In this article, I review the Apos x Community Gremlin balanced tube amplifier. The Gremlin boasts an open design and dual 12au7 vacuum tubes. Pricing starts at 120 USD.
Disclaimer: This sample was provided by Apos for an honest review. All observations and opinions here are my own, based on my experience with the product.
APOS X Community Gremlin
Table of Contents
Specifications
- Uses 12au7 or 6922 tubes
- Three-level tube with Class A buffer output
- Inputs: XLR, 4.4mm
- Outputs: 4-pin XLR balanced headphone jack, 4.4mm balanced headphone jack
- Uses a DC 18- 24v power supply
- Output power: 1250mW @ 32Ω
- Frequency response: 20Hz-50KHz (+/-0.5dB)
- Signal to noise ratio: 110dB
- Minimum distortion: 0.01% (1KHz)
- Separation degree: 104dB (1KHz)
- Suitable headphones: 8-600Ω
- Dimensions: 5″ W, 3 1/4″ D, 2 1/2″ H
Design
The Gremlin’s design is bound to stir strong opinions—there’s no middle ground here. With its open-frame construction and dual layers of transparent plexiglass, it proudly puts its guts on display. Whether you see that as a bold industrial flex or a cable management nightmare is entirely up to you.
Built as a fully balanced-only amplifier, there are no single-ended inputs or outputs in sight. Around the back you’ll find balanced dual 4-pin XLR and a 4.4mm input, while the front panel houses matching balanced outputs, the power switch, and a satisfyingly smooth and nicely weighted volume knob. A set of four green LEDs glow from the underside (they can be switched off via a jumper on the left), while a second jumper on the right toggles between 12AU7 and 6922 tube compatibility.
Despite the open chassis, the Gremlin still gets plenty warm—particularly around the XLR inputs—so it’s worth giving it some breathing room. Power-wise, it packs a punch with 1250mW into 32 ohms, making it more than capable of driving most full-size headphones. Inside, you’ll find a hybrid topology with vacuum tubes (matched Ray Tubes CORE 12AU7) in the preamp stage and a solid-state output. Add to that a low noise floor of 100dB and excellent channel separation rated at 104dB at 1kHz.
Sound
For testing, I fed hi-res FLAC files from my PC into the SMSL RAW-DAC1 via USB, then into the Gremlin using my ddHiFi BC30XLR cables. I’ve been using the Gremlin as my daily driver for a few weeks, so it’s had over 50 hours of burn-in.
While many people associate tube amps with warmth and euphonic colouration, the Gremlin leans more towards clarity and transparency. It definitely rewards you for pairing it with a clean, capable source.
I’ll admit, I was a little sceptical when I first fired up the Gremlin—I was expecting a few compromises in the sound quality given the modest asking price. After all, you get what you pay for, right? But in this case, I think it’s fair to break my own rule and say it: the Gremlin genuinely punches above its weight. It doesn’t have the same kind of liquid magic as high-end tube amps like my Feliks Audio Elise, but it handily outperforms other budget tube amps that I’ve tested.
The Gremlin has a way of pulling you into the music without drawing attention to itself. It doesn’t try to impress with exaggerated warmth or artificial thickness—instead, it adds just enough tube character to smooth the edges and flesh out the midrange, letting the emotion come through more naturally. Paired with the HD650, there’s an added sense of depth and dimensionality; vocals feel a bit more lifelike, and the whole presentation takes on a slightly more liquid, organic quality.
With the Sivga P2 Pro, the Gremlin gives the planar drivers a touch of roundness and weight that complements their clean, fast nature. Bass gains a soft bloom, and the treble smooths out just enough to keep things non-fatiguing without losing air. It’s not the most technically aggressive amp out there, but that’s not the point—it’s about tone, texture, and musicality.
The noise floor is impressively low—dead silent with full-size headphones and even sensitive IEMs—and there’s no unwanted hum or hiss getting in the way. What you get is a clean, open sound with just enough tube magic to make long listening sessions feel more intimate and engaging. It’s a subtle but addictive shift that makes you want to reach for one more track… and then another.
Select Pairings
FiiO FH19: No audible background hiss. Buttery smooth presentation with sweet, natural vocals and a laid-back but airy and extended treble. Thundering sub-bass with excellent control. Mid-bass is rich and detailed but leaves lots of room for the mids to breathe. Soundstage is expansive with outstanding width and depth. You couldn’t ask for a better pairing than this one.
Sendy Aiva 2: Reserved but satisfying sub-bass, punchy mid-bass with good definition and reassuring impact. Silky vocals and a slightly warm midrange with great instrument separation and layering. Soft, airy treble with moderate detail retrieval. The soundstage has a balanced, elliptical shape, with near equal proportions in width and depth.
Harmonicdyne Zeus Elite: Somewhat bright tonality with a forward treble. This pairing was a little glary – the Zeus Elite is better suited for warmer sources and even the Gremlin’s tubey goodness couldn’t quite mitigate the sharpness of the Zeus Elite’s treble. But the bass was impressive in terms of weight and control. The soundstage is reasonably wide but the overall resolution is only average.
Verdict
The Apos x Community Gremlin is a sonically impressive little amp that punches well above its weight. It delivers a clean, engaging sound with just the right amount of tube character, and it does so at a price that makes it genuinely hard to fault.
The open-top design and LED lighting give it some visual flair that’ll likely appeal to a broad crowd, and the ability to roll tubes adds versatility and longevity. Sure, the lack of single-ended inputs or outputs might be a limitation for some setups, but adding those would’ve almost certainly pushed the price higher. As it stands, the Gremlin is a well-executed, great-sounding amp that’s very easy to recommend.