RAAL Requisite CA-1a Ribbon Headphone Review

Discussion in 'Headphones' started by purr1n, Dec 26, 2023.

  1. purr1n

    purr1n Desire for betterer is endless.

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    A few years ago when I was at an event the Schittr, someone grabbed me to check out the RAAL Requisite SR-1a ribbon ear speakers. "Hey Marv, you gotta check these out!" The rest is history. Read about the SBAF Golden Schlong Winner SR-1a here: https://www.superbestaudiofriends.o...udio-sr1a-review-holy-moly-buy-this-now.8041/

    TLDR; In a nutshell: https://www.superbestaudiofriends.o...bon-headphone-review.14057/page-2#post-422944

    I knew that that RAAL Requisite had been working on a circum-aural version which has come out as the the CA-1a (Yes, I'm a late to the party.) I decided to grab a pair for the SBAF loaner program after a few members mentioned that the CA-1a was worthy, trading off technicalities of the SR-1a for more extended lows and more even frequency response. This is an accurate assessment. The CA-1a comes with two pairs of pads. One set has cutouts to allow more air. The sound of this pad is a cross between the fully encircled pads and the SR-1a. The fully encircled pads actually make the CA-1a tonal response somewhat like an HD650.

    IMG_1561 (1).jpg

    The first part of the journey was to find good system synergy. (I don't know what's up with me these days about this system synergy stuff but I seem to be more nitpicky about curating components for the total system approach lately.) The CA-1a while being easier to deal with tonally compared to the SR-1a, still requires careful matching with amp. The transient attack and treble timbre of these ribbons headphones can be a bit "hard" or "spitty" on the wrong set up. We all know that transducer and amp matching with nothing new, e.g. the HD800 can sound dreadful on the wrong system (and even then some people will not like the HD800.) Also, the CA-1a, despite the new TI-1b transformer adapter box (needed because the ribbon is 0.2-ohms, basically a metal foil strip), is still on the inefficient side. We need an amp that has plenty of gain (and power) and that doesn't sound too tightly strung.

    I tried quite a few amp pairings with the TI-1b transformer adapter. Here are my notes a la Car and Driver rankings:
    1. Sixth Place: Ferrum Orr / Hypsos (with Yggdrasil LiM). I was hoping the Orr's smooth elegant refined presentation and high power would work. However, this amp didn't do anything for me with the CA-1a. From a tonal and timbre perspective, neither worked. This amp was too neutral. It didn't round out the transient attack either. The gain was also lacking. With some tracks, I had the volume maxed out with the Hypsos on high-gain. There wasn't enough dynamic oomph either.
    2. Five Place: Saga with Vidar 2 with Yggdrasil MiB). Now we are getting some oomph. I know the Vidar slams like crazy with tight lows. However the highs were too solid-state. And even then, I'm starting to really understand the limitations of ribbons when it comes to monster bass slam. (Still better than e-stats though).
    3. Fourth Place: Pietus Maximus. This worked slightly better than the above. The Modius E with with the Cinemag's helped and did better than the Yggdrasil LiM. However, given that Pietus and Ferrum are so similar sounding, it's no surprise this didn't work for me.
    4. Third Place: Jotunheim 2 (with Yggdrasil LiB). I happened to have this lying around so what the heck. Wow, ain't bad. It's not the end-all-be-all, but it works as a budget solution. FWIW, because of its simplicity (stack a Bifrost 2), I did use this for a while listening to music and even taking a few video calls. The video calls were a revelation of that ribbons can do. I usually take video calls with Grados or Sennheisers. Sometimes with the ESP950. Dang, talking about listening through everything: shitty microphones, compression, how people use their airways, tongue, and lips to make words. That was spooky. I can only imagine what @zerodeefex hears when he takes calls with the SR-1a (with dual mono Tyrs - "certified" to work with the RAAL ribbons). Anyway, I wanted better. Nothing wrong with Jotunheim 2, would totally recommend this, but too mid-fi for me. I'm a high-roller.
    5. Second Place: Mjolnir 3 (with Yggdrasil MiB). Hmm, now we are getting somewhere. This is good. Sure, the Mjolnir 3 isn't that dark and only slightly warm. Maybe is has to do with what @roshambo123 said about the Mjolnir 3, that the transients in the highs are rounded. I did have to crank up the Mjolnir 3 quite a bit. Overall very good sounding, lots of plankton, but I couldn't help but feel there could be more slam. This last bit I know is hard for a ribbon. At the end of the day, I couldn't help but play back Paul Simon's Diamonds on the Soles of Her Shoes to remind myself of a listening session I had with the Sennheiser HE1. To be honest, I preferred this set up to the HE 1 (with it's built in DAC). FWIW, my wife who dislikes the HFM nano-planars and all e-stats for having "too much separation" loved this setup.
    6. First Place: HH Scott 222D Integrated Stereo Amplifier (with LiM). This vintage piece was painstakingly restored by @bobboxbody. Yes!!! This space heater is purrfect. If you think your Mjolnir 3 is a space heater, the 222D is about three times more deadly.
    MOD ADD INDEX:
     
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    Last edited: Jan 9, 2024
  2. purr1n

    purr1n Desire for betterer is endless.

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    A little detour before I take measurements. I'd like to give @bobboxbody a shout out for being such a valuable resource and member of SBAF. @bobboxbody fastidiously restores vintage tube stereo amplifiers such as this: https://www.superbestaudiofriends.org/index.php?threads/hh-scott-lk-48-restoration-mods.13326/

    I actually purchased the HH Scott 222D from him a few months ago and just did not have time to unbox it until now where I had a good reason. FWIW, shame on you guys for not buying the amp on the FS section. What @bobboxbody was asking for it was too reasonable - essentially a gift, a labor of love, for 1960s tube amplifiers. This was the time when the secret to good audio transformers was not yet lost. There was no way I was going to let this go outside of SBAF. If I hadn't grabbed it for safekeeping, @zerodeefex was. (And yes, shame on you guys for completely ignoring the Eddie Current Ultralinear, which I think he was asking $1200. I eventually bought it myself and gifted to @ChaChaRealSmooth for being gearmaster).

    @bobboxbody not only provided all needed tubes (all vintage except the outputs?), but also labelled where the tubes go in along with biasing the output tubes. appropriate. There are a million tubes that do all sorts of stuff on the amp (I have still yet to figure it out). Finally, he included a full set of tube protectors for the 12AX7s and spade to banana connectors in the back.

    Anyway, check out the restoration job. Repainted transformers and shiny parts.
    IMG_1562.jpg

    Anyway, hail to vintage meets modern. Hail to two headless panther pieces of gear!
     
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    Last edited: Dec 26, 2023
  3. purr1n

    purr1n Desire for betterer is endless.

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    RAAL Requisite CA-1a
    Frequency Response
    Diffuse Field Compensated
    upload_2023-12-26_15-33-6.png

    RAAL Requisite CA-1a
    Frequency Response
    Diffuse Field & 1/db Octave Compensated
    upload_2023-12-26_15-45-39.png

    Response is a big jaggy. We've seen this is underdamped HiFIMan planars. I wonder if the tension is a bit different on the CA-1a compared to the SR-1a, maybe to allow it to extend down to 20Hz. There is a decent dip localized at 3kHz which isn't offensive. I am hearing stuff in the highs that isn't reflected in the FR. Let's take a look at CSDs next.
     
    Last edited: Dec 26, 2023
  4. purr1n

    purr1n Desire for betterer is endless.

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    Cumulative spectral decays below. This wasn't expected from the FR: some ringing at 7kHz. Usually we see a big narrow dip in the FR when this occurs. This makes sense and likely a contributor to the subjective hardness or spittyness that I mentioned earlier with some amps. More relaxed or transient rounded amplification works best with CA-1a. The effect is worse in the R channel than left.

    Also notable are the "ripples" in the lower-mids to middle-mids. We will see this in some orthos and all e-stats. In the case, they are gone after 1-2kHz. The rest of the floor in the upper mids to high treble is super clean. Overall decay is super duper fast.

    I've noted that these ripples, often indicative of underdamped planar types do contribute to a more liquid sound. Yes, the CA-1a is more liquid compared to the SR-1a which is more grainy relatively speaking. It's give-and-take. Tradeoffs. I know some people will prefer the SR-1a. Others will prefer the CA-1a.

    RAAL Requisite CA-1a
    CSD L
    upload_2023-12-26_15-59-4.png

    RAAL Requisite CA-1a
    CSD R
    upload_2023-12-26_16-7-21.png

    To be continued. Nap time for me. Curious about distortion and impedance.
     
    Last edited: Dec 26, 2023
  5. YMO

    YMO Chief Fun Officer

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    New Raal headphones have PS1 graphics similar to a Cybertruck, my god stop the Hype Train.

    But on a serious note, is the Raal still not for those who want less speedy transients and more warmth? Something bright/cold with speed doesn't make me go crazy, and with all the praises of the SR1a I just haven't gotten to the point to really start caring even when their headphones are closer to my spending level.
     
  6. Armaegis

    Armaegis Friend

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    Did Raal stop making their dedicated ribbon amps? I really liked the HSA-1b.
     
  7. internethandle

    internethandle Almost "Made"

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    You heard it here first folks, the upcoming Yggdrasil Likes its Boner.
     
  8. Tchoupitoulas

    Tchoupitoulas Friend

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    Yeah, Raal no longer offers them. They weren't made by Raal but by a Serbian outfit, SAEQ, who collaborated with Raal in designing them for the needs of the ribbon drivers.

    https://saeq-audio.com/headphone-amplifiers-shop

    You can still get the HSA amp from them, now it's the HSA-1c
     
  9. penguins

    penguins Friend, formerly known as fp627

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    @purr1n - Now that you've heard the CA1a on a few different amps, how does this compare to the SR1a and OG Utopia in terms of technical performance on the MJ3, 222D, or (another) suitable speaker amp?

    Still have this as a candidate for super duper resolution mode when my OG Utopia dies.

    --------------------
    For perspective of anyone wondering - based solely on my memory - SR1a has probably the best technicalities compared to any production HP I've ever heard. OG Utopia 2nd. CA1a somewhere between 3 and 6 the two times I heard it and this probably depends on the chain too. But I ultimately never got the SR1a as it has 3 big problems for me - 1) not comfortable on my head - pinched the temples enough to get a free headache every time I tried it. Could be solved by building my own headband but that would be it's own hassle. 2) bass quality is good, but quantity is bad without an additional external sub 3) cost - not just the HP, but the amp, sub, pre-amp, and likely any other associated I would need to build or buy.

    SR1a also had the problem of being hard to pair with amps - in addition to the above, without the right amp it did trend towards too e-stat like as well - great transients, clarity, and typical e-stat strengths, but e-stats also sound really artificial to me because there's no actual presence. It feels like a very resolving but not quite realistic reproduction of music.

    Utopia was hard to pair too until I found the right tube combo on the Stellaris. With the wrong tubes that 5.5k peak still bothers me and I have to stop listening pretty fast.
     
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  10. purr1n

    purr1n Desire for betterer is endless.

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    I believe it was @Hands who said that speedy transients requires thinner lows (same thing as brighter/cooler). I tend to agree with this. Utopia is probably the closest when it comes to good bass with some warmth and speedy transients. Here are SR-1a vs CA-1a frequency responses overlaid:

    SR-1a (cyan) vs CA-1a (orange)
    Frequency Response
    upload_2023-12-26_18-37-3.png

    Utopia is better with respect to plankton. However, I'd say that Utopia is relatively easy to get to this level from where I am at and what I've been exposed. It's really just a matter of getting final pieces (tubes, DACs, cables) with DNA Stellaris or my EC 45 Custom. Heck, throw in Starlett, ZDS, DSHA 3F. Maxing out CA-1a is still a little bit of unknown if you are nitpicky like us. I am thinking the x2 Tyr monoblock combo of @zerodeefex would be the way to go for the CA-1a as well. Throw in a DAC with an output stage that can drive an transformer volume control into the Tyrs, and that would be magic. However this set up is ridiculous. More for its size, since Tyr's actually run cool and both suck up less wattage at the output at low output than Aegir (yes, I've measured it).

    I should mention that the Mjolnir 3 (and Yggdrasil MiB) is good enough. It's arguably more resolving than the HH Scott 222D, but a bit less slammy, and definitely not quite as lush. Yes, the ribbon sounds lush with the 222D. The Scott is also more mid-centric, this presentation helping to fill in the 3kHz FR dip. However, I can cheat a bit because it's got bass and treble knobs.

    Ultimately, I do feel that your assessment of SR-1a being tops overall with technicalities, followed up Utopia, and the CA-1a dropping to positions 4 and 7 may be spot on. The only stat I'd throw up there is the HEV/HE90 Orpheus, the OG Orpheus. The Sennheiser stats have a harder transient attack to STAX and the HE90 is just damn resolving. FWIW, I didn't feel the latest Sennheiser HE-1 was close, and even then the HE-1 had problems in the highs: an obvious spotlit peak at 9kHz "ssss, ssss" (shows up a dip in some measurements) and sort of a mild V shaped tuning. I figured I'd mention this because it seems the Internet is abuzz yet again with the HE-1 as the bestest. For those who have been around in this hobby, it's not. Then again, I'm kind of a theoretical source first person (practically amp first, and only because good vinyl is hard to source), so the transducers are just along for the ride.

    Finally, the CA-1a does pass the Bjork Hollow (16-Bit Remix) first minute test. It's not quite as dynamically slammy as the ZMF Atrium, but bass heft and sustain is up there. The expectation is that the bass should be frightening. This is where stats and even the nano-diaphragm to a lesser extent planars fall apart.
     
    Last edited: Dec 26, 2023
  11. Clemmaster

    Clemmaster Friend

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    Would love to try it with LTA Z10+ Integrated and Vinnie Rossi VR120 :heart:
     
  12. JK47

    JK47 Friend

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    Hopefully if you have time, FR chart comparing the the two sets of pads?
     
  13. Serious

    Serious Inquisitive Frequency Response Plot

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    My 2 cents:

    I quickly gave the CA-1a a shot on the Viva Egoista 845 amp. I much preferred it with the open pads: less closed in sounding, more of a neutral tonal balance IMO.

    Even still, I heard a big upper mid dip that ultimately led me to prefer the SR-1a based on its tonal balance alone, (despite the very much audible 2kHz bump). And in terms of stage size and overall sense of transparency, etc I think it wasn't even close.

    Keep in mind that I'm not that much of a fan of the SR-1a myself, anyway. Same for Raal tweeters. I'd take a modded HD800 or the Utopia over it - I tend to like dynamic drivers. I suspect it might also be related to the required transformers. Plus the ribbon just seemed overwhelmed in the bass, even on the CA-1a.
     
  14. purr1n

    purr1n Desire for betterer is endless.

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    CA-1a with Open Pads (yellow) vs CA-1a with Closed Pads (orange)
    Frequency Response
    upload_2023-12-27_11-13-3.png

    This is how the open pad looks like.
    IMG_1563.jpg

    @penguins: I would be curious how they fit you. I can max out the strap with my big Asian block head, but I think your head is even bigger than mine. I also had some issues with the protruding clip at you see that right. That clip protrudes inward to allow the headband strap to wrap under and through. I had to bend tie headband a bit outward in the middle and then inward a bit at the sides.

    I am tending toward the open pads despite less bass below 100Hz. Again, the full closed pads did make it sound HD650ish, reducing technicalities and aspects that make the CA-1a less "ribbon" sounding for better or worse.

    Totally get that. I basically hate all ribbons on speakers, except for the bigger RAAL ones. I do wonder if the transformer brick is holding it back. I almost get the sense that the original passive box that came with the SR-1a was better. Would be curious to compare the TI-1b with the open baffle comp barrels and the original passive box with the SR-1a.
     
    Last edited: Dec 27, 2023
  15. purr1n

    purr1n Desire for betterer is endless.

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    Here are the Cumulative Spectral Decays for the Open Pads. As expected, they are a bit more ringy, less damped throughout, compared to the fully enclosed pads.

    RAAL Requisite CA-1a
    CSD L
    upload_2023-12-27_11-48-59.png

    RAAL Requisite CA-1a
    CSD R
    upload_2023-12-27_11-51-45.png
     
  16. purr1n

    purr1n Desire for betterer is endless.

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    Finally, you guys know how much I love toilet paper. This is for taming the highs and hard transient edges for greater compatibility with more amps particularly of the solid-statey sounding variety. This can be helpful for the less damped but more lively presentation of the open pads. Or for folks who prefer a darker presentation.

    The design of how the pads mount to the cups makes it super easy to do. The pads have tabs at the top and bottom and slide into the cups. A single sheet fits right in between the where clips slide in.

    IMG_1565.jpg

    CA-1a with Open Pad with TP over driver
    Frequency Response
    upload_2023-12-27_12-4-4.png

    CA-1a with Open Pads no TP (yellow) vs CA-1a with Open Pad with TP (blue)
    Frequency Response
    upload_2023-12-27_12-1-10.png
     
    Last edited: Dec 27, 2023
  17. penguins

    penguins Friend, formerly known as fp627

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    CA1a fit comfortably without issues the 2 times I've tried it. No issues from that little clip either. My only concern was actually how hygienic the foam will be over time given it's openness - but it doesn't look like particularly expensive foam and knowing that RAAL didn't deliberately rip people off on their SR1a replacement ribbons, I'm also hoping replacement foam will be reasonably priced. Worst case, I suppose we can buy foam and cut it ourselves?

    SR1a fit:
    The SR1a fits too if I use the large headband setting - it's just the clamping force being concentrated into those 2 little pads (i.e. force not dispersed) that happen to sit right on the pressure point in the temples for me and also use way too soft of a foam to provide any real resistance. Initial reaction was to just put a bigger pad / different material there to help disperse and absorb the force.

    However, I soon realized that wouldn't work - it won't resolve the other fit problem where it's actually too loose on my head - but the way the SR1a headband is designed the only likely solution for me without making a new headband or hat or something is to add more clamp which means faster headache.

    General gripe:
    There's also another issue I don't see addressed often - it seems that a lot of headphones and bands are designed for people with average or smaller heads and they simply add more clicks or notches to the headband to make it fit bigger heads without actually designing it to work for large heads as well. The ergos, clamping, fit, seal / sound, and/or whatever else is most likely going to be off. Kind of like swapping a left and right shoe - technically, your foot fits in the shoe, but nothing feels good.
     
  18. Tchoupitoulas

    Tchoupitoulas Friend

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    I had a pair of CA-1a for four months earlier this year. I really liked them but sold them to a friend for a couple of reasons: 1) I couldn’t justify having another high-end headphone along with my others, and my SR1a did much of what I’d want from a headphone like the CA-1a, given that my other headphones have me covered for a deeper bass response or a warmer sound signature and 2) the slight tizziness/hardness in the treble was a dealbreaker.

    I won’t offer a full set of impressions as I’m relying on memory but here are a few thoughts to complement what Purr1n mentioned above.

    General impressions
    The CA-1a is like the SR1a but without the vast, open staging or quite the resolution and outstanding imaging, layering, and separation of the SR1a. The CA-1a have excellent imaging and staging, for headphones, but they’re a different species from the SR1a. The CA-1a with the coffee bean pads, i.e. those with holes in the pads, make for a more studio-neutral kind of tuning, like that of the SR1a but with more overall bass and without the sub-bass roll off of the SR1a. The sound is still quite thin and dry and cool, more analytical than euphonic or mellifluous. (By “thin” I mean lacking in lower-mid richness).

    The donut, or fully enclosed pads make for a mellower, richer sound, with more warmth from the bass. It’s not as suffocatingly warm as the HD 650, which is too humpy in the mid-bass and too rolled off in the treble, for my tastes (I’m an HD 600 guy). The hardness in the highs is less noticeable than with the coffee bean pads.

    Where both versions stand out are the superb resolution and the speed of transient attacks. No, these aren’t super impactful headphones, nor do they have the slam of the Atrium, but the snappy attacks do make the CA-1a sound toe-tappingly fun and engaging. I also love the pristine clarity of the presentation; they’re like the HD 650 but with the opposite of the veil. The more I think of it, the more I suspect the CA-1a sound a good bit like the Abyss 1266 Phi with CC pads. The Abyss has way more slam and macrodynamic strength. And it has more rumble in the sub-bass and a tighter, more powerful bass presentation. It’s also more spacious in its staging. But the Abyss also has the same kind of pristine clarity and slight brightness as the CA-1a, both having that bit of treble zing. Where the CA-1a is better than the Abyss is in its mid-range evenness and resolving quality. The CA-1a is less recessed and more evenly balanced in its overall tuning. Both are a little thin in the lower mids - if, that is, the CA-1a have the coffee bean pads installed; with the fully-enclosed donut pads, the CA-1a has a fuller sound and more richness in the lower mids.

    In terms of clarity, the CA-1a have a lot in common with the Utopia, and I’d be interested in seeing a direct comparison with the two. I didn’t have my old Utopia at the same time as the CA-1a but I wonder if the Utopia offered up more plankton. I found the Utopia to be more pleasing, but then I had it paired with my Stratus, and even though the Bliss (my preferred amp for the CA-1a) was good, it’s not at the level of the Stratus. The CA-1a has faster transients than the Utopia, if memory serves, but not by too much, and I could be wrong here. Both headphones are similarly resolving. The Utopia gave me less treble trouble than the CA-1a did. The CA-1a has a more open and spacious headstage with similarly precise imaging. As it happens, the guy who bought my CA-1a sold his Utopia, preferring the Raal.

    [​IMG]

    Mitch’s filters
    A quick note about the filter sets offered by Mitch at Accurate Sound, which get a lot of praise (hype?) on other forums (see here for them, you can get a free trial version, and here’s a review of the filter set for the SR1a, which provides a useful explanation). I tried the filtersets and wasn’t a fan, in spite of the universal praise they get on head-fi. I can see why people like them but the filter actually made the treble tizzier and more fatiguing to me. (I also didn’t favor the filter sets for the SR1a). They’re worth experimenting with if you get the CA-1a.

    [​IMG]

    Amp pairings
    The CA-1a is less hard to drive than the SR1a. I used the TI-1a transformer box (the same as the TI-1b but with the different, metal enclosure of the original interface box for the SR1a). This transformer box allows the use of headphone amps.

    For my tastes, I preferred warmer sounding amp pairings:
    • My old V281 was pretty decent but it didn’t do anything special and didn’t add any meat or substance to the slightly thin coffee bean padded presentation.
    • The Mjolnir 2, with various tubes, was really good, and a bit more energetic and warm (again, depending on toobs).
    • The Ragnarok v 1.5 (on high gain) likewise did a great job with the CA-1a, although it didn’t help with the treble. I’d like to say both the MJ2 and the Rag gave the CA-1a more punch, but I wouldn’t swear an oath on it.
    • The Monoprice Cavalli LAuX did a decent job of driving the CA-1a: it’s a great option if you can snag one used for under $500.
    • Schiit Jot R. This was great, for the price. It added a good amount of bass emphasis, although I didn’t use the bass shelf that can be switched on for the SR1a. It was a less refined, smooth option than some of the other amps mentioned here, but for the closeout price you can get the Jot A for right now - $200 - it works very nicely. I’m not entirely clear about the differences between the Jot A and R. I understand that the Jot A is designed to accommodate the much more sensitive LCD-R, although I don’t know for sure.
    • The best amp I heard the CA-1a from was the Holo Bliss, which had the right amount of warmth and the kind of rich, vivid sound that suited the CA-1a nicely. It drove them adequately.
      • (I should note that the Bliss also made for a great pairing with the SR1a, better in many respects than the HSA-1b, but it required the volume pot to be turned up all the way with quieter classical pieces like piano sonatas, and I wasn’t comfortable driving an amp to its limits, especially as the Bliss’s volume pot isn’t just an attenuator as it ramps up the gain as you turn it).
    I didn’t get to hear the CA-1a with my HSA-1b (I bought the latter with funds from the sale of the Bliss, after also letting the CA-1a go). But my friend really likes the pairing. He said it adds nicely to the bass. He also really liked the CA-1a with the TI-1b transformer box and the Piety! He said it didn’t drive them perfectly but that the tonality was lovely.

    A note on pads
    One of the real treats of the CA-1a are the pad-rolling options. You effectively get two different headphones in one, and both the pads make for sound signatures that make sense in and of themselves. In other words, both sound right. Neither sounds like a poor, compromised version of the other for the sake of adding a different tuning option. This makes the CA-1a quite versatile. Since the pads are cheap, it’d be fine to stock up on them, and, for the fun of experimenting, I’d considered buying a couple of sets of the fully enclosed ones and then cutting out different sized (or placed) holes of my own.

    B-stock sales and value proposition
    I picked up my pair in a b-stock sale. I already had the TI-1a transformer box so the “naked” headphones only cost me $1,500. You can get the headphones with the transformer interface for $2k, and if you pair them with a $500-750 amp (at, say, used prices), you can have a killer setup, especially when you consider the two tunings afforded by the donut and coffee bean pads. I’m not sure if the CA-1a competes directly with the Utopia - again, I’d need to A/B them - but it’s well worth noting that a $2k b-stock pair of headphones is snapping at the heels of the Utopia.

    I wouldn’t get the CA-1a instead of the Abyss 1266. They don’t have the bass, slam, impact, or macrodynamic strength of the Abyss, or quite the expansive staging, but they’re better tuned and more versatile than the Abyss, and they’re more resolving in the midrange. Ultimately, they’re great headphones, albeit with a few caveats, and it says something that I prefer the CA-1a in many respects to vastly more expensive headphones.
     
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  19. purr1n

    purr1n Desire for betterer is endless.

    Staff Member Pyrate BWC
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    RAAL CA-1a Distortion. The following are with the open pads, which have more distortion than the closed pads.

    Second Order
    Distortion Surface (Distortion is in absolute SPL)
    upload_2023-12-27_17-32-24.png

    Third Order
    Distortion Surface (Distortion is in absolute SPL)
    upload_2023-12-27_17-35-47.png

    Fourth Order
    Distortion Surface (Distortion is in absolute SPL)
    upload_2023-12-27_17-38-47.png

    Commentary:
    • Third order dominant in the lows and upper bass. High distortion at high SPL. The CA-1a doesn't like to be pushed to ear bleeding levels. Third order subsides to reasonable moderate levels below 85db. None of this should be an issue for those who listen a low to moderate SPL.
    • High second order distortion at moderately loud to very loud SPL. Even around 85db, a little bit elevated.
    • A couple of narrow distortion speaks at specific frequencies, most evident in the second order surface, but existing in the third and fourth as well. Possibly related to the reverberation of the ribbon under tension?
    • Quite clean in the mids and highs.
     
  20. purr1n

    purr1n Desire for betterer is endless.

    Staff Member Pyrate BWC
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    There are a couple of FR dips in the upper mids and up. I am assuming the tizzier treble could be an effect of filling these dips in. (We don't know for sure because of the site for Mitch's filters, we only see the measured frequency response and effect of the convolution filter to 5kHz). Getting to perceptive neutral is just as much an art as science. Can't just make the frequency response totally flat. This is coming from someone who has built plenty of speakers and crossover networks. Science gives us a starting point. Final tweaking is always done by ear, a few db here or there to compensate for a transducers distortion and transient characteristics. Finally, I am not convinced the high frequencies are even for any two ribbons.
     

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