Passion in Electronics
A good way to protect your speaker from overloading is by using a limiter circuit. This circuit protects your speaker by limiting the input signal to the amplifier by a certain level.
This circuit uses an IC from New Japan Radio Inc. It is NJM2761 which is specially designed for limiting audio signals. It is designed for powered speaker system to protect the speaker from overloading.
Continue reading “Audio Limiter Circuit”Here’s a 3 band tone control with subwoofer output circuit. Take note that the main output are full range. This is not a 2.1 crossover circuit. It is powered with single power supply so you can use a battery or a simple ac/dc power supply.
Continue reading “3-band Tone Control with Subwoofer signal Output design”
Here’s a simple amplifier you can build. it uses the popular TDA2030 amplifier IC. It can deliver up to 35W which is good enough for room audio. It is in bridged mode meaning it is using 2 IC with the output of the other IC is 180° out of phase.
Here’s a simple circuit you can build for your own low power home audio project. It only uses a NPN transistor rather than the most conventional OPAMP versions. It is simple and easy to build using an universal board. It can be powered by 9v or 12v single power supply.
Continue reading “Simple 2-way crossover circuit using npn transistor”
Here’s a simple circuit you can use to boost more bass from your music. It can be powered by 9V battery or a 12V DC adapter. Take note that this is just basically a 1 band tone control with +- 17dB range at 60Hz bass frequency. You need it to connect before the amplifier input. This can’t be connected directly to speaker. The output of this circuit will be connected to the input of your amplifier and the input of this circuit will be connected to your audio source(i.e. mp3 player).
Here’s a simple electronic stereo audio selector switch that can be used for arduino. You can directly connect the pin 1, 16, 3 and 18 to arduino for selecting the source. This pin can accept as low as 2V for logic high according to its datasheet so no need for level shifter.
Here’s a simple guitar headphone guitar amplifier project that you can use for practicing. The headphone amplifier uses a LM386 that can be able output up to 0.7W than can be use also for small speakers. It also has an auxiliary input that can be used to connect your phone or an MP3 player for you to jam and play along with the song you are playing. It has a simple built-in overdrive channel.
Continue reading “Simple Guitar Headphone amplifier with overdrive and aux input”
Here’s a phaser guitar effects schematic from an electronics magazine. I have build it some years ago but unfortunately I lost it so I cannot share the prototype. Anyway if I have time in the future, I might build 1.
So I purchased a guitar overdrive effects kit from Alexan just for fun. If you are looking for a cheap DIY effects for your guitar, this one is for you.
Schematic
The design is not a true-bypass configuration, meaning the signal is still passing on the buffer circuit in bypass mode. What is bad about that? Well the buffer circuit cuts of some of the low frequencies of your signal and it also adds some noise to it.
At bypass mode, the low frequency cut off is just small and negligible. It cuts -3dB at around 30Hz.
Tone Control Response
Below is the simulation I made and compared it to Ibanez Tube Screamer FX pedal. Volume and gain set to maximum and the tone control set to 0%, 50% and 100%. As you can see, gain on the alexan overdrive is lower due to passive tone control design used. It also has more aggressive low frequency roll-off, which mean the alexan has thinner sound.
On the other hand, alexan has more gain on the overdrive circuit because it uses a 1M gain potentiometer rather than the 500k used in ibanez tube screamer. But do you need that high gain? I don’t think so, higher gain means higher noise.
If you are looking for a mic preamp with bass and treble control, you may consider this one. I designed it for my future mixer build. I am planning to build one someday when I am not too busy.
ABOUT THE CIRCUIT
The circuit is only on design stage, not yet done any prototype but it is working on my simulation. This is an improved version of the preamp on my audio mixer design I posted.
The rolloff on the 10k-20kHz range is caused by the capacitor C8. This is done to make sure the system will not allow any radio frequency to pass especially AM radio signals. If you want that roll-off to be more aggressive, you can increase it. Treble frequency is set by C3 and C4 while C2 is for setting the bass frequency. Increasing those capacitor values will decrease the frequency. For instance you want the bass to have more boost on the lower end frequency, just increase the value of C2.
Gain is set by R1, if you want more gain, increase R1 value. Potentiometer used are 100k, using 50k or lower will decrease the boost and cut range by around 3dB.
Simulation Results
All range: bass and treble at 0%, 50% and 100%
Bass control (0%-100% at 10% increment)
Treble control (0%-100% at 10% increment)
