I listen to music when I commute using the subway. Since it's very noisy in the subway the bass sound of the music tends to be masked. So I made a small headphone amplifier that can boost bass sound as needed. Did you use this instructable in your classroom?
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I listen to music when I commute using the subway. Since it's very noisy in the subway the bass sound of the music tends to be masked. So I made a small headphone amplifier that can boost bass sound as needed. Did you use this instructable in your classroom? Add a Teacher Note to share how you incorporated it into your lesson. I found a suitable amplifier IC named LM This IC was developed for portable audio devices, and used to be widely used in computer sound cards.
It only requires 2. According to the datasheet, you need DC blocking capacitors in the output, which is typical of single supply amplifiers.
However you can modify the circuit to use dual supply to eliminate the need for these large capacitors. As you can see, using each battery as positive and negative power supply dual power supply , you can eliminate the output capacitors.
This is a big win for portable design, not to mention the cost saving high quality, large capacitors required for amplifier output are not cheap. LM allows setting of gain by using external components to set negative feedback - much like typical op-amp circuit. I decided to include timing components combination of capacitors and resistors to give the amplifier bass boost. The topology is called "shelving filter". You can customize the component values to change boost frequencies and the amount of boost, to suit your phones and music you listen to.
I recommend using metal film thin film resistors instead of thick film carbon resistors for lower noise. Capacitors that audio signal goes through should be film or C0G type ceramic. Avoid other types of ceramic capacitors such as X5R, X7R, etc. Ceramic capacitors however pick up vibrations as noise only audible if you tap the capacitor directly - some of you might not like that. I used the gain setting of However I recommend unity gain 0db setting for most cases - simply swap R1 and R2 as described in the schematic.
This simple headphone amplifier delivers punchy sound and long battery life. You can use rechargeable AAA batteries for the best economy as well. Reply 1 year ago.
Question 1 year ago on Step 6. More by the author:. About: I am an electronic artist living in Brooklyn, NY. I work with LEDs, microcontrollers, and analog electronics to create objects that I find beautiful.
I listed out my requirements as below, and started designing. Use two AA or AAA batteries I didn't want to use 9V batteries Long battery life Decent sound quality - doesn't have to be audiophile-grade, since it'll be used mostly in subways Switchable bass boost. Add Teacher Note. I used a 3 position switch to switch between boost off, and two levels of boost. The final version of the circuit schematics is attached here. Participated in the Audio Contest View Contest. Did you make this project?
Share it with us! I Made It! Electronic Affirmation Mirror by bekathwia in Arduino. MarilynnM2 1 year ago. Reply Upvote. Answer Upvote.
View lm4880 datasheet:
Datasheet Texas Instruments LM4880