Even as an experienced audio hobbyist, the Japanese high-end audio scene seems a world unto itself, where tube electronics in particular have become a form of high art. These products are deep manifestations of their designers' philosophies about circuits, materials, aesthetics, and features … and that’s before we even get to the sound.

I would gladly dive into this world firsthand if I had the time for an extended return to Japan. The next best thing: getting my hands on boutique tube electronics for an Audiophilia review. I could easily fill my docket with exciting gear by just taking reviews as enquiries roll in from manufacturers all over the world. However, the Aurorasound HFSA-01 ($3680) is a piece I sought out specifically. I was interested as soon as I saw it in a press release. I shot a note to SoCal-based importer Alfred Kainz of highend-electronics. Turns out I was quick enough to secure an early review unit and a hearty thanks to Mr. Kainz for arranging the loan.

Aurorasound, while not quite a household name, has been steadily building a reputation for analog excellence on a range of phono stages which vary in price from attainable to uber high end. There are also some luxe preamplifiers and tube power amps in the portfolio. Aurorasound, Headquartered in Yokohama is the creation of Shinobu Karaki, an electrical engineer with decades of experience as a circuit designer for Texas Instruments. The HFSA-01 is the most affordable amp from Aurorasound and the only integrated in the lineup. It appears positioned to bring a much wider customer base to the Aurorasound brand. The retail price is $3680, which on paper is extremely competitive for a handmade tube amp from Japan. Can it offer a legitimate entry into the rarified world of Japanese high-end audio?

Features & Specifications

At first glance, the HFSA-01 has a typical feature set for an EL84-based integrated: 3 line inputs, one MM phono input, a headphone jack, and both 4 and 8 ohms speaker outputs—14 x 2 watts of push-pull power delivering the tunes. But the details get interesting fast. First, there’s a mono switch. Our publisher and the Audiophilia crew have opened my mind to great mono recordings, many of which are overlooked and undervalued. We’re not the only ones rediscovering great mono and Karaki-san was wise to accommodate this trend.

The tone controls will be welcomed by some but purists can use the “direct” toggle switch. The tone controls are also the basis of the coolest hidden feature I’ve encountered in an audio product (OK maybe the only hidden feature). When the included template is placed over the tone control knobs, they can be used to create equalization curves for pre-RIAA vinyl records. Not only is this cool, but it's handy for collectors of historical recordings, offering functionality without increasing bulk or bill of materials cost, or complicating ‘normal’ LP playback. Pre-RIAA curves are a rare feature usually offered on standalone phono stages which easily retail for more than the HFSA-01.

Under the hood, the circuit is a hybrid design, but in the opposite configuration of most hybrid integrated amps on the market. The preamp section is completely solid state, built around opamps from (naturally) Texas Instruments while the power amp section is all good old fashioned EL84 goodness.

Always worth mentioning, there is no remote included with the HFSA-01. Ordinarily this would be a bummer, but I honestly didn’t miss it in this case.

The complete specifications, along with the circuit diagram are available on the highend-electronics product page.

Design & Build

The aesthetic design of the HFSA-01 is harmoniously aligned with its analog focused feature set. Amid a sea of vintage inspired product launches channeling the 1970’s era of wood side panels and big VU meters, Aurorasound takes it one generation further, back to the dawn of the LP era. Despite the vintage look, there is a modesty about the design. A cool confidence, like it's never trying too hard.

Physically interacting with the HFSA-01 is a pure joy, as it should be when a remote is not included. Resistance on the knobs is just right, and the power button and toggle switch provide delicious tactile feedback.

Internally, the quality of components appears top notch. As a point of pride, like many true high end tube amps, the transformers are custom wound to spec for Aurorasound.

A neat cosmetic option has recently been announced. For an upcharge of $199, the knobs can be upgraded to walnut to match the side fenders—a nice touch, although, after several weeks of use, the default plastic knobs are wonderful.

Overall the HFSA-01 is a beautifully conceived and assembled piece of hardware.

Daily Use & Setup

As with most integrated amps, setting up the HFSA-01 is a plug-and-play affair. It has a brief, muted soft start period. I found it took a few tracks for the sound to warm up fully. Give the amp room to breathe, because after a while it gets physically warm as well. Totally standard for a tube amplifier, though.

After getting used to the HFSA-01 in my system, I found that the mechanics of listening became more of a ritual. Much like hand brewing my morning coffee (like I used to enjoy before having kids). Powering up the electronics, taking grilles off the speakers, letting everything warm up and equilibrate while I pick out an album . . . something to embrace and look forward to each day.

Review System

My primary source for this review was the Sota Escape Turntable with Ortofon 2M Blue cartridge. When I did mix in some digital, I fed bits from my Wiim mini streamer through the Ferrum ERCO DAC and onto the Aurorasound. I had a nice variety of speakers on hand. I didn’t go for the usual suspects when it came to speaker pairing, and I hope that will be insightful to many readers. Just no room in the office for Klipsch

Speakers: resolving Canton Vento, well-rounded PSB Synchrony, the detailed yet flattering Care Orchestra Deep Breath EVO, all monitors of moderate sensitivity and impedance. Not the obvious suspects for a lower-power amp. Given its small form factor and natural placement in a small room, I hope it is useful to many readers to understand how it fairs with office-friendly speakers.

Amplifiers used for comparison were the class D Swiss army knife Cambridge Audio EVO 150, and the Class AB Musical Fidelity M3si (review forthcoming). Analog cables were Audio Art Classic Series.

Listening

One of the classic tricks of audiophile systems is creating the illusion that sounds are emerging from space and not directly from the speakers. These days it's easy to assemble an affordable system that can throw a large soundstage with detailed imaging. While always exciting, this ability needs to be combined with great tone and musicality for a truly high-end experience. Especially true when trying to accommodate any sensitivity to listening fatigue. The HFSA-01 indeed offers this elusive combination. With the Canton Vento 20s on the stands I was spinning Sing and Dance with Frank Sinatra (Impex Records, 2020), and music seemed to be blooming right in the middle of my room. For a 1950 recording, the detail was remarkable and at the same time, there was a luxurious ease to the presentation. Sinatra’s voice was living in three dimensions between the speakers while the band (a bit distant, surely an artifact of the recording) was spread behind him, expanding a good bit wider than the speakers. Truly marvellous. The mono switch was absolutely clutch here, reducing noise for even more refinement.

Bela Bartok’s Piano Concerto No. 1, while hardly a standard of the light classical repertoire, became an early favourite of mine in my college years when diving into classical music. Its rhythmic intensity can be unnerving, emotional, and even angry at times. One could listen to it while marching into battle. Ferenc Fricsay’s 1961 recording with Geza Anda and the Radio-Symphonie-Orchester Berlin (Deutsche Grammophon, 1979) captures this driving energy without losing control of the rhythm that holds it all together. I used this record to hear how close the HFSA-01 gets to the Class A/B Musical Fidelity M3si in terms of slam and grip. It’s there but it’s not overly emphasized. The agitation in the music is communicated but the physical harshness is not as present in the listening experience with the HFSA-01. The piano was wonderfully reproduced by both amps, but when it comes to hard-biting percussion, Class A/B high current brings the extra edge. The HFSA-01 was the champion of gorgeous orchestral tones.

Since I picked up the 50th Anniversary box set edition of Nuggets: Original Artyfacts from the First Psychedelic Era on Record Store Day I’ve incorporated it into all my review listening in some form. This is culturally relevant music to me, a white kid who grew up in the suburbs. The bands featured within were the original generation of angsty white kids from the ‘burbs. The ’60s garage movement produced just a handful of hits but was a widespread early movement in musical counterculture. Fascinating to me growing up, it stayed a constant in my musical lexicon. By audiophile standards the recording quality of this set is, well let’s just say it's highly variable. Tape provenance? Forget about it. But for me, a high-end system needs to at least do this music some justice. I am pleased to report the HFSA-01 satisfied in this regard. It was great with the speakers I had on hand, and could even be better with some big old dusty Altecs. When the mood strikes the HFSA-01 can properly rock out.

Casual daytime listening in the office often features electronic ambient selections from Ultimae Records of France. With Auraosaound in the chain, this made for a nice engaging distraction from my day gig. I find electronica is always a useful test for bass. While not as fast as bass from the M3si, I found the HFSA-01 could help my speakers move some air. The general output was pretty impressive for the specs. And again, this was with 4-ohm monitors. While I paired the HFSA-01 with non-conventional speaker choices, this gave it a proper workout and demonstrated its flexibility. In the right setting (smaller space) compact 2-way monitors paired well. This format of loudspeakers is more widely available and easier to accommodate in-room, adding to the wide appeal of the HFSA-01.

I put plenty of miles on the headphone output of the HFSA-01 listening to electronic albums as well. The headphone circuit appears to tap into the main power section to utilize that EL84 goodness. With tube-loving Sennheiser HD6XX the tone and spatial presentation were luscious from top to bottom. I did need to crank the volume a bit due to their 300-ohm impedance. With my Sendy Audio Peacock, I found pure absolute bliss—a fantastic mix of romance and detail from these planar cans.

Conclusion

The Aurorasound HFSA-01 ($3680) offers a pure musical performance, and just as importantly, it delivers music with a purity of purpose. It’s not a solution to a problem but rather a realization of a particular vision of musical enjoyment. For analog enthusiasts willing to work within the surprisingly minor constraints of its power rating, the Aurorasound HFSA-01 should bring a lifetime of musical engagement. A passionate recommendation and an Audiophilia star are in order.

Further information: Aurorasound