Finding an amplifier that can drive some of the most power-hungry headphones around, but still be nimble (with an incredibly low noise floor) for some of the most efficient headphones has been somewhat of a quest for me through the years. Some amplifiers can indeed straddle this chasm, but none have done either extreme with full justice. They can either handle the more powerful headphones, but leave somewhat of a noise floor that detracts from headphones like the Focal Utopia (lower impedance and fairly efficient). Conversely, some amplifiers can drive highly efficient headphones quite well with the blackest of backgrounds but can leave you wanting for more drive and authority when listening to say the Hifiman flagship headphones, the Susvara. Having the one amplifier to “rule them all” has been a fool’s errand for me somewhat through the years, but with the newly released AMP-23R, this quest has finally become a reality! Throw in the fact that this unit is also a top-flight speaker amplifier, you really can have your cake and eat it too! The successor to the AMP-13R by Bakoon, Enleum’s new AMP-23R has upped their game with their new flagship headphone amplifier and is the end-game solid-state model that I have been waiting for to literally drive anything that I may throw at it!
For the design of the AMP-23R, Enleum (formerly Bakoon International) opted to go for a new design that reflected their heritage from the Bakoon International days while still sharing the exact same footprint to the AMP-13R (though the AMP-23R is taller). This previous amplifier had some unique design characteristics, but in the end, it had to limit circuit design and parts usage for such a low height. The AMP-23R resolves these issues with a taller chassis and classic new look trailblazing a new path forward as well as a new identity for Enleum. Due to the incredible success of the AMP-13R, the task at hand to improve upon it was not taken lightly. While the technology is fundamentally unchanged, every little detail has been updated and upgraded for the AMP-23R. These upgrades include:
1. Ensence Module: This is the input section of the circuit. The 23R’s module has been re-designed with closer attention to the detail on the printed circuit board design. This module now operates at higher voltages. As a result, this amplifier now requires a good amount of heatsink which is directly attached on top of the module.
2. JET2 Bias: This is a major improvement over the AMP-13R’s JET Bias. This second iteration results in much better stability of the circuit and it is now more accurate across all operating temperatures. The downside is that Enleum now has to monitor every single unit during assembly to match the transistors’ behaviour via software, whereas it was a simple automatic process on the AMP-13R.
3. Power Supply: With the increase in height allowance, the designers changed all critical power supply components to higher-rated current components (similar to what they selected for their previous AMP-41 and AMP-51R speaker amplifiers). This allows substantially improved higher current delivery over the AMP-13R’s power supply design. According to the designers, this results in better bass performance and the amplifier being more reliable over extended periods of time.
4. Attenuator and Input Buffer (voltage-current conversion): Being incredibly important to the amplifier, these circuits (while very similar to the AMP-13R) have been improved through software enhancements. As well, the number of MPUs (microprocessor units) has been reduced from three separate ones to just one single MPU for the AMP-23R mostly for added efficiency and reduced complexity.
The full list of the amplifier’s specifications can be found here:
|Maximum Power||25 W @ 8ohms, 1kHz 45 W @ 4ohms, 1kHz 4W @ 60ohms, 1kHz|
|Gain||22.5dB max (Speaker, Headphone High Gain) 7dB max (Headphone Low Gain)|
|Gain Control||MPU Controlled Stepped Attenuator|
|Frequency Response||10 Hz – 100 kHz|
|Input Impedance||10 kohms (Voltage) / 10 ohm (ENLINK)|
|Inputs||2 RCA Inputs / 1 ENLINK (BNC)|
|Outputs||5 Way Speaker Binding Post & ¼” Headphone Output|
|User Interface||One Button & Gain Phase Control / Remote Controller|
|Dimensions||230 mm (W) x 230 mm (D) x 55 mm or 82.5 mm incl. isolation (H)|
|Weight||4.0 kg (net) / 4.5 kg (shipping)|
Right off the bat, I wanted to try my most power-hungry headphones that I had on hand, the Hifiman Susvara. I absolutely love these headphones and think the world of them, but that love does come with a requirement for plenty of good clean power on tap to have them sound at their best. With my trusty Chord DAVE as my digital to analog converter and my M1 MacBook Pro with Zoom as my source, I was off to the races. For this session, I decided to settle on an old standard of mine that is pretty difficult to pair with the Susvara as this recording is very demanding of these headphones and many an amplifier that I’ve tried has come up short. “Pictures at an Exhibition” by Modest Mussorgsky can be a difficult recording, to say the least for the Susvara if your amplifier isn’t fully up to the task. The DSD version that I have by the Weiner Philharmoniker / Gustavo Dudamel is one of my favourites of this classic work by this legendary composer and has often been a “go-to test track” for me with these headphones. Well, I can very safely say that the AMP-23R (in high gain mode) can very easily drive the Hifiman Susvara with complete ease and without breaking a sweat! My previous “go-to” solid-state amplifiers like the Benchmark HPA4 or HeadAmp GS-X mini could indeed play this recording quite well, but they did break quite a sweat to get through its most complex passages. The Enleum amplifier however made these headphones seem like a kitten to drive instead of the monster they can be for most amplifiers. This amplifier is dynamic and filled with energy and life. The dryness that many solid-state amplifiers convey with this recording and these headphones was replaced with such a musicality and euphony that had me smiling from ear to ear. Make no mistake about it, this amplifier kicks like a mule with incredibly rich dynamics and spot-on tonality that for me made this a completely enjoyable and memorable experience! The high levels of current that this amplifier could output into this hard-to-drive planar magnetic headphone truly opened up the Susvara’s ability to cast a vibrant and encompassing sound stage that was actually the largest I’ve ever heard them sound! Bass notes were no longer hinted at but rather took their proper place in relation to the rest of the audible frequency range. Anyone looking for a fuller bottom end with these headphones needs to hear them on the AMP-23R as soon as they possibly can! Transparency and clarity were equally there in this pairing and I was so very impressed with the AMP-23R’s ability to portray even the smallest of details and nuances within a recording with complete ease. This amplifier was simply the best I’ve heard these headphones sound and I’ve heard the Susvara through many top-flight desktop headphone amplifiers (and several speaker amps as well). If you own these headphones, please check this amplifier out…you will not be disappointed!
After a quick 180o switch, I decided to play my Focal Utopia headphones. These are likely the very best dynamic driver based headphones I have ever heard. Very much unlike the Hifiman Susvara, the Utopias are incredibly efficient and very easy to drive. But that advantage comes at a risk of hearing a higher noise floor from your system (especially among the more powerful headphone amplifiers). As soon as I plugged these headphones into the AMP-23R I immediately was relieved that I heard absolutely nothing; just pure blackness. I did have to run the AMP-23R on the Low Gain setting however to best drive these Focal headphones, but the results were well worth the few button clicks on the amplifier’s remote control. I have been a life-long Led Zeppelin fan and for me, they are in my top 5 bands of all time. As a result, Robert Plant’s vocals hold a very special place for me and his newest release with Alison Krauss and follow up to their Grammy Award winning album “Raising the Roof” was my selection for this session a few days later. Right off the bat, the Utopia’s incredibly high bar of punch and dynamics was raised even higher with this setup! This Qobuz stream via Roon was spectacular and just like with the Susvara, the bass notes on the Utopia seemed to hit even harder and with better definition and detail. This amplifier can really bring out a stellar bass performance from your headphones, even if they are generally accepted for having a more “polite” presentation in this area. Both Robert’s and Alison’s vocals were upfront and as clear as I’ve ever heard them with incredible treble extension and transparency. The other added bonus that this amplifier provided was an increased sound stage and was quite a profound change for me with these headphones actually. Normally they tend to be on the intimate side of things with regards to the soundscape that they can portray, but the Enleum amplifier offered such an improvement in this area that I simply could not go back to using my Chord DAVE alone to drive them.
Finally, I decided to use the recently released (and pretty incredible) Audeze LCD-5 planar magnetic headphones. I previously reviewed them here: https://headphone.guru/the-audeze-lcd-5-flagship-headphones-as-good-as-it-gets/. I absolutely love these headphones for their naturalness and incredible transparency. I would put them in the “medium” level of difficulty to drive. They do sound their best with a reasonable amount of power behind them, but they do not require uber-powerful levels upfront to sound their best. And just as with the Susvara and Utopia, the LCD-5s (on low gain) just shone with the AMP-23R amplifier brilliantly. This combination is quite the 1-2 punch for sonic goodness. “A Distortion of Love” by Patricia Barber on DSD is one of my absolute favourite jazz recordings that I often use for reviews. I find that it helps me understand a unit’s ability to catch the many nuances and details that are contained within and its ability to help prepare a mental soundscape of the performance. Well, I can safely say that the Chord DAVE – Enleum AMP-23R and LCD-5 was literally the best time I’ve experienced with this recording. Patricia’s vocals on “Summertime” were sublime and sultry and had me smiling throughout the track. I was rediscovering this past favourite of mine all over again. The bass that this amplifier can tease out of your headphones is truly an experience like no other. You get plenty of heft and energy, but this comes with a level of detail and control that is unmatched. The midrange of Patricia’s vocals was equally impressive. They were in perfect unison with the bass range and the transition to the treble was flawless. Cymbals were perfectly placed behind Ms. Barber but offered a level of realism and clarity that seemed to transport me to the recording studio. Finally, I want to mention just how much this amplifier adds to the already impressive soundstage of the LCD-5s. This pairing, to my ears, was the very definition of “End Game Setup” and I was so thoroughly impressed that I had to listen to this recording three times straight.
I absolutely love this amplifier! It has everything you might be looking for in a “one-amplifier-to-rule-them-all” as it can drive (with complete ease) the most power-hungry headphones you can throw at it, but still be equally light handed with some of the most efficient headphones around (and everything in between). The background of this amplifier is dead-black even with some of my in-ear monitors! For this review, I did borrow my brother’s Totem Sky bookshelf speakers over the holidays and we were both very thoroughly impressed with what we heard. Don’t let the smallish size fool you, this amplifier packs some serious punch! A beautifully constructed chassis; especially with the three isolation legs which should aid in isolating your amplifier from any vibrations from within your listening room, really looks great in your setup from a visual point of view. The only drawback is the rather hefty price tag of $6,600 CDN (without isolation) and an additional $600 CDN (with isolation), [or $5,000 USD and $5,500 USD with isolation] but high-end audio isn’t for the faint at heart and if you are looking for one of the very best solid-state amplifiers for your top-of-the-line headphones or speakers, I wholeheartedly recommend you check out Enleum AMP-23R; you won’t be disappointed!
I would like to thank Vince at REDDOTAUDIO (reddotaudio.ca), the sole importer of Enleum into Canada for helping facilitate this review and his excellent support!
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