Enclosure not stated · 3 knobs
From the vendor
An active acoustic guitar simulator based on the Woody circuit by Mark Hammer. Uses two TL074 quad op-amp ICs to shape the body resonance and string attack of an electric guitar signal, producing a convincing acoustic character without carrying an acoustic instrument. The Ac-Sim is a two-band acoustic guitar simulator based on the well-known Woody circuit by Mark Hammer. All credit for the original circuit design goes to him. The effect shapes an electric guitar signal to produce an acoustic character by independently processing two frequency regions — a lower body resonance band and an upper string attack band — then blending the results. The Lower control manipulates the body resonance of
Schematic
The schematic is in the vendor's build document. Open the build document. No KiCad fragment has been drawn for this circuit yet.
Parts list 55 rows
Report a wrong parseGot parts in a drawer? See what you can build with them.
| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 27 | ||||
| R1 | 12k | 12k | Virtual ground divider | |
| R2 | 12k | 12k | Virtual ground divider | |
| R3 | 1M | 1M | Input pull-down to VR | |
| R4 | 2M2 | 2.2M | Input bias resistors | |
| R26 | 2M2 | 2.2M | Input bias resistors | |
| R5 | 10k | 10k | Input noise filter | |
| R6 | 12k | 12k | IC1B bias | |
| R7 | 10k | 10k | IC1B input | |
| R8 | 10k | 10k | IC1C summing network | |
| R9 | 10k | 10k | IC1C summing network | |
| R10 | 10k | 10k | IC1C summing / feedback | |
| R11 | 22k | 22k | Lower band resonance shaping | |
| R12 | 22k | 22k | Lower band resonance shaping | |
| R13 | 10k | 10k | IC1D feedback | |
| R14 | 150k | 150k | Upper HP bias resistor | |
| R16 | 10k | 10k | IC2A summing | |
| R18 | 10k | 10k | Upper band summing | |
| R19 | 12k | 12k | UPPER pot load | |
| R20 | 10k | 10k | Lower band shaping (IC2B) | |
| R21 | 10k | 10k | Lower band shaping (IC2B) | |
| R22 | 10k | 10k | Lower band shaping (IC2B) | |
| R23 | 3k3 | 3.3k | LOWER pot series resistor | |
| R24 | 12k | 12k | Lower band load | |
| R25 | 22k | 22k | VOL buffer feedback | |
| R27 | 10k | 10k | IC2D bias | |
| R28 | 1k | 1k | Output series resistor | |
| R29 | 100k | 100k | Output load / impedance | |
| Capacitors 18 | ||||
| C1 | 220u | 220u | Main supply decoupling — polarised electrolytic | |
| C2 | 47u | 47u | VR rail decoupling — polarised electrolytic | |
| C3 | 10n | 10n | Input coupling — box film | |
| C4 | 680n | 680n | Lower band coupling — box film | |
| C5 | 3n3 | 3.3n | Lower band resonance caps — box film | |
| C6 | 3n3 | 3.3n | Lower band resonance caps — box film | |
| C7 | 3n3 | 3.3n | Lower band resonance caps — box film | |
| C8 | 100p | 100p | Upper band HF roll-off — ceramic | |
| C9 | 10n | 10n | Upper band coupling — box film | |
| C10 | 39n | 39n | Lower band shaping caps — box film | |
| C11 | 39n | 39n | Lower band shaping caps — box film | |
| C12 | 39n | 39n | Lower band shaping caps — box film | |
| C13 | 39n | 39n | Lower band shaping caps — box film | |
| C14 | 10u | 10u | Volume stage coupling — polarised electrolytic | |
| C15 | 10n | 10n | IC2D bias filter — box film | |
| C16 | 680n | 680n | Output coupling cap — box film | |
| C17 | 330p | 330p | Input noise filter — ceramic | |
| C18 | 470p | 470p | Upper HP trimmer filter — ceramic | |
| Diodes 4 | ||||
| D1 | 1N4001 | 1N4001 | Reverse polarity protection | |
| D2 | 1N4148 | 1N4148 | Soft clipping in upper band feedback path | |
| D3 | 1N4148 | 1N4148 | Soft clipping in upper band feedback path | |
| D4 | 1N4148 | 1N4148 | Soft clipping in upper band feedback path | |
| ICs 2 | ||||
| IC1 | TL074 | TL074 | Quad op-amp, DIP-14 — TL074CN RC4136 | |
| IC2 | TL074 | TL074 | Quad op-amp, DIP-14 — TL074CN RC4136 | |
| Potentiometers 3 | ||||
| LOWER | A10k | A10k | Body resonance control — 16mm board-mount | |
| UPPER | A10k | A10k | String attack / brightness — 16mm board-mount | |
| VOL | A100k | A100k | Output volume — 16mm board-mount | |
| Trimmers 1 | ||||
| R15 | 500k | 500k | Upper HP corner adjustment — 9mm trimpot | |