By using the LM3886 it is possible to build a very small PCB but with the performance of the more complex and expensive commercial power audio amplifiers. Of course I’m not comparing this amplifier with some super ones available in the market, but you’ll remain amazingly surprised listening to how good it sounds.
Initially I built this PCB because I was fed up to hear the annoying low frequency noise from the speakers of an old amplifier. The issue came from the power supply that clearly wasn’t very good. The residual 50Hz signal from the AC line, technically called ripple, was so high that it generated an awful fixed background sound. By installing this PCB, after the existing PSU, I solved my issue.
I have always been fascinated by LCDs. Their capability to make numbers, letters and drawings on a glass plate is something magic. Thanks to this project I learnt a bit more about them and I discovered the tricks of the wizardry. Despite this, and even if the LCD displays have become obsolete, I still think they are the result of an amazing technology.
- SP0004 – Phase shifter for bridging two amps
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.
This is the PCB I used to test all my projects. When I drew it, I took the cue from the project published on electroniq.net (I hope the attribution is made to the right author because I found many clones on the internet). I changed something on that schematic making the improvements I thought were right also in order to try to use the components I already had available.
The project offers an universal solution that allows you to find and set the best cutoff frequency for an audio system’s sub-woofer with no special equipment. Beyond this, in my opinion, practical listening is the best way to compare audio configurations and devices: charts, parameters and calcs are very important but they may not be respected when put into practice. This crossover gives you the possibility to set six different cutoff frequencies: 63Hz, 80Hz, 100Hz, 125Hz, 160Hz and 200Hz.
The XR-2206 from Exar© is a great IC because, with a few components, it makes it possible to build a circuit that generates analogically various waveforms with a frequency from 0.01Hz to 100MHz. This capability allows you to build quite easily a function generator useful to test audio devices and all the circuits that require a low frequency input.
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.