Kevin Parker pedalboard on a budget2015 documented board rebuilt for ≈ $137

This is the circuit-led choice. The Small Stone is a four-stage OTA phaser: its early circuit used four CA3094 cells and current adaptations use LM13700 OTAs, with the Color switch adding feedback for the deeper, hollowed sweep. Behringer's factory VP1 schematic shows four LM13700 all-pass stages and its Tone switch changes that feedback relationship. That preserves the warm moving notches and one-knob workflow that matter before Parker's reverb and final drive far better than a cheap Phase 90-style JFET phaser would.

Trade-off. The VP1 is not claimed as a component-for-component Small Stone. Its LFO and surrounding values differ across the circuits, and Small Stone revisions themselves do not all sweep or change level identically. The VP1 can lose some volume when engaged, uses a much larger enclosure than the Nano reference and its Tone positions do not map to exact Color-switch settings. Match the slow sweep and resonant depth by ear rather than copying a knob number.

The Holy Grail is a digital algorithm pedal, not an analogue spring circuit, and Parker's exact program is undocumented. The DR600 therefore preserves the useful choices rather than pretending to clone an unknown setting: it has dedicated Spring and Hall algorithms, independent Level, Tone and Time, plus a Modulate mode when the pre-drive wash needs extra movement. Placed before the Blues Mood, even an ordinary hall tail is compressed and dirtied into the smeared Tame Impala texture this core path is meant to teach.

Trade-off. None of the DR600 programs is Electro-Harmonix's algorithm. Most importantly, Modulate is a chorus-like detuning of the reverb tail, while Holy Grail Flerb is reverb followed by flanging, so it is only a moving-reverb alternative and not a Flerb replacement. The Behringer also trades the Holy Grail's rugged metal box and one-knob immediacy for a plastic treadle enclosure and four controls. Begin with Hall unless evidence for Parker's mode appears later.

The BD-2 is not a Tube Screamer: its two discrete op-amp-style gain stages, hard-clipping section and amp-like tone shaping create a wide, touch-sensitive drive that can become ragged at higher gain. Mooer's MBD2 Blues Mood targets that same wide-frequency American amp family, keeps Level, Tone and Gain, and adds Bright/Fat voicings; a controlled Bonedo comparison identifies Bright as the setting nearest a stock BD-2. Most importantly, it can occupy the same last position and distort the phase and reverb together.

Trade-off. No published Mooer schematic proves the BD-2's discrete gain-stage topology or component values inside the Blues Mood, so this earns a functional match rather than a topology claim. The Blues Mood is true bypass instead of BOSS buffered bypass with electronic switching, its gain and tone tapers will not transfer one-for-one, and Fat deliberately adds low end that the stock pedal does not. Use Bright first, then judge the compression and cleanup against the whole wet signal rather than against an isolated overdrive demo.