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As declared on the last post, I have published a very recent project, built after the andy-progetti website’s birth.
This circuitry is an elementary phase shifter but I think it represents the best solution for bridging two amplifiers. I don’t know if you already know the theory of bridged amplifiers, otherwise, on the Wikipedia’s website, you can find the main information about it.
The function of the board is shown in figure 2. The bridger supplies the original input signal to one of the amplifiers and to the other one the specular version of that signal. In that way, the two amplified signals might be applied directly to the speaker: one to the positive terminal and the other to the negative one. Therefore, GND will not be the negative signal for your speaker anymore.
Even if in theory the bridge increases the output power four times, in practice it is not possible, but ensures a doubling of it.
The stereo version of the phase shifter
Due to the simplicity of the circuitry, I decided to put a stereo version of the bridger onto the same PCB . Hence, four amplifiers will be required.
If you want you can replace the OP amps NE5532 with your favourite ones. Even the value of the resistors is not important as long as you choose the same for both of them however, consider that it would be better not to choose values under 10kΩ.
Make the phase shifter PCB
If you are thinking of making your first PCB this project could be good for you.
Before testing the bridger, remember to use a dual power supply. In general, and for these specific OPs, ±12V or ±15V are ok; otherwise make sure to use proper values according to the data sheet of the model you have chosen to use.
Download the project
Pressing the button below you can download a compressed file with all the necessary material to build this project:
- the NE5532 data sheet;
- the pictures of the final project, the schematic, the PCB mask and the PCB layout as shown in this post;
- the schematic and the board files in Eagle format.
If you need some help please do not hesitate to contact me or leave your comments below. Enjoy it!
I have decided to share my knowledge and my projects for free, so I have not inserted any annoying ads on andy-progetti.com. Despite this, if you like my website, please help me in developing it by leaving comments and suggestions, or by making a small donation pressing the button below. Grazie di cuore, Andrea Dal Maso
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