The One Control Purple Plexifier 4K is a compact overdrive/distortion pedal built to replicate a vintage plexi amplifier. One Control describes it as a British AIAB, short for amp in a box: instead of modeling a whole rig, it aims to capture the tone of classic British plexi amps in a stompbox you can run into any clean setup1. It sits in the distortion lane but is voiced as an amp-style gain rather than a pure fuzz or modern high-gain box.
The pedal is the newest member of a line with history. Delicious Audio calls the original Purple Plexifier "the first Amp-In-A-Box design" by One Control2, and the 4K is a new 4-knob version that One Control says "evolved into a more modern and balanced sound"1. As of late October 2026, One Control's product page lists it as sold out1.
A plexi-style amp in a box
The idea behind the Purple Plexifier is straightforward: get the character of a vintage British plexi amp from a pedal. One Control says the 4K is "designed to capture the legendary tone of classic British plexi amplifiers, delivering vintage rock tones with modern versatility"1. For a player, that means it works as a gain stage into a clean amp, or as a push into an amp already breaking up.
The enclosure is a high-quality mini-size aluminum case1, matching the machined and anodized compact aluminum housing Delicious Audio noted on the Purple Plexifier V22. At about 160 grams, it takes up very little pedalboard space.
The 4-knob version
The four controls are what mark this version out. One Control says the 4-knob design "enhances operability compared to its predecessor"1.
| Control | What it does |
|---|---|
| VOL | Adjusts the volume1 |
| DIST | Adjusts the strength of the distortion1 |
| MID | Adjusts the way out of the middle range1 |
| TREBLE | Adjusts frequencies around 2kHz, for fine-tuning the balance3 |
The TREBLE description comes from the related Japonism Edition page, which shares the same circuit and control set3.
The knob layout is itself the change from the earlier versions. On the V2, all four controls (Volume, Gain, Mid and Treble) sat on top of the case, "while in V1 the mids knob was a side trim pot"2. So the 4K continues the top-mounted four-knob format of the V2 while updating the sound. On the V2, Delicious Audio described the thick mid-range as something that "can be scooped or flattened with the MID control" for a fuller tone2, which gives a sense of what the MID knob does tonally.
Power: 9V, 3mA
The 4K runs at a 9V driving voltage with a current consumption of 3mA1. That draw is low enough that it places almost no demand on a shared pedalboard supply. For comparison, the V2 drew 4mA at 9V2.
Built-in battery use is also possible, though batteries are not included1. On the V2, Delicious Audio recommended "the use of a balanced power supply to maximize the life and quality of this effect"2.
Both the standard Purple Plexifier 4K and the Japonism Edition are listed as sold out on One Control's site as of October 202613. The Japonism Edition, with Ukiyo-e artwork painted on the case, was produced for a limited time only3.
How it compares in the range
One Control's amp-in-a-box and distortion line includes several other 4K-series pedals players may weigh it against, including the Dyna Red Distortion 4K, the Anodized Brown Distortion 4K and the Rebel Red Distortion 4K. The Purple Plexifier 4K is the plexi-voiced entry, where those pedals cover other amp characters.
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Mike Hermans
LEP INTERNATIONAL
Questions
Can the One Control Purple Plexifier 4K run on a battery?
Yes. One Control lists built-in battery use as possible, though batteries are not included with the pedal. It also runs on a 9V DC power supply, drawing only 3mA, so it is easy to place on a shared or daisy-chained supply. With a battery installed the weight rises from about 160 grams to about 200 grams.
Is the Purple Plexifier 4K true bypass?
Yes. One Control specifies true bypass switching for the Purple Plexifier 4K, so when the pedal is off the signal passes through without buffering. The earlier Purple Plexifier V2 also used true bypass switching.
How does the Purple Plexifier 4K differ from the earlier version?
The 4K is a new 4-knob version that One Control says evolved into a more modern and balanced sound. Its four controls sit on top of the case, whereas on the original V1 the mids adjustment was a side trim pot. The 4K also draws less current, 3mA instead of the V2's 4mA at 9V.
Does the Purple Plexifier 4K have a mid control?
Yes. The MID knob adjusts the middle range of the tone. On the earlier Purple Plexifier V2, Delicious Audio described the thick mid-range as something that can be scooped or flattened with the MID control for a fuller tone.
Is the Purple Plexifier 4K still available?
As of late October 2026, One Control's product page lists the Purple Plexifier 4K as sold out. The related Japonism Edition, a limited-run version with Ukiyo-e artwork on the case, is also listed as sold out and was produced for a limited time only.
Sources (3)
- PURPLE PLEXIFIER 4K (OC-PP4Kn), One Control USA
- One Control Purple Plexifier V2, Delicious Audio, 2024-06-11
- PURPLE PLEXIFIER 4K Japonism Edition (OC-PP4Kn-JE), One Control USA
