GOODSOUND!GoodSound! "Equipment" Archives

Published April 1, 2006


HeadRoom Micro Amp and Micro DAC

Micro Amp

Micro DAC


I love HeadRoom, but mine is no simple fanboy crush -- I’ve got good reasons for it. First, it was a HeadRoom amplifier, the discontinued Little, that introduced me to the real joy of headphones and hooked me on quality sound. Without HeadRoom, I probably wouldn’t be writing for GoodSound! now. Second, the release two years ago of the Total BitHead USB-enabled, battery-powered headphone amp illustrated the inventive approach HeadRoom takes not only to product development, but to company image as well. Third, in addition to its own website,, HeadRoom has supported headphone sites such as since, well, before there was And fourth, HeadRoom folk such as its president, Tyll Hertsens, are some of the friendliest, most approachable people you’ll find.


HeadRoom’s Micro DAC digital-to-analog converter ($299 USD) and Micro Amp headphone amplifier ($299) have the same casework; only their faceplates and innards differ. Each has an aluminum body 1.5"H by 3.5"W by 4.5"L. The DAC weighs 9 ounces, the Amp 9.6 ounces; both weights include the batteries. That means the Micros weigh just over a pound together; in contrast, the Total BitHead weighs 5.5 ounces. You don’t need to be a he-man to carry around a pound, but it’s a noticeable amount of weight. If you’re walking around the city all day, the Total BitHead is probably the better choice (hence its inclusion in HeadRoom’s Mobile line).

The Micro DAC and Amp cases have a slight convex curve and rubber surrounds around their front and rear panels. These surrounds have long indents on the top and ridges on the bottom, which allows the units to be secured to one another when stacked. The connection is tight enough that you can move them around on your desk without worrying that the top one will fall off.

Each rear panel has two thumbscrews (one on each end) that allow the user to remove the plate to insert the two 9V batteries that power each unit. HeadRoom claims a battery life of 15-18 hours for the Micro Amp, eight hours for the Micro DAC. Dead center on each rear panel is an input for a wall-wart power supply (provided). The batteries are inexpensive, and the convenience of not having to find an outlet meant that I used the Micros exclusively with batteries. I found HeadRoom’s claimed battery life to be conservative.

One thing all the Micros’ faceplates have in common is HeadRoom’s new logo, ablaze with a red LED in the upper left corner. Starting at the DAC’s front left is the line out on a 1/8" output, then a 1/8" input for optical or coaxial digital signals. It wasn’t as easy as I had hoped to find a mini-optical adapter for a regular TosLink cable. It took me three RadioShacks to find one; apparently, this adapter has been discontinued. You may want to make sure you have one on hand if you plan to use the Micro DAC with such a connection. Next is a USB input so that you can use the Micro DAC with your computers, then two identical switches: the input selector (optical, coaxial, or USB) and the power switch (external or battery operation).

Like the Total BitHead, the Micro DAC uses the Texas Instruments/Burr-Brown PSM2902 USB chip. Unlike the BitHead, the DAC uses this chip only to convert the USB signal into a S/PDIF digital signal, which is then processed by a Cirrus CS4398 DAC chip. The Micro DAC’s coaxial and optical inputs can accept word lengths of 16 to 24 bits at 44.1kHz, 48kHz, or 96kHz.

On the left of the Micro Amp’s faceplate is a line input, then the headphone output, both 1/8" connections. In the middle are two small switches: the first toggles HeadRoom’s Crossfeed circuit on and off, and the second selects among three gain levels: High, Low, and Medium. Next is a volume knob that’s big enough to grab easily, or find by touch if your amp is in a briefcase or backpack. Last is the power switch, to select external or battery power.

HeadRoom has a lot to say about their Crossfeed circuit on their website. Briefly, it sends some of the signal from the right channel to the left, and some of the signal from the left channel to the right. HeadRoom claims this helps create a coherent aural picture instead of a separate blob of sound in each ear. The usefulness of Crossfeed seems to vary with the recording.

HeadRoom also provides some neat ways of carrying the little Micros around. The Micro Strap goes around the Micro Amp, and provides a platform on which you can secure your MP3 player with Velcro. A kickstand lets you tilt the player up so that you can see it clearly while sitting at your desk. When you’re ready to head out the door, you can carry the Micros in a Micro Bag. To use the Amp and DAC together when on the go, you’ll need the Micro Strap Extender, which secures both units, and a bigger Micro Bag. If this is confusing, a call to the nice people at HeadRoom, at (800) 828-8184 or (406) 587-9466, will get you squared away on which bag suits your needs.


I did most of my listening with the Micros using my laptop computer and the iTunes library I’ve compiled for my iPod. The tracks have varying bit rates, but nothing is less than 192kHz. I also used the Micros with a Sony SCE-775 SACD player with an optical cable feeding the Micro DAC. I used both Grado SR-60 and Etymotic ER4P headphones, but the specific review observations here refer exclusively to my listening with the Etymotics.

The first album I used to evaluate the Micros was David Johansen and the Harry Smiths’ Shaker [CD, Chesky JD236] -- good sound and toe-tappin’ blues. On "Let the Mermaid Flirt with Me," instruments such as brushed drums and acoustic guitar were reproduced with truthful timbres. This was one of those recordings nicely helped by HeadRoom’s Crossfeed circuit. The track’s bizarre separation of instruments in the left and right channels works fine on speakers but is unsettling on headphones. Crossfeed helped me enjoy the music without obsessing over the instruments’ placements inside my head.

I then played the always fun (and eponymous) album by the Scissor Sisters [CD, Universal B0002772-02]. The opening percussion and guitar of "Take Your Mama" were crisp and clean, but I knew within seconds that the batteries in either the Micro Amp or the Micro DAC were dying -- the sound quickly became distorted. Luckily, I had extra batteries ready to go. Up and running again, I noticed how deep and powerful the bass was. It was even more noticeably deep and controlled on Their Law, the new greatest-hits collection from The Prodigy [CD, XL XLCD190].

I chose the Scissor Sisters and Prodigy albums because I listen to both frequently on my iPod. This gave me a good baseline from which to compare the Micros. The difference was like night and day. My overall impression of the sound quality of these albums went from "OK" to "very good." No need to worry that the Micros weren’t doing their job.

On recordings such as Bob Dylan’s Desire [Columbia CH 90318], I was impressed with the soundstage the Micro combo portrayed. The tambourine, piano, and drums on "Isis" offered a very wide picture, not the narrowly confined one that headphones sometimes produce -- and the tambourine’s sound was incredibly lifelike.

The most noticeable improvements introduced by the Micros were a bigger soundstage, better resolution, and a wider dynamic range. Played on my iPod or directly from my computer, these same tracks sound pretty lifeless, their dynamic ranges inconsistent with those of the original recordings. The Micros helped fix that problem handily.


I compared the HeadRoom Micros with two other headphone rigs: HeadRoom’s own Total BitHead, which I’ve used for laptop listening since 2004, and Benchmark’s DAC1, which isn’t portable but has received widespread enough praise to become something of a . . . benchmark. Neither competed directly with the Micro DAC-Amp, for two reasons. First, the Total BitHead retails for $199 and the Benchmark for $975; neither is in the price class of the Micros, which together cost $598. Second, the Total BitHead allows for similar functionality as the Micros, but the Benchmark has no USB input and can’t be used as a portable.

The Micros blew the Total BitHead out of the water. On "Belleville Rendez-Vous (French Version)," from the soundtrack of The Triplets of Belleville [CD, Higher Octave 96811 2], the Micro Amp and DAC were better able to catch nuances and resolve detail. Toward the very beginning of this track are some sounds that are often imperceptible through speakers, but the DAC-Amp displayed them perfectly through headphones. Another example of this occurs about two minutes into the track, when some percussion instruments enter. The Micros articulated these sounds well and made them distinct from other instruments in the mix.

The Total BitHead’s presentation of the music was much more laid-back than the Micros’. When the bass kicks in on the Belleville track, the Micros almost had me up and dancing; the Total BitHead only made me tap my feet. Depending on your application, this might be preferable -- with the Total BitHead, I was able to attend to e-mail and other online tasks while still enjoying the music, but the Micros had me paying too much attention to the music to get anything else done. The Micros replace the sweetness of the Total BitHead with a more detailed, precise sound.

Still, the Total BitHead is much smaller and lighter, and attaches nicely with Velcro to the back of my laptop’s screen. That isn’t going to happen with the Micros. The BitHead can also run entirely off power derived from its USB connection to the computer; no such luck with the Micros. I’ll continue to use the BitHead with my laptop, because portability is important for me. If I had a desktop computer, however, the better sound of the Micros would inspire me to replace the BitHead with them.

Because this review focuses on the combination of the Micro DAC and Micro Amp, that’s how I compared them with the Benchmark DAC1; I didn’t evaluate the Micro Amp separately. The Micros gave a wider soundstage and a mellower sound than the Benchmark, which offered better instrumental timbres, more detail, and deeper bass. These characteristics were easily heard using one of my perennial favorites, Charles Mingus’s Mingus Ah Um [CD, Columbia/Legacy CK 65512]. On "Goodbye Pork Pie Hat," the Micro combination made the instruments seem spread out in space but failed to offer the last bits of detail -- such as the fingers of one of the horn players tapping his instrument. Similarly, the Benchmark was better at separating instruments from one another. The upbeat opening of "Better Git It In Your Soul" has lots of instruments and at least one voice. Listening to this track through the Benchmark, I heard very sharp images of each and every one of these sounds, but in a more confined space than through the HeadRoom Micros. The images of the instruments were softer through the HeadRooms, but the space the musicians occupied extended well past the soundstage the Benchmark provided.


The good news for headphone enthusiasts is that there is now a plethora of products available to enhance their listening pleasure. That’s also the bad news. You can choose from the ultraportable Total BitHead to portable but bulky solutions such as the Micros, tubed headphone amps, and beyond. You need to consider which characteristics are important to you, how you listen to headphones, and how much you want to spend on a headphone system. There’s no easy solution, so allow the auditioning process to be a fun addition to your hobby.

HeadRoom’s Micro Amp quickly took over from the Total BitHead as my favorite inexpensive headphone amplifier. The sound it produced simply had more clarity and a feeling of more power behind it. But unlike the BitHead, it lacks a USB input, so there’s a tradeoff. To add USB functionality to the Micro Amp you’ll need the Micro DAC, but the combo costs three times as much as the BitHead. If I sat in front of a computer all day listening to headphones, I’d probably consider the money well spent. If more portable players had digital outputs, the setup could be invaluable. But the Micro combo costs $598. The Total BitHead won’t give you the same performance, but it will give you better sound than your computer or iPod will on its own, and will keep $399 in your pocket.

The Micro DAC and Micro Amp perform as well as anyone could hope, are finished to high standards, and fill the largely ignored niche of USB-enabled portable audio components. HeadRoom provides excellent customer service and aggressively supports headphone hobbyists. With the Micros, my love affair with HeadRoom products continues.

...Eric Hetherington

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