Enleum HPA-23RM Review

This is the first product from Enleum that I’ve tried, and it looks to be a product that has a lot of potential. The HPA-23RM is a new reference amplifier that is in the high-end range. It’s priced at $2,999 and includes some interesting technology that could make this a must-have part of your headphone setup. Does the 23RM reach that level?

What You Get

• Enleum HPA-23RM reference headphone amplifier
• Raspberry Pi USB-C Power Supply

Build

High-end amplifiers sometimes like to have complicated designs, but the 23RM is very simple. That simplicity might come as a detriment to its versatility due to it lacking certain inputs and outputs, but it makes for a very clean construction. It’s reminiscent of Chord’s design for their Hugo models. In fact, these units might make a great pairing. It’s a minimalistic look, with dimensions that don’t scream high caliber, but it’s easy to carry around and retains a fine level of class.

On its front, you have a gain switch, a battery indicator, a volume pot, and your headphone outputs. This is probably one of the few amplifiers in this range that only feature 3.5mm and quarter-inch unbalanced sockets. On the back, you have a USB-C charging port and left/right RCA inputs.

Design

Under the hood, the 23RM features similar amplifier technology to the award-winning AMP-23R, but the circuitry is much different. It combines the amp with a JET2 Bias circuit encased in the Ensense module. These circuits use discrete transistors designed to feature an ultra-wide frequency response with zero negative feedback. MOSFETs are used for voltage outputs, and bipolar for the current output.

Sound Impressions

With the 23RM, I used a MUSE HIFI M3 as my DAC and hooked it up to my iPhone. Ideally, you’d have a more versatile DAC to use with this high-end amplifier, but I found this pairing to be a quick solution that gave me a good sense of its potential. Two headphone outputs on the front are 3.5mm and quarter-inch. They do not respond the same way though, and that was quickly apparent to me when I first started testing headphones with it. From what I gathered, the voltage output with the 3.5mm jack sounded a lot more mellow than the current jack. Both had a similar level of detail retrieval but differed in how those details were presented in the mix.

I settled on using the current option more than voltage, as the difference was night and day. First off, if you’re looking for bass drive, you’ll probably want to use the current jack exclusively. It produces the heaviest impact, along with the thickest tone. The 23RM really filled out the Sennheiser HD600 here, responding with more solidified frequency content. Pairing the Dan Clark Audio Expanse with the 23RM, the bass is less concentrated in the mid-bass but expands the sub-bass to express a grounded layer of rumble.

In general, instruments felt taller, and the headphones were able to move around the space more. Imaging felt more concise and brought the sounds out in front of you for a more live atmosphere. This is easier to achieve with good amps when you’re primarily listening to high-end open-back headphones like the HD800s and the HiFiMAN Susvara, but what really brings the 23RM to the next level is the transparency of the midrange. There is just an unrivaled level of clarity presented here when using the 23RM. Vocals will stand out the most, offering an exceptional amount of liveliness.

This was best realized by pairing the Susvara, as it felt like you were in the studio listening to the track being recorded. I kept finding it fascinating how much breath these frequencies were able to express, making each performance feel like a tangible object not produced by a driver. Even the HD600 was able to grant me this reaction, as the 23RM never failed to impress no matter what you put through it. That realism is also met with the crispiest upper-mids and treble that puts a sizzling tail on many different sound elements. It underlines a large section of frequencies, resulting in a wonderful texture that enlightens each performance.

Summary

Sitting back and listening to an assortment of headphones with the Enleum HPA-23RM has been a highlight of my year reviewing audio products. While it may not look like it, this amplifier houses exactly the type of performance you’re looking for in this price range, with power and significant enhancements to your listening experience. Even though it’s missing some features like balanced headphone slots, I feel like I didn’t miss them. The level of transparency and drive this amp is capable of is highly immersive and synergizes incredibly well with many different headphone combinations.

The Enleum HPA-23RM is available at Audio46.