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A perfect system? RAAL-requisite VM1a & SR1a Review

by Makiah Shenay May 24, 2022

A perfect system? RAAL-requisite VM1a & SR1a Review

What makes the perfect system? For us, and likely yourselves as well, it's not just about sound quality. Instead, we feel as though an optimal system consists of a combination of various elements. An ideal system has to feature a series of top-notch components, such as: a headphone or transducer, amplifier, and source.

Let’s start with the most critical piece of the puzzle, which is the headphone, in this case. What features should the perfect headphone have? We feel that the ideal headphone should sound amazing with all forms of media and music, be built with longevity in mind, be reasonably easy to service, and feel comfortable to wear. Ideally, the lifespan of a headphone should be a long one. A product shouldn’t fail, but on the off chance that it does, it should be easy to replace crucial components. After all, none of us enjoy being without our favorite headphones for too long. While unlikely to be user-serviceable, the perfect amplifier and source should be equally well built, with the backing and support of an outstanding company and team who can quickly get our perfect system back up and running if something should happen. With that said, I can think of no better source than a Direct Stream DAC from Bricasti Design. Each unit is hand-assembled, shipped, and serviced right from their headquarters in Massachusetts.

From the viewpoint of sound quality alone, there are a lot of contenders for the “perfect” headphone, since none of us share exactly the same preferences. However, a headphone that is built tough, is user-serviceable, and has outstanding sound quality does exist. This very same headphone also takes EQ amazingly well. It also has a complementary direct-drive amp that offers a variety of settings to adjust tone & presentation based on user preferences. If you haven’t already guessed it, we’re talking about the RAAL-requisite SR1a Ribbon Headphone and VM-1a Ribbon Headphone Tube Amp system!

Playback System and Media Choices


Our source was the Bricasti Design M3 Direct Stream DAC, utilizing direct streaming over LAN through Roon for music, and AES input from our Windows Workstation for movies and gaming. We used a Kimber Kable Axios Silver Headphone Cable for SR1a, with matching Kimber Kable Select Silver XLR Balanced Interconnects, and two Kimber Kable Ascent PK14 AC Power Cables. Movies were played using JRiver with bit-perfect audio output into our source. For direct comparisons, we listened to and enjoyed the following:

  • Pink Floyd - Dark Side of the Moon: DSD256 "Master Tape" Pull
  • Nu:Tone/ Kool Keith - Future History: Metaphor 6000
  • Archspire - Bleed the Future: Drone Corpse Aviator
  • Inception: DTS-HD MA5.1 Downmixed to 48kHrz/24bit 2Channel via JRiver
  • Monster Hunter Rise PC: 192/24 Output via Windows 10 ASIO Driver

One of the best features of VM-1a is the variable operation modes and options for tube rolling. These two features allow for a variety of tweaks and adjustments to help fine-tune the amp to your tastes. There are three operating modes available on VM-1a, which are: Ultra-Linear, Triode, and Pentode. Pentode had more power, driver, and body, while Triode was a bit more articulate and lean. All in all, Ultra-Linear presented the best of both worlds, so we chose it for this review.

We retained the stock EL-34s for this content, but chose to swap over to a 1940 NOS JAN-CHS VT-231 Sylvania White Label tube, because we found that it provided more articulation and detail. This tube combination preserved VM-1a’s natural tone and body without sounding harsh or “sharp” by any means.

Sound and Comfort

We found SR1a to be quite comfortable over both short and long listening sessions. The initial fit does require a bit of adjusting, but the headphone holds its position well, only requiring adjustments every few weeks or so. However, we encourage using a headphone stand to preserve your preferred angle of the ribbon drivers. While we didn’t find the headphone too heavy or cumbersome, comfort will ultimately vary from user to user, so it’s well worth demoing the headphone beforehand. Thankfully, we will continue to be present at larger and smaller shows across the country, so be sure to stop by our table to experience SR1a for yourself.

SR1a alone carries an ultra-linear studio neutral tonality, with outstanding detail, speed, and articulation. It presents sound within a stunningly deep, open, and genuinely holographic soundstage. While its bass response will be a bit lean for some, it takes to EQ amazingly well. We used the following EQ-profile within Roon while listening, and we're delighted with how well SR1a & VM-1a handled the boost to deep synth bass-lines in "Metaphor 6000". Despite the added sub-bass, Keith's unique voice and tactile cadence remained perfectly balanced within the mix.


In the past, we've found that SR1a’s presentation can come off a bit unnatural, over-sharpened, lean, mean, and down-right fatiguing on some amps. Archspire's "Bleed the Future" album can be exhausting to listen to with such pairings. Even SR1a’s beautifully deep and open soundstage can be a little artificially “precise” at times on these amps, making sounds appear from out of thin air, without any natural decay and reverb. When paired with VM-1a, however, SR1a provides the same limitless detail, but with a more natural and organic tone. Quite frankly, this is the most effortlessly cohesive sound-staging we’ve ever experienced. Listening through "Drone Corpse Aviator", the SR1a and VM-1a perfectly blend the vocals, kick drums, and bass guitar riffs within the wall of distorted guitars. Amidst all this chaos, we're still able to pinpoint each individual instrument within the mix, without any hint of congestion.

However, we continue to be blown away by the terrifyingly realistic soundstage the SR1a & VM-1a combo have. This is a quality that is especially evident when enjoying movies or video games that have well-engineered sound design.

SR1a & VM-1a System with Cinema & Gaming


We were utterly blown away and shocked while viewing Inception for the first time with SR1a. That opening scene with the sounds of the waves crashing sounded and felt indistinguishable from reality. As the movie progresses, each and every scene is presented with terrifying transparency. Gunfire is especially jarring given how true to life SR1a and VM-1a present it. Spoken words were incredibly vivid; each actor’s voice was perfectly in-line with their visible distance within the scene and relative to other characters. That massive, deep, and effortless soundstage only adds to the shock value as we find ourselves caught off guard again and again. To say that it's immersive feels like an understatement. We often felt as though we had fallen into the movie itself!

As avid Monster Hunter fans, we’ve logged thousands of hours into each iteration, and we adore how well-produced and engineered the soundscapes, effects, and backing tracks are. We’re thankful to have had two PC releases back to back, so we fired up both Rise and World. As we explored through the “Flooded Forest” and “Rotten Vale”, we were greeted with a layer of detail we had not experienced before. We were greeted with quiet and deeply nuanced sounds, such as the distinct “squish” of our footsteps in the “Vale”, and a vivid “splash” as we ran through the “Flooded Forest”. This system, again, presented these sounds in a way which was indistinguishable from reality. It was quite uncanny and even felt a bit distracting at times. Down in the “Rotten Vale”, especially, we found ourselves a little unnerved by just how realistic each step felt and sounded. Honestly, though, this system gave us a level of insight that we had not heard before. We now have a much bigger appreciation for these games, and we’re eager to explore more of the map, as well as uncover more of these unique interactions. It’s like experiencing an all-new entry to the series for the first time!

AKG K1000 "Bass-Heavy" Comparison


To help create some context, we're excited to have an AKG K1000 “Bass-Heavy” on hand for comparison. Like SR1a, it's more of an ear-speaker than a traditional headphone. While the two share a similar mounting style for the drivers, they are worlds apart. It's abundantly evident how technological improvements have benefited audio-playback systems and headphones over the last two decades. Twenty years ago, K1000 was the detail and soundstage king. To help put things into perspective, we sat down with the Bricasti Design M3 feeding into our HeadAmp GS-X mk2 and listened through a one-of-a-kind copy of “Dark Side of the Moon”, alleged to be a 1:1 analog to digital DSD pull from the master tape itself! While we can’t confirm its origins, we can say that this is by far the best we’ve heard this album sound!

Sadly, however, this two-decade old flagship was no match for SR1a. While impressive at one time, it is over-sharpened and anemic in the bass by today's standards. Its speed, detail, and open stage are still exciting to listen to at times, but it simply sounds a bit artificial and exaggerated compared to the SR1a and VM-1a combo. The bass guitar was too punchy and lacked good low-end extension. The drums, while vivid and tactile, lacked body. Even David’s voice sounded coarse and strained. Guitars, however, sounded stunning, lively, and beautifully tactile. However, so many of the various sound effects, which were engineered and panned for helping create ambiance, just sounded forced. Once again, when going back to SR1a, there was an abundance of detail and articulation which was presented with an otherworldly effortlessness and gorgeous organic tone. Fans of this once legendary K1000 will find SR1a to be an immediate and rewarding upgrade.



Perfection doesn't come without its costs, and while few headphone systems require this level of investment, we feel that ultimately when paired together with a top-of-the-line source like the M3 Direct Stream DAC, there’s nothing that directly compares to the RAAL-requisite SR1a Ribbon Headphone and VM-1a Direct Drive Ribbon Headphone Vacuum Tube Amplifier system. Limited to just music playback, one could argue that there are other comparable systems based on individual preferences. However, in our experience, this system has unparalleled tone, detail, and texture which is evident across all forms of music and multimedia. All of this is showcased within a true-to-life soundstage, presented consistently, and with impressive effortlessness. For any lover of well produced music, cinema, television, and gaming, this is hands down the best complete headphone playback system we've heard. Time and time again, we found ourselves astonished by its combination of truly out-of-your-head imaging and flesh & bone tonality. With a bit of system tweaking and a powerful equalizer, such as what’s found within Roon, it can easily exceed the wants and needs of even the most discerning audiophile.

Not to mention, the entire platform on which the headphone is built and assembled upon allows for unmatched longevity. There is no other headphone, which performs at this level, that is as easy to service and maintain as the SR1a is. The peace of mind associated with owning a headphone like SR1a is truly priceless. Combined with its out-of-this-world sound, one listen is all it’ll take for you to know that this is your perfect system!

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