Allnic Audio HPA-300B

REVIEW
Kevin Fiske
Jul 22, 2025

Integrated amplifiers that incorporate headphone outputs are not uncommon. But with very few exceptions, the head-fi element is strictly secondary, almost an afterthought. One notable exception is the Allnic Audio HPA-300B, which is recognised for offering exceptional audio quality for headphone enthusiasts. According to most of the audio industry, if we want to listen to replay of the highest quality through headphones then we need to buy a dedicated headphone amplifier as well.

It’s not just marketing at play here. Speakers and headphones present amplifiers with different technical challenges due to their respective impedances and power requirements. Things begin to look a little different, though, if we put efficient speakers with benign phase angles into the mix. Might a headphone amplifier that outputs just eight Watts into eight Ohms be sufficient to drive headphones and speakers to a high standard? Korean audio engineer Kang Su Park says yes, and as evidence, he offers his newly launched HPA-300B integrated headphone amplifier.

Gimme

Allnic Audio products are a visual riot. They sport an unmistakable design language that some might call industro-skeletal. Others might describe it as steampunk. The Allnic Audio HPA-300B is true to type; all chunky, satin-aluminium, hulking transformers and chokes under matt-grey shields, perforated tube cooling towers, stout handles, and glowing amber analogue meters. It’s a gimme for those who buy their audio with their eyes, but the HPA-300B’s appeal is more than skin-deep.

It weighs a stout 23.6 kg, and as might be expected, most of that heft is in the output transformers. It is also a substantial price. However, while the RRP of £12,600 might be towards the top end for a headphone amplifier, Park wants us to regard it as a fully-fledged high-end integrated amplifier as well. The obvious question is whether the attempt to meet the somewhat divergent demands of both headphones and loudspeakers has resulted in an amplifier that is too hobbled by technical compromise. One that does both with a degree of competence, but no more than that.

The HPA-300B certainly offers the right mix of inputs and outputs to be taken seriously as a dual-purpose amplifier. On the back we find three sets of RCA and two sets of XLR inputs, plus banana output sockets for speakers.

Sockets

On the front are two four-pin XLR headphone sockets and two 6.3mm single-ended sockets. A mute button turns off the speaker output for headphone listening. A small rotary knob allows source selection, chosen inputs indicated by an annotated line of LEDs. The extensive rotary volume control is motorised. Behind it sits Allnic’s Constant Impedance Attenuator, which maintains a steady 10kω resistance throughout. The two analogue meters, left and right channel, show the auto-bias status. Deflection gives warning that a tube requires replacement.

Allnic Audio HPA-300B rear panel

The rectifier, driver and output tubes each sit inside their clear polycarbonate towers, capped with perforated aluminium disks. The 300Bs have tube locators, stamped from what looks to be Teflon, slid over their narrow tops. All the tube sockets sit in a semi-liquid rubber compound. This is one of several design features intended to make the amplifier more resistant to microphonic feedback.

I fed the Allnic Audio HPA-300B the balanced output of a Mola Mola Tambaqui DAC, set to 2V. I also switched between a Grimm MU1 network player and a Jay’s CDT3 MK3 CD transport as sources. An icOn5 Balanced did passive line stage duties. Allnic claims a signal-to-noise ratio of -90dB, a test result distinctly on the good side for tubes. I think we can believe it. Park’s attention to suppressing the transfer of vibration, coupled with a comprehensive and practical approach to circuit grounding. This results in the HPA-300B being the quietest tube amplifier I have encountered in the last two decades.

Sweet return

It’s said that we should never go back, but I’ve owned three different amplifiers that used 300B output tubes. The last of these was some nine years ago, and the Allnic proved to be a sweet return in some ways. The 300B is a tube praised for its rich, liquid mid-range. Still, I think the worship is somewhat overdone, partly because, in reality, its sonic qualities can be equalled by alternative tubes and even particularly well-implemented solid-state designs, and partly because in pretty much every implementation that I have heard, the 300B lacks energy at both ends of the frequency spectrum. Me, I’d take the more capable VT-4C/211 over the 300B anytime.

However, the realised performance of the 300B – indeed any output tube – is significantly at the mercy of the quality of the circuitry driving it, as well as that of the output transformers it feeds into. Park designs all the transformers and chokes used in Allnic products, and based on the evidence of the Allnic Audio HPA-300B, he is still right at the top of his game.

Fast and energetic

The amplifier sounds fast and energetic, both through headphones and speakers. It is less a typical 300B amplifier, if such an animal exists, more a modern-sounding amplifier that happens to use tubes.

Unusually – perhaps even uniquely for the sector – Park’s design doesn’t have a fixed output impedance but is auto-adaptive to work optimally with any load. I listened to a wide range of recordings via the headphone outputs, using a Sennheiser HD650, an Audeze LCD5 and a HiFiMAN Susvara headphone. The results with the Sennheiser and Audeze headphones were satisfactory in different ways. The 300 Ohm Sennheiser in particular seemed to appreciate the quality of voltage delivered by the Allnic and exhibited better soundstaging abilities than I had heard it achieve with some other amplifiers. Its un-EQd balance, smooth and on the warm side, and with a mid-range standing slightly proud of the bandwidth extremes, made it feel as if the headphone was working with the Allnic rather than being bossed by it, resulting in a presentation that invited ‘kick back and relax’ listening.

Spotlight

The 14 Ohm LCD5 sounded altogether more analytical and detailed. It’s natively richer and more weighty bass response provides some compensation for the Allnic Audio HPA-300B’s disinclination to dig particularly deep. The Audeze’s mid-range is even more prominent than that of the Sennheiser, and it casts quite a spotlight on the character of the 300B driver tubes. I found the combination able to deliver simpler, primarily vocal tracks, to a notably high standard. Through the Allnic, Amy Lee’s voice on Synthesis by Evanescence, particularly on the track ‘Never Go Back,’ where her ability to convey emotional vulnerability and then, almost within the exact millisecond, turn on an astonishing degree of feminine power, triggered multiple hairs-on-the-back-of-the-neck moments.

Allnic Audio HPA-300B Black

I did wonder if it might be a little unfair to note the Allnic’s relatively modest low-end extension. However, a quick check of the same tracks through the same headphones driven by two solid-state alternatives confirmed the verdict. The Allnic is enjoyable enough, but a deeper and more textured low-end is available elsewhere if that’s what we crave. In defence of the Allnic Audio HPA-300BB, it should be noted that both of the alternatives tried are dedicated headphone-only amplifiers. The HPA-300 B doesn’t compromise loudspeaker or headphone output at all. However, those who will never use loudspeakers have the option of the HPL-5000XL and HPA-10000 dedicated headphone amplifiers.

Household reference

Into the household’s PMC MB2se reference speakers (90dB/eight Ohm nominal), the Allnic HPA-300B brought a smile to faces at the rediscovery of the uncanny way in which tube Watts sound differently to solid-state Watts; somehow more powerful. Marcus Miller’s track ‘Boomerang’ from the 2001 album M2 thundered through the PMCs’ 12-inch woofers, entertainingly, if not with the ultimate in extension or grip. More suitable material was found on the Canadian finger-style guitarist Antoine Dufour’s 2020 album Reflect. The Allnic rendered his Mario Beauregard guitar in all its organic sonic beauty. It was simply dripping with glowing, limpid tonal quality and a beguiling spatial airiness.

Context here, as with so much in audio, is everything. There’s a reason why almost all manufacturers, including Allnic, produce dedicated headphone and speaker amplifiers. However, Kang Su Park spies a particular cohort of buyers who demand excellent performance from headphones and loudspeakers. They also demand compactness and affordability. The Allnic Audio HPA-300B is for them.

Technical specifications

Type: valve headphone/loudspeaker amplifier
Tubes: 1x 6DR7/13DR7 (gain and driver stage), 1x 5U4GB (rectifier), 2x 300BX (output)
Inputs: 3x pairs RCA unbalanced inputs, 2x pairs XLR balanced inputs
Headphone output: Two quarter-inch jack sockets, two four-pin XLR balanced
Loudspeaker output: 4Ω, 8Ω
Frequency response: 20Hz-20kHz (±0.5dB)
Voltage Gain: +28dN
Optimum headphone impedance: 10Ω-600Ω
Output: 8W per channel
Maximum input voltage: 3W RMS
THD: < 0.1% (1kHz, 1V)
S/N Ratio: -90dB (CCIR, 1kHz)
Power consumption: 168W
Dimensions (WxHxD): 43x42x24cm
Weight: 23.6kg
Price: £12,600