DD-20

Boss DD-20 GigaDelay. The Boss DD-20 has since been obsolesced by the Boss DD-500

Controls

• Knob 1 - "E. Level": (Effect Level) Fully counter-clockwise results in an inaudible delay effect. Fully clockwise results in repeats that are just as loud as the original dry signal before tapering off.
• Knob 2 - "F. Back": (Feedback) Select the number and intensity of repeats starting at fully counter-clockwise with one repeat and fully clockwise resulting in enough repeats to begin self-oscillating.
• Knob 3 - "Tone": Turned fully counter-clockwise this knob emphasizes bass; turned fully clockwise emphasizes treble frequencies in the delayed signal. The knob at noon results in delay repeats without and frequency alteration.
• Knob 4 - "Mode": Use the Mode knob to select among several delay types:
  • Sound on Sound (SOS): "sampler" Record loops and then record on top of the loop you've already recorded.
  • Twist: Causes an acceleration in the delay and shifts the delayed note pitch up when the left pedal is depressed. When the pedal is released, the delay slows down and the pitch drops back down.
  • Warp: When the left pedal is pressed the number of delay repeats slowly increases. When pedal is released the number of delay repeats slowly returns to original setting.
  • Tape: Results in an effect similar to a tape delay where additional tape heads pick up signal and play it back. Imagine having 2 full volume repeats instead of one before the delay volume begins to decay.
  • Analog: Frequency-tuned to sound like an analog delay. Treble frequencies are rolled off for delay repeats.
  • Standard: Unmodified digital delay
  • Dual: Sort of a slapback effect, not unlike the "Tape" setting but with far less time between the delay repeats. Creates almost a small-room reverb tone.
  • Pan: Bounces the delay effect between the left and right stereo outputs
  • Smooth: A delay effect with the addition of a built-in Reverb.
  • Modulate: Modulates the delay sound. As if you put your delay-wet output through a chorus pedal.
  • Reverse : A reverse-gated delay sound, makes your instrument sound like it's being played on a tape or record being played backwards.
• Knob 5 - "Delay Time":
  • simple knob-turn: speed up or slow down delay on order of milliseconds.
  • push-down and knob turn: speed up or slow down delay on order of hundreds of milliseconds.

• Button 1 - "Tap":
• Button 2 - "Tempo": Changes manner of Tap Tempo operation: quarter-note to triplets to dotted whole note.
  • Buttons 1 & 2 together: "Light": This controls whether the backlight on the digital display is on or off.
• Button (red) 3 - "Write":
• Button 4 - "Select":

• Footswitch 1 (left) - "On/Off": This turns the pedal On and Off
• Footswitch 2 (right) - "Select": This selects from each of the 4 banks

Input and Output Jacks

• Input A (mono)
• Input B
• Control Pedal input
• Headphones Out
• Output A (mono - dry + wet)
• Output B (stereo or only Input B)
• AC Adapter input

If only Input A has a instrument plugged in, it's possible to use Output A and Output B. Output A will be the "dry" signal and Output B will be the "wet" signal with all the delay repeats.

If Inputs A and B have instruments plugged in, Output A will have the dry + wet signal for Input A, while Output B will have the dry + wet signal for Input B.

Output Modes

1. DD-20 is set to accept a basic instrument. Input A expects a -10 dB "instrument" level signal
   • Use this mode when the delay is being used between an instrument and an amplifier
2. -10 dB Basic instrument level signal, Output A = Dry, Output B=Wet
   • Use this mode when you have separate instruments or separate signals for Input A and B, and Output A and Output B are individually going to separate amplifiers.
     • Example: 1 instrument into a chorus pedal with stereo outputs, and then plugging the left chorus output into DD-20 Input A and the right chorus output into DD-20 Input B.
3. DD-20 is set to expect 4 dB signal into Input A. This function can be enabled at Power-On by pressing down the left pedal down plugging in the AC adapter
   • Use this mode when the DD-20 is being used in an amplifier's effects loop.
4. DD-20 is set to expect 4 dB into both Inputs.
   • Technically it's possible to use the DD-20 in two amplifier effects loops, with each loop using a single input and output before returning to their respective amplifier effects loops returns.

General Information

• https://www.boss.info/us/products/dd-20/
• http://www.bossarea.com/boss-dd-20-digital-giga-delay/

It's interesting to note that for 40 years Boss has been successful with pedals employung broad "metal cap/flap"-style footswitches. Dunlop/MXR, Digitech/DOD and the legions of boutique and home builders seem to have put Boss on the defensive and now Boss has returned to their CE-1 era button-style footswitches.

Modifications

http://music-electronics-forum.com/t16606/

Looping Features

Sound-on-Sound mode.

Pedal Manual

https://static.roland.com/assets/media/pdf/DD-20_OM.pdf

Phase Inversion

No schematic means that we're unable to determine, without an oscilloscope, if the DD-20 inverts the signal phase. That said, the schematic is probably so complicated that it would be almost impossible for the lay person to be able to trace and determine whether this pedal inverts. Once we get it up on a bench with an oscilloscope, we'll report here if the phase is inverted.

Schematic

None available.

Artists

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Additional Sources

1. https://www.youtube.com/watch?v=0X-Mvo-Sy2M