This will be a very brief review/impressions of the Archel 2 Pro, since I bought it partially on a whim and partly due to my growing curiosity as to how the recent emergence of several ultra-low distortion, inexpensive, headphone amplifiers performed, rather than it being something I was likely to use myself.
The unit in question is mine, purchased as part of the initial pre-order (at $119.99). Units ordered when these units hit general availability (11/29/19) are supposed to be $149.99.
The package is a simple, no-fuss-nor-fanfare box lined with form-fitted protective foam and company artwork printed on the exterior. Inside you’ll find the amplifier itself (in a protective wrapper), a boxed power supply, a small lint-free cloth and a Geshelli sticker.
This unit is housed in a simple, extruded, aluminum “project-box” sleeve with custom printed/drilled plexiglass front and rear panels. Various anodized colors are available. There is an option for an all-plexiglass case as well. Form factor is the same as other Geshelli products. Switchgear is simple, directly exposed, PCB-mount tactile switches. The volume potentiometer has nice tension but, quite reasonably, does not feel as smooth as on higher priced units. This is definitely a function-over-form product.
The front of the unit, features tactile switches for power on/off (hold) and changing the color of the power LED, switching between 3.5mm and RCA inputs and toggling between high (4x) and low (unity) gain (hold), LEDs indicating power status (left) and gain (right) and a nicely finished, aluminum, volume knob.
Gain, input and LED color settings are retained between power-cycles if done via the front-panel switch. And the LED brightness is not blinding … enough to add some color/interest on a desktop in normal indoor/evening lighting.
NOTE: When you first connect the unit to power it defaults to ON, so be very careful if you are setting the thing up for the first time, or use a power-strip to power your system on and off from a single switch! Ideally disconnect your headphones between sessions and zero the volume before connecting them!
The rear panel houses the power-socket and two stereo inputs, one 3.5mm TRS and the other standard RCA connections. Switching between these is done by pressing (short) the “Input/Gain” button and the actual switchover is relay-based - a nice feature on something at this end of the market.
Overall, when paired with appropriate headphones, the Archel 2 Pro delivers a clear, crisp, fast, neutral/reference sound. Resolution/detail are very good, tonality is even and pure, with a “lean” characteristic I find with most very low distortion amplifiers (if you’re looking for an amplifier to add “body” or “weight” to the output of your source, this is not where to look).
Long listening sessions were fatigue-free and the music was engaging. Differences in sources are discernible without much effort. Transparency is excellent. Instrumental timbre is natural. Vocals exhibit no strain nor sibilance, though in a state-of-the-art chain micro-dynamic nuances are not as easily discerned as, say, direct from the source unit’s output.
Only cranking things up to very enthusiastic (in most cases, rapidly-unhealthy) levels really starts to show the limits of the unit and results first in a loss of dynamics/sense of compression, followed by more egregious and obvious divergences from a clean, undistorted, delivery.
Using the low-gain setting with sensitive, hiss-prone, IEMs is exhibits no audible noise or hiss at all. The background is completely black and, of course, remains so with more demanding, full-size, cans.
There is some slight channel imbalance audible here with sensitive IEMs, and my most sensitive headphones, at the low-end of the dial - though with most full-sized headphones this likely won’t be apparent unless in “high” gain mode. With IEMs it can be addressed using an iFi Audio “iEMatch” or “Ear Buddy”. On my unit it is gone by around the 21:00 position on the dial (depending on transducer). This not something that is uncommon with inexpensive volume potentiometers - and there is likely to be some unit-to-unit variation here.
Power is adequate for most headphones at reasonable listening levels, however higher impedance/lower-to-moderate sensitivity models will let you hear the limits of power/performance available here. With the HD6XX and ZMF Vérité, for example, at higher volumes, I ran into clipping with high-energy peaks and big bass-drops (its worth noting that the HD6XX almost doubles its impedance around its resonant frequency, halving the available power), and a general sense of unease and edginess elsewhere.
High Level Comparisons
I was not able to audibly distinguish between the Archel 2 Pro and the Atom unless pushing the power limits of the Geshelli unit. Features are similar, though the Atom has nearly four times the available power - which is readily apparent with more challenging headphones at higher volumes, as well as pre-outs. Thus if you want similar technical and audible performance but with more power and/or pre-outs then the JDS Labs Atom is a more compelling alternative and at 2/3rds the price.
Sound via Magni 3 has a bit more weight/body and impact, and a hint of warmth vs. the Archel 2 Pro. The Schiit unit may be a better fit with a leaner sounding source and/or brighter headphones. Magni 3 has more power (almost 6x as much), also, and generally is capable of cleanly driving all but the most pathologically power-hungry cans well beyond tolerable listening levels. Archel 2 Pro offers slightly better apparent clarity and perhaps a slightly darker feeling backdrop (at least with sensitive IEMs).
The Liquid Spark has a warmer signature even than the Magni 3, and a more present low-end than the Archel 2 Pro, but this comes at the cost of a slight loss in clarity, resolution and, of course, neutrality. Again, the Archel 2 Pro has significantly lower power capacity, losing out by a factor of about four to the Monoprice unit. But the Geshelli unit is technically superior as long as you stay within its power capabilities.
The Geshelli Archel 2 Pro is a highly technically competent amplifier. It has a reference-signature, exhibits excellent resolution, clarity, tone and speed, class-leading low-noise performance (even with ultra-sensitive IEMs), and performs wonderfully with most reasonable headphones at sensible listening levels.
In and of itself, there’s a lot to like and recommend and very little here to sway one away from buying, and enjoying, the Archel 2 Pro, provided you’re not trying to drive demanding headphones while listening at high levels. And doing so in the knowledge that, currently, it is essentially the best objective/technical performer in its class.
However, when taken in the context of the market and when considering value, things are not quite so clear cut …
At $150, it is ~50% more expensive than its three most immediate/obvious competitors - the JDS Labs Atom, Monoprice Liquid Spark and Schiit Magni 3. All of which run rings around the Geshelli unit in terms of available power, all offer pre-outs and are, at least for me, significantly more aesthetically pleasing/more nicely finished. Audible differences are extremely small, and completely absent for me vs. the Atom.
Unless you’re simply “following the numbers” or are looking for an amplifier to make an aesthetic match with other Geshelli products, it’s somewhat hard to make a compelling case for the Archel 2 Pro over the usefully cheaper, audibly-indistinguishable, better featured and much more powerful, JDS Labs Atom.
As a technical/engineering accomplishment, the Archel 2 Pro is very impressive and worthy of note. But if I was buying at this end of the market, I would spend my money on the Atom (or the Magni 3 or Liquid Spark, depending on what I was pairing them with). I wouldn’t be giving up any useful performance in doing so, I’d have a usable pre-amp, and no worries about being able to drive pretty much any headphone I might care to enjoy in the future to any level I desired, while saving money doing so.