Geshelli Labs Archel 3S Pro

HiFi, Audio
Geshelli Labs Archel 3S Pro — The Swiss Army Knife of Headphone Amps

This is part two of three in my Geshelli Labs special. We started with the J2S DAC; today it’s the Archel 3S Pro, the middle child of Geshelli’s headphone amplifier range. At $369.99 base, the Archel 3S Pro sits below the flagship Erish 3 Pro in the lineup but does something the Erish doesn’t — it gives you tone controls. Real, proper, hardware Baxandall bass and treble knobs. In 2026. From a small audiophile shop. I love everything about this idea.

Build & Design

If you’ve seen the J2S, you know what to expect. Same powder-coated steel case, same plexi front and back, same family resemblance. The Archel 3S Pro is a slightly taller, deeper unit because it has to fit those extra controls and the bigger power supply, but it’s recognisably from the same workshop. Mine arrived in matching colours to the J2S — once you’ve started building a Geshelli stack, you can’t help yourself.

On the front you’ve got a power button with its illuminated LED ring (pick your colour at order time, eight options), an Alps blue audio-taper volume pot, the bass and treble knobs, and a “tone defeat” relay-bypass button that takes the tone stage out of the signal path entirely when you don’t want it. There’s a high/low gain switch and a 6.35mm headphone jack.

Round the back: balanced XLR input, RCA input, RCA preamp output, and the input from the external 12V FCC Level 6 power brick. There is no balanced headphone output. This is the one thing about the Archel 3S Pro that will rule it out for some people — and it’s worth knowing up front. If you’re committed to balanced cables, the Erish 3 Pro is the one you want. If you live in single-ended land, read on.

The Best Config

Like the J2S, the Archel 3S Pro is socketed. The stock TI OPA1655 opamps are fine; the upgrade options are where it gets interesting. You can specify Sparkos SS3601 (+$80), Sparkos SS2590 (+$120), Burson V7 Vivid Pro or Classic (+$110), Burson V5i (+$59), or Staccato OSH-S (+$88) at order time. I went with the Sparkos SS2590, which seems to be the consensus “best” choice on the various Head-Fi impressions threads, and which keeps the family character with the J2S.

So my best-config Archel 3S Pro lands at around $490 with shipping. That’s still under the price of a Schiit Jotunheim 2, and there are people on Head-Fi who’ll tell you it eats the Jotunheim 2 for breakfast. More on that in a moment.

Sound

Listening was through the J2S in best config as the source, with headphones rotated through the Sennheiser HD800S, Audeze LCD-X, Hifiman Arya Stealth, Meze 105 AER and Focal Clear MG. I left the tone defeat engaged (i.e., tone controls bypassed) for the bulk of the critical listening, then experimented with the controls to see what they actually do.

Bass

With Sparkos opamps and tone defeat on, the Archel 3S Pro presents bass that’s quick, articulate and well-controlled. It has the kind of low end that doesn’t draw attention to itself but does everything right. On the Hifiman Arya Stealth — which can sound a bit thin in the bottom octave on weaker amps — the Archel 3S Pro provided enough current to really wake the planar drivers up. There was speed and authority where on lesser amps there’s just a polite suggestion.

The LCD-X paired beautifully too. Audeze planars need an amp that can move air and the Archel 3S Pro, despite its modest physical size, has the grunt for it. The 2-watts-per-channel-into-16-ohms spec isn’t fairy dust.

Mids

Cleaner and slightly more neutral than the J2S DAC’s character would suggest. The Sparkos opamps in the amplifier give the mids a bit more snap and definition than they have when the same opamps are sitting one stage upstream in the DAC. Vocals on the HD800S were the highlight — that famous 800S midrange clarity is preserved completely, but with just a touch of body underneath that the Sennheiser sometimes lacks on more clinical amps.

A Head-Fi user in the official Archel 3 Pro impressions thread described it as “clean, but without sounding sterile, as a lot of people describe op-amps.” That’s a perfectly chosen sentence. There’s no glare, no etched-in detail, no fatigue. Just clean.

Treble

The treble on the Archel 3S Pro is where I started reaching for the tone controls. With tone defeat engaged it’s perfectly fine — a touch polite, very smooth, no harshness. With the treble control disengaged from defeat and set neutrally it’s near-identical. Push the treble control up about two clicks and you get a bit of the air and sparkle that the HD800S thrives on. It’s subtle, well-implemented, and never tips into harshness — exactly what Baxandall tone controls should do. On the Focal Clear MG, which I find slightly over-zealous on top with some sources, I left the treble at flat.

Soundstage & Imaging

Pleasingly wide. Not Erish-3-Pro wide — and we’ll get to that next time — but the Arya Stealth and HD800S both gave me their characteristically expansive presentations without feeling compressed. Imaging precision is good without being surgical. There’s a “music in a room” quality to it rather than a “instruments on a graph” one, which I suspect is partly down to the Sparkos discrete opamps doing their gentle harmonic-distortion thing.

Dynamics

Really good. The amp has obvious headroom and never sounded strained on any of the headphones I tried. The LCD-X in particular benefits from an amp that can punch when asked, and the Archel 3S Pro punches. Drum hits have authority. Crescendos build and release without congestion. For its physical size and price, the dynamics are excellent.

The Tone Controls

I want to spend a moment on these because they’re the whole reason this amp exists, and they’re brilliant.

The Baxandall topology Geshelli have used is the proper old-school way of doing tone controls — bass and treble shelves, gentle slopes, no nasty filter ringing. The relay-switched defeat means that when you don’t want them, they’re genuinely out of the signal path, not just at the centre detent.

Why does this matter in 2026? Because most modern recordings are mixed for streaming on cheap earbuds and a startling number of older recordings sound rubbish on flat-response headphones. I have albums in my collection that I’ve avoided for years because they’re just unpleasant on the HD800S. With the Archel 3S Pro, two clicks of bass boost and one click of treble cut transformed late-80s digital recordings I’d written off as unlistenable. Old Dire Straits albums, mid-period Genesis, anything Phil Collins ever drum-machined his way through — suddenly back in the rotation.

Snobs will tell you tone controls are a sin against high fidelity. Snobs are wrong. Tone controls let you fix bad recordings without buying a different headphone. They’re a feature, not a bug.

Comparisons

Against the Schiit Jotunheim 2, the Archel 3S Pro is the more sophisticated-sounding amp by a margin. The Jotunheim 2 is a lovely thing in its own right — I rate it highly for the money — but the Archel 3S Pro with Sparkos opamps reveals more detail, has a slightly blacker noise floor, and obviously brings the tone-control flexibility the Schiit doesn’t. There’s a Head-Fi thread where someone says of the Archel: “this thing blows the Jotunheim 2 out of the water” and while I’d put it more politely, I wouldn’t actually disagree. The Schiit is the better-built object; the Geshelli is the better-sounding amp.

Against the Burson Soloist 3X GT I’ve got on my desk, the Burson is a different proposition entirely — it’s a $1,500+ amp with discrete everything and a much bigger power supply, and it shows in absolute terms. But the Archel 3S Pro is surprisingly close in subjective enjoyment, particularly for the kind of music I actually listen to.

Against the Lake People G111 (which I reviewed earlier this year), it’s a more flexible amp with a more characterful sound. The Lake People is the more clinical, ruler-flat reference; the Archel 3S Pro is the more involving listen.

The Single-Ended Question

If you’re going to buy this amp, you need to be honest with yourself about cables. Single-ended only means single-ended only — there’s no XLR4 socket on the front, there’s no Pentaconn 4.4mm. If your headphones live on balanced cables, you’ll need adapters or new cables, and at that point you might as well skip up to the Erish 3 Pro instead.

For me, with a mostly-single-ended cable collection, it’s not been a problem. My LCD-X has a stock 6.35mm and stayed there. Same for the Clear MG. The HD800S I have on a balanced cable, but the included 6.35mm adapter is fine for evaluation.

Verdict

The Archel 3S Pro with Sparkos opamps is one of the most enjoyable mid-priced headphone amps I’ve heard in ages. The tone controls — yes, the tone controls — are a genuine differentiator that adds real-world value to a real-world music collection. The build is unfashionable but solid. The sound is grown-up, slightly warm, and never wears out its welcome over long listening sessions.

Pros

  • Working hardware Baxandall tone controls with proper relay defeat
  • Sparkos opamp upgrade path is a real difference, not snake oil
  • Plenty of power for current-hungry planars
  • Excellent value at this price even before considering the tone controls
  • Custom colours and small-shop charm

Cons

  • Single-ended headphone output only
  • Build aesthetic still very DIY-flavoured
  • Lead time can stretch to several weeks
  • Stock opamps are fine but the unit really wakes up with the upgrade
  • No remote — you’ll be reaching for the volume knob

Ratings:

  • Build & Design: 7 / 10
  • Sound (in best config): 9 / 10
  • Features: 9 / 10
  • Value: 8.5 / 10

Part two of three. Next time: the flagship Erish 3 Pro, where Geshelli pull the trigger on a fully balanced output stage and stop messing about.