The Gremlin tube headphone amp is a little monster with a ferocious bite. With 1250mW of output power, it has the muscle to drive most headphones that cross its path. It may be ugly, naked, and small, but don't judge a beast by its cover. For just $120, you're getting a Class A, fully-balanced tube amp with matched tubes—something unheard of at this price. It delivers sound that’s sumptuous and lush, with musical tonality and heart-melting mids. Once it gets its claws in you, you won't want it to let go.
Feeding the beast: Tubes + transistors
The Gremlin is a hybrid headphone amp that combines the precision of transistors with the warmth of vacuum tubes. While solid-state amps (which rely solely on transistors) deliver accuracy, they lack the soul of tubes. In the Gremlin, the vacuum tubes in the pre-amp stage flood your music with rich harmonics and a warmth that solid-state amps can’t touch.
Always hungry: the Gremlin's Class A appetite
The Gremlin is a predator that never rests. With a Class A design, it's always on the hunt, keeping the current flowing without pause. Other amps flip their transistors on and off to save energy and keep cool—efficient, sure, but prone to distortion that muddles the sound. Not this beast. Its relentless operation means every note is delivered with the raw purity and ferocious detail that only Class A amplification can provide.
A poised predator: a fully-balanced amplifier
With a fully-balanced design from input to output, the Gremlin cancels out the kind of hums, buzzes, and interference that can creep in with unbalanced systems. This means you get a cleaner sound—especially important if you're using sensitive headphones or high-end equipment that picks up every little detail. The Gremlin gives you the best of both worlds: the warm, rich tones of tube amplification with the minimal interference of balanced design.
Matched Ray Tubes: the Gremlin’s natural weapon
The Gremlin comes armed with a matched pair of CORE 12AU7 from Ray Tubes to give you that signature tube warmth right out of the box. When tubes are matched, it means they’ve been carefully tested to ensure they work together as a pair, delivering the same output and frequency response. This results in better soundstage, clarity, and stereo imaging—key elements for an hi-fi listening experience. And if you're looking for even more depth and detail, we recommend upgrading to a pair of matched Ray Tubes SELECT 12AU7 tubes. Choose the 12AU7 SELECT and you'll get both sets—letting you tube roll and discover the extent of the Gremlin’s power.
Embark on the quest for your perfect sound
The Gremlin Amp is made for audio lovers who want to explore the world of sound. It works with any 12AU7 or 6922 tubes, new or old, allowing you to easily swap and try new types. Whether you prefer a lush or linear sound, the Gremlin lets you customize your audio setup whenever you want a change.
STACK THE PARTY
Add the Stacker to your order if you plan on using the Merlin DAC with the Gremlin amp. This translucent acrylic platform lets you stack the two together like a proper adventuring party. It's precision-cut to cradle the Gremlin's lower acrylic plate and keep it snugly perched without adhesive or screws. Our very own Sean Flynn designed the stacker, and our buddies at Salad made it a reality. We’ve priced it to be a no-profit product—the price you pay simply covers our costs. But we’d like to keep the DIY community ethos going, so we’re working with Salad to make it an open-source download on GitHub. Print it, tweak it, remix. If you come up with something great, send it our way at communityfeedback@apos.audio so we can show it off.
Product Highlights
Class A headphone amp with 1250mW of output power at 32Ω
Fully-balanced architecture with 4-pin XLR and 4.4mm inputs and outputs
Low noise floor: 100dB SN
Excellent channel separation: 104dB at 1kHz
Wide headphone compatibility: suitable for headphones with an impedance range of 8-600Ω.
Comes with matched pair of Ray Tubes CORE 12AU7
Specs
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
An Apos 𝒙 product
Apos 𝒙 is the next generation of grassroots products. It bridges designers, manufacturers, and the community to turn ideas and feedback into unique creations. By involving the community at every stage and supporting designers, Apos 𝒙 ensures that products reflect the desires and creativity of their users. Participate today.
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Community Participants
These affiliates, influencers, and audiophiles gave us early feedback that helped refine the final version of the product. If you’d like to participate in future launches, fill out our form.
"For the price, it's absolutely amazing. It performs well above its price point, is wonderfully upgradeable, and suitable for most headphones on the market at any performance level." -Passion for Sound
"Really enjoyable. A steal." -Joshua Valour
"Great detail, soundstage, and channel separation. Does a great job at keeping the treble in check. Has great sounding-midrange and musical bass." -Forever Analog
"An absolute beast. I love what Apos is doing here. It's a banger." -Gadgetry Tech
"The Gremlin is a shockingly good balanced amplifier. It sounds really, really good." -Joshua Valour
"Just shut up and take our money, Apos. Grab the Gremlin and thank me later." -Passion for Sound
"TLDR: Just buy it! I highly recommend it. This thing is amazing." -TylerElectric
"This is very good. This thing is super cool. I think it'll be the door-opening component to the tube universe for a lot of people." -United States of Analog
"This amp with SELECT tubes can outperform the TOPPING L70 ($350) and the TOPPING A70 PRO ($500). A really great little amp." iiWi Reviews
"It's good and it's fun and it looks cool. Apos had fun with this. The owner manual's is hilarious. You gotta read it. It's a nice, solid amp to use all around." -Wave Theory
"The sound is fantastic." -Mr Ayrit
"An affordable masterpiece. One of the best buys currently available. Sound quality, musicality, driving power--everything is great." -Tharbamar
"A W for sure. It's silly to me that you can get all of this for this price. A banger." -Badseed Tech
"I will say straight up that Apos have done a bang-up job designing the Apos Gremlin. It tickles both my inner engineer and the sound lover. Discrete, balanced, tubes, Class A, and at that price? You have to be kidding me. And it sounds both good and interesting! I can tell that true enthusiasts have been at work here, so this is an easy “Headfonia Recommended”!" -Headfonia
Apos x Community Gremlin Tube AmpSale price$120.00 USD
The Apos x Community Gremlin Tube Amp offers a unique blend of tube warmth and solid-state precision, delivering a lush and musical soundstage. Valued for its affordability, the amp is praised for its minimalistic design and exceptional sound quality. Customers highlight its impressive output power and balanced architecture, making it a standout choice for audiophiles.
Summary topics
Tube Warmth (28%): Many customers brought up that the tubes are great and well worth the extra money for the clear top tubes.
Design Aesthetics (7%): Customers expressed satisfaction with the design, as it was described as simple, minimalistic, and interesting.
Sound Quality (47%): A substantial number of customers loved the sound, describing it as natural, precise, and great.
Value for Money (17%): A significant number of customers pointed out that the Gremlin is an incredible value for the price.
Soundstage (13%): Customers raved about the soundstage, with many describing it as big, open, and natural.
"very lush mids and nice sparkle and air in the treble with great soundstage and layering." — Shaun k.
"In any case the sound is clear, neat and with a good soundstage." — Cesare B.
"The sound stage is huge and instruments along with the male and female vocals sound very natural." — Mitch U.
Reviews
Immersive Sound
"Schon mit den Standard Röhren liefert der Gremlin ein immersives Klangerlebnis. Dank umstellbarer Spannungsversorgung, lassen sich leistungsstärkere Röhren verwenden. Die russische 6N1P-VI wurde für Funkmessgeräte entwickeln und ist Innen vergoldetes für eine bessere Ansprechbarkeit beim Pulsieren. Der Klang wird für einen schmalen Taler via eBay noch einmal deutlich aufgewertet. Die Erwärmung der Grundplatte lässt sich mit erhöhten Füßen für eine bessere Luftabfuhr vermeiden. Der überdimensionierte Ziegelstein wurde durch ein 24V/1,5A Steckernetzteil ersetzt (29x48x63 mm @ 141 g). Zusammen mit dem neuen Topping DX1 II DAC und den Quadbird Kiwi Ears Septet mit längeren Schaumspitzen lässt sich ein Highend Klang unter 500 € realisieren. Danke Apos für dieses Geschenk an die Community."
— Erkus (5/5)
Fantastic
"This is my best audio purchase in years. Cheap in price, massive in sound. Not much else needs to be said... Just get Select tubes too."
— Darius Z. (5/5)
Siemens 12au7 Vacuum Tube
"I have a Siemens vacuum tube at home, and the sound is amazing. Although it's a vintage vacuum tube, it produces a clear and transparent sound. It seems like the headphone amplifier was set up well."
— Jung L. (5/5)
Fast, clear and unmistakably tube
"I have to start with the packaging because it was genuinely cool and different. Even the old-English style wording and presentation made opening the Gremlin feel like part of the product. The Gremlin itself feels extremely solid and is surprisingly heavy for such a small amplifier. It feels like a proper piece of equipment. One small thing confused me at first. I got no sound from my 4.4 mm cable even though I thought I had pushed it all the way in. It turns out it needs one final little push until you feel it click into place. Once I figured that out there was absolutely no problem, but perhaps the connection could give a slightly clearer indication that the plug is fully inserted. I am using it with a pair of HIFIMAN Ananda Nano, currently with a Fosi ZD3 using MUSES02 op-amps as the DAC. What surprised me most is how fast and clear the combination sounds. There is definitely tube character, but it doesn’t become overly warm or slow. You still get the clarity and speed of the Nano, together with that unmistakable tube quality. For me, that balance works extremely well. I’m now seriously curious about pairing the Gremlin with the Apos Druid R2R DAC, so there is a very good chance that will be my next purchase. Finally, the customer service from Apos has been exceptional. If I could give that part 10 stars out of 5, I would. :-) Very happy with the Gremlin."
— Andreas L. (5/5)
"Great Amp, works well with Merlin"
— Craig (5/5)
Super piece. Fast delivery
"Love the Sound of this amp. The look is also great. Highly recommended"
— Christian L. (5/5)
Great power and completely silent. Drives my headp
"I changed my old hybrid amp for the Apos x Gremlin because I wanted more power and better precision than my old portable DAc and ATH-M50xBT setup could provide. It works perfectly stacked with the Druid DAC. I use it with my Audio-Technica ATH-R70x, and I also added the Apos pads (the ones from the ATH-R70x Refine). It's my main hub for Spotify, movies, and gaming. Right now, I’m using the basic Ray Tubes 12AU7 Core, and it sounds excellent with everything. My playlist goes from classical, jazz, and lounge to electronics, synthwave, ambient, pop, rock, and heavy metal. For chill tracks, the sound is natural and spacious, and movies or games feel incredibly immersive. What really blew me away is the weight and punch of the sound—especially in metal and electronic music where the bass is fast and tight. I didn't expect such a full-bodied sound without touching any EQ. With my old setup, I was constantly tweaking software correctors, but with the Gremlin, I completely forgot about EQ. The amp is also completely silent with zero background hiss. I have a pair of Ray Tubes 12AU7 Select in a box to swap later, but even stock, it's a beast. I can't go back to my old gear, so I'm selling it. Highly recommended!"
— AaA (5/5)
Tube Roll: JAN-GE 12AU7A / 6189 Brings the Gremlin
"I have been listening to the Apos Gremlin with the Ray Tubes 12AU7 Core and recently rolled in a matched pair of NOS JAN-GE 12AU7A / 6189 tubes. The change was immediate and worthwhile. The Ray Core tubes had good energy and clarity, but in my system they could sound a little brassy or forward on certain tracks. The JAN-GE 6189 tubes moved the Gremlin in a more natural and balanced direction. The biggest improvement was separation. Instruments had more space around them, vocals were better centered, and the overall presentation felt less congested. Bass remains controlled, the midrange sounds even and natural, and the treble stays clean without becoming metallic or fatiguing, which I found was not always the case with the Ray Core. The Gremlin still has the fun, engaging character that makes it appealing, but the JAN-GE tubes give it more composure and refinement. My next tube roll will likely be a true NOS Czech Tesla 6922 in a few months. I am interested to hear how the Gremlin changes when moving from the 12AU7 family into the 6922 family, particularly whether the Tesla adds more air, speed, and dimensionality while preserving the natural balance I am getting from the JAN-GE tubes. For anyone tube rolling the Gremlin, the JAN-GE 12AU7A / 6189 is an easy recommendation. It is not a flashy or exaggerated tube. It simply makes the Gremlin sound more organized, more natural, and easier to listen to across a wider range of music. For the price, this was an excellent upgrade."
— Elmer F. (5/5)
Great tube amp with responsive and helpful support
"TLDR: Super pleased with the tube amp that I got for 120 USD and been rediscovering old songs and enjoy listening to music again and get a lot fun from this. I first contacted Apos, because I wasn't sure if they came with power supply for my region (Sweden), but they quickly replied and assured me that it would be no problem. Fast forward 2 weeks and I get all the cables I need for my balanced setup and I get a buzzing sound when turning the volume wheel. I wasn't completely sure what to check for and asked them for some advice and they replied within a day and gave great tips. I ended up switching out the short 4,4mm balanced cable I had between the dac and the Gremlin and the buzz got completely removed and it's now working completely. I did also check for ground loops and other suspects, but it ended up being a cheap and easy fix. I am not going to go too deep into the audio, but I enjoy the Gremlin both with headphones and iems and I get a bit more kick from the drums and bass than what I usually had before, which I do enjoy greatly. Can't recommend it enough :)"
— RokkuBilly (5/5)
Don’t Think, Just Buy the Gremlin!
"I was very surprised at the sound of this little amp. I picked up a well matched pair of NOS 1957 RCA 12AU7 Black Long Plates and the sound is incredible! The sound is warmer with more low end bass, better dynamics and a much wider soundstage than the stock tubes. The value is unreal - Fully balanced, Class A, Discrete hybrid tube amp with plenty of power. If I paid 4-5 times this price, I’d still be overjoyed with this purchase. Great way to get started tube rolling. I’m new to tubes, but a big fan so far. IMO, tubes have a much bigger impact on the sound than a DAC does."
— Glen H. (5/5)
Q&A
How much is the voltage on the LED dip-switch? I like to slave a quiet 40mm PC-Fan with PWM-Adapter on the bottom as the Gremlin has no convector like the xDuoo MT-02 it became very hot downside. I suggest bigger feets for better air vent.
Hello. The voltage is 12V. However, the switch works on the ground side, so connecting a fan is not suitable.
Would the Russian 6N1P-EV tube work as a substitute?
Hello. The 6N1P-EV would not work as a substitute for the stock tubes.
Will the Amperex 7308 Gold Pins work with the Apos x Community Gremlin?
Hello. Yes, the Amperex 7308 Gold will work with the Gremlin as a 6922 variant.
In regards to power, what is the maximum current draw (in amps) through the DC port? This spec is not stated anywhere.
Hello. The actual power consumption is DC 24V/0.8A, with the minimum required power supply specification being 24V/2A. There is no limit to the maximum current; for example, 3A, 4A, 5A, 6A, etc., are all acceptable.
