Just before I installed RAAL HSA-1b, I was playing an unusual EMI LP called Renaissance Suite, which included music from Joël Santoni's 1974 film La Course en Tête (HQS 1415). This film records the career of Belgian bicycle star Eddie Merkex in a strange and wonderful artistic way. The most peculiar thing is that this score was composed and arranged by the British early music expert David Munro, and performed by the London Early Music Union, which is full of vitality. Imagine a sports documentary featuring the sounds of playing the flute, tromba marina ("nun's violin"), and rauschpfeiffen accompanied by people in tight shorts and bright shirts riding thin bicycles on the hills of Europe.
Using 300B Elekit TU-8600 to drive LS3/5as, Renaissance Suite shows the sound of wood and gut strings, making Munrow's early music feel authentic, medieval and exotic. Its temper is fresh and festive, but its voice is soft.
When I connected Gold Badges to the RAAL HSA-1b amplifier, the sound became significantly firmer and clearer. With HSA-1b, the flow and momentum of the sheet music dominates my consciousness. Music is more dynamic. When the music is louder, David Munrow's work is more meaningful.
When I switch from Falcons wooden box to RAAL's SR1a wide-open full-band ear monitor? From speakers to earbud speakers? I experienced a clearer and more focused "view" of the recording.
RAAL's steel cage head-mounted transducer is unique in the earphone market. They are durable and affordable ($3,500). The dipole tape of SR1a is placed in a stainless steel cage completely away from the head. They are true ribbons, and the amplifiers they present have an almost complete short-circuit load impedance: 0.2 ohms, including cables. The user manual recommends the use of 100W amplifier power (footnote 1). With enough amplifier juice, SR1a provides concentrated, colorless, low-distortion sound levels that (I believe) exceed the super-resolution Stax SR-009S static and my beloved JPS Labs Abyss AB-1266 Phi TC and HiFiMan Susvara planar magnetic element.
SR1a headphones require so much high-current amplifier power, so it seems logical that RAAL-requisite manufactures an amplifier that can drive their headphones or my speakers with a single touch of a switch on the front panel.
HSA-1b RAAL's new HSA-1b amplifier (footnote 2) is the first solid-state speaker and headphone amplifier I have tried. When I connected it to a floor-standing Stenheim Alumine Three speaker and heard that it can effectively drive a pair of speakers worth US$32,900, I knew it was a different kind of speaker from Linear Tube Audio’s 10Wpc (8 ohm) Z10e/ Headphone amplifier, I reviewed it in Gramophone Dreams #36 or Ampsandsound's 8Wpc (8 ohm) Bigger Ben, and I described it in Gramophone Dreams #47.
RAAL's HSA-1b is a rugged small red knob-style 11.7 pound amplifier with a moderate size, 3.5" high x 8.6" wide x 12.6" deep. It uses two bipolar junction transistors (BJT) for each channel , The pair of bolts are connected to a single 8" × 3.5" × 2" aluminum radiator.
The manufacturing quality is so high that in its case, the HSA-1b appears to meet military specifications. In appearance, the high degree of fit and finish has both the seriousness of industrial strength and the charm of home decoration.
In addition to (and next to) the mandatory IEC power socket, the rear panel of the HSA-1b has two line level inputs: a single-ended (RCA) and a balanced (XLR). There are also two pairs of banana plug jacks for connecting stereo speakers. Under the speaker jack, it reads "Serbian SAEQ designed and produced for RAAL requirements".
According to Aleksandar Radisavljevic, the head of all RAAL-requisite, “SAEQ stands for Serbian audio equipment. It is a company of a very good friend I’ve known for 20 years, Mr. Dragan Domanovich. I am very impressed with his sound speaker amplifier, once we After completing his headphones, I asked him if he could make an amplifier for SR1a, which would be marked as RAAL-requisite and offered exclusively as RAAL-requisite. He was eager to make the necessary modifications to the topology of his favorite amplifier. After more than a year Iteratively, Dragan got the sound that all of us Rr and SAEQ wanted. Now that SAEQ is capable, they are also making it."
The front panel of the HSA-1b has a 5/8" diameter professional audio type power switch, lit by a red light. On its right side is a four-pin XLR headphone output connector, which is a male rather than a normal female , So that only RAAL's SR1a ribbon earphones can be connected; the HSA-1b package includes a gender-changing female to female XLR adapter so that users can connect HiFiMan's 83dB/mW Susvara and other power-consuming, low-sensitivity earphones to HSA-1b The high-current SR1a output, on the right is the four-pin female connector of traditional balanced earphones, and then the 3.5mm (unbalanced) TRS jack. Above the earphone connector is a row of three switches for users to choose between SR1a and traditional earphone drivers. SR1a output, headphone or speaker output, balanced and unbalanced input. On the far right is the big red panel control volume knob of HSA-1b, which controls its click sound, 24-step attenuator.
Radisavljevic told me in an email that HSA-1b uses bipolar junction transistors because "they are current-driven devices, not voltage-driven devices like MOSFETs." Therefore, "BJTs have higher switching losses. But it has lower conduction losses."
I told Radisavljevic the "incredible drive" I heard from HSA-1b, it is driving the 15 ohm, 83dB/2.83V/m?? sensitive Falcon LS3/5a speaker, its power and surprising easy. I asked him to explain how his little "headphone" amplifier does this. He replied: "The driver is there, because it can provide 7 amps to a 0.4 ohm load, so 15 ohms is meaningless to it. It is basically a speaker amplifier that has been further optimized to drive low impedance. Load." In another email, Aleksander introduced me to some specifications not listed on the RAAL must-have website: "The gain is about 10dB of RCA input. With XLR input, if you have a high-output DAC, you can Choose to reduce the gain."
Inside the HSA-1b, a small printed circuit board extending vertically from the XLR input board has a six-position DIP switch, which can be used for "internal sensitivity adjustment of XLR input". According to the instruction manual, the user has 3 choices: 10dB, 6dB, 0dB. My device is preset to 6dB.
"The output impedance of the traditional [headphone] output is 5.3 ohms. The power from this output to 32 ohms is 250mW, and the power from this output to 300 ohms is 26mW. The power output of the SR-1a/Ribbon output (drive dynamic or planar magnetic Headphones)) 1900mW at 32 ohms and 200mW at 300 ohms." If my math is correct, it means that the leftmost toggle switch is set to the down position and the ribbon output is about 7.75V.
HSA-1b Elsewhere in this issue, I am reviewing Stenheim Suisse's $32,900/pair aluminum three-seater floor-standing speaker. These 41-inch tall speakers look very expensive in red, black and gray aluminum cabinets. Their appearance is very tasteful and modern. Most importantly, they reproduce recordings with sharp, non-refraction clarity, which is incredibly fascinating.
Stenheim's website states that the sensitivity of Alumine Three is 93dB/2.83V/m (footnote 3), and the recommended minimum power of the amplifier is 10W. So naturally, with a bit of naughty persuasion, I tried to power them with 10Wpc HSA-1b.
It is difficult for me to decide whether to start my RAAL-Stenheim audition with Champion Jack Dupree or Jacqueline Du Pré. It was hot and stuffy that day, and the air smelled like fish, so I went to the Gutter Blues (16/44.1 FLAC Atlantic/Qobuz) with the masterpiece made by New Orleans pianist champion Jack Jerry Wexler in 1958. I was surprised how sweet Dupree’s piano sounded, and how rich and realistic the bass of Wendell Marshall from Alumine Three’s dual 8" woofers sounded. Champion’s wobbly N'awlins attitude is fully reflected. My only concern is how or why it is usually bright-tough Atlantic recordings sound a bit thick and soft.
Then I turned to Jacqueline Du Pré, the most famous cellist in the UK. Playing her Haydn and Mann: Cello Concerto, from 1969 (24/48 FLAC-MQA Warner Classics/Tide), the softness disappeared, and the real and real sense of occlusion and presence came back. The strings of the London Symphony Orchestra conducted by Sir John Barbirolli pass with just the right posture and precision. The HSA-1b + Alumine Three combination produces a fresh, open and clear sound. Violin transients and cello harmony entered my room, very realistic. This recording rarely feels so compelling.
During the audition period from June to July, I listened to dozens of albums, among which RAAL HSA-1b powered Stenheim Alumine Threes. I rarely feel that more power is needed.
RAAL's necessary SR1a HSA-1b drives Falcons and Stenheim speakers very well, but the main reason for its existence is to power RAAL's SR1a full-band headphones without the RAAL amplifier impedance converter. I hope it can at least be compatible with the amplifier I made from Pass Labs XA25 or Schiit Audio for SR1a (Jotunheim R.
When Pass Labs XA25 powers the RAAL headset (via RAAL's impedance converter), the recording sounds clear and straightforward, and it feels like the original, unobstructed view captured by the microphone. The trance music I like has a soul.
And color. It is never old-fashioned or sentimental in the new era. Instead, the sense of rigor and agility evokes ancient bloody memories.
This is exactly what the environment wizard Steve Roach did in his 1993 album Origins (16/44.1 FLAC Fortuna/Qobuz). In Origins’ third track "Clay, Wood, Bone, Dirt", Daniel Nagle’s didgeridoo’s low, hum, and guttural sounds beat all other man-made sounds. Stimulate blood memory. Using SR1a driven by HSA-1b, the long flutter cavity resonance of didgeridoo tube and the short resonance sound of clay pot appeared in the semicircle in front of me, tangible and tangible.
Footnote 2: RAAL Advanced Loudspeaker, Djordja Simeonovica 419000 Zajecar, Serbia. Tel: (381) 64 144 1111 Website: raalrequisite.com, raalribbon.com. American distributor: Requisite Audio Engineering, 2175 Goodyear Ave., Suite 110 Ventura, CA 93003-7761. Phone: (818) 437-0779. Website: requisiteaudio.com
Footnote 3: I estimate that the B-weighted voltage sensitivity of Stenheim Alumine Three is 91dB/2.83V/m, which is much higher than the average. ??John Atkinson
As always, I like the journey your article has brought us. The champion Jack Dupree is now wailing from the speakers in my bedroom/office (it's a tragedy), and the sound may be enough to make the wife, toddler and babysitter downstairs frown. One day, I would love to hear about the level of improvement of headphones you wrote here, but so far, I have found that the combination of DragonFly Red and Sony MDR-7506 is the point of diminishing returns-$300! I took Sony to the local physical store and put them together with Focal Clears and Stellias on their headphone bar, but couldn't justify the difference. The salesperson asked me to try DragonFly Red, which benefited me a lot; I was fascinated after the first few bars. Blue's voice is more relaxed, but as a percussionist (well, a previous life at this point) I enjoy the extra influence heard through Red.
Very well written, as always! As the owner/enthusiast of Stax 9S, I agree that RAAL may be more determined. When I tried them, I found them exciting. In fact, it was too thrilling for me. I felt that my ears were on the edge of a snare drum or saxophone. But for a few super premium headphones (such as Ferrari), this is an amazing addition. cheers!
Dear Mr. HR, I am a Stax distributor and admirer. In the end, I sold my personal Stax and stopped selling Stax altogether.
This may be a good thing, but isn't it? Maybe it's too complicated, too professional, too unique, too cumbersome. Maybe it's like the Porsche 911 Turbo picking up TacoBell on Drive thru.
Music is like hanging out with old friends, Stax Music is like solving problems with my analyst.
If these RAALs are similar to Stax, they may sell very slowly compared to equipment such as Diana of the Abyss. ( I guess)
Thank you for bringing us this report, I can hardly imagine that they can trust anyone else. (Tyll is lonnnnnnnng Gooooonnnnnnne) Although not announced, you always seem to be Tyll's replacement.
I have been a STAX headset user since I bought the SR-5/SRD-6 in the mid-1970s. Followed by Lambda Pro/SRD-7 Pro and several other sets.
Which amplifiers do you use to drive STAX mobile phones? I found that some solid-state amplifiers have problems driving the load provided by the STAX adapter. At the time, SAE 31B seemed to work particularly well, and Hafler DH-200 appeared at the end of the decade.
I am happy with the mid-level Sennheisers (580/600/650 series) and Schiit Class A SS amplifiers and Schiit Valhalla 2 with Russian tubes (they soar the music in a comfortable and relaxing way). I have heard of newer and great headphones, and now I am considering ABYSS Diana, but I am not in a hurry. I am following and planning the latest version of Woo Firefly.
In my retail era, Stax is almost the only headset I have. I have their headset series and matching electronic products. Before RMAF in 2011, I met Schiit Guys. I am very interested in their manufacturing philosophy and philosophy. I am a headphone expert. I bought their products a few months later. I still like Schiit, even though their name and power switch are on the back.
Sennheisers is better than any speaker system I have encountered. (Although their sound quality is at an intermediate level compared to the latest good thing, 1266 Abyss.)
P.S. I expect the PS audio speakers of the FR series will be necessary. Call-fingers interlocked!
Post time: Oct-28-2021