Gramophone Dreams #53: RAAL-requisite HSA-1b headphone/loudspeaker amplifier Page 2

Throughout Origins, the scale and air-moving power of these not– Carnegie Hall instruments was presented less transparently but with more earthy color and fleshy body than with the Pass Labs XA25. Overall, with the SR1a, the RAAL HSA-1b delivered a richer, meatier, more colorful sound.

Vs Jotunheim R
Schiit Audio's Jotunheim R amplifier was designed and built for just one purpose: to deliver up to 13 amps directly into RAAL's low-impedance SR1a ribbon headphones. If you buy the Jot-R from Schiit, it costs $799, or $999 with Schiit's True Multibit DAC card installed. The Jot-R may also be purchased from RAAL-requisite as part of a package that includes the SR1a Earfield Monitors (without the interface box), the Jotunheim R amplifier, and a foam-lined Pelican-style hard carrying case that sells separately for $350–$500. The complete SR1a + Jot-R + briefcase-sized carrying case costs $4000, $4500 with Schiit's Multibit DAC installed in the Jot.

Before I acquired the Jotunheim R, I used the SR1a with its interface box connected to the output of either the Pass Labs XA25 or Schiit's Aegir power amplifier. But the sound from the Jot-R driving the SR1a was much more powerfully and brilliantly rendered. The RAAL interface box began collecting dust.

To warm up the Jotunheim R (and my ears), I spent a whole night listening to dense orchestral music. The Jot-R + SR1a displayed an uncanny ability to sort and separate instruments, melodies, rhythms, and subrhythms. Without mental strain, I could examine orchestras section by section. The Jotunheim's force and clarity (with baffle-step compensation engaged) almost equaled that of the Pass Labs amp.

The main recording I used to detect sonic differences was "Buddy & Maria Elena Talking in Apartment," from Buddy Holly's Down the Line: Rarities (16/44.1 FLAC Geffen/Qobuz). This track is from a tape made on an Ampex recorder by Buddy himself in his living room on Fifth Avenue. With the microphone in front of him, Buddy is sitting on a couch near a window to his left. At the start of the track, Elena is talking on the phone about 20 feet away in the kitchen.


With the HSA-1b, the room's ambient noise energy, plus the street sounds coming through the window and the rich character of Buddy and Elena's voices, seemed fully recovered. Spatial mapping was absolute. When I switched from the RAAL amp to the Schiit amp, I noticed a reduction in ambient room sound but also an increase in the clarity of the sounds cars made while passing on the street outside the window. This slight leanness reduced the tone quality of Buddy and Elena's voices but improved enunciation.

Overall, I thought the Jotunheim R was slightly—I repeat slightly—leaner, drier, crisper, and more energized than the HSA-1b. This slight crisp leanness translated into a greater sense of transparency, but I preferred the weightier, more colorful presentation of RAAL's HSA-1b.

Skinny wire vs fat wire
My SR1a headset came stock with relatively thin 7' cables that I have used happily since I received them with the SR1a in January 2020. All of my Gramophone Dreams #32 observations were made with them. When the HSA-1b arrived, it included RAAL's thicker, optional SR728 Silver Headphone Cable ($1050). I installed it at the same time I installed the HSA-1b amplifier, so all of my above observations were made using the optional silver cable.

I planned to exchange the silver cable for the original copper cable at some point in the review process to see if anything changed sound quality–wise. When I finally did, I laughed out loud, because compared to the thick silver cable, the skinny cable sounded, well, thinner.

Tone and textures were less fully resolved.

To verify this observation, I used Alice Coltrane's live 1978 album Transfiguration (16/44.1 FLAC Rhino-Warner/Qobuz), focusing particularly on the second track, "One for the Father," which I repeat-played all the way through, alternating cables but never changing volume levels. The fat silver cable always played bigger, denser, and more colorfully. With the fat cable,

the microphones sounded closer to the piano's strings and hammers. With the silver-wire cable, the notes from Alice's piano came through with the impression of belonging to a single, whole body of energy emanating from a massive wood and strings instrument. With the stock cable, individual notes floated separately, detached some from the main corpus of piano energy.

Conclusion: RAAL's optional SR728 Silver Headphone Cable is a necessity—not an accessory. A necessory.

Wrangling the Abyss
If RAAL's HSA-1b is to be considered as more than a house-brand amp for driving the SR1a ribbons, it must also drive today's best dynamic and planar-magnetic headphones.

I am grateful to have some of those "best" headphones here—most especially the 88dB/mW, 47 ohm JPS Labs Abyss AB-1266 Phi TC, which is my #1 reference open-back planar-magnetic headphone. It, along with HiFiMan's Susvara (and the SR1a), are the audio X-ray tools I use to "view" the nanodetailed inner spaces of recordings—details my floorspeakers cannot access.

I began my RAAL-Abyss auditions with the Phi TC connected to the HSA-1b's Conventional headphone output. Coincidentally, as I was starting my auditions I discovered St. Vincent (singer-songwriter Annie Clark) on Roon; her naked torso on the cover of Masseduction (16/44.1 FLAC Loma Vista Recordings/Qobuz) caught my eye. The image looked a lot like a "dragged-pigment" Gerhard Richter painting, so I played it, thinking maybe I would find some edgy music by a hip young Brooklyn-type avant-garde performer. Which I sort of did. (Annie Clark is from Tulsa, Oklahoma, like photographer-filmmaker Larry Clark.)

By Masseduction's third track, "Masseduction (piano version)," I was hooked on Clark's lush, low, testosterone-fueled voice and her twisted bad-girl attitude. The RAAL amplifier driving the Abyss headphones gloriously reproduced the bottom registers of Clark's vocals, showing me yet one more view of RAAL's amplification prowess. However, the AB-1266s did not seem as completely transparent as they do driven by the Pass Labs XA25 or Ampsandsound Bigger Ben amplifiers.


Hoping for better, I connected the Abyss (via the included sex-change coupler) to the HSA-1b's SR1a output. The sound got bigger, faster, cleaner, and more compelling. Transparency, though, was still not up to Pass Labs or Ampsandsound levels.

During repeat plays of St. Vincent's Björk-inspired "Pills (piano version)," the sound was sharply defined, hypertextured, and well-tempered with plenty of gain and no noticeable clipping. Clark's prepared piano gave off deep, guttural, rough-textured sounds. Though heavily pimped, autotuned, and compressed, Annie Clark's faux-child Pills voice was cuter and pluckier than it was with the Abyss driven by my Pass Labs XA25.

Powered through the HSA-1b's SR1a output, the Abyss sounded brighter, more open, and more dynamic than it did through the "Conventional HP" output. Thank God for the sex-change adapter.

Susvara blues
One unusually hot night in June, shirt off and sweating, I went to the kitchen for more lemonade. As I entered, it seemed I had left the oven on. Then I realized: The heat I felt as I approached the stove was actually a faint breeze from the open window. That realization triggered me to go back to the studio, put on HiFiMan's Susvara headphones, and sit in front of a fan contemplating our collective American past with some chain gang sweatbox music: Negro Prison Blues And Songs recorded live (1947–1948) at the Mississippi and Louisiana State Penitentiaries by Alan Lomax (16/44.1 FLAC Bescol/Tidal).

My favorite songs from that album are always "Murder's Home" (by Jimpson & Group) and "Early in the Morning" sung by Little Red, Tangle Eye, and Hard Hair. Both songs were recorded in mono with a single microphone, and both songs put my mind right there in the prison yard with the singers. If you've never experienced the apparition-like reality of an uncompressed, unedited, single-mike field recording, this Lomax album would be a perfect place to start.

I didn't even try to drive the $6000, 83dB/mW insensitive, 60 ohm impedance Susvara planar magnetics with the HSA-1b's Conventional HP output. I went straight to the SR1a output, which smiled and danced gracefully with HiFiMan's hardest-to-drive open-back cans. The Susvara rendered every prison song with an unnervingly vivid illusion of a full, coherent, human-occupied reality.

With high-impedance phones
The last thing I needed to check was how the "Conventional HP" output might drive ZMF's high-sensitivity (99dB/mW), high-impedance (300 ohm) ZMF Vérité closed-backs ($2499.99), which I described in Gramophone Dreams #35. The elegant Vérité features monkeypod wood cups and 50mm "Ultra-thin" polyethylene naphthalate dynamic drivers with a vapor-deposited beryllium coating. Powered by Ampsandsound's Bigger Ben amp, the Vérité sounded smooth, superarticulate, super-3D, and 100% natural. With the HSA-1b amp, their sound on DakhaBrakha's latest album, Alambari (16/44.1 FLAC DakhaBrakha/Qobuz), was a quarter-teaspoon too soft and 3ms too slow but delivered bucketsfull of relaxed DakhaBrakha artistry. With the RAAL amp, the Vérité closed-backs played on the lush side of neutral.

Listening power
As a reviewer-prattler, I endeavor to discover and advocate only those products I believe advance the cause of deep listening. Whenever I discover a "deep listening" product that sounds a lot better than its competition, I am obliged to stand up, applaud loudly, and declare its excellence. To that end:

In my 100-year-old-Herb view, RAAL-requisite's SR1a pure ribbon Earfield Monitors, connected with RAAL's optional SR728 silver cable to RAAL's new HSA-1b headphone and speaker amplifier, represent the cutting edge of what is currently possible in high-resolution audio reproduction. And, in case you hadn't noticed: RAAL-requisite's style and coolosity factors are off the charts.


thethanimal's picture

As always, I love the journey your articles take us on. Champion Jack Dupree is wailing through my bedroom/office (what a tragedy) speakers now, probably loud enough to raise some collective eyebrows from the wife, toddler, and nanny downstairs. One day I’d love to hear the level of headphone refinement you write about here, but so far I’ve found the DragonFly Red and Sony MDR-7506 combo to be the point of diminishing returns — at $300! I took the Sonys in to the local brick and mortar shop and lined them up against Focal Clears and Stellias at their headphone bar and just couldn’t justify the difference. The salesman did me a solid though by making me try out that DragonFly Red; I was hooked after the first few bars. The Blue had more ease to the sound, but as a percussionist (alas, in a past life at this point) I enjoyed the extra impact I heard through the Red.

PeterG's picture

Great write up, as always! As a Stax 9S owner/lover, I agree that the RAALs are maybe even more resolving. When I tried them, I found them to be thrilling. Actually, for me, too thrilling, I felt like my ear was on the edge of the snare drum or sax bell. But an amazing addition to the handful of super premium headphones--like a Ferrari. Cheers!

tonykaz's picture

Dear Mr.HR,
I was a Stax Dealer and admirer , eventually I sold my personal Stax and quit selling Stax altogether.

It might've been too much of a good thing but was it? maybe it was too much complexity, too specialist, too unique, too fiddly. Maybe it was like a Porsche 911 Turbo for picking up the TacoBell at the Drive thru.

Music is like hanging out with an old friend, Stax Music was like a problem solving visit with my Analyst.

If these RAALs are anything like Stax they will probably be slow sellers compared to gear like Abyss Diana. ( my guess )

Thank you for bringing us this report, I can barely imagine anyone else they could trust with this. ( Tyll is lonnnnnnnng Gooooonnnnnnne ) You always seemed to be Tyll's replacement although un-announced.

Tony in Venice Florida

Ortofan's picture

... did you decide to sell/use in their place?

I've been a STAX headphone user since buying the SR-5/SRD-6 in the mid-1970s. That has been followed by the Lambda Pro/SRD-7 Pro and several other sets.

Which amps were you using to drive the STAX 'phones?
I found that some solid-state amps had trouble driving the load presented by the STAX adaptor. At that time, the SAE 31B seemed to work particularly well, as well as the Hafler DH-200 which appeared at the end of the decade.

tonykaz's picture

Hello again,

I became delighted with Mid Level Sennheisers ( 580/600/650 Series ) and Schiit Class A SS Amplification and Schiit Valhalla 2 with Russian Tubes ( which soar the musical heights with a comfortable ease ).
I've heard the newer outstanding headphones and am now considering the ABYSS Diana but I'm in no hurry.
I have my eye on and am planning for the latest version of Woo Firefly.

Back in my Retail Days, Stax were pretty much the only headphone to own. I had their range of Headphones and their matching Electronics. I was not quite a headphone guy until RMAF 2011 when I met the Schiit Guys, whom I was interested in for their manufacturing concepts and philosophy. I bought into their Products a few months later. I still love Schiit despite their shitty name & power switches on the Rear.

The Sennheisers are better than any Loudspeaker system I've ever encountered. ( even though they are mid level sound quality compared to the latest great stuff : 1266 Abyss.)

Headphones will change with careful Wire selection.

Schiit Tube gear changes with careful Tube Selection.

Tony in Venice Florida

ps. I'm anticipating the FR series of PS Audio Loudspeakers will be must have. Phew -- fingers crossed !