Enclosure not stated · 3 knobs
Electro Harmonix '77 OpAmp Big MuffVerified
Based on the Electro-Harmonix Op-Amp Big Muff Pi· 18 other boards clone it
- Category
- Distortion
- Build
- Perfboard
- Layout
- Verified · Effects Layouts (blog) marks it as built and working
- Tags
- Distortion, Electro Harmonix, Fuzz
From the post
In the late 70s, Mike Matthews and EHX took the Big Muff on a detour from the traditional 4 transistor circuit in favor an IC-based circuit. It sounds very similar to the traditional Muffs, with the tone control being a little more flat than the traditional mid scoop. The circuit uses two favorite opamps from the 70s–the JRC4558 (used in the Ibanez Tube Screamer) and the LM741 (used in the Distortion +/OD250). The IC Big Muff would have probably faded into the background of Big Muff lore if it weren't for Smashing Pumpkins guitarist/frontman Billy Corgan. His use of a late 70s IC Muff on Siamese Dream has made the pedal highly sought after.
I've drawn the layout to use right angle pcb mount pots, mounted on the solder-side of the board. Also, if 741 chips aren't to your liking, you can use something like a TL071 in its place. Just increase the 820k resistor between the power and pin 3 to 1M.
Schematic
This is a board layout, a drawing of where each part goes, and the post may link the schematic it was drawn from. Open the layout at Effects Layouts (blog). No KiCad fragment has been drawn for this circuit yet.
Parts list 39 rows
Report a wrong parseGot parts in a drawer? See what you can build with them.
Check before you build · 1 value the reader of this layout was not sure of
- LED resistor at bottom left beside the 47Ω: the populated board prints 2.2K, the colour wiring diagram prints 4.7K for the same part; 2.2K entered
| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 16 | ||||
| ×1 | 5.6K | 5.6k | read from the layout by eye | |
| ×2 | 1M | 1M | read from the layout by eye | |
| ×1 | 1.2K | 1.2k | read from the layout by eye | |
| ×1 | 100K | 100k | read from the layout by eye | |
| ×1 | 470K | 470k | read from the layout by eye | |
| ×1 | 8.2K | 8.2k | read from the layout by eye | |
| ×2 | 220K | 220k | read from the layout by eye | |
| ×1 | 56K | 56k | read from the layout by eye | |
| ×1 | 330K | 330k | read from the layout by eye | |
| ×1 | 820K | 820k | read from the layout by eye | |
| ×1 | 2.2K | 2.2k | LED resistor; wiring diagram prints 4.7K; read from the layout by eye | |
| ×2 | 47Ω | 47 | read from the layout by eye | |
| ×1 | 560K | 560k | read from the layout by eye | |
| ×1 | 62K | 62k | read from the layout by eye | |
| ×1 | 47K | 47k | read from the layout by eye | |
| ×1 | 10K | 10k | read from the layout by eye | |
| Capacitors 11 | ||||
| ×1 | 150pF | 150p | read from the layout by eye | |
| ×1 | 4.7nF | 4.7n | read from the layout by eye | |
| ×1 | 10nF | 10n | read from the layout by eye | |
| ×1 | 100nF | 100n | read from the layout by eye | |
| ×1 | 120nF | 120n | read from the layout by eye | |
| ×1 | 150nF | 150n | read from the layout by eye | |
| ×1 | 220nF | 220n | read from the layout by eye | |
| ×2 | 1uF | 1u | electrolytic; read from the layout by eye | |
| ×1 | 4.7uF | 4.7u | electrolytic; read from the layout by eye | |
| ×2 | 10uF | 10u | electrolytic; read from the layout by eye | |
| ×1 | 220uF | 220u | electrolytic; read from the layout by eye | |
| Diodes 7 | ||||
| D1 | 1N4148 | 1N4148 | read from the layout by eye | |
| D2 | 1N4148 | 1N4148 | read from the layout by eye | |
| D3 | 1N4148 | 1N4148 | read from the layout by eye | |
| D4 | 1N4148 | 1N4148 | read from the layout by eye | |
| D5 | 1N4148 | 1N4148 | read from the layout by eye | |
| D6 | 1N4148 | 1N4148 | read from the layout by eye | |
| ×1 | 1N4001 | 1N4001 | printed 4001; read from the layout by eye | |
| ICs 2 | ||||
| ×1 | 741 | 741 | single op-amp; read from the layout by eye | |
| ×1 | 4558 | 4558 | dual op-amp; read from the layout by eye | |
| Potentiometers 3 | ||||
| Volume | B100K | B100k | Potentiometer | read from the layout by eye |
| Tone | B10K | B10k | Potentiometer | read from the layout by eye |
| Sustain | B10K | B10k | Potentiometer | read from the layout by eye |
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