The JHS 424 Gain Stage is a preamp pedal that puts the sound of a vintage TASCAM Portastudio 424 multi-track recorder into a compact stompbox. Where the original 424 was a 4-track tape machine, the pedal reduces it to a single channel strip, and JHS describes it as a historically accurate recreation of the original 424 MKI circuit, built with the original UPC4570 and NJM4565 op-amps12. JHS classifies it as a preamp, distortion and overdrive pedal in one, and says it delivers "the rubbery clean tones, high head room, and smashed out fuzz" of plugging a guitar straight into a vintage 4241.
In practice that means one box can serve several jobs. As a DI through its balanced XLR output, it replicates the textured, lo-fi sound of plugging directly into a Portastudio without the bulk of the machine itself; paired with an amp, it works as a boost, overdrive or fuzz unit depending on where the gain knobs sit3. It launched in August 2025 at $24942, and JHS founder Josh Scott is the designer behind it156.
What it does: a Portastudio channel strip for guitar
The TASCAM Portastudio 424 was a 4-track cassette recorder, and the 424 Gain Stage takes one of its channel strips and puts it on your pedalboard2. JHS says the pedal gives "all the elastic, lo-fi tone inspired by a guitar being plugged straight into a vintage 424 multi-track recorder"1. Pedal of the Day describes the same character as "all the elastic, lo-fi tone you get from plugging a guitar rig straight into a TASCAM Portastudio 424"9.
How hard you push it changes what it is:
- Boost: use it as a gain stage to boost your signal9
- Overdrive: a colorful overdrive at moderate gain settings9
- Fuzz: push the gain knobs into full-on overloaded fuzz9
Bass Musician Magazine's reviewer mapped the range in more detail: with Gain 1 low it works as a warm, harmonically rich preamp adding a subtle tape-like bloom to notes; with Gain 1 higher it lands in a distinctly vintage overdrive/fuzz voice; and with Gain 2 past 3 o'clock it becomes a gated fuzz, tight and aggressive10. MusicRadar's reviewer found it starts out delivering clean but warm sounds, and that experimenting with the two gain knobs against each other adds grainy lo-fi grit until the whole sound is suffused with it6.
The controls
The five knobs and one switch map directly to the controls of a 424 MKI channel strip, which is the point of the pedal: you are turning the recorder's trim, channel fader, EQ and master fader16.
| Control | What it does | 424 MKI equivalent |
|---|---|---|
| Gain 1 (Trim) | Sets how much preamplification is added to the input signal | TRIM control |
| Gain 2 (Channel) | Sets the volume level of the second gain stage | CHANNEL fader |
| Bass | Cuts or boosts bass frequencies; left is less, right is more | EQ section |
| Treble | Cuts or boosts treble frequencies; left is less, right is more | EQ section |
| Volume | Controls the output volume; left is less, right is more | MASTER fader |
| Ground Lift | Dip switch on the left side; lifts the ground if you hear hum or buzz on the XLR output | n/a |
MusicRadar's reviewer notes that Gain 1 is the equivalent of the Trim knob on the input of a 424, Gain 2 represents the original's channel fader providing a second gain stage, and the Volume knob equates to a Portastudio's master fader6. Bass Musician Magazine's reviewer put it more simply: "Gain 2 mimics the channel fader"10. A single soft touch footswitch handles bypass86.
Power and connections
The pedal takes a top-mounted 1/4" input on the right and a top-mounted 1/4" output on the left, plus a balanced XLR output on the left side that works as a direct out straight into a mixer or interface1. JHS states the 1/4" output and XLR output can be used simultaneously1.
Pedal of the Day suggests a routing trick for players who want both amp and DI sounds live: put an active A/B/Y switcher at the end of your rig, send the A output to your amp and the B output to the pedal's input, and take the XLR output into a mixer or interface, letting you flip between the amp and the pedal or play through both9.
History: the TASCAM 424 MKI circuit
The idea followed the popularity of artists including Mk.gee and Tame Impala, who both use old Portastudios to achieve their sounds4. Scott told Guitar World he made the official call to build it around January 2025, prompted by friends who kept texting him wanting something practical for live guitar rigs11. He also said bigger conceptual versions with more features and more powerful interfaces were developed alongside the released pedal and are planned for the future11.
The 424 is not JHS's first console-style preamp. Guitar Pedal X describes it as "a kind of distillation / Junior version" of JHS's more expansive Colour Box Studio Style Console/Preamp, which carries 10 knobs and two 2-way toggle switches against the 424's five controls2. Where the Colour Box models a studio console, the 424 models a tape machine's channel strip.
What reviewers said
Published reviews were positive across the board:
- Guitar World rated the build 4.5 stars, calling it the expected robust build from JHS with a great soft click footswitch8.
- MusicRadar's Trevor Curwen found it moves from clean, warm sounds to grainy lo-fi grit as you juxtapose the gain knobs6.
- Bass Musician Magazine's Cláudio Ribeiro found it pairs "shockingly well with modern octavers and synth pedals"10.
- Pedal of the Day called it versatile with unique tones, "like discovering a sound you had in your head for years but couldn't quite place"9.
- Guitar Pedal X's Stefan Karlsson wrote that "the device seems to perform pretty exceptionally and exactly as it's supposed to, and that's good enough for me"2.
John Mayer demoed the pedal in a video while Josh Scott recovered from a serious bike accident7. In that demo, Mayer described the pedal as less a paint color than a whole different brush, and said it makes you play different stuff and changes your relationship with the instrument7.
Videos
Andertons Music Co
60 Cycle Hum
Eirik Stordrange
News
Questions
Does the JHS 424 Gain Stage take a battery?
No. It runs from an external 9V DC center negative power supply only, with no battery option, and draws 50mA. JHS warns that using more than 9VDC may damage the pedal and void the warranty, so it needs a properly matched supply.
Can I use the XLR and 1/4" outputs at the same time?
Yes. JHS states that the 1/4" output and the balanced XLR output can be used simultaneously. The XLR on the left side works as a direct out straight into a mixer or interface, and a Ground Lift dip switch on the same side lifts the ground if you hear hum or buzz on the XLR connection.
Is the JHS 424 Gain Stage true bypass?
No. The 424 Gain Stage uses a buffered bypass with silent, soft touch switching. That means the buffer stays in your signal chain even when the pedal is off, which suits long cable runs but is worth knowing if you prefer a fully true bypass board.
What op-amps are in the JHS 424 Gain Stage?
JHS replicated the original TASCAM 424 MKI circuit using the original UPC4570 and NJM4565 op-amps, the same chips found in the 424 MK1 recorder. Guitar World's review confirms both op-amps are present under the hood of the pedal.
How is the 424 Gain Stage different from the JHS Colour Box?
Guitar Pedal X describes the 424 as a distillation, or junior version, of JHS's more expansive Colour Box console-style preamp. The Colour Box carries 10 knobs and two 2-way toggle switches, while the 424 has five controls, and it models a Portastudio channel strip rather than a studio console.
Did John Mayer use the JHS 424 Gain Stage?
John Mayer demoed the pedal in a video published while JHS founder Josh Scott recovered from a serious bike accident. In the demo Mayer said the pedal changes your relationship with the instrument, describing it as less a paint color than a whole different brush.
Sources (11)
- 424 GAIN STAGE, JHS Pedals
- Guitar Pedal X, Guitar Pedal X, 2025-08-12
- JHS 424 Gain Stage Preamp, Delicious Audio, 2025-08-19
- JHS Pedals 424 Gain Stage: Lo-Fi Portastudio Preamp, gearnews.com, 2025-08-12
- “Yes, it does the Mk.Gee thing!”: Lo-fi lovers rejoice as JHS launches new pedal inspired by a classic multi-track recorder, guitar.com, 2025-08-12
- JHS Pedals 424 Gain Stage review, MusicRadar, 2026-03-16
- John Mayer demos JHS Pedals' 424 Gain Stage, Guitar World, 2025-09-01
- JHS Pedals 424 Gain Stage review, Guitar World, 2025-10-02
- JHS Pedals 424 Gain Stage Preamp Distortion Overdrive, Pedal of the Day (www.pedal-of-the-day.com), 2025-09-21
- Review: JHS 424 Gain Stage Pedal... Lo-Fi Roots, Serious Bass Utility, Bass Musician Magazine, 2025-12-15
- JHS Pedals' Josh Scott on Notaklön, his bike accident & John Mayer, Guitar World, 2025-10-21
