RAAL-requisite - Official Thread

RAAL-requisite represents the coming together of two well known names in the high-end audio firmament. The Serbian “RAAL” group, probably best known for their ribbon tweeters and speakers, and “Requisite Audio Engineering”, out of California, producers of a gamut of highly regarded studio components.

As a joint venture, they’re are know for their SR1a EarField™ Monitor ribbon-driver headphones, and the HSA-1b Switch-Drive headphone/speaker amplifier.

New, pending, releases mean its long overdue to give the brand as a whole its own thread, even while the existing products have their own, respective, dedicated threads.

So this is the spot to discuss RAAL-requisite as a brand, and for commentary and speculation on what they may bring to the market in the near, and not-so-near future.


There has been some high-level discussion from RAAL-requisite, across different interviews and so on, about what they have in the pipeline.

The two most immediate projects of interest for SR1a/RAAL-requisite fans are the long-rumored circumaural (over-ear) ribbon-drive headphones and the much more recently mentioned tube-based amplifier. RAAL-requisite has a goal of showing both of these new products at the upcoming CanJam in September - though aren’t quite ready to commit to that yet.

Things of note so far …

Circumaural “SR1a”:

I don’t know what this will actually be called … maybe “SR1a C” or “SR1c” … or something entirely different.

Current commentary has it targeting a $2,900 (or lower) price-point. It will use a shorter ribbon than the SR1a, though no word on whether it is wider and/or has greater/lesser surface area. Native bass reproduction should be flat to 30 Hz. And the cups will be setup such that they are angled relative to the ear by 15 degrees, which should help preserve some of the SR1a’s much-vaunted ability to image and stage in a speaker-like fashion.

Tube Amplifier

I’ve heard this referred to as the “VM1a”, tubes mentioned were 6LZ for signal and EL34 for power. A single-ended, push-pull design (single-ended means it should retain more tuber-goodness than a balanced design would do), with a currently projected price of $6,500.

I am likely in for one of each … especially if the VM1a ups the available power for conventional headphone and speaker drive (assuming it retains both those capabilities from the HSA-1b … which I’ve not heard anything about).


The YouTube clip mentions it’ll be a 3" ribbon vs. 4" in the SR1a (25:39).


I vote for CR1a! I hope Florida is treating you well…


Excellent news! Both the circumaural phones (for more ribbon goodness) and a direct drive tube amp, which I didn’t think would come about from any source to power the SR1a. As much as I like The HSA-1b over my Jot R
I am really becoming addicted to the sound of the SR1a with my PrimaLuna EVO 400 with EL 34’s in Ultralinear mode and 70 watts/channel into the interface. Spooky good sound.

When I read that, it reminded me of those little button batteries.

1 Like

Just thought of something, I hope they stick with the same headphone connector type, I’ve already got some aftermarket cables set up with those 3.5mm’s.

Don’t use aftermarket cables with the raals. They are so low impedence that cable inpedence will measurably change FR. You need cables specificaly designed for them unfortunately

The specifics of impedance and pin assignments have been taken into account by this manufacturer in this case and I have communicated directly with the owner who makes their TOTL cables himself. The proof as always will be in the listening.

(and I have tried one pair from a different outfit where i don’t think these factors were taken into consideration and I think the female connector is wired out of phase, live and learn). LOL!


They should.

Since the overall impedance of the cable assembly is so low, the 3.5mm TRRS connector gives more connection surface area than mini-XLR or even more common 3.5mm TRS connections - which helps keep the impedance as low as possible.

The headphone is actually wired to use all four connection points to take full advantage of that.


Speaking of SR1a cables …

I’ve talked about the ones I’ve built in the SR1a thread. They’re lower impedance than the official ones, which results in a slight, but apparent, reduction in treble energy when used with the ribbon-interface box.

To listen at my desk (which is deliberately further from my headphone rig now than a normal cable will reach) I’ve taken to using my 0.05 ohm SR1a cable, which is as big as can be practically used without becoming an ergonomic pain, in conjunction with a separate extension cable.

This extension cable is something I run to a clip on the side of my desk (or you could run it to your feet), as it is too thick and heavy to actually run to the headphones themselves … not to mention the conductor bundles for each channel/phase are individually too large for the the cable entry on 3.5mm TRRS jacks. But it only adds 0.03 ohms total to the cable impedance, so I can then plug my custom SR1a cable into that.

Net result is an overall <= 0.08 ohm cable (extension plus headphone cable), up to 21 feet long.

When listening without the extension cable, i.e. when I’m sitting near my rig just to listen, I use the 0.1 ohm direct cable I built originally.


Yoy mention on the adapter box specificaly. Is this less of an issue on the hsa-1b?


Less of an issue on both the HSA-1b and the Jotunheim R.

1 Like