Review - Drop Cavalli Tube Hybrid (CTH)

Review - JDS Labs Atom (long term)

Review of the JDS Labs Atom (long term)

As I mentioned in the Loxjie P20 review, my intention is to post reviews of some of the equipment that I have been using for a while in my reference chain when testing and reviewing other gear such as headphones and IEMs. More than a review of a new product I have received, this is to be based around my use of the item and what I have found after using it long term.

I feel that if I share these opinions it will help those who read (or watch) my reviews get a slightly better feeling for my personal tastes, making it easier to form an opinion about whether my reviews are something that guides or misguides them. Audio is very subjective because everyone hears sound in a different way and has their own preferences.

Today I have decided to share my thoughts and opinions of the JDS Labs Atom amplifier, again trying to put it into context and explain a little about my usage in the process.

It is difficult to review an amplifier, at least for me, as there are two completely different ways of looking at it. There is the scientific way, which is to provide measurements and specifications, showing the exact performance of the amplifier. The second way is from a subjective point of view, giving personal opinions on how the amplifier affects the sound being heard and whether that is of a personal preference or not.

Again, as mentioned in the P20 review, I have found myself to be a bit of a hypocrite in this regard.

My main aim with equipment such as DACs and amps is for them to be as transparent as possible, so that the only things that are providing changes to the sound are the source (i.e: the music) and the speakers or headphones.

However, I am also a person that has different moods and preferences on different days, some days I prefer some extra bass, other days I am just looking for neutrality. In these cases I not only switch between headphones/speakers but also add in EQ to taste.

I feel that amplifiers (or other parts of the signal chain) that are not 100% transparent are the equivalent of having an EQ baked in to them. This means that this “EQ” may be pleasurable to some and unpleasurable to others, or, in my case, I may enjoy a certain piece of “non-transparent” equipment one day and not so much the following day.

As I said, this is a bit of hypocrisy on my behalf as I say that I want an amplifier to be totally transparent and disappear (i.e: measure perfectly) but at the same time can find pleasure in amplifiers that do the exact opposite to this.

But enough chit chat and on to the amp.


There is no space for subjectivity in the build quality of a product. You may prefer the looks of one or another but the build quality is not something open for debate.

In the case of the JDS Labs Atom, the build is cheap.

While it doesn’t look bad (in my personal “subjective” opinion), the case is a plastic lightweight black box with a plastic knob that feels cheap when touching it.

There is a white led light ring around the knob that is a nice touch (again, in my personal opinion) and the volume knob also serves as the off switch when turned completely to zero.

On the front panel, other than the volume, there is a ¼” headphone output, a high/low gain switch and an input select switch, both of the push button kind.

With nothing on either side, there is a white JDS Labs logo on the top of the unit and that is all until we get to the back panel.

On the back of the unit, there is a port for the 16VAC wall wart power supply, a 3.5mm TRS input, a set of RCA inputs, and a set of RCA outputs. That is all we have as far as connectivity, although the second input is something that is not found on many units in this price range.


The functionality of the Atom is also straightforward and basic. The input selector on the front allows you to switch between the RCA and 3.5mm inputs, while the headphone socket also serves to switch between outputs, with the RCA outputs becoming active when nothing is plugged in to the headphone output.

The RCA outputs are a preamp out, meaning that the volume knob on the front of the unit controls the volume of the RCA outputs when they are active. This is useful if using the Atom to control a set of desktop powered speakers or monitors, or some other device without a volume control (or at least without an easily accessible one).

My personal preference would be to have a switch to turn the RCA outputs on or off without the need of unplugging the headphones, maybe even with an option for the RCA outs to be a simple pass through without volume control, but I am not complaining given the price of the unit and the second input is a nice feature that I prefer to have over the selection switch if I was asked to choose.

The volume knob used is analog and there is some slight imbalance in channels when you are at a very low setting, but I am talking about a setting where the sound is barely audible, therefore this should not be an issue for anyone really.

Power and other specs…

I do not have the equipment to be able to perform tests on the amplifier in order to provide my own measurements with regards to specs, however, you can find extensive measurements of the Atom on Audio Science Review ( with all the details as far as power, THD, SNR etc.

All I can say from my subjective point of view is that the Atom has a lot of power for such a small (and cheap) device, managing to provide this power without any noticeable distortion or colouration to the sound, at least to my ears.


As I just said, I do not notice any colouration to the sound in my opinion. It is very difficult to judge something as being transparent by ear, as all I can do is compare it to other items that I also consider to be flat or neutral, such as monitors etc, but the headphones used always come into play also.

However, in my totally subjective opinion, I would consider the JDS Labs Atom to be neutral and I feel that I can use the reference of the Atom in order to get a feeling for any colouration introduced by other amplifiers.

Issues and solutions…

It is worth noting that when I first got the Atom, I experienced an issue with it not turning off even when the knob was clicked into the “off” position. This seems to be something that happened to various people according to posts I have read on forums and was caused by a relay sticking in the “on” position.

When this happened, I contacted JDS Labs customer support on a Sunday and they replied within 2 hours. Their response was to give the Atom a good “bang” on the top with my hand.

While this seems like a brutal way to fix something, I followed their advice and hit it. This caused the realy to unstick and the unit to switch off. Since then, I have not experienced this issue again. 


I feel that the JDS Labs Atom was a purchase that was well worth the 100€ price tag. At the time, there was nothing that came close to the performance of the Atom at a similar price point, in fact, it outperformed amplifiers costing much more.

Since then, there have been a few releases by other companies that compete directly with the Atoms price point, offering the same quality of performance, some with even more power and a better build quality, such as the Schiit Magni 3 or Heresy (which I am still waiting for in order to be able to compare to the Atom).
In my case, the Atom is my most used amplifier and I have performed detailed listening tests on all headphones and earphones that have been through my hands since I purchased it. Everything I review (and many more) has been connected to the Atom at some point and I have used it to form my opinions.

Would I recommend the purchase?

From a technical point of view, yes... but… I feel that the Schiit offerings may offer a slightly better build quality and more power for the same price. However, I can’t recommend the Shiit products until I finally receive them and get to test them out.

(Clarification: the fact that I have not received the Schiit units I purchased in February is not the fault of Schiit, they are in a shipping container that has been stuck since March due to the Covid outbreak).