2019 Chapter 5:
Buzzword Bingo
Big SNIP
The Present: Coherence, Continuity, Nexus, Unison USB
Of late, you may have noticed a change in how we name our technologies. Names like Coherence™, Continuity™, Nexus™, and Unison USB™ are now getting out there. And this change isn’t by chance. It’s something I started purposefully last year, as I realized that some of the analog technologies I was developing were actually (a) gonna work, and (b) be pretty cool. That’s when I realized that we should claim some of these technologies…
Smaller SNIP
And so, here we go: our current names of key technologies that we consider
important.
Coherence™. This is our combobulated tube-BJT hybrid topology that delivers on the promise of hybrid designs the most, at least in our experience. Unlike other hybrid topologies we’ve used, Coherence allows us to run a high voltage at the tube stage (better for tubes), use the tubes for voltage gain (better application of a tube’s strengths), combine the tube and transistor stages without input, output, or interstage coupling capacitors, and integrate it with a wide variety of output stages, including Continuity. This topology you’ll see in Lyr 3, and (to a lesser extent), in Vali 2, though Vali still uses output coupling capacitors to simplify the power supply requirements and keep cost down.
- Importance: like I said, it’s the best hybrid topology we’ve found to date, and (as far as I know), we’re the only ones using it. Hence it’s worth naming as a differentiator to all the other hybrid topologies out there.
- Found in: Lyr 3, Vali 2
Continuity™. This is our constant-transconductance output stage that I’ve already written a couple of chapters about (Lyr 3 and Aegir chapters). It’s a big deal because it addresses a problem baked into literally every Class AB amplifier out there: the problem of transconductance droop as the amplifer falls out of its Class A biasing region. It also addresses the problem of N and P device mismatch, another gotcha that is baked into most Class A and Class AB amplifiers out there (except for a few using Sziklai output stages or something like that). It is a relatively simple topology that extends the benefits of Class A bias by adding additional output transistors as the stage exits Class A. Is it as good as weighs-a-billion-pounds-and-can-double-as-a-grille Class A? Maybe, maybe not. You tell us. Is it a panacea that fixes every Class AB stage? No, it still runs plenty hot and isn’t really applicable for low-bias or higher-power applications without heroic heatsinking, or a complete re-engineering of how it works (as mentioned above).
- Importance: this is a unique take on the Class AB transconductance droop problem as enumerated by Bob Cordell and John Broskie, and is present in every Class A amp, and (as far as I know), we’re the only ones using it. Again, something worth claiming as a differentiator.
- Where it’s found: Lyr 3, Aegir
Nexus™. This one may be the most difficult to describe, because I haven’t yet written a chapter on it. Nexus refers to what I’ve called the “holy grail” circuit, one that allows us to run SE in to balanced out and balanced in to SE out in a single discrete gain stage, while preserving high-impedance signal inputs and offering an N/N gain relationship on the inverting and non-inverting inputs. That whole bunch of technoese almost describes the Pivot Point topology of Jotunheim, with the exception of the N/N gain relationship. So, it may not sound very exciting, especially when Pivot Point works so well as it is, and does not require the insane amount of matched parts that Nexus needs. But it’s very exciting to me, and it’s definitely the best all-purpose topology we’ve developed. Expect a chapter comparing this to Pivot Point and Crossfet, as well as, say, Supersymmetry, in depth in the near future.
- Importance: as far as I know, this is the only discrete toplogy that succeeds in delivering SE or balanced in to SE or balanced out while offering high impedance signal inputs and maintaining an N/N gain relationship.
- Where it’s found: Ragnarok 2
Aside: Supersymmetry is a great name. Nelson Pass is a very smart guy. Supersymmetry’s patents were also licenced by TI. Coincidence? Maybe. But names are important. Hence this chapter
Unison USB™. This refers to our new USB interface that Mike and team have been prototyping for the last year, and in beta on for the last three months or so. Sounds pretty boring in a world where you can talk to the air and have Alexa play your favorite house mix for you? Yeah, well, enjoy your compressed Bluetooth sound over a walkie-talkie speaker, and the paranoia of wondering if Jeff Bezos is listening to you take a dump. Instead, we’ll concentrate on solving the problem of getting great audio over a general-purpose interface using a general-purpose microprocessor and our own single-minded code. Which actually turned out to be quite a challenge. Which also ended up working so well that Mike now prefers it over SPDIF. Yes. Mike. No, no alien pods have been found decomposing near his house. Maybe the reason it works so well is that it’s designed to do one thing and one thing only: transfer PCM digital audio from a source and convert it to I2S. That’s it. No 500x DSD, no MQA, no Brutoof, no shamalamadingdong, no 32/768 or 64/1536, no unicorn formats period.
- Why it’s important: it provides exceptional performance, frees us from commercial USB interfaces, and allows us to interface USB audio data with a wider variety of (ahem) nontraditional DACs. It is also our own technology, not XMOS, not CMedia, not Tenor, and we are actual USB-IF members with our own VID, which is something not many other high-end companies can claim.
- Where it’s found: nowhere yet. It’s still in beta. Not sure where you’ll see it first. Bug Mike. He loves you.
And that’s it. Four names. Four technologies. Two of which aren’t even in any products that have shipped yet, with one still in beta. I personally don’t think this is overkill, and I also personally think it’s important that we have some differentiators.