A very simple two transistor surround sound decoder or vocal remover preamplifier based on two combined common collector and common emitter Class A audio amplifiers. This method of surround sound decoding simply isolates the out-of-phase audio in a stereo mix.
Watch the video on how to build: https://youtu.be/4wfMt4YOYYA
- Low power consumption: ~10mA @5v.
- No frequency band limitations on output.
- Can be used with virtually any linear input audio amplifier at any power output.
- Very high linear quality, being based on the Class A audio amplifier.
- Small and low cost design; makes it easy to integrate into any application.
Refer to the schematic diagram to follow these steps.
- Connect a linear audio source to resistors
R5
andR6
. The audio source must be a stereo mix. - Connect the input of your audio amplifier to the output of the preamplifier on the collector pins of transistors
Q1
andQ2
. - Change the resistance of
R5
orR6
to change the gain of the preamplifier; if the output volume is too loud or too quiet.
- Mid-high range frequency constant click/popping sound: This is caused by wireless interference. The circuit is not protected from EMF interference. Please remove any wireless devices (such as a cellphone) at least 10 feet away from the circuit or turn them on airplane mode while in use.
- Some vocals/mono audio sound is still leaking into the out-of-phase audio: Assuming that the audio you are playing doesn't natively have any vocals in the out-of-phase audio, it is important that you use ±1% tolerance resistors or less to limit this from happening. Regardless, vocals can still leak through as a result of the resistor and other componant tolerance.
- This repo is licensed under the BSD 3-Cause license. Any images are licensed under CC BY-SA 3.0. Refer to
LICENSE
for more info.