The Mad Professor Dual Blue Delay with Deep mod is a limited-edition version of the Finnish company's Dual Blue Delay, a dual delay pedal carrying two delay types on one board: a tape style short delay with a maximum delay time of 315ms, and a long modern delay with up to 810ms of time1. The Deep mod version, announced in May 2020 as one of four "lockdown special" modified pedals, changes the short side of the pedal so that it replicates exactly the sound of the Deep Blue Delay circuit2.
Two delay voices in one pedal
The Dual Blue Delay was launched at Summer NAMM 2017. MusicRadar framed it as a follow-up to a pedal the site called the stuff of legend: "Mad Professor's tape-voiced yet digital Deep Blue Delay", with the Dual Blue Delay extending that idea into a two-voice design3. gearnews.com described it as "a versatile, modern dual delay pedal" that "looks like it could offer a lot of useful delay sounds for players that need a versatile, modern dual delay ped"1.
The two voices are arranged as follows:
| Voice | Character | Maximum delay time |
|---|---|---|
| Short delay | Tape style | 315ms1 |
| Long delay | Modern delay, with tap tempo | 810ms1 |
The mode footswitch switches between the two delay voices, or both channels can be combined for dual-delay sounds1. The two voices can also be run together in parallel, which gearnews.com's writer felt "makes it very useable as well"1. Each delay has its own set of dedicated controls, something the gearnews.com writer singled out: "I like that each delay has its own set of dedicated controls"1.
Beyond the two basic voices, holding the on/off switch depressed for about one second dials up a rhythmic multi-head mode, and the phase of the multi-head mode can be changed as well1.
The Dual Blue Delay with Deep mod is a limited-edition modified version of the standard Dual Blue Delay. gearnews.com reported in May 2020 that it was one of four new limited-edition pedals, each a modified version of an existing pedal from the company's back catalog2.
The controls
The Dual Blue Delay gives each voice its own dedicated control set1. For reference, the Deep Blue Delay circuit that the modded short side is modeled on carries four controls: Level, Delay, Repeat, and a Bypass footswitch, with the Delay knob setting the delay time4. Delicious Audio's buying guide describes the same three-knob layout on the Deep Blue as controlling "Delay Time, Delay Level, and Repeats"5.
Deep Blue Delay lineage and the Deep mod
The Deep Blue Delay, the pedal this design descends from, is a digital delay with a tape-voiced character3. Guitar Pedal X confirms the circuit type plainly: "the Deep Blue is a Digital Delay"6. Guitar World's review lists a delay time range of 25ms to 450ms, true bypass, and standard input and output jacks4. Mad Professor re-launched the Deep Blue Delay in its Handwired Series in August 2025, alongside the Royal Blue Overdrive and Sweet Honey Overdrive6.
On the Deep mod version of the Dual Blue Delay, the SHORT side is made to replicate exactly the sound of the Deep Blue Delay circuit. gearnews.com explains what that opens up: slap back, room-emulating, always-on echo, and the ability to set it darker than the Deep Blue Delay itself2. In practice that turns the short voice into a dedicated ambient echo layer, while the long voice keeps its modern delay character and tap tempo12.
Questions
What is the maximum delay time on the Mad Professor Dual Blue Delay?
The pedal carries two delay voices with different maximum times. The tape style short delay tops out at 315ms, while the long delay voice gives you a modern delay with up to 810ms of time. On the Deep mod version, the short side is made to replicate exactly the sound of the Deep Blue Delay circuit, which itself runs from 25ms to 450ms.
Does the Dual Blue Delay have tap tempo?
Yes, but only on the long delay voice. MusicRadar notes that tap tempo is available on the long delay channel, and gearnews.com adds that this makes the pedal easy to use live. The short, tape-voiced delay does not have tap tempo.
Can both delays run at the same time?
Yes. The two delay voices can be run together in parallel, and the mode footswitch can be used to switch between the two voices or to combine both channels for dual-delay sounds. Holding the on/off switch down for about a second dials up a rhythmic multi-head mode.
What does the Deep mod change on the Dual Blue Delay?
The Deep mod is a limited-edition modification of the standard Dual Blue Delay. On the modded version, the SHORT side is made to replicate exactly the sound of the Deep Blue Delay circuit, so you can use it for slap back, room-emulating, always-on echo, and it can be set darker than the Deep Blue Delay itself.
How do you engage the multi-head mode?
Keep the on/off switch depressed for about one second, and the pedal dials up a rhythmic multi-head mode. gearnews.com also reports that you can change the phase of the multi-head mode.
Sources (6)
- Summer NAMM 2017: Mad Professor Dual Blue Delay, gearnews.com, 2017-07-14
- Mad Professor adds four new "Lockdown Special" modded pedals, gearnews.com, 2020-05-19
- Summer NAMM 2017: Mad Professor launches “clever, intuitive” Dual Blue Delay pedal, MusicRadar, 2017-07-05
- Mad Professor Deep Blue Delay review, Guitar World, 2024-02-01
- Best Tape Delay Pedals And Tape Echos In 2020, Delicious Audio, 2025-02-17
- Guitar Pedal X, Guitar Pedal X, 2025-08-26
