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JDS Labs Atom Amp+ HEVI Review

 JDS Labs has a new offering for us which we will discuss in our JDS Labs Atom Amp+ HEVI Review. The Atom Amp+ HEVI is a product that gives everyone what they have always asked for from the company. Specifically, it is an amp sporting a casing made of CNC aluminium with a large, easy-to-grip volume knob. 

The Atom Amp+ HEVI is a revamp of the award-winning and crowd-favourite headphone amp from JDS Labs. It is a small and compact amplifier with flawless build quality, which makes it lightweight. The Atom Amp+ HEVI also looks premium thanks to its sleek design and build.  

We will further discuss details about the amplifier in this JDS Labs Atom Amp+ HEVI Review. Aside from its design, we will also look into its functions, features, specifications, and performance. 

But first, let us see what is inside the box. 

JDS Labs Atom Amp+ HEVI Packaging

The Atom Amp+ HEVI ships in a basic-looking black cardboard box. There is nothing much to see on its exterior since JDS Labs kept things to a minimum. Inside, you will only find the Atom Amp+ HEVI and its 16VAC Power Adapter.

JDS Labs Atom Amp+ HEVI Review – Design and Functionality

We noticed its weight when we unboxed the product for our JDS Labs Atom Amp+ HEVI Review. The Atom+ Amp Hevi received some extra weight and is now twice as heavy as its regular counterpart. It boasts a beefier 480g compared to the usual 260g. 

The weight increase comes from its robust anodised top plate, adding some heft to the amplifier. Moreover, it became a tad taller by about 0.7cm. Other than that, its dimensions are similar to the original version. 

Interestingly, the Atom+ Amp HEVI, despite its increased weight, is still more lightweight than other desktop amps. 

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How did that happen? Fortunately, the experts at JBL Labs opted for a different route. They chose a separate power supply to avoid too much weight on the product. 

Thanks to the choice of materials, the overall quality is noticeably optimised. While the previously used plastic gets the job done, it tends to pick up scratches when you stack devices together. But thanks to the shift to metal, the scratch issue became a thing of the past.

Metal is also a better conductor than plastic, making it another benefit to the amplifier. It allows the product to decrease the temperature that builds up internally. So, it helps preserve the life of its capacitors and transistors.

Design-wise, the Atom Amp+ HEVI looks highly similar to the original version, with the volume wheel as the main difference. It sits more forward and is easier to turn, while the top plate, as previously mentioned, is now metal-made.

Additionally, its bottom plate and sides are still injection-moulded enclosures.

The Rear of the JDS Labs Atom Amp+ HEVI

Let us also discuss the rear portion of this unit in our JDS Labs Atom Amp+ HEVI Review. Generally, it looks the same as its predecessor, but the Atom Amp+ HEVI feels heavier on our desk. It gives off a premium and quality feel, which is good. 

You can still use the new version as a preamplifier, and it still sports the same headphone output. Specifically, the latter is a 6.3mm single-headed headphone jack. 

Key Features of the JDS Labs Atom Amp+ HEVI

The Atom Amp+ HEVI is a budget-friendly amp, but can it deliver high-quality audio? What makes it better than other amplifiers? Learn more from our JDS Labs Atom Amp+ HEVI Review as we discuss each product feature in detail. 

Preamp Outputs

The knob of Atom Amp+ HEVI adjusts the volume of its RCA preamp outputs. As a result, you can control the loudness of your powered speakers.

Top-Notch Performance of the JDS Labs Atom Amp+ HEVI

Atom Amp+ HEVI is the most groundbreaking analogue amplifier offered by JDS Labs. It achieves superior performance from its four-layer star-grounded design.

Ultra-High Power to Drive Most Headphones and IEMs

Atom Amp+ HEVI has the same output buffer as the JDS Labs flagship, Element Line. It pushes 1W clean audio per channel, even if most headphones only require milliwatts for listening. The company keeps a reasonably sized power supply for Atom Amp+ HEVI rather than providing overkill power.

Dual Inputs

With the Atom Amp+ HEVI, you will not need a separate amp and preamp. This product combines the two devices, allowing you to connect up to two sources. Plus, you can choose from RCA input and 3.5mm with a single button push.

Dual Gain for Increased Efficiency

The 1.0x low gain has hand-matched potentiometers highly suitable for driving efficient IEMs. The gain increase enables the Atom Amp+ HEVI to power full-size sets when matched with the appropriate 2VRMS Atom DAC+.


  • Frequency Response: +/- 0.01dB (20Hz-20kHz)
    – @ 2VRMS, 1kHz: 119 dB
    – @ 50mV, 1kHz: 90 dB
  • IMD SMPTE: -95 dB
  • SNR: over 122 dB (20-20kHz)
  • Noise (20Hz-20kHz): 1.99 μV
  • Crosstalk @ 10kHz 150 Ω: -92 dB
  • Output Impedance: less than 0.7 Ω
  • Input Impedance: 10k Ω
  • Channel Balance: below 0.6 dB
  • Max Continuous Power:
    – @ 600Ω: 136mW (9.05VRMS)
    – @ 150Ω: 545 mW (9.04VRMS)
    – @ 32Ω: 1 Watt (5.66 VRMS)
  • Weight: 0.48kg
  • Dimensions: 12.7 x 14.7 x 3.5cm
  • Dual Gain: 1.0x and 4.5x

Hands-on with the JDS Labs Atom Amp+ HEVI

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We used the product to share our experience in this JDS Labs Atom Amp+ HEVI Review. We will discuss its audio quality and how well it performed during our product tests.

It offered plenty of headroom even without using the gain switch. We also tested the audio after setting low gain; surprisingly, the amp had high flexing left. 

The Atom Amp+ HEVI pumped out high volume levels for most headphones we used. It had no difficulty driving planar or dynamic headphones and IEMs, making it highly universal. 

This product worked excellently as our main amplifier and performed well when we included it in our secondary setup. Aside from adequate power, it delivered high-quality signals that allowed us to enjoy our audio.

The Atom Amp+ HEVI did not have any unwanted noise. Its 1.0x low gain was perfect for driving most headphones, except for the highly demanding models. Surprisingly, we noticed no noise when we increased the gain and volume levels.

The EMI shielding performed excellently, and Atom Amp+ HEVI did not have buzzing or other unnecessary noise during our tests.

The bass of the Atom Amp+ HEVI was deep and clean with exceptional control. It had an adequate focus with subtle warmth, offering a unique sweetness to the sound. Plus, massive low-end impacts were exciting but retained their natural tone.

We noticed the deep, lush, and impactful low-end when we played bass heavy tracks.

As expected of the Atom Amp+ HEVI, it delivered fast and responsive bass. It was not heavy but also not recessed or thin. It was perfectly balanced on the warm side, combined with a solid sub-bass punch and pleasantly textured upper bass.

The bass was the best part of its sound signature, which made us enjoy listening to electronic music.

The midrange of the Atom Amp+ HEVI was articulate, airy, and clean with slight recession. It was the fascinating part of its sound signature.

Its upper mids had excellent control, while the extension was brilliant. Its lower mids were colourful and added fun to the sounds of each track we played.

The midrange had a black background, making the instruments stand out perfectly with its pleasant space, detail, and resolution. Also, the Atom Amp+ HEVI was good at retaining the quality of recordings. High-quality recordings were superb, while low-quality ones had harsh sounds.

The transparency of the Atom Amp+ HEVI makes it ideal for mixing, recording, and mastering. This amp delivered unparalleled dynamics and layering, which made all similar products in its price range dull-sounding. 

The Atom Amp+ HEVI delivered crisp and precise highs during our tests for this JDS Labs Atom Amp+ HEVI Review. It was lively, detailed, and highly transparent, with excellent clarity, making it ideal with high-end headphones.

The treble was not fatiguing since the amp did not add harshness to the sound. We loved the brilliant top end of the frequency response and its airiness that made the entire sound revealing. 

The broad soundstage had an excellent depth, causing the midrange to be occasionally recessed. Despite that, it formed a holographic experience that enhanced our listening experience, especially when watching movies and playing video games. Listening to music with this treble response also gave us a pleasing overall experience.

We also noticed the cleanliness and breathiness of the treble range with the impressive extension to the top octave. The amp had excellent control across the spectrum, and while there was bleeding, it had no overlapping. We also did not notice peaks, dips, sibilance, or similar issues during our product tests.

This amp handled congestion well due to its broad soundstage. Its pace, rhythm, and timing were also excellent, resembling the audio quality of amplifiers that cost higher.

In our experience, the Atom Amp+ HEVI showcased increased levels of excellence. It is especially true when the amplifier displays its efficiency when paired with quality headphones. 

It is also worth noting that there were no hissing/distortions, even when we used it in high-gain settings. The product performance significantly outpaces its price point, and given its incredibly affordable price tag, this unit can be an exceptional deal.

JDS Labs Atom Amp+ HEVI Review Summary

The Atom Amp+ HEVI is an excellent addition to the product line of JDS Labs. It retains its classic neutral sound at an affordable price point. The company also made multiple improvements to this amp.

The Atom Amp+ HEVI has an upgraded metal enclosure that is more durable and no longer feels like cheap plastic. Also, its compact design allows it to fit desktop audio setups.

For the audio, it has a low output impedance, guaranteeing consistent output across all loads. It delivers a neutral and transparent sound representation without compromise. Plus, it has more power that can drive the most demanding headphones.

Aside from its design and audio quality, the Atom Amp+ HEVI offers an excellent user experience. It is a highly versatile amp that can work as a preamp when connecting this to powered speakers. 

The best thing about the Atom Amp+ HEVI is its price-to-performance ratio. It is highly affordable and offers excellent value since it is efficient and offers high-quality audio.

The Atom Amp+ HEVI is an excellent amp recommended to those looking for budget-friendly options. It is straightforward, has a durable build, performs efficiently, and delivers high-quality audio.

Learn more about Atom Amp+ HEVI when you visit the official product page of JDS Labs.