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Inductor Choke: The Analog Delay

Bloodhoney

This is the exact magic of that circuit. When we talk about "delay" in the context of the Coyote/Moonrock's choke, we have to separate it from the way a guitar player usually thinks about delay (like a tape echo or a Bucket Brigade chip repeating a signal). Instead of delaying the audio itself, the inductor is causing an envelope delay—a delay in the attack of the note. Here is exactly what's happening under the hood when Rusty Strings digs into a heavy chord.

The Physics of the Choke

As you know from dealing with audio electronics, an inductor is basically a coil of wire that stores energy in a magnetic field. Its defining characteristic is its strong opposition to any sudden change in current flow. The governing mathematical rule here is:

\[ V = L \frac{di}{dt} \]

Where voltage (\(V\)) is proportional to the inductance (\(L\)) times the rate of change of current over time (\(\frac{di}{dt}\)).

The "Delay" Mechanism (The Swell/Bloom)

When you strike the strings hard, you produce a massive, sharp transient. That's a huge, immediate spike in current, trying to rush through the circuit.

  1. The Wall (The Choke): Because that transient is a sudden, massive change (\(\frac{di}{dt}\) is very high), the inductor fights back. It induces a reverse voltage (counter-EMF) that essentially blocks that sudden rush of current.
  2. Transistor Starvation: In this circuit, that inductor is sitting right in the path feeding a high-gain silicon transistor. Because the inductor just slammed the brakes on the current, the transistor is momentarily starved of current. Its bias point drops so low that it effectively turns off or gates heavily. If you listen closely to the attack, you'll hear a tiny, compressed, splatty "tick" or silence.
  3. The Release (The Bloom): A few milliseconds later, the transient passes. The current stops trying to change so violently (\(\frac{di}{dt}\) drops toward zero). The inductor's magnetic field stabilizes, and it stops fighting the current.
  4. The Swell: As the current is finally allowed to flow freely, the transistor "wakes up" and fully biases into its active region. The fuzz roars to life.

That time it takes for the inductor's magnetic field to charge and stabilize is your delay. It creates a dynamic, reverse-tape volume swell that is completely dictated by how hard you pick. If you pick softly, the transient is smaller, the inductor doesn't fight as hard, and the fuzz stays relatively normal. If you hit it hard, the choke slams shut, and you get that delayed, blooming attack. It's a brilliant way to use passive component physics to manipulate the dynamic envelope of a gain stage!

Reverse-tape Volume

It’s a descriptive term borrowed from old-school studio engineering to describe the shape of the sound. If you picture the workflow in vintage analog recording studios—the kind cutting classic rock or blues on 2-inch tape—a favorite trick was to record a guitar track, physically take the tape reels off the machine, flip them backward, and print the playback. When you do that, it completely flips the natural physics of how a guitar string sounds:

  • Normal Guitar Strum: You get a sharp, loud, instantaneous attack the moment the pick hits the strings, followed by a long, trailing decay as the strings vibrate and fade out.
  • Reverse-Tape Playback: The sound starts completely silent, slowly and smoothly swells up in volume (the reversed decay), and then abruptly stops at peak volume (the reversed pick attack).

Why it applies to the Coyote/Moonrock:

When that inductor chokes out the voltage, it effectively erases your pick attack. The pedal goes dead silent for a fraction of a second, exactly when you hit the strings. Then, as the inductor releases its chokehold on the current, the volume of the fuzz rolls up and blooms into existence. It artificially creates that "swelling up from nothing" envelope, making your live guitar sound exactly like a backward tape loop.

It's a fun, highly expressive effect, but it can completely throw off your timing when you're playing. Because the sound actually blooms after your pick strikes the string, you almost have to play slightly ahead of the beat to make it sit right in a mix. For someone getting back into the groove and knocking the rust off the strings, a pedal that intentionally delays your attack and fights your natural picking rhythm can definitely be a wild ride.