The Mad Professor Dual Blue Delay is a dual delay pedal from Mad Professor, the Finnish company behind pedals like the Twimble overdrive and the Big Tweedy Drive1. It carries two delay voices: a tape-voiced short delay with a maximum time of 315ms, and a long delay with a modern voicing and up to 810ms of time1. The two can be used one at a time or run together in parallel, which makes it a versatile option for players who want both a quick slap-back echo and a longer, modern delay on one board1.
It was announced at Summer NAMM 2017 as a bigger, more advanced version of the company's Deep Blue Delay, with release planned for September 201721.
The controls and footswitches
Each of the two delays has its own set of dedicated controls, so the short and long voices can be dialed in independently rather than sharing knobs1. A mode footswitch switches between the two delay voices, or combines both channels for dual-delay sounds12.
The long delay channel adds tap tempo, which makes it easy to set the delay time to the tempo of a song in a live setting1. Holding the on/off switch depressed for about one second dials up a rhythmic multi-head mode, and the phase of that multi-head mode can also be changed1.
| Control or switch | What it does |
|---|---|
| Mode footswitch | Switches between the two delay voices, or combines both channels for dual-delay sounds1 |
| Dedicated controls per delay | Each delay voice has its own set of controls1 |
| Tap tempo | Available on the long delay channel1 |
| On/off switch (held about one second) | Dials up a rhythmic multi-head mode1 |
| Bypass mode | Switchable between buffered and true bypass1 |
The switchable bypass is worth noting for pedalboard planning: buffered mode suits setups where the pedal stays in line with long cable runs, while true bypass suits boards where it gets switched out entirely. The wet-out jack sends only the delay-affected signal out separately, useful if you want to route the echoes to a different amp or path from your dry sound1.
History and versions
The Dual Blue Delay grew out of the Deep Blue Delay, Mad Professor's tape-voiced yet digital delay that MusicRadar called "the stuff of legend"2. The original is a compact single-voice pedal: a digital delay with 25ms to 450ms of delay time, Level, Delay and Repeat controls, true bypass, and power from a 9V battery or 9V DC adaptor drawing 25 to 32mA3. The Dual Blue Delay keeps the tape-flavored short delay concept but adds the second, longer modern voice, the parallel routing, tap tempo and the multi-head mode1.
In 2020, Mad Professor released a limited-edition version, the Dual Blue Delay with Deep mod, one of four modified pedals drawn from the company's back catalog4. On that version the SHORT side is made to replicate exactly the sound of the Deep Blue Delay circuit, so slap back, room emulating, always-on echo can be dialed in directly4. It carried a European RRP of EUR 345.964.
The Deep Blue Delay itself returned in 2025 in Mad Professor's re-launched Handwired series, described as a digital delay with an analog direct path and no noise reduction circuits on the decay56.
What reviewers said
Coverage at launch was positive. Gearnews found the pedal promising overall:
"Overall it looks like a fairly user-friendly experience that covers a lot of bases and should be one to check when they become available."
The same writer liked that each delay has its own dedicated controls and that the two voices can run together in parallel, calling that combination very usable1. Of the demo videos published at launch, Gearnews wrote that "both sound good to my ear"1.
For comparison, the original Deep Blue Delay was reviewed by Guitar World's Trevor Curwen, who listed its side-mounted outputs as a minus point3.
Videos
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Questions
Is the Mad Professor Dual Blue Delay true bypass?
It can be. The bypass mode is switchable between buffered and true bypass, so it can be set up to suit different pedalboards. A wet-out jack also lets you send only the delay-affected signal to a separate output.
Does the Dual Blue Delay have tap tempo?
Yes. Tap tempo is available on the long delay channel, the modern-voiced side with up to 810ms of delay time. Holding the on/off switch down for about one second also dials up a rhythmic multi-head mode.
What is the difference between the Deep Blue Delay and the Dual Blue Delay?
The Deep Blue Delay is a single digital delay with 25ms to 450ms of delay time and Level, Delay and Repeat controls. The Dual Blue Delay is a bigger, more advanced version with two delay voices, each with its own dedicated controls, that can be run separately or together in parallel.
What does the Deep mod change on the Dual Blue Delay?
On the limited-edition Deep mod version, the SHORT side is made to replicate exactly the sound of the Deep Blue Delay circuit, so you can dial in slap back, room emulating, always-on echo. It was one of four limited-edition modified pedals released in 2020.
What is the max delay time of the Mad Professor Dual Blue Delay?
The short, tape-voiced delay channel reaches a maximum of 315ms, and the long, modern-voiced delay channel reaches up to 810ms. Each delay has its own set of dedicated controls.
Sources (6)
- Summer NAMM 2017: Mad Professor Dual Blue Delay, gearnews.com, 2017-07-14
- 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
- Mad Professor adds four new "Lockdown Special" modded pedals, gearnews.com, 2020-05-19
- Guitar Pedal X, Guitar Pedal X, 2025-08-26
- New Pedal: Mad Professor Deep Blue Delay (Handwired), Delicious Audio, 2026-05-20
