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DIY LME49720NA Portable CMOY Headphone Amplifier

It was on Friday and heavy rain outside.

As usual in that condition, the traffic jam from my office to home will be very high. So I decided to go to my favorite electronic parts shop nearby instead directly went home.

Firstly, I don't have any plan to buy anything. I just came there to have a little chat with the owner. But things changes when I saw this high quality PCB of the headphones amplifier. I certainly want to make one for myself.


This is a high quality dual layer PCB and the thickness is around 2 mm.

To complete all the components required, I also buy them as well. Various components I choose from Dale resistor, Takman resistor, Wima capacitor and ALPS potentiometer. Those components have a good quality and still affordable for me.



The next day, which is Weekend, it is the time for me to start assembly them together.

As usual, I always checked all resistor value to make sure they are perfectly match between channel.

This little detail are necessary if you want your project as perfect as possible.



This CMOY headphone amplifier using op-amp IC for the main amplification component. The best practice with every op-amp is require dual rail power supply. This means you will need + and - polarity and center tap to ground.

The dual rail power supply is easy to build when using power transformer from AC outlet, but this CMOY headphone amplifier was intended to become a portable amplifier and only using a single 9 volt battery. That is why it need additional components to convert this single 9 volt battery to dual +/- 4.5 volt using TLE2426. This little IC will do this conversion better compares to the original CMOY schematic that only using a pair of resistors.


In this project, I use LME49720NA a high performance dual op-amp that intended for audio purpose.

It will put on the high quality IC socket. This might be useful for the op-amps rolling later on.


The potentiometer for volume control is built-in with power ON/OFF switch. This is for more simple in the CMOY design.


I use this Wima MKP10 for the signal decoupling capacitor. So far it is the best film capacitor for it's price range.


All components are installed perfectly. It is look like a battle ship now.



My initial test is using the iPod Video with the 30 pin connector line out adapter. This adapter will bypass the internal iPod volume control and headphone amplifier so the signal is pure pass through to this CMOY amplifier.

The sound from this amplifier very good indeed. It is lot of power.


Then the next step is find a small tin case to cover the PCB securely.

Finding the case is quite easy for me since a lot of tin can are selling at the store in front of my house. So I just pick the most suitable casing for this CMOY headphone amplifier.


I choose this tin casing which I think the size will fit.


I measured it first and make a holes on it for the input and output terminals.


It is all done and looking good.


This is small but powerful headphone amplifier. It has a lot of gain. I test it with any headphone or earphones I got and they are all sound fantastic.

By comparison when using this amplifier, there are lots of sound improvement especially in the power and dynamic compare if I directly connect to the iPod.

Disclaimer: Any statement and photos in this article are not allowed to copy or publish without written permission from the writer. Any injury or loss from following tips in this article is not under writer responsibility.
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