Understanding Headphone Amps

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[Updated September 9, 2015]

It’s challenging to discuss a home theater category like headphone amps and remain within the practical—and financial—bounds of middle class consumers. Many home theater owners have never even heard of this gear category, let alone own such a component.

However, the value of headphone amps, for people who truly love great sound, can’t be disputed. The good news is that many companies, like Schiit Audio and others, produce affordable hardware that can dramatically improve the quality of your sound when you’re wearing your cans and enjoying your favorite album (or movie).

The following is an excerpt from my book Home Theater for the Internet Age, from Chapter 9: Headphones.

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Curt Robbins


Headphone Amps

Headphone amplifiers are probably the single most misunderstood area of audio entertainment (if you’ve even heard of this tech). Infamous for being expensive toys owned by audiophiles, they are a relatively uncommon device within a home theater. What does a headphone amp do? Simply put, it’s an output from your receiver that re-amplifies the signal to improve the sound produced by your headphones.

In most receivers, even high-end models, the built-in headphone amp is a super-cheap afterthought. Audiophiles and music enthusiasts claim that, if you have a good pair of headphones, you’re cheating yourself by not getting at least an entry-level headphone amp to bring out their potential. “Using a dedicated headphone amplifier will step up the performance of any home theater to an entirely new level,” Frank Iacone, a 35-year industry veteran known for his heartfelt Twitter feed and reviews on headfi.org, told me in an interview. Because most middle class consumers have never used a headphone amp—and very possibly never listened to high-end headphones—it’s one of those situations where people simply don’t know what they’re missing.

OPPO HA-1 headphone amp for twitter - 2

Prices for headphone amps range from $60 to $16,000. That’s right, if you have a large pile of money and are wondering what to do with it, you can purchase 3,200 copies of this book or a headphone amp that costs more than an entry-level Toyota. The kids can walk, get the amp!

Tube, Solid State, & Hybrid

There are two primary technologies employed in building headphone amps: Analog vacuum tubes and digital solid-state circuitry. Vacuum tubes are way old school; some audiophiles collect antique tubes that are more than 50 years old. Solid-state amps, which involve digital processing and circuitry, are typically less expensive than their tube-based brethren and feature a more accurate, less “warm” sound. The third type of headphone amp, called a hybrid, merges these two technologies, theoretically offering the best of both worlds. Good applications of this approach achieve this, while poor executions fail to sufficiently exploit each type’s advantages.

Audiophiles Divided

The audiophile community is divided regarding which approach, tube or solid state, provides nicer sound. In reality, each type offers distinct pros and cons and is implemented in a wide variety of quality levels by different manufacturers. In the end, the model best for you is determined more by your wallet than your feelings regarding the warmth, intimacy, or accuracy of a particular model’s amplification technology.

However, one typically doesn’t spend the kind of money we’re talking about on headphones and headphone amplifiers and not appreciate the nuances of high-end audio. For many, the differences in sound quality between comparable quality tube and solid-state amps is significant (another religious war among audiophiles). My own opinion, quite frankly, is that I appreciate the lower cost of solid-state amps while also somewhat desiring the more accurate sound reproduction and efficiency that they deliver (which I also prefer in my AV receivers). But this certainly doesn’t mean that solid state is better. It’s simply my personal take on the matter (and my wallet’s influence).

From a sound perspective, I’d rather have a $1,200 Woo Audio WA2 tube amp (pictured below) than a $120 Vali solid-state model from Schiit Audio. However, this reflects a desire for a high-end amp, not a disdain for digital amps, preference for tube amps, or any leaning toward Woo Audio over Schiit (both of which are great companies offering models you should seriously consider). My budget—and the quality of my headphones—dictates that my purchase will probably involve a cold aluminum solid-state Schiit Audio Asgard 2 for $250 (the “practical” model for which I continue to lust).

Woo Audio WA2 for blog

Pros & Cons

One disadvantage of tube amps is that they can require up to 10 minutes to heat up in preparation for use. This is an old school characteristic indeed, and about the most retro electronic wait period of our modern drive-thru, microwaving, Twitter filled world. Fans of tube tech, however, swear it’s worth the patience and dollars (and boast of the romantic glow provided by their vacuum tubes—probably especially nice during the holidays).

An advantage of solid-state amps is a reduction in background noise. Some audiophiles actually prefer an elevated background noise level, especially for live performances or fully analog productions. One advantage of solid-state amps that doesn’t really touch home theater applications is mobility. Some models are designed to accompany a mobile device, offering small size, battery power, and significant improvements in audio quality compared to the anemic default output of mobile gadgets (especially when paired with good headphones).

Upgradable Tubes

A neat feature of vacuum tube amps for hobbyists is the fact that you can swap out—and thus, upgrade, within certain technical limits—the tubes. Some hyper-hobbyists even keep two or three sets of tubes, reserving each for a particular type of music. Many replacement tubes are relatively inexpensive (Schiit Audio sells a set of four tubes for its $350 Valhalla model that runs $40). While the cost of the initial amp itself might be somewhat hefty, the expense of playing hobbyist with different tubes—or replacing units that have burned out—can be manageable and fun.

Reputable Brands & Models

What is more important than whether a headphone amp employs vacuum tubes or solid-state circuitry is its sound quality, period. Companies such as Woo Audio (USA), HiFiMAN (USA), Bryston (Canada), OPPO (China), and Schiit Audio (USA) offer a wide range of both tube and digital amps.

Woo Audio manufactures expensive tube-based models featuring exquisite hand-crafted build quality and leading edge design that are made in New York City. Ranging in price from $550 to $16,000, Woo offers some of the best (and most attractively designed) tube amps money can buy. If you’re sweet on their products but on a budget, consider the $600 WA3 or $700 WA6.

Schiit Audio, headquartered in California, produces beautifully sculpted aluminum amps. Most of their models are solid state, but they also offer a couple hybrid and tube models. Schiit amps perform like Canadian and American models costing several times more. It’s relatively small product line, priced between $100 and $750, are all American made from American parts (Schiit even has face-to-face relationships with its local vendors). The company provides what reviewers cite as excellent and personalized customer service.

Shiit Audio Valhalla for blog

Premium Blu-ray player manufacturer OPPO in 2014 released a $1,200 solid-state headphone amp that has received rave reviews. The audiophile-quality OPPO HA-1 features an attractive display that compliments the unit’s leading edge features (it can even simulate those sexy analog VU meters from way back when). Like other OPPO products, the HA-1 is controllable via the OPPO Remote Control App for mobile devices.

“The hardware inside the HA-1 are some of the beefiest I’ve seen in a headphone amp. It looks like a barely scaled down loudspeaker amp,” said Geoffrey Morrison when reviewing the model for Forbes. Reviewer John E. Johnson, Jr., writing for hometheaterhifi.com, added, “And, wow! What a sound. Built like a tank, and gets as hot as a tank in the Sahara due to its Class A output.”

If you want to check out entry-level tube-based headphone amplification on a budget, look into the Bravo Audio V2, a $70 ($55 street price) single-tube amp. “It’s a nice little tube amplifier in its own right for those of us who want to experiment with that highly desired ‘tube sound’ without paying the exorbitant rates many tube amps cost,” said an amateur reviewer on Head-Fi.org.


Curt Robbins is author of the following books from Amazon Kindle:

You can follow him on Twitter at @CurtARobbins, read his AV-related blog posts at rAVe Publications, and view his photos on Flickr.

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