Gain
How much transparent drive you add.
- Turn up More grit while still feeling dynamic.
- Turn down Mostly clean, with a light edge.
Pedals / Transparent dynamic overdrive
Blue Mood
Transparent dynamic overdrive · play-tested
seth — fish
seth@ninevolt:~$
Knobs
In the TUI each knob runs from low (left / 0%) to high (right / 100%). Start near noon, then nudge while you play.
Tone
Treble balance.
- Turn up Brighter and more open.
- Turn down Warmer and darker.
Level
Output loudness.
- Turn up Louder.
- Turn down Quieter.
Inspired by
Boss BD-2 Blues Driver (1995) — two cascaded discrete op-amp stages (JFET/BJT, not 4558), mid-focused pre-clip EQ, amp-like soft saturation, Fender-style recovery tone, and post-clip bass gyrator. Transparent and touch-sensitive vs the Tube Screamer mid hump (Green Screamer).
Signal path
| Step | What it does |
|---|---|
| Input HPF ~85 Hz | Input coupling / sub trim. |
| Pre-clip HPF ~700 Hz | First-stage R5/C4 — bass rolled off before clip (mid-forward drive). |
| Pre-clip LP ~2.8 kHz | C5 treble roll-off — gain peaks in upper mids before saturation. |
| Gain up to ~39× | Gain knob (1 + gain^1.05 × 38; analog stages ~100×, scaled for digital). |
| Discrete op-amp clip | Soft-knee saturation — most BD-2 grind from op-amp overload, not diodes alone. |
| Post-clip bass shelf | Gyrator-style low recovery — keeps body without TS mid scoop. |
| Tone LP + body blend | Tone sweeps treble; flat full-range balance vs Screamer mid hump. |
| Level + clamp | Level output trim (0.22 + level × 1.05). |
How we modeled it
BD-2 path: 700 Hz HPF → 2.8 kHz LP → gain → discrete soft clip → bass recovery → Tone → Level. Dynamics come from soft-knee saturation and pre-clip mid focus, not a TS-style mid hump.
Simplifications
- Two discrete op-amp stages collapsed to one gain + clip block - Fender tone stack reduced to Tone LP + body blend + bass shelf - No buffered bypass or second gain stage - Diode pairs (D7–D10) not modeled separately — folded into bd_clip