Micro CMoy Opamp2227

Philips SHS3200/37 EarbudsMini headphone amp encased in an Altoids box


It’s made from Texas Instruments amp circuitry. It’s actually in an Altoids box, so if it’s character you’re looking for, you got it. It’s kind of like a DIY kit, except it’s already done.

The knob is slightly larger than the thickness of the box, so it doesn’t sit perfectly flat on the table. That’s disastrous to me and anybody else with OCD. I’m also not a big fan of the toggle power switch; I’d rather see a button.


It’s inexpensive, made from consumer-quality components and very creative. All in all, for $35 it’s an amazing deal. You get what you pay for. In this case, it’s an Altoids box fitted with a headphone amp.


Curiously Strong Headphone Amp

It’s inexpensive, made from consumer-quality components and very creative.

Ok, let’s just get this out of the way: yes, it’s an Altoids box.  It’s cute, creative, and curiously strong.  Don’t get confused, though.  This is a quality headphone amp, designed with great components and craftsmanship, and it will drive your headphones like peppermint never did.

Let’s start with the not-so-hot stuff about the Micro Cmoy Opamp2227.  The loudness knob is slightly larger than the box, and protrudes beyond the bottom of the case.  This means it’ll never sit on a desk perfectly flat.  However, I’ve learned to deal with this over the hours.  I just rest my hand on top of the unit.  To make it louder, slide the unit to the right and it turns the knob “up” against the desk.  Slide the unit to the left and it turns it down.  Ridiculous?  You’re ridiculous.

Next, nothing is labeled.  There are two 1/8” jacks on the front, but they’re not labeled.  One is an input, one is an output, and your memory is your only friend.  This sucks for the elders, the Murphy’s Law-ers and the entire pot-smoking community.

My last “complaint” is about the unit’s interaction with petty thieves.  They intended to steal Altoids.  Everybody loses.

Now, on to the good stuff.  On the scale of innovation, the Cmoy gets ten stars.  It is the ultimate Rag Shop headphone amp.  I love the enclosure, and I love that every piece used to design the amp can be revealed.  The most significant parts are the opamp chip (a highly-regarded Texas-Instruments product) and the potentiometer (a highly-regarded Panasonic product).

If you itemize the parts used in the Cmoy, they come to about $20 (including cost of the Altoids).  I’m estimating that is about average for parts in headphone amps.  The difference is, markup on the Cmoys is significantly lower, so you get a fair deal.

How does it sound?  For an Altoids box, pretty darn good.  For a headphone amp, kind of average.  But (big but) it is the kind of average that’s contingent upon your wants and needs.  Remember, it uses some audiophile-grade components… and it’s $35.

I’m taking a signal straight from my PowerBook’s 1/8” output (volume halfway) and the Cmoy is driving AKG K701 headphones.  They sound crisp, clear, and “free,” as in loud but still preserving the dynamic range.  Plugged straight into the computer, the headphones sound and respond the same (audibly), only not as loud.

An interesting end note for the adventurous: the Cmoy is not exclusive to any one manufacturer.  It is a hobbyist’s creation, and there are several online tutorials that can guide you all the way from purchasing the parts to completion.

Technical Info

Price: $35

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