The Black AMP

A Most Delightful Audiophile Headphone Amplifier And Control Center

The Black AMP offers exquisite layering and separation of instruments, quick and precise attack with no lingering delay. With a bright, wide-open soundscape without harshness or fatigue.  The Black AMP  renders each musical voice in transparent detail magnifying impact and soulfulness of the aural presentation.  A unique quality of the Black AMP is  its enhancement spatial definition creating a full but specific soundscape upon which your music plays out.

Controls
Input selection for three sources
Signal Level
Power
Sensitivity/Gain

 

I/O
Balanced XLR Output (front XLR-4)
TRS Phone Output  (front 1/4″ phone)
Balanced Input (rear XLR-3)
Unbalanced Input (rear  RCA)
AAWLink (rear XLR-4)

Technology
Current-Mode Operation
No Feedback
Current Drive
True Balanced Topology

The remarkable sound of the Black Amp

is based on these technological philosophies:

Current rather than voltage domain operation to create power gain.

The Black Amp is a fully Complimentary-Symmetrical Class-A, Current Carrier Technology Headphone amplifier. This gives us speed and consistent linearity with frequency resulting in extraordinary detail, fast dynamics, and precise resolution.

The amplifier does not try to control the transducers, be they coil or planar technologies. It simply drives them in their natural current mode of operation so as not to ‘force’ the music out of them but rather let them render the music naturally. The Black AMP offers both push and pull electrical current carrying audio information through the headphones, letting them act as true transducers reproducing sound with unaltered timbre.

No feedback and a unique bi-directional current drive system

No feedback and a unique bi-directional current drive system

The amplifier does not try to control the transducers, be they coil or planar technologies. It simply drives them in their natural current mode of operation so as not to ‘force’ the music out of them but rather let them render the music naturally. The Black AMP offers both push and pull electrical current carrying audio information through the headphones, letting them act as true transducers reproducing sound with unaltered timbre.

Topology

The Black AMP is four independent, no feedback, current mode power amplifiers configured as two truly balanced mono-block power amplifiers.  Each channel operates on its own with no internal commingling of any of the four audio information signals or processes. Eliminating common ground gets rid of signaling contamination due to electrical and magnetic field interactions between the channels. Everything is floated above ground in a truly balanced environment.

 

Key Empowering Concepts

Feedback is not good.  It means taking some of the output and subtracting it from the input in an active dynamic loop.  In the voltage mode transistors display a phase or time shift as the frequency goes up.  This means that the output is not really in sync with the input and gets more out of sync as the frequency goes up.  You see this as rising distortion in the amplifiers.  In addition, anything that changes in the load impedance or any stored return energy creates new signals at the input that are not part of the original music stream.  The quality and timbre of the music changes on the fly.

By employing current mirrors with matched complementary symmetric transistors in their natural  Class-A current mode we get linearity, low noise, and ultra-high bandwidth without feedback.  In the Black Amp only the original pure music signal is passed through the amplifier to the load.

Distortion that changes with frequency sucks the life out of the music. This is the result of feedback.  The Black AMP circuitry has a consistent performance character from octaves well below to octaves well above the 11 octaves of the audio band.  This means no changes in phase, amplitude, or distortion over the entire audio range  as the frequency goes up.

With standard amplifier design the distortion level changes with frequency; meaning that the amplifier is really a different amplifier to the load, speaker or headphone, at each musical note or frequency in the audio band. The low frequency harmonics and thus timbre are different than high-frequency harmonics and timbre. Literally, the load, speaker or headphone, interacts with a different amplifier at different frequencies thus timbre changes with musical pitch.

In the Black AMP the harmonic structures are treated the same at all frequencies, the timbre is not modulated by the frequency.

Output drive to headphones is very special.  Moving coil or planar, all headphones are pure electromechanical transducers.  They don’t store energy as do speakers – they are about ampere-turns and magnet fields.  This means they work on current flow rather than voltage potential.  The current sourcing and sinking output of the Black Amp drives all headphones as they should be, in their natural current mode. Current mode gain and output allows us to design while avoiding feedback.  This eliminates the dynamic music ‘muddling’ sonic signature found in all other amplifiers. The Black Amp gets the right gain, the right drive, and the right sound.

Active power supply – Power from your house mains can be pretty gnarly and has a deleterious effect on the sonic output of a power amplifier.

The Black AMP employs active capacity multipliers to clean up and stabilize the power supply.  Superior to active voltage regulation for current amplifiers, they don’t employ voltage feedback to control the power supply but instead do it naturally in the current mode.

Your headphones are the last link in the musical chain between information stored in time and the ‘now’ of your life as a listener.  This permits those headphones to do their best job of moving air to bring an illusion alive in your head. An amplifier that adds nothing but power and takes away nothing.  This is the passion of the Black AMP.

Some Customer and Listener remarks about the Black AMP

The Black AMP headphone amp, in particular, sounded completely honest in its Sgt. Friday approach to sound–the music and only the music. I’m not sure how much of this can be pigeon-holed as neutral, because it was somehow far more interesting than that.

The Austin Audio Works headphone amplifier offered a clean transparency in the bottom octaves that seem to draw out more details in the music, especially in terms of the transients that define the physical activity of the performers required to produce such low frequencies….

Marc Phillips

Reviewer, Part-Time Audiophile

I have been a longtime tube enthusiast though I have listened to and owned many discrete amps as well. At the end of the day, smoothness they provide has been the driving factor. When I first listened to the Black Amp, I knew it was different. It is the smoothest discrete amp I have ever listened to. It has speed and articulation without sounding clinical. I have struggled to find amps that have authority with the T-1 headphones I use primarily. This amp has no problem with them at all. It has relegated my WA-2 to only get occasional use at this point. I have both a Yulong & Cambridge Audio balanced DAC and both are very good pairings with this amp. I have not used the single ended side of the Amp, but as a balanced device it is miles beyond anything I’ve heard that is even close in price.

For my T-1’s this is a perfect amp, but it does a great job on my set of TH-x00 as well (totally different listening experience between the two sets of cans) and I have listened extensively with the HD-800’s and Alpha Primes. I never thought I would move on from my VTL or my WA-2 but the transparency and presence of this amp are amazing and it does it without becoming dry or clinical. I am looking forward to Austin Audio Works future offerings

Tim L

This amp brings a clarity to the table that is missing from my other amps. It is SS obviously, so it has a speed and transient attack that is fast but not not overly square or grainy. This is true from bottom to the top of the frequency response, with upper mids and lower treble being fast and clear without any steeliness and glare. The FR is balanced and nothing jumps out at me as out of place. The bass is textured and detailed. The voices and mid centric instruments are neither forward nor recessed – everything is in place. Overall I think the amp is a click to the right of neutral, and this probably enhances its sense of clarity …..Really, this is a tube amp at heart but without most of the drawbacks of tube amp. Yeah I really liked this amp and was bummed when it left. I think it kills in sound in it’s price category if you’re looking for a tube sounding amp without having to deal with tubes.

Pat

Being an audiophile means that you are an explorer, an adventurer and (let’s face it) at least a little bit of a masochist. I have spent many, many years on my personal sonic journey, and have heard transcendent highs and grating lows in that time. Speakers, headphones, DAC’s, turntables, moving magnet, moving coil, solid state, tube, digital, analog, professional grade, high-end, boutique, lo-fi, summit-fi, etc. are all manner of gear that has passed through my life. Around 2012, my quest became centered on headphone rigs, as I was confined to small quarters and could not spread out and set up a speaker rig. I dove quick and deep into this equipment category, and soon after getting my bearings, ended up owning HD-500s, T1’s, HD-800s and JH-16s. However, somehow driving these amazing beasts to their highest potential proved to be harder than I had thought it would be. I had naively approached amplifiers as somehow second-tier to speakers, but these new and highly resolving headphones demonstrated to me that there was so much more to amplifiers than I had originally appreciated. So again, I dove straight in. I tried solid state, tube and hybrid set-ups at varying price points and power levels, but there was always something keeping me from achieving what I knew was possible. Some amps stayed longer than others, but the synergy I craved was only ever glimpsed, not fully achieved. That is until Barry Thornton showed up with his current-mode “Black Amp”. Holy moly!

The Black Amp has done what I have always felt was impossible – it is a solid state amp that is more listenable and lovable than tubes. It has tamed the sometimes shrill HD-800’s, while at the same time remaining clear, precise, fast, open and unfathomably powerful. It plays a magic trick on your audiophile senses; you start out amazed at some specific aspect of the sound quality like how fast and accurate it is, or the incredible soundstage, or the intense blackness of the background, or maybe it’s the deep slam that it can deliver, but then that analytic amazement just melts and you are just left with a deep well of satisfaction and enjoyment as you forget to analyze any further, you just keep listening. Seriously, this thing can be so hard to review because it is just so engaging to listen to. It draws you into a space INSIDE the music — you become the flow, the timbre, the texture and the rhythm. I probably look like an idiot every time I listen to this thing because it either plasters a smile on my face or I am eyes-closed and enraptured. There has never been a single piece of equipment that I have encountered that has brought me as much satisfaction and joy as “The Black Amp”. This thing is something magical to behold

Scott P

Buttery smooth highs with good HF extension, completely fatigue free even at higher SPL or with harsh tracks, nice I/O flexibility, mellow timbre and cohesive tone, good spatial rendering, compact size, would probably allow me to listen to any HD800 without crying tears of blood.

Ed C

I plan to get one because:
Super non fatiguing
Excellent clarity, separation, and tone. Some things that stood out which I didn’t notice mentioned in other reviews:

  • Piano tone is really, really good, the weight and feel was just right
  • Bass has good extension despite being lighter
  • The Black Amp is very chill without being warm or rolled off in the treble. I need more chill in my life.
  • I found the previous point especially surprising because the treble is both extended and clear. I have never heard this without music getting “hot” sometimes. I think Barry used some black magic to keep this amp smooth with this treble.
  • The noise floor (I think that is the term) is excellent. I turned the volume all the way up and heard no noise whatsoever. Can’t say the same for the Black Widow or Stratus.
  • What really sold me on purchasing the Black Amp in the near future is the excellent tone, clarity, and separation coupled with fantastic smoothness.
Larry H

So far, halfway thru my playlist, I think the HE6SE has never sounded this good.
Bass guitar is resonant with good tone and decay and goes as low as needed with no drop off, excellent separation on all instruments, cymbals , chimes, strings, orchestral, classic rock, opera, jazz, vocals have all been upgraded, very easy to follow a single instrument or just sit back and feel like your hearing it all. It’s always going to be headphones but that sax is front center left near the piano, percussion is wide and articulate, guitar center, gentle and subtle on full display, loud, complex and busy, easily distinguished with resonances and decay from all instruments realized.

In all, I would say it’s like having a new headphone, so much more delicacy and resolution.

Brian H

The Black AMP Specifications

Output Drive

The Black AMP is a current mode amplification process. Instead of the typical artificial ‘zero’ impedance output of feedback based amplifiers, the Black Amp output is high impedance. This is a current source driving the headphone transducer in a more ‘natural’ process, the result of no global or stage feedback.

Noise

Signal to noise is over 115 dB (weighted, that is 60 Hz limited) from a 2 volt RMS output. Noise is one of the important factors that limits resolution and the details needed for a true soundscape. The Black AMP’s unique clarity and resolution is rooted in noise between the spectral elements of the musical signal.

Distortion

A key technical feature of the Black Amp is that the distortion does not change with frequency. The four images below are the signal and the distortion. Note that all the distortion is second (even) harmonic energy. Even harmonics are melodic in nature as opposed to the usual distortion of feedback which is odd harmonic based and thus dissonant in sonic nature. Note the fourth image, the distortion above 50 kHz.

100 Hz

1 kHz

10 kHz

50 kHz

Square Waves

Square-waves reveal both stability and bandwidth issues. Without resorting to using feedback, the Black AMP is flat and stable out to a megahertz assuring no interactions and odd-harmonic artifacts to reduce resolution and musicality. In technical terms, the Black Amp behaves flawlessly through and past the audio band.

100Hz

1 kHz

10 kHz

50 kHz

How does this technical data equate to sonic performance?

The data shows that the dynamic nature of the amplifier does not change with frequency, and that frequency range far exceeds that of the audio spectrum. A change in distortion based on frequency says that the amplifier is essentially a different amplifier at each frequency. This means that overtones or harmonics for any specific instrument being reproduced are different when amplified in such a topology.

The amplifier is the same source to the transducers at all frequencies. Damping , distortion, gain, all remain the same when seen by the speaker or headphone.

This performance consistency is the key to timbre-fidelity and spacial coherency and better sonic image.