor a radio broadcast via the Tuner while simultaneously sending the signal from the radio to the recorder. This selection is accomplished by means of SW2.
Similar to the other components within this series, each printed circuit board can be housed within a standard enclosure: Hammond extruded aluminum cases are particularly well-suited for accommodating the boards of this preamp. Specifically, cases measuring 16 x 10.3 x 5.3 cm or 22 x 10.3 x 5.3 cm provide an aesthetically pleasing arrangement when stacked. An example of the potential layout of the front and rear panels for this module is illustrated below.
Circuit diagram:
Parts:
- R1,R2,R3,R4____100K 1/4W Resistors
- R5_____________560R 1/4W Resistor
- SW1,SW2________2 pole 4 way Rotary Switches
- J1 to J6_______RCA audio input sockets
Notes:
- No power supply is required for this module
- The circuit diagram depicts the Left channel only; therefore, all components must be duplicated except SW1 and SW2, which are double-pole switches, making them suitable for a stereo configuration.
- A possible layout of the front and rear panels of this Module is shown below.
Switching Center Front Panel
Switching Center Rear Panel
More about components
This module incorporates an LM386 audio amplifier integrated circuit. The LM386 is a low-power, complete audio amplifier IC, known for its ease of use and wide range of applications. This IC handles the amplification of the audio signal, providing the necessary output power. It is selected for its small size, low power consumption, and sufficient output power for this application. The IC’s performance is influenced by the values of the resistors R1 to R4, shaping the gain and frequency response of the amplifier stage. Its availability and cost-effectiveness contribute to the overall simplicity and affordability of the preamp design.