Electro-Harmonix Deluxe Memory Man
BBD analog delay with chorus/vibrato — the dreamy edge of The Edge.
We don't ship reference schematics until they've been hand-authored against authoritative sources (manufacturer service docs, ElectroSmash analyses, GEOFEX writeups) and reviewed in the simulator. Until then, the BOM, signal chain, controls and mod notes below are accurate, and you can still add this pedal to a project — it just won't include a circuit yet.
About
Two MN3005 BBDs in series provide up to ~550 ms of warm analog delay. A built-in compander (NE571) reduces BBD noise; an LFO modulates the BBD clock to add chorus or vibrato to the repeats. The wet path is high-pass / low-pass filtered to give the warm, dark, slightly degraded repeats that define analog delay.
Signal chain preview
6 stagesQuick facts
- U2 / The Edge's 'Where the Streets Have No Name' and countless other U2 textures lean on the DMM.
- The compander dramatically lowers noise but slightly compresses transients in the repeats — part of its musical character.
- Modern reissues use the NOS MN3005s while supplies last; the XO and Nano versions substitute MN3205 + voltage-doubler.
Controls
- Blend
- Feedback
- Delay (clock rate)
- Chorus depth
- Vibrato switch
Mod recipes Pro
3 mods- Oscillation tame
Stops runaway self-oscillation at high Feedback.
How: Add a 100k resistor in series with the Feedback pot's wiper to limit maximum feedback gain to ~0.95.
- Tap tempo (advanced)
Replace the analog delay pot with a tap-tempo controlled CV.
How: Use a PIC/AVR + DAC to generate the BBD clock voltage; replace the Delay pot wiper with the DAC output. Not for the faint of heart.
- Brighter repeats
Less of the classic 'wet path getting darker each repeat'.
How: Increase the low-pass cap on the BBD output stage from 0.0047 µF to 0.0022 µF; lift one of the anti-aliasing filter poles.