Bass Boost CMoy Headphone Amp

Philips SHS3200/37 EarbudsPortable headphone amp with a bass boost feature


It’s in an Altoids box. That’s kind of cool. It uses a high-grade Texas Instruments chip. The gain gives a good even boost, and the bass boost feature really fills up the bottom end, delivering awesome presence.


There is a great deal of noise when the gain is not engaged. Same goes for the bass boost – when it’s not engaged, there is a little bit of noise. There is no volume control, either. That’s dependent solely on your audio device or an inline volume control.


For almost $40, not a bad deal at all! The bass boost feature is absolutely awesome. I’m a little disappointed there is no volume control, but I guess there’s only so much room in an Altoids box.


Curiously Strong Bass

For almost $40, not a bad deal at all! The bass boost feature is absolutely awesome. I’m a little disappointed there is no volume control, but I guess there’s only so much room in an Altoids box.

In a mini box where about 75 small, white, edible disks once sat, there is now headphone amp circuitry.  It’s cool, it’s creative… it’s a headphone amp encased in an Altoids box.  It has a few things missing, but makes up for it with two great features and quality components, relative to other Cmoys.

There is no volume control on the unit.  That’s determined by your sound source’s output (iPod, portable turntable, etc).  The maker’s explanation for a fixed gain is pretty practical: no potentiometer means less circuitry the signal has to pass through.  That’s combined with an ergonomic reason: when you access your sound source, your hands are already there and it should have a volume control… and how many do you really need?  So instead of a volume control on the amp, there is a gain control.  This gives a good, even boost to your headphones.  That’s more important when dealing with high-impedance headphones in the range of 150+ Ohms, but I’ve had it engaged all day, just for fun.

When the gain is not engaged, there is a small grounding problem.  I have the unit hooked up to the audio output of my PowerBook, and there is a hum in the AKG K701 headphones I’m using.  As soon as the unit is placed on my computer’s titanium shell and cuddled with my hand, the hum goes away.  It also goes away when the gain switch is flipped on.

The BassBoost feature alone is well worth buying the unit.  It gives such an incredibly clear and powerful lift on the lower end (14.1dB, almost three times bass loudness), adding more low frequency presence than any other headphone amp I’ve ever heard.  Big bass is a signature of my generation, and a design to emphasize this is perhaps best delegated to someone of my generation.

The designer of the BassBoost Cmoy is an engineering undergrad at the University of Missouri.  He set out to improve the general Cmoy design as well as to innovate the functions and features.  The result is a tweaked version of a regular Cmoy, employing the same TI opamp (OPA2227P) but with higher quality components and even custom-printed circuit boards for a professional look.

One non-audio improvement is a DC power jack.  Although it’s not included, recommendations are made to get your own for under $10.  The entire unit will run on a 9V battery, but when DC power is plugged in, the battery is politely bypassed.

Normally, I am not a huge fan of the AKG K701 headphones.  However, when they are met with a great amp and given a little pat on the behind (a.k.a. bass boost) they come alive.  Such is the case with the BassBoost Cmoy.  It delivers such incredible bass response that it’s actually hard for me to listen to anything else right after using the feature.  However, with lesser headphones like the AblePlanet Clear Harmony phones, the bass boost can muddy up the mix, especially at louder volumes.

Some people may not like the frequency spectrum being altered because it doesn’t accurately reflect the master recording.  However, that’s very subjective and depends on your personal preferences.  Some people hook up massive car audio systems with bass that can be heard two blocks away (including me) because that’s how they like to hear their music.  I’m happy this Cmoy has an option to adjust the bass.

So there it is.  Leave it to a young entrepreneur to take a great product and make it greater.

Technical Info

Price: $40

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