Some input from John (Product Manager Origin Effects) about the Halcyon Gold on TGP:
It's cool to see so much interest in our Adaptive Circuitry. While we're obviously not going to tell you what's in the secret sauce, I suppose we can rule out a few guesses - hopefully this will help people understand how they might use it in their rig.
1. It's not a Treble Bleed. Treble bleeds are passive circuits that prevent against the treble loss that occurs in guitar electronics due to cable capacitance. The amount of treble retained is dictated by the position (resistance) of the guitar volume pot. No matter how hard or softly you play, the same volume knob position will give you the same amount of treble loss.
In the Halcyon Gold/Green, the entire mid-hump of the pedal is reduced as you clean up from your guitar, or from playing dynamics. The effect of the pedal's TONE pot is also reduced. So, like a treble bleed, you'll hear more treble as you turn your guitar down, but you'll also hear more bass, and any tone-shaping you've done with the TONE control will also be reduced. The Adaptive Circuitry works by making the "voicing" of the pedal proportional to clipping. It responds to input signal level, not pot resistance. So, more clipping = more mid-hump and tone control. No clipping = mid hump removed. As such, you'll get the same effect if you leave the volume knob alone and play softly.
In the M-EQ and DCX, only the top-end roll-off is adaptive, but this is still dependent on how hard you're hitting the pedal.
2. It's not to do with input impedance, like a Fuzz Face etc. This means you can put the Adaptive pedals anywhere in the chain, regardless of buffers.
3. There's no sidechain-type behaviour like with a compressor, where you need to worry about attack and release. As mentioned above, it's to do with clipping and, therefore, dependent on input signal level. If the Halcyon is clipping, it's mid-humping. So, the same way the tail of the note decays from overdriven to clean, the frequency range of the note will decay from mid-humpy to flat. People tend to report that it seems very natural, like it's just a part of how the overdrive reacts. You don't so much notice that these pedals are doing it as much as you start noticing that other pedals aren't.
In the case of the Halcyon Gold, it has another advantage. Someone earlier correctly pointed out that the Klon GAIN knob also increases the mid-hump from flat to pokey as you turn it up. This means players have to choose whether they want the "flat" Klon sound or the "pokey" Klon sound when setting the GAIN control. The Adaptive Circuitry allows you to run a higher-gain sound for that mid-forward tone, then roll the volume back/play softly to get the "transparent" thing. Doing this on a real Klon would get you a clean tone, but you'd always have that prominent mid-hump.
For those wondering about parts cost and complexity, this Adaptive Circuitry takes a lot of extra components and whole new design approach to implement correctly. As much as we'd like it to have been easy, the result isn't really a simple Klon with "adapt" added; it's a rather complicated Adaptive pedal with Klon added!
Charge Pump:
We use a different charge pump chip to the Klon and we run our chip at a higher frequency, still giving similar MASSIVE voltage swing to the Klon. It's the same chip and implementation that we've used on all products since the original RevivalDRIVE. The Klon buffer actually oscillates at very high frequency when the gain control is turned down, which may well cause issues with certain setups. Ours doesn't cause this issue, as it's the same as our other pedals that people have been using for a few years.
Magic Diodes:
We've used multiple modern-day diodes in a parallel configuration to replicate the electrical parameters of the original NOS diodes. Matching the performance of the diodes in Chris Buck's Klon to an accuracy of <5%. This took a lot of testing but we'll spare you the graphs.