JDS LABS ATOM AMP 2 and ATOM DAC 2 REVIEW

JDS Labs Atom Amp 2 and Atom DAC 2 cost just $129 per box giving you a fully capable headphone DAC and headphone amp for less than $260. The price is certainly right, but will this stack measure up when it comes to sound quality? Oscar Stewart finds out for HiFi PiG

JDS Labs have been on the scene for a while, starting way back in 2007 when founder John Seaber found the ChuMoy headphone amp, but was disappointed at the poor bass response from his headphones. He hacked a bass boost circuit onto a messy prototype board, hit play and was blown away, JDS Labs was born. 

As a reviewer, I’ve had the pleasure of watching them grow from making amps designed by other engineers to their own fully-fledged models including the early C421 portable amp, the original Element and Atom. In this review, we will be looking at their latest Atom releases, as a combo, which includes the Atom DAC 2 and the Atom Amp 2 with matching Stack audio cables. The company motto is “sound as science” and they use measurements to back up their products and whilst it’s a more objectivist approach, they still aim to deliver on the audible front for very reasonable prices. 

BUILD QUALITY AND FEATURES OF THE JDS ATOM DAC2 AND AMP 2

The original Atom series was based on ensuring users got the best quality for a reasonable price, this meant that the casing of the DAC and Amp in the series was made from plastic. Whilst they were well finished and durable, many people requested they be made with a metal casing. Whilst this wasn’t included in the Atom+ models, users will be glad to know the Atom DAC 2 and Amp 2 now come with aluminium casings. 

On the Atom Amp 2, the volume pots are hand-matched and the build quality overall is superb and they have managed this for only a $20 increase over the normal Atom Amp+ which is a little bonkers in my opinion.

The Atom Amp 2 uses its volume control as the power on/off switch and has 1 pair of RCA inputs, along with a 3.5mm input. On the front you have a 6.3mm headphone output and 4.4mm output. It’s important to note that this is a single-ended amplifier – the benefits of balanced are a topic of heated discussion so we won’t get into that, however, it’s nice to have a 4.4mm output for convenience as this is now a very common connector. There are a pair of RCA outputs on the back allowing the Atom Amp 2 to be used as a pre-amp and it is powered by an external AC power supply. The amp has 2 gain settings which are changed via a push button on the front, the same goes for changing between the RCA and 3.5mm inputs.

The Atom DAC 2 has the same ring LED design on the front as the original Atom DAC, there is a push button on the front that allows you to change between the 2 inputs. One input is USB-C and the other is optical, there is now a power switch on the back of the DAC too which is handy as you had to use an inline rocker switch. There is a single pair of RCA outputs on the back of the DAC and there is no volume control, this is a pure and simple DAC. It supports up to 32/384kHz PCM via USB and 24/192kHz via optical, it comes bundled with a USB-C cable with a ferrite core, a cable that does the job with low jitter. 

The Stack RCA cables are mouldable and fit neatly between the DAC and headphone amp, due to the way they mould to the shape you need them to be they help keep the units neatly stacked. The connectors are tight on the outputs/inputs on the DAC and amp and they are the perfect partner for this setup. 

The Atom Amp 2 has a big increase in output power over the Atom Amp+, now this is something most customers didn’t really need and something JDS Labs usually avoid as they don’t chase numbers like this. But some in the community were calling for more power, so they decided to give in and create the Atom Amp 2 – for those with inefficient headphones and those who want MOAR power… even if it’s not needed. Peaking at 2.65w into 32Ohms this amp has more than enough power for most headphones. The Atom DAC 2 is mostly a slight revision of the older version in a metal casing. The Atom DAC+ was already a high-performing DAC and the changes here just push the specs rather than it being a revolutionary new product. JDS Labs are very much a grounded and sensible company, backing up their sound with measurements and well-designed products along with stringent QC. 

SOUND QUALITY

JDS Labs is a no-nonsense brand and their products reflect that! Starting with the Atom DAC 2, you get a no-frills plug-and-play DAC. Using either the optical or USB inputs you get very clean and linear sound. There are no switchable filters on the unit itself and it also doesn’t have volume controls (this means bit-perfect sound, though). 

I’ve had a few of the iterations of the Atom DAC and they are very dependable, along with being audibly transparent. The Atom DAC 2 never shows itself up and simply converts digital to analogue without issue. This is another one of those fantastic budget DACs that gets out of the way of the music, with absolutely no noise, hiss, or colouration.

Stacking the Atom DAC 2 with the Atom Amp 2 is a perfect match! Being the same footprint, it gives you a neat and tidy desktop setup ready to drive most headphones. I’ve been using this setup with my Beyerdynamic DT880 600Ohm, Fiio FT5, German Maestro GMP400 and other headphones, even testing it with the HiFiMAN Susvara. Throughout my time listening with this setup, it always had enough headroom even sounding rather good with the Susvara (only lacking a tiny hint of dynamics that more powerful amps extract).

Starting with the Susvara you get good volume levels out of this combo and there is a ton of detail, it really is a very transparent-sounding combo that has good articulation and control. Sum 41 – Fat Lip still has all that bouncy energy it deserves, with an articulate and punchy bass line and gritty layered vocals. This combo is tight and there is no overhang from the bass – it’s snappy! The only thing that it misses out from in the bass department when compared to more powerful amps is a slight bit of punch.

Mayday Parade – Angles on the other hand sounds lovely through this combo. There is body backing up the acoustic guitar, the layering is superb, and the vocals have natural tonality to them. This is a huge step up from the original Atom Amp and Atom Amp+ which just could not handle such headphones. The Atom Amp 2 does a remarkable job of powering these hard-to-drive planars.

Using some more suitable headphones with this amp results in a very clean and natural sound – this is a linear combo, but don’t mistake that for boring. This is one of those combos that allows you to hear your headphones as they were tuned, it doesn’t add or take anything away. 

With the Beyerdynamic DT880 600ohm, you get a nice linear sound that’s crisp and detailed. Bury Tomorrow – Quake is easily handled with excellent control and separation of the layers, the crunching guitars and guttural vocals come across with power, yet they are not shouty or forced. The bass hits with authority but without a hint of bloom, the cymbals are clean and crisp without becoming bright. This is what JDS Labs do well! The Atom Amp 2 and DAC 2 show that sound backed up by science does work very well depending on your setup. 

On to the Meze 109 Pro, listening to Avenged Sevenfold – So Far Away, there is a realistic tonality to the acoustic guitar and vocals. These headphones are quite easy to drive and don’t really present much of a challenge for most amps, but they are clean enough to differentiate between different amps. Once again, the JDS Labs combo comes across as effortlessly clean with no noise or audible colouration, representing the music in an unaltered way, and it works ever so well with the 109 Pro headphones. 

I have been using this little stack for gaming too, with my German Maestro GMP400’s and it does a very good job in terms of the sound staging and stereo imaging.

QUIBBLES

No quibbles with this combo at this price – this stack performs above and beyond what the price point would suggest. 

CONCLUSION

JDS Labs slowly perfect each product with each refresh. The current iteration of Atom, the Atom 2 and DAC 2, both set the bar high for what can be achieved for a reasonable price. They are extremely well built and come with the promise that you will receive excellent customer support should anything go wrong – this should not be overlooked. 

The Atom Amp 2 and DAC 2 combo has plenty of power for most headphones and offers up impressive performance for the asking price. The footprint is small and it sits neatly on your desk, the fact you can use it as a pre-amp is also useful. It’s hard to find words to describe a neutral, uncoloured setup, as that’s what this is – what it does do is allow you to hear your headphones as they were tuned and to help find a pair you truly appreciate. 

AT A GLANCE

Build Quality And Features:

Solid metal build quality

Handy features like multiple inputs and gain settings along with a pre-amp output

Sound Quality:

Neutral and linear sound backed up with objective measurements

The above doesn’t mean this is a boring-sounding combo though, it just delivers clean sound output

Value For Money:

The value proposition really is incredible here, you get a combo that’s made in the USA and designed from the ground up to deliver uncoloured sound for less than £300 

We Loved:

The functionality, size, build and sound quality

We Didn’t Love So Much:

Nothing to note

Elevator Pitch Review: If you want a linear and clean DAC/Amp setup for your headphone setup this really is hard to beat for the price. It’s based on science yet sounds excellent in use, there are objective measurements to back up the subjectively neutral sound, it allows you to hear your headphones as they were intended. 

Price: The Amp 2 and DAC 2 are $129 each, the Stack RCA cables are $14.99

OSCAR STEWART

SUPPLIED BY JDS Labs

SUPPLIED SPECIFICATION

Atom Amp 2:

Performance

• Frequency Response, 20Hz-20kHz+/- 0.01dB
• SINAD @ 2VRMS, 1kHz120 dB
• SINAD @ 50mV, 1kHz93 dB
• SNR (20-20kHz)124 dB
• IMD SMPTE-97 dB
• Noise (20-20kHz)1.33 μV
• Crosstalk @ 10kHz (RCA Out)-101 dB
• Input Impedance10k Ω
• Output Impedance0.7 Ω
• Channel Balance< 0.6 dB
• Max Continuous Power @ 600Ω143 mW (9.28VRMS)
• Max Continuous Power @ 300Ω286 mW (9.27VRMS)
• Max Continuous Power @ 150Ω570 mW (9.25VRMS)
• Max Continuous Power @ 32Ω2.65 Watts (9.22VRMS = 26Vpp)

Connectivity

• Headphone Outputs4.4mm and 6.35mm (1/4″)
• Analog Inputs RCA and 3.5mm
• Preamp Output RCA

Configuration

• Dual Gain1.0 and 4.7x
• Volume Potentiometer Taper 15A, Hand Matched Gangs

Atom DAC 2:

Performance

• Frequency Response, 20Hz-20kHz+/- 0.12dB
• SINAD @ 1kHz, 20-22.4kHz113 dB
• THD+N, 20Hz-20kHz< 0.0004%
• SNR, 20Hz-20kHz117 dB
• IMD CCIF, 19/20 kHz -6 dBFS-105 dB
• Noise, A-Weighted-111 dBV
• Dynamic Range, AES17, A-Weighted119 dB
• Linearity Error -90 dBFS-0.05 dB
• Crosstalk, 1kHz, 100k Input-121 dB
• USB Jitter Components @ 12kHz-129 dB
• Maximum DAC Line-Output, 100K2 VRMS
• PCB Stackup4 Layers

Data Support

• Audio Formats (USB) 16/44.1kHz thru 32/384kHz PCM, DSD64-DSD128
• Audio Formats (TOSLINK) 16/44.1k thru 24/192k PCM
• USB InterfaceUAC2 with UAC1 Fallback 
• USB Driver OS Support Windows 7/8/10/11, macOS, Linux, Android, iOS, PS4/PS5, Nintendo Switch 

Connectivity

• Digital Inputs USB Type C and TOSLINK
• Line Output RCA