The Mocking Bird Delay is an ambient modulated echo pedal from Side Effects, a pedal builder from Greece. It is built around the PT2399 digital delay chip but keeps your dry signal fully analog, and it adds pitch-shifting modulation to the repeats through Rate and Depth knobs. Paolo De Gregorio, writing on Delicious Audio, called it "an ambient modulated echo based on the beloved PT2399 digital chip featured in many creative digital reverbs"1.
The controls
The pedal has six knobs covering delays from 50 ms to 1 second1. The controls the Delicious Audio write-up names are:
- Time: sets the delay length. Past the middle position, the repeats turn into a crackling, hissing lo-fi character1.
- Rate and Depth: apply pitch-shifting modulation to the delay1.
- Tone: darkens the tails for a warmer, tape-style sound1.
- Feedback: its position determines what the second footswitch does1.
There is also a Tails on/off switch, which decides whether the ambience fades out or cuts off when the pedal is disengaged1.
The second footswitch is a performance tool: it triggers self-oscillation or a momentary delay effect, depending on the Feedback knob position1. A comparable arrangement appears on the Dr. Scientist Sunny Day Delay V2, whose second footswitch can trigger the modulation section or, used momentarily, ramp the repeats to maximum2.
One trick worth knowing: put the Time knob to minimum and crank the mod Depth, and the pedal becomes a chorus-doubling effect1.
Versions and the PT2399 circuit
The Mocking Bird Delay has been around since 2017. Delicious Audio's 2022 write-up covers what the site calls V3, distinguishing it from the original release (V1) and from videos of the pedal shot around 2020 (V2)1. The V3 brings less noise on the dry signal path and a much wider LFO speed range, among other smaller tweaks1.
The PT2399 at its heart is a common chip in creative delay design. GuitarPCB's documentation describes it as providing smooth delay effects with a maximum delay time of approximately 600 milliseconds, with subtle artifacts possible at the maximum that vary with each chip's tolerance3. Guitar Pedal X's Stefan Karlsson has written that "PT2399 delays can be so lush and magical," citing the Mad Professor Deep Blue Delay among examples4. Other PT2399-based designs in the same family include the Anasounds Dystopia Experimental PT2399 Delay, which Guitar Pedal X described as a PT2399 delay with a more worn-out tape sound, "Pain" modulation and a 4-step sequencer5.
Delicious Audio's verdict on the Mocking Bird itself was warm: "Superb product, Mockingbird Delay will give you hours of fun."1
Videos
collector//emitter
Do Noise
SideFx pedals
Questions
Is the Side Effects Mocking Bird Delay analog or digital?
It is a hybrid. The delay line runs on the PT2399, a popular digital delay chip, but the pedal retains your dry signal fully analog, so the untouched part of your tone never passes through the chip. At longer delay times, past the middle of the Time knob, the repeats take on a crackling, hissing lo-fi character that comes from the chip being pushed.
Does the Mocking Bird Delay have true bypass?
No. The Mocking Bird Delay uses buffered bypass, which Delicious Audio notes does not color your signal. A buffer can be a practical choice on a large board, since it keeps the delay trails consistent and drives long cable runs, but players who specifically want their guitar connected directly to the amp when the pedal is off will want to know it is buffered.
What is the delay time range of the Mocking Bird Delay?
The six knobs cover delays from 50 milliseconds up to 1 second. That spans tight, slapback-adjacent settings through long ambient washes. Note that the PT2399 chip itself tops out at roughly 600 milliseconds, and the repeats get noticeably lo-fi as the Time knob passes its middle position.
What does the extra footswitch do on the Mocking Bird Delay?
The second footswitch triggers self-oscillation or a momentary delay effect, depending on where the Feedback knob is set. That gives you a way to kick the pedal into runaway repeats or a temporary echo burst on the fly, and return to your preset sound when you lift off.
Can the Mocking Bird Delay trails fade out when the pedal is turned off?
Yes. A Tails on/off switch lets you choose whether the ambience fades out naturally or cuts off when the pedal is disengaged. With tails on, the repeats continue to decay after you switch the effect off, which suits ambient playing; with tails off, the pedal stops dead.
Sources (5)
- New Pedal: Side Effects Mocking Bird Delay V3, Delicious Audio, 2022-03-21
- Dr. Scientist Sunny Day Delay V2, Delicious Audio, 2023-08-10
- NostalgiTone-Space-Modulator, GuitarPCB, 2024-09
- Guitar Pedal X, Guitar Pedal X, 2025-09-11
- Guitar Pedal X, Guitar Pedal X, 2023-12-20
