When I spotted the Manley Absolute Headphone Amplifier this past year at AES, I was dying to review it! I have been a fan of Manley gear since I started my career in the music industry in 2010. So when I saw this amplifier, the first audiophile product I had personally seen from them, I was excited to see what it had to offer. I’ve had the pleasure of spending some real quality time with the Absolute. So what can you expect from this beautiful tube amp? Today, let’s take a closer look with this Manley Absolute Headphone Amplifier review!

Manley Absolute Headphone Amplifier Review

In the Box

-Manley Absolute Headphone Amplifier and Preamp

-IEC cable

-Manley Remora Remote (9V battery included)

-Documentation and Warranty Info

Specifications

-Amplifier topology: Triode vacuum tube output stage, switchable topology single-ended or push-pull

-Vacuum tubes: 2 x 12AX7 (ECC83) and 4 x 6AQ5A (EL90)

-Inputs: 2 x RCA (input 1 and preamp output = pass-thru when amplifier is on standby or off)

-Input impedance: 50 kOhms (pass-thru=300 kOhms)

-Maximum input level: 7.7 VAC RMS (+20dBu) — Conditions: XLR output, PP mode, 16 ohms load, VOL max, EQ out, 1 kHz tone

-Gain:

-Load 16 ohms: 15 dB (min FB), 7 dB (max FB)

-Load 62 ohms: 21 dB (min FB), 13 dB (max FB)

-Load 200 ohms: 26 dB min FB), 17 dB (max FB)

– Conditions: XLR output, PP mode, VOL Max, EQ out, 1 kHz tone

-Input sensitivity: 366

Design

Look and Feel

The look of the Manley Absolute Headphone amp is strikingly beautiful. It reminds me of the interior of a classic car, with curvaceous metal side rail handles detailed with swirly veneer.

Additionally, it is eye catching because of its exposed tubes. They have a light glow which combines wonderfully with the light glow of the LED status lights. The opaque, black housing cover dulls these lights.

Lastly, the knobs, buttons, and volume wheel have high quality and are of the same sturdy metal as the side rail handles. As a result, they look and feel expensive. The volume wheel in particular is fun because it corresponds to LEDs above it. It’s tactilely satisfying when it clicks as I turn it.

Ins and Outs

The Manley Absolute Headphone amp has two input options. Both are RCAs. They live on the top left of the back of the unit and are selectable via the button labelled “IN” on the front of the headphone amp.

The Manley Absolute Headphone amp has three output options. Two are for headphones and the other is for if one wants to use the amp as a preamp. The headphone output connector options are 6.35 mm (¼’’) or 4-pin XLR. The preamp output is RCA connectors. These three options are selectable via the button “Out” button.

Sound

Sound Modification

Output Tube Topology: PP and SE

The output tube topology of the Manley Absolute Headphone Amplifier is switchable via a button on the front face plate: PP and SE. This button changes the order of the tubes around which gives different sound characteristics to the output signal.

PP (or push-pull) has a tighter sound, and plays the signal with less distortion. According to Manley, “When in push-pull mode the two output tubes split the signal into two phases, a positive phase and a negative phase. One tube pushes the positive phase and the other tube pulls the negative phase.”

SE (or parallel single-ended) has a more colorful sound. It has more of a feeling of tubiness to it. Manley says, “single-ended mode distortion is higher, but this distortion is dominated by even-order harmonics which are pleasing to the ear, or more “tube-sounding”, adding warmth and euphonics, air and space, especially nice with female vocals and simple compositions.”

For example, when I was listening to the song Roll with the Punches by Dawes, the guitar seemed like it had more emphasis in the attack in the upper mids when in PP mode. However, when I switched to SE mode, the harmonics of the guitar felt fuller and more warm in the middle part of the midrange. It felt somehow smoother there. Additionally, Taylor Goldsmith’s vocal felt more blended into the mix in SE mode, whereas it felt more articulate in PP mode.

Feedback

In order to minimize distortion and stabilize the output, many amplifiers have a feedback design where the output signal feeds back into the input. The Manley Absolute Headphone Amplifier is no exception and actually has a control for the amount of feedback that goes back into the input. The more feedback (when the knob is counterclockwise), the more stable the output is. As a result, it has a cleaner, quicker response. When the feedback is not applied (when the knob is turned all the way clockwise), the output level increases and you’ll hear more tube bloom. Manley recommends more feedback when listening to thick, complex arrangements and less feedback when listening to simpler, more sparse arrangements.

For example, I was listening to the song Fever by Ray Charles featuring Natalie Cole. When I listened with the FB control completely clockwise, the level was significantly louder (perhaps consisting of about 3 lights on the volume control different?) than when the control was all the way counterclockwise.

One of the biggest differences in sound between these two manifested in the high frequencies. In Fever, right before the last verse, the cymbals start to pick up energy and climax in a few big crashes. When the FB knob was all the way clockwise, the cymbals sounded more forward, but felt more colorful. The harmonics of them seemed to cloud up the definition of the attack a bit. This was very aesthetically pleasing, but nonetheless, the attack was more specific when listening with max feedback (fully counterclockwise). Additionally, the upright bass sounded rounder when the FB control was all the way turned to the right. By contrast, it had a more clear attack and sustain when the FB control was turned all the way left.

EQ – Bass and Treble

For testing the Bass and Treble EQ controls of the Manley Absolute Headphone Amplifier, I set the feedback to its maximum (turned all the way to the left) and set the tube topology to PP mode. With this setup, the amplifier has the least distortion and is the most clean. Pressing the EQ button engages the EQ. When the Bass and Treble knobs are straight up the middle, the EQ is neutral. However, by turning either to the right, the respective bass or treble boosts. Likewise, when turning either knob to the left, the respective bass or treble cuts.

The EQ circuit is a Baxandall circuit. Named after Peter Baxandall, an English audio engineer who designed the curvature, this type of EQ shelving is supposed to be smooth and very natural sounding. And that natural sound was just what I experienced with the Absolute’s EQ.

For example, I was listening to the song Quizas Quizas Quizas by Pink Martini. When I turned the treble all the way up, no harshness came my way. Rather the curve felt like a slow slope that made the the percussion, strings, and vocal maintain their harmonic complexity, but just be a little bit louder in the mix seemingly from the base of the lower treble upward.

Likewise, with the bass all the way up, it lost no harmonic complexity. The upright bass just took a step forward in the mix.

Balance/Mono

The balance knob has a detent in the middle so you can perfectly send the music out both left and right. Additionally, the mono button is super useful for older recordings with funky panning.

Versatility

The controls on the Manley Absolute Headphone Amplifier are not only fun to adjust. They are useful and versatile tools to getting what you want out of the sound.

And while the sound is versatile for varying complexities of arrangements, it is also versatile for headphone power needs. From the Focal Clear, to my little Beyerdynamic DT 240, to the 600 ohm Beyerdynamic T1 to the power hungry Hifiman HE6se, the Manley Absolute drove the headphones loud enough to enjoy thoroughly. With the HE6se, the volume wheel was close to max for me, but I still felt like i was getting enough power from the amp. I heard some coloration (from the tubes perhaps) but it felt aesthetically pleasing.  

Overview

Overall, the Manley Absolute Headphone Amplifier doesn’t only have a beautiful look. It has a fun, versatile sound that is aesthetically pleasing. It works for a wide variety of headphones and music.