REVIEW: Beyerdynamic A 20 Headphone Amplier
Tuesday, December 31st, 2013
by Warren Chi & Frank Iacone
If you've been eying Beyerdynamic's flagship A1 headphone amplifier - and from afar because it lies outside of your budget - you'll be glad to know it now has a baby brother! Launched in July of 2013, the A 20 is Beyerdynamic's latest headphone amplifier. And at $679, it slots in right behind it's flagship sibling in terms of pricing, making it much easier on the wallet.
Input Impedance: 25 Ω
Maximum Amplification: 18 dB
Frequency Response: 10 Hz - 100 kHz (-1 dB)
T.H.D.: 0.01% at 170 mW / 250 Ω
Channel Separation: > 80 dB at 1 kHz / 250 Ω
Output Power: 100 mW / 600 Ω, 150 mW / 30 Ω, 170 mW / 250 Ω
Maximum Output Power: 170 mW / 250 Ω
Signal-to-Noise Ratio: > 100 dB (unweighted)
Output Impedance: Headphone Output 100 Ω
Input Voltage: 100 V ~ 240 V AC; 50/60 Hz
Power Consumption: < 10 W via integrated switching power supply
Audio Connections: 2 x 1/4" (6.35 mm) stereo output jacks; 1 x RCA (L/R) line output; 1 x RCA (L/R) audio input
Housing Only: 164 mm x 194 mm x 48 mm
Housing, including button, rubber feet, RCA phono sockets: 164 mm x 212 mm x 55 mm
Net weight (without packaging): 1640 g
The A 20 features a fully discrete design, and is designed primarily for headphones from 30 Ω to 600 Ω. The total harmonic distortion is impressively low - only 0.01% at the A 20's maximum output power of 170 mw / 250 Ω. On the rear of the unit, the inputs looped-through, allowing for signal pass-through even with amp powered down. On the front of the unit, there are two single-ended headphone jack - wired in parallel - allowing two headphones to be used simultaneously.
The Beyerdynamic A 20 is unquestionably sleek and stylish.
Design & Build
There's no doubt about it, the Beyerdynamic A 20 is one sleek and stylish amp.
There is a definite familial resemblance to its more-upscale sibling - the A1 - in terms of its front facade, jacks, and knobs. But unlike the A1, it's not surrounded by that silly-looking neck pillow.
Yay! No neck pillow this time around
The A 20's chassis is milled from a single block of aluminum (or aluminium for our brethren across the pond), and finely brushed for just the right amount of texture. The top panel is plastic, similar to the plastic neck pillow that cradles the A1. At first glance, this gave us a bit of pause. But we are happy to report that the plastic top plate is incredibly strong and sturdy. It easily held the weight of a Woo Audio WA7 (approximately 9 lbs.) over extended periods of time.
Speaking of the build, the A 20 is a screw-less design. Other than four post screws stealthily hidden in the A 20's rubber feet, and a few screws with which to secure various jacks, there are no superstructure fasteners of any kind. Despite this, there is no play or wiggle anywhere, and the entire unit feels solid, unified. It's built like a... well... like a Beyerdynamic A 20.
The A 20 comes with two power cords, one of which is terminated in a NEMA 5-15 (Type B) grounded plug for U.S. households, with the other being terminated in a CEE 7/7 (Type E+F) plug for European households. At the opposite end, both cables are terminated in standard IEC (C13) for the A 20. And while Frank and I appreciated the inclusion of both cables, we didn't use them. Instead, we opted for our Nordost Blue Heaven power cords.
Frank's Rig consisted of an Apple iMac with Audirvana/Amarra software, an Oppo BDP 105, and Nordost Blue Heaven cables throughout. For comparison purposes, Frank also used a Burson Conductor SL headphone amp in place of the Beyerdynamic A 20 as a comparison unit. My rig was a laptop feeding a Mytek Stereo 192-DSD DAC, with a mix of Nordost Blue Heaven and Nordost Heimdall cables.
When it came to headphones, we kind of lost our minds with this review. Here is a partial list of the headphones and IEMs that we paired with the Beyerdynamic A 20:
- Sennheiser HD 800
- Beyerdynamic DT 770 Pro 80-Ohm
- Beyerdynamic T1
- Denon AH-D7000
- Fostex TH-900
- Denon AH-D7100
- Sennheiser HD 650
- Audeze LCD-2.2
- Audeze LCD-3
- Audeze LCD-X
- MrSpeakers Alpha Dog
- Audeze LCD-XC
- Etymotic ER-4PT
- Tralucent Audio 1Plus2
- Ultimate Ears 18 Pro
Performance & Sound
Thanks to Beyerdynamic's generosity, we were able to give the A 20 an extended series of detailed auditions. Taking full advantage of this, we decided to put it through a widely-varying gauntlet of dynamic headphones, planar magnetic headphones, and IEMs (in-ear monitors).
Overall we both found the A 20 to have a relatively neutral presentation. While Frank found the A 20 to be slightly on the warm side of neutral and without any harshness to speak of, I perceived it as being colder than neutral with a tendency towards brightness. However, we both agreed that the A 20 is close enough to neutrality that such differences can be chalked up to having used different headphones and rigs, not to mention having individual ears and personal signature preferences. We also agreed that the A 20 was very transparent, with no solid-state glare or haziness, thus culling detail from our music effortlessly.
|Sennheiser HD 800|
Frank's Sennheiser HD 800: The A 20 did very well in driving the Sennheiser HD 800 easily.
Listening to Ella Fitzgerald's excellent recording Clap Hands Here Comes Charlie with a HD 800 reference headphone was both enjoyable and deeply involving.
The A 20 was very musical, the tonality of the HD 800 was never bright, and Ella's vocal was centered in the front of the sound stage on "A Night In Tunisia". The band was focused within their own individual spaces, with air and space around each individual instrument.
Even with the HD 800's 300-Ohm load, the A 20 sailed through "Have I Told You Lately That I Love You" from Elvis's Stereo '57 album, engulfing me in the music. The more I listened with the HD 800 the more involved I became with the recording session, as it captured me in the performance. The laughing and playing around in the studio let me hear how Elvis really was, and it was evident that he was having a blast with his band.
At one point, the A 20 and the HD 800 completely disappeared, and I lost the realization that I was listening with electronics. I just closed my eyes, and it's like I was there, feeling the passion and the inspiration this recording session achieved.
I could not let go of the performance, and I did not want the music to end even when the album did. Music and Tonality were exceptional and Elvis never sounded better.
|Beyerdynamic DT 770 Pro (80-Ohm)|
Warren's Beyerdynamic DT 770 Pro 80-Ohm: Since the A 20 is a Beyer amp, I instinctively wanted to reach for some Beyer headphones. Unfortunately, both my DT 1350 and my DT 880 headphones were away on long-term loans. That left me with a humble pair of DT 770 Pro (80-Ohm) closed-back headphones.
I didn't know it at the time, but this turned out to be very serendipitous pairing.
Taking a jaunt through Taylor Eigsti's "Get Your Hopes Up" from his Lucky to Be Me album, I was rewarded with a very nicely weighted low-frequency response that remained unusually clean and tight from the sub-bass through the mid-bass and into the lower mids. Both the double bass and Taylor's lower-octave piano work came alive with excellent separation and texture. I've always been rather annoyed by bass bleed, or thick and indistinct lower mids, so I was delighted to find almost none of that here.
The entire mid-range presentation of the A 20 and DT 770 pairing was exceptionally clean - cleaner, more detailed, and better separated than I've ever heard from a DT 770. There was no hint of stridency or congestion all the way through the upper mids and into the highs. And the highs came through with both richness and shimmer surrounded by a wonderful and airy openness - which surprised me considering the DT 770 is a closed-back headphone. The staging and imaging characteristics were also very good, almost on-par with the best I've heard from a pair of closed-backs.
In hindsight, the pairing of the A 20 and the DT 770 sounded the most "correct" out of all the pairings I've tried. It sounded "right" - to the point where I enjoyed the music viscerally and without cerebral interference.
If - by some strange chance - you're looking at the A 20 with the intention of driving a Beyerdynamic DT 770, you can stop reading this review right now, and simply buy the A 20. Your search is over, mission accomplished.
Frank's Beyerdynamic T1: While the Beyerdynamic T1 was more difficult to drive than the HD 800 - as the A 20's volume control had to be moved up considerably to get more volume - but the A 20 still did very well in driving the T1.
Again, with Elvis's Stereo '57, the T1 sounded extremely transparent and had musicality and terrific treble extension. The bass was full extended and the treble was extended and sparkly. The T1 is very synergistic with the A 20.
The A 20 and the T1 on Amber Rubarth's Sessions From The 17th Ward sounded excellent. The T1 let me hear the inner detail in the recording with clarity. I could hear the hands hitting the skins of the bongos on the track "Hold On." Amber's voice was focused in the front of the sound stage and the instruments were strategically placed within the sound stage. Dave Eggar's Cello was playing in the left rear of the stage was focused, and had air and detail. I could hear the strings of the instrument and the woody sound of the cello's body, and his finger work was very vivid. Amber vocal sounded very sexy and seductive.
The T1's resolving power was exceptional with the A 20. I was very involved with the "Down Home" acoustic track. The music was focused and I could identify every musician and hear the strings of the violin clearly on the right, and Chuck Palmer's percussion clearly in the rear of the sound stage with exceptional clarity. The cello was easy to identify to the left in the sound stage. Amber's voice was playful and exceptionally transparent on the "NovaCaine" track. This album highlighted the sound stage and the A 20 delivered a deep and extended sound stage with good front to back depth with air and space between the performers. The sound stage is very accurate in this recording and the A 20 was musically involving while listening to this recording.
And even though the HD800 resolved more inner detail and had a more expanded soundstage than the T1 (Amber's voice moved a little further back, but still was focused and very vivid with clarity and articulation), the T1 had slightly deeper bass on the A 20. Both the T1 and HD800 were playing very easily and sounded alive and reference quality.
Warren's Denon AH-D7000: Based on my earlier experience with the DT 770, as well as Frank's experience with the T1, I began to suspect that the A 20 might have certain sound shaping characteristics with regard to the lower frequencies. Specifically, it occurred to me that the A 20 might have an extremely analytical and flat bass presentation. To test this, I turned to a bassy favorite amongst audiophiles, the Denon D7000.
Going back to Taylor Eigsti's "Get Your Hopes Up" I was treated to a flatter and more realistic low end than I typically get from a D7000. The bass was nearly as extended - but noticeably tighter than - most D7000 auditions. Double bass and piano notes had a refreshing mass to them, without too much accompanying boom. There was a bit of bloom in the lower mids, particularly evident in some of the guitar work, but it wasn't anything I couldn't easily live with. The highs were a bit thinner and more prominent than I would prefer, but hats and cymbals were still pristine and enjoyable with a pleasant airiness.
Turning to Marta Gomez's "Lucia" from her Entre Cada Palabra album, I was rewarded with natural sounding mids that exaggerated very little beyond my liking. Everything, from the guitar to the percussion to Marta's vocals, was served up with plenty of detail and good tonality. Overall, this pairing was reminiscent of a traditional audiophile presentation, emphasizing extension at each end.
Frank's Fostex TH-900: The Fostex TH-900 was an excellent match for the A 20. Even with its low 25-ohm impedance, the A 20 drove them easily.
Wycliff Gordon's Dream Of New Orleans is another excellent binaural recording. Listening to this album with the TH-900, the trombone had the correct tonality. The instrument had bite, and again I was treated to hearing all the detail in this recording. I could hear the percussion sound of the trombone coming through clearly. Gordon's instrument had transparency, and the drums were hitting hard and I could hear the cymbals and the space between them. "When The Saint's Go Marching In" had my toes tapping, and the A 20 let me become involved with the performance and total consumed with the music.
And while the sound stage was not as open as that of the T1, where the instrument separation was larger and wider and deeper, the Fostex TH-900 was still an excellent match for the A 20.
Warren's Denon AH-D7100: After hearing about Frank's TH900 audition, and following my own D7000 audition, I became more convinced than ever that the A 20 would prove adept at tidying up the low end of whatever was thrown at it. For a definitive test of this theory, I decided to plug in Denon's D7100. For those of you not familiar with the D7100, it is a fun-sounding headphone with a very lively bass response.
Validation is a nice feeling. As predicted, the A 20 did much to bring the D7100's low end into line, drying up much of the wetness that the D7100 is known for. The A 20 won't make your D7100 analytical or neutral by any means, as there remained some rather incredible sub-bass, leading into an emphasized mid-bass. But it did alter the D7100's low-frequency presentation quite noticeably.
If you don't listen to many bass-heavy genres, you'll be able to appreciate this pairing for what it has to offer. With Alabama's "Born Country" - from their For The Record: 41 Number One Hits album, the D7100 lends this song some greater gravitas with its elevated bass response, especially in the kick drums. The forward vocals in this track were tamed by the D7100's slightly recessed mid-range, which resulted some satisfying harmonies that didn't overshadow the rest of the performance. The highs were clean, crisp and bright without being strident.
|Sennheiser HD 650|
Warren's Sennheiser HD 650: At this point, it occurred to me that the A 20 might be able to help me with a long-term love-hate relationship of mine. Sennheiser's HD 650 is one of those headphones that has proven difficult for me to get into. I find it to be very dark, fairly wet, somewhat stifling, and overly intimate at times. Because of this, the HD 650 sounds very... um... vaginal, to my ears.
Sadly, the A 20 is not a miracle worker. In a pitiful attempt to rock out with the HD 650, I ran Soul Asylum's "Misery" (Black Gold: The Best of Soul Asylum) through it. It was still too dark for me. And while the bass response of this pairing was very enjoyable, being neither too warm nor too thin, the pros of this pairing ended there.
The mids were decent and respectable, but nothing worth noting. Roll off began far too early in the upper mids, resulting in some spectacularly boring percussion. The highs were fairly dismal in that they were nearly absent, and certainly devoid of air. In short, I did not like this pairing at all. But don't fault the A 20 for this, as this was simply a case of the HD 650 being an HD 650 for me.
Planar Magnetic Headphones
Beyerdynamic markets the A 20 as an amplifier for your dynamic headphones: "with the A 20 you will rediscover your dynamic headphones." Because of this, we were initially hesitant to pull out some bigger guns here. But then we remembered that many personal audio enthusiasts (ourselves included) own a variety of headphones - both dynamic and planar magnetic - and occasionally an electrostatic or two. In the interests of being thorough, we decided to just go for it.
Still, as a caveat, we'd like to point out that Beyerdynamic doesn't specifically recommend the A 20 for your planar magnetics or orthodynamics.
Frank's Audeze LCD-2.2: The LCD-2.2 played exceptionally well on the Beyer A 20. I was concerned that the power output of the A 20 might have some issues driving the LCD 2.2, but the A 20 managed to deliver a musically engaging presentation. I experienced no issues driving the LCD-2.2 to musically satisfying levels.
While I prefer using amplifiers with more power for planar headphones, I would definitely say that the LCD-2.2's presentation was very detailed with well extended treble and good, solid bass. At the same time, I would have to say that the LCD-2.2 does scale better with more powerful amplification.
It was evident that the Burson Conductor SL made them sound more open and even more extended with better bass and treble extension.
Warren's Audeze LCD-3: Of all the headphones I chose to pair with the A 20, the LCD-3 was easily the most holographic of the bunch. I am at a loss to explain why this was so, as I've never found the LCD-3 to be particularly expansive or deep in terms of staging. And yet, there I was, in the midst of a studio recording that I could have sworn was a live-performance.
Listening to Taylor Eigsti's "Get Your Hopes Up" yet again, I was amazed by the sense of realism here. Everything sounded natural and viscerally present. I was finally beginning to understand what Frank was on about with Elvis's Stereo '57 album. Of course, this was an anomaly. It had to be. Nothing about it made sense. It's not like the A 20 was able to magically reveal some kind of hidden detail, because this wasn't even a live recording to begin with.
I also noticed that this pairing's bass response was somewhat shy of what the LCD-3 typically delivers. But since I'm one of those who have always found the LCD-3's bass a bit much, I did not mind this in the least.
Warren's Audeze LCD-X: Audeze's new LCD-X is absurdly easy to drive (22 Ω, 96 dB/mW). Because of this, I've been going around trying it on every amp that comes in, even those that don't seem like they'd be a good match.
With the A 20, what I heard time and time again was something highly reminiscent of an early Eighties (i.e. sub-woofer-less) home audio system. The bass control here was quite remarkable. For me, and for anyone else that suffers from bass fatigue, this is a welcome and refreshing breath of fresh air.
Taking a trip back to 1984, Alison Moyet's "Invisible" was a perfect example of how this Eighties-ification played out on some actual Eighties music. In addition to the tight mid-bass, I very much enjoyed this pairing's forward mids for Alison's vocals. Upper mids broke though this airy presentation like beams of sunlight, with a clean and refined snap about them. And the highs were wonderfully shimmery but not harsh.
Overall, this pairing sounded very transparent, with excellent detail and separation to boot.
|MrSpeakers Alpha Dog|
Frank's MrSpeakers Alpha Dog: The new MrSpeakers Alpha Dog played surprisingly well on the Beyer A 20. Like the LCD-2.2, I was concerned that the lower power of the A 20 would have some issues driving the Alpha Dog, but the A 20 handled the Alpha Dog with musicality, and had no issue driving this orthodynamic to satisfying listening levels, with good soundstage and nice depth and focus.
MrSpeakers's Alpha Dog was very surprising playing Van Morrison Pagan Heart form his Born to Sing: No Plan B Album. Van's voice was articulate. I could hear every lyric clearly. The guitar strings were snapping and you could hear the detail of the instrument. On the last track Educating Archie, Van's classic saxophone was robust and had body and air. I could hear him blowing into the mouthpiece and the instrument had life and you could feel Van's passion while he was playing. His voice was live and exciting and I was completely consumed with the music.
Switching back to Elvis's Stereo '57, the Alpha Dog was able to repeat the experience of transporting me to the recording session, while keeping the performance clean and musical. Although, I would have to point out that the HD 800 was more open and less restrictive, with a wider soundstage that made the recordings more alive. Clearly, the A 20 was favoring the 300-Ohm dynamic headphone, more so than the planar's more demanding load.
Warren's Audeze LCD-XC: In rounding out the planar magnetics, I opted for Audeze's LCD-XC to complement Frank's MrSpeakers Alpha Dog impressions - seeing as how both are closed-back planars.
Before I get into the results, I would like make one thing very clear: I did not have high hopes for this pairing. Both the A 20 and the LCD-XC are exceedingly clean and controlled in terms of low-frequency output, with neither one ceding an inch to looseness in terms of bass response. My concern here was that their respective tautness would not work synergistically at all. I was - unfortunately - correct.
While I wouldn't say the bass was outright anemic, I do need to point out that it was undesirably thin, at least for my ears. Is this a bad thing? Well, that would depend on how you like your bass. For those of you who consider the Q701 to be a bit warm - and I happen to know several of you out there who do - this pairing might just be what you've been searching for. Having said all that, let's take a look as where this pairing did shine: vocals.
With The Barden Bellas' "Finals Medley" from the Pitch Perfect OST, I was rewarded with an exemplary mid-range that happened to work well with this female acapella arrangement. Anna Camp's opening verse was sweetly angelic, Brittany Snow's high notes were delicate and fluttery, Hana Mae Lee's beat-boxing was neither strident nor smoothed-over, and Anna Kendrick came through with honesty. If you're in that stage of audiophilia where mid-range is everything, you'll enjoy this pairing.
Again, I'd like to note that I tried this pairing out of personal curiosity, as the A 20 wasn't meant to drive planars in the first place. On top of that, I don't think there are many enthusiasts eying this combination anyway, making this trial all the more academic. And so it remains, in my mind, an ideal pairing for a rather select group of people.
I also have a suspicion that Beyerdynamic's flagship amp, the A1, would fare much better here. I look forward to trying that out someday. I'll be sure to report on my findings if and when that happens.
In-Ear Monitors (IEMs)
As a final torture test, Frank and I decided to subject the A 20 to a battery of sensitive and efficient IEMs. Yes, we know that the A 20 has 100 Ω of output impedance. And yes, we know that the A 20 is way overkill for IEMs. No, we don't care... because we also know that any enthusiast worth his or her sodium chloride has an IEM, or two, or ten. So again, just to be thorough...
Warren's Etymotic ER-4PT: Don't try this at home. No, really, don't do it. This pairing results in an uncomfortably n-shaped signature that isn't very pleasing. With Superhumanoids's "So Strange" from their recent album Exhibitionists, the LF response was just too lean. The lower mids were very prominent to the point of being borderline shouty. The upper mids are similarly lacking in timidity. Together, they exhibited too much bloom for my tastes. And the highs, while smooth, were rolled-off and lacking that crispness that I typically enjoy from my ER-4PT.
Now, I'd like to make it clear that this is just a bad pairing. The A 20 and the ER-4PT each have their merits, apart from each other. And the Etymotic ER-4PT remains one of my favorite IEMs. This is simply a case where the synergy just wasn't there. I mentions it only as a warning: if one of your main IEMs is an ER-4PT, and you intend to use it for desktop listening with an A 20, you've been warned.
|Tralucent Audio 1Plus2|
Warren's Tralucent Audio 1Plus2: Next up is one of the darling IEMs in our hobby - the 1Plus2 from Tralucent Audio. For this, I cued up Michael Franks's "Now That The Summer's Here" from his Time Together album, which was recommended to me by my friend and fellow audiophile, John Sharpe.
By the way, John Sharpe (http://www.sharpeshots.com) is a spectacular commercial photographer. Like my other friend Lee Shelly (http://leeshellyphoto.com) - who is an absolutely brilliant commercial photographer in his own right - John is one of the few people I would trust with product photography if I were an audio manufacturer. If all manufacturers supplied product photography that was a good as John's and Lee's, high-end audio would be far sexier than it is today. If you're a 2-channel hi-fi manufacturer in Canada and you need some shots, call John. If you're a high-end personal audio manufacturer here in the States, call Lee.
Listening through Tralucent's Silver+Gold cable, I found the 1Plus2 absolutely delightful when paired with the A 20. The bass was pleasantly weighted, serving as a solid anchor for the rest of the song's elements. It wasn't perfect though, as it could be sporadically woolly between the mid-bass and lower mids, but it was euphonic, being wrong in all the right ways. The mids, having been brought forward by the A 20, were exceedingly balanced throughout, with a natural and realistic tonality. The vocals were neither forward nor recessed, and the guitar was warm and rich, laden with harmonic goodness. I was also rewarded with a very smooth transition into some wonderfully glittery and shimmery highs. Yes, the highs were rather bright. But in this case, they were clean as well, bordering on pristine. This resulted in instantaneous ear spoodge when the chimes came in at the start of the song.
Moving on to Tralucent's Uber cable, I found that the bass tightened up admirably, but still carried the same impact as before. The mids moved forward, especially the lower mids, enabling the guitar to remain full and rich while offering more detail. The highs, while still shimmery, were not as airy or wispy as before, having given up some of their gossamer presence at the very top.
|Ultimate Ears 18 Pro|
Overall, I enjoyed the Tralucent 1Plus2 with the A 20, with both the Silver+Gold and Uber cables. But if pressed, I would readily admit that the Uber cable offers a much more refined listening experience that pairs better with the A 20.
Frank's Ultimate Ears 18 Pro Custom In-Ears: The Ultimate Ears 18 Pro in-ear monitors did very well with the A 20, and the performances were very quiet and hiss free.
Many amplifiers, even expensive TOTL amplifiers, are unable to play sensitive IEMs without hiss. With the UE18, the A 20 delivered excellent sound without any noise or hiss coming from the 102dB UE18.
Conclusions (a.k.a. TL;DR)
Frank: Beyerdynamic's A 20 has an excellent mid-range, with good bass and excellent treble. The A 20 let me enjoy every headphone I used with it. The HD 800 and T1 sounded exceptionally good with the A 20. The Fostex TH-900 performed admirably as did the Audeze LCD-2 and MrSpeakers's Alpha Dog. Both planars did benefit from the more powerful Burson Conductor SL, but still can be used and enjoyed with the A 20.
My favorite headphones while using the A 20 were the Beyerdynamic T1 and the Sennheiser HD 800, followed closely by the Fostex TH-900. The A 20 did not disappoint me using these reference headphones and always performed admirably. The A 20 performed with musicality and involvement rarely found from products in this price range and brought out all the musicality of these three reference cans.
If you're using headphones with higher impedance headphones, such as the offerings from Beyerdynamic or Sennheiser, or highly-efficient in ear monitors, the A 20 should be a strong consideration. If you're using more power hungry planar headphones, the Burson Conductor SL with 2W of power may be the better choice.
If you in the market for high quality headphone amplifier, the A 20 should merit your consideration. The German built amplifier is built with high quality parts and performs well. A legendary German company builds the A 20 with dedicated craftsman in Germany that take great pride in their work. The fit and finish are excellent. The A 20 is musically involving and is musically engaging. If you're in the market for a musically satisfying product the A 20 may be just what you're looking for.
Beyerdynamic has succeeded with another first-rate quality product that most music lovers would be proud to own.
Warren: Beyerdynamic's A 20 is - without a doubt - one of the cleanest sounding headphone amps I've heard in quite some time. In fact, the one key facet of its performance, that I would impress upon anyone who'll listen, is that it is clean, pristine, and transparent as ****.
Signature-wise, the Beyerdynamic A 20 is aggressively tight in terms of controlling LF response, bordering on being lean and analytical at times. For neutral headphones (e.g. AKG K/Q 701) and various studio monitors, this may lead to a duller listening experience. But for most headphones, the result is a neat and tidy bass devoid of boom or bloat. In some cases, I found the A 20's compulsive bass control to work in my favor, as it helped to make some of my bassier cans (i.e. Denon's AH-D7000 and AH-D7100) far more balanced.
I agree wholeheartedly with Frank about the A 20's midrange - it was excellent. Tonality was highly accurate, separation was effortless, and detail resolution was beyond reproach for an amp anywhere near this price range. And did I mention it was clean? Holy **** was it clean!
If there is any flaw to be found with the A 20, that would have to be its rendering of highs. For those of you familiar with the Beyerdynamic DT 880, it could be said that the A 20 is a DT 880 in amplifier's clothing. At times, I found the highs to be somewhat excessive, giving the A 20 a decided slant towards brightness for me. I wouldn't say its a fatal flaw, but I would caution those with treble sensitivity to look elsewhere. It's simply not going to be your cup of tea.
Having said that, I would recommend the A 20 to those who want a clean, neutral-bright amp with impeccable build-quality for their mid-fi rig.
For those looking to upgrade to their first "serious" headphone amp, I would offer the following comparison: the Beyerdynamic A 20 is the amp that the O2 (Objective 2) wants to be when it grows up. If one were to imagine a cleaner O2, with far superior detail and separation, bigger (but not hairier) balls for better dynamics, and musicality to boot - the Beyerdynamic A 20 is that mental image, realized in physical form.
Editors' Note: In the interest of full disclosure, we'd like everyone to know that - as of December 19th, 2013 - Frank Iacone has been affiliated with Woo Audio, a headphone amp manufacturer. However, we would also like to note that all of his impressions for the Beyerdynamic A 20 were recorded and finalized months ago, long before his affiliation with Woo Audio began. As such, we have concluded that there is no cause for concern in the case of this A 20 review.
Original content provided by Audio360.org and is available at: http://www.audio360.org/amps-dacs_a0016_review_beyerdynamic_a_20_headphone_amp.php
Edited by warrenpchi - 12/31/13 at 7:22pm