(Last Updated On: March 27, 2017)

On a shoestring budget for an amplifier to boost the sound quality from your high-end headphones?

After months of painstaking research, you decided to break open your piggy bank for that pair of high-end headphones that you have been dreaming of. But to your greatest dismay, the sound quality was well below your expectation. This was unlike the reviews that you read religiously from headphones-related forums.

Not giving in, you dug in and did further readings. You found out that this pair of headphones you bought is actually a high impedance pair. Impedance is a measure of how much something resists electrical current. (Often measured in OHMS Ω). The higher the impedance, the more power it needs to drive the headphones to its peak performance.

Power up your headphone with CMoy
A CMoy setup for phone

Most high-end headphones, such as Sennheiser HD-800, have large drivers (more wires coiled) and are expected to be driven by higher-voltage professional studio equipment, hence explaining their higher impedance.

The onboard amplifier in your laptop or mobile phone will not have the sufficient power to drive high impedance headphones. Not only will they be too quiet to enjoy but they also won’t sound right in different frequencies.

To fix this, you will need to buy a better quality amplifier. But alas, you had just shelled out a large sum of money on your headphones. And, you are not ready to commit to another lavish spending.

This is where you can turn to the CMoy headphone amplifier.

For a more in-depth article on amplifier, you should read “External DAC: Is it an absolute necessity for your headphones?

CMoy Headphone Amplifier (CMoy Amp)

CMoy is a term derived from its inventor, Mr. Chu Moy. He was the founder of the first headphone forum, HeadWize (now defunct). It was where he published the famous article – “A Pocket Headphone Amplifier”. The article was the blueprint to build an affordable and portable amplifier.

The steps to build the CMoy amp are well documented. The project involves

    1. collecting the required components
    2. having some basic understanding of circuitry
    3. putting the components together

The last part will involve getting your hands dirty with some electrical soldering. So if you have some prior experience, it will sure come in handy!

However, if you are a total noob, have no fear. You can find the step by step tutorial, How to Build the CMoy Pocket Amplifier, on the TangentSoft CMoy Tutorial website. The CMoy amp does have its cult-like followings. A quick google search will bring up loads of results that should be able to answer any question that you have.

Inside of the CMoy amp
Inside of a CMoy amplifier

Key components for the CMoy Headphone Amplifier Kit

The first step towards a successful DIY CMoy amp project is to find all the parts required for assembling the amplifier. Here’s a little deep-dive on the DIY Kit you’ll come across as well as the components that you’ll need to pick for the project.

A good DIY CMoy kit should

    1. contain every piece needed to electrically assemble the amplifier
    2. the instruction manuals on how to put the pieces together.

The components needed to build the CMoy amp might seem daunting to beginners. Hence, we compiled a list of the essential components below.

A complete CMOY DIY Kit will include the following components:

2Circuit boardProtoboard is always highly recommended
33.5mm Jacksfor audio Input and Output
4Op AmpThe Op Amp (Operational Amplifier) is especially one of the key parts in your headphones amplifier. This is the component that does the actual amplification in the CMOY circuit.
5Metal film resistorsIncluding a Gain resistor
6Polyester Film capacitorsAs well as power supply capacitors
78 pin DIP socketFor allowing other Op Amps to be used
8PotentiometerA volume control knob with built in twist-on/off switch is highly recommended
9Power LED indicatorIt’s an optional but makes you CMoy amp look cool
10Battery connectorUsually a 9 v battery clip
11EnclosurePeople often build them on mint tins

All the parts need to be of specific types and measurement values for the CMoy amplifier. The best place for this information is the Part Lists and Suggestions article from the TangentSoft CMoy Tutorial.

It’s important that you check out the guidelines on this tutorial down to the last letter, not only for the precise models of components required but also for the build instructions.

Selecting the right CMoy DIY Kit

Not all CMOY kits are created equal. As such, there are kits that include cheap low-quality parts and circuit boards. So how do you look for an amplifier kit constructed with only high-quality components? Follow the usual steps of checking online reviews and manufacturer reputations.

A popular place to get DIY CMoy amp kit is from JDS Labs.

Ok, this is too much work, where can I buy one?

Not everyone is blessed with good soldering skill or actually have the time to master it. Fortunately, you can buy ready-made CMoy headphone amplifier online at a reasonably cheap price. It doesn’t hurt that they come in attractive enclosures too. They are available on Amazon.

Custom Enclosure

Lucid Labs is an American company that sells a variety of CMoy amplifier. It ranges from the classic red Altoids mint tin to the rad-looking, bumblebee-colored penguin tin. They are able to work with headphones from 30 Ohms to 300 Ohms.

Classic CMOY Altoid Red Mint Tin
Classic CMOY Altoid Red Mint Tin
CMoy Altoid Wintergreen Tin
CMoy Altoid Wintergreen Tin
CMoy Newman Tiger Tin
CMoy Newman Tiger Tin
CMoy Newman Polar Bear Tin
CMoy Newman Polar Bear Tin
CMoy Amp with Penguin Tin
CMoy Amp with Penguin Tin

High impedance headphones, like Beyerdynamic DT-1350-80 and AKG K701, are known to work well with the CMoy amp built by Lucid Labs.

Custom Performance

As different headphones have their own impedance level, there is no one-size-fits-all CMoy amp. Companies like JDS Labs can help customize the CMoy amp according to the needs of your headphones.

Can I use this for low impedance headphones?

If the CMoy amp kit works well for high impedance headphones, it should work equally well for low impedance headphones too right? Wrong.

Within the classic CMoy design, we have one op amp running the show. This op amp amplifies voltage which high impedance headphones need. But if we send amplified voltage through a low impedance (less than 30 Ohm) headphone, this increases the amount of current running through the connected circuitry. This might exceed the current limit of the amplifier, resulting in sound distortion and an overall decrease in sound quality.