Benson Amps Portable 424 MKII Distortion Pedal

Benson Amps Portable 424 MKII Distortion Pedal | No Limit Guitar Co, Idaho Falls

The Benson Amps Portable 424 MKII is a distortion pedal unlike anything else on the market — a direct adaptation of the preamp circuit from a classic cassette 4-track recorder, capturing the raw, grimy, characterful distortion texture that those extraordinarily spartan, slow op-amp designs produced during the cassette demo era, now in a portable pedalboard format. The 424 MKII's low input impedance loads down a guitar pickup in a way that no conventional high-impedance pedal input does — producing a distinctive, characterful signal interaction that is core to the circuit's personality. A switchable input buffer circuit gives players the choice between the authentic low-Z experience of the original 4-track circuit and a buffered high-impedance input mode that opens up the pedal's versatility for different chain positions and playing contexts. Gain, Trim, Treble, and Bass controls with 18-volt internal headroom. The results: sounds like an old 4-tracker, but more portable.

Product Overview

Benson Amps founder Chris Benson grew up making demos on cassette 4-track recorders — as did most of the Benson Amps staff — and when players started discussing the distinctive distortion characteristics of those slow, spartan op-amp preamp circuits, Benson set out to capture that specific character in pedal form. The 424 channel strip preamp circuit had, as far as Benson could determine, never been adapted for pedal use before. After trying several circuits, it became the clear favorite — primarily because of its dazzlingly low input impedance that interacts with a guitar pickup in a way that loads it down and produces the circuit's characteristic tonal personality.

The low input impedance is the technical specification that most directly defines the 424 MKII's sound in its default lo-Z mode. Standard guitar pedals are designed to present a high impedance to the guitar's output — typically 500k to 1M ohm — which allows the pickup to see a load that doesn't significantly alter its frequency response or output level. The 424 MKII's low impedance input loads the pickup differently, rolling off high frequencies and changing the pickup's damping characteristics in ways that produce the darker, grittier, more compressed tonal character associated with the 4-track source material. This is not a flaw to be corrected — it is the circuit's defining tonal mechanism, and it produces results that conventional high-impedance distortion circuits simply cannot replicate.

The switchable buffer circuit — engaged by pressing the side button — inserts a high-impedance buffer before the 424 preamp circuit, restoring the pickup to its normal operating conditions before the signal hits the low-Z preamp. In buffered mode, the pedal's character opens up significantly — the high-frequency content that the low-Z input rolled off is preserved, the gain and distortion character changes, and the pedal becomes more conventionally placed-anywhere-in-the-chain friendly. The tonal range in buffered mode is substantial — clean boost with subtle EQ shaping, treble boost, warm and dark overdrive textures, and all-out chaotic grind that climbs fuzz mountain without breaking a sweat. The Gain and Trim controls recreate the gain staging of the original 4-track preamp — the Trim knob operates with a taper that is unusual precisely because it matches the unusual taper of the original hardware, kept as-is for authenticity rather than corrected for conventional pedal expectations.

The 18-volt internal headroom means the 424 MKII can push into an amplifier's front end with significantly more clean output than a standard 9V-headroom pedal before the pedal itself starts to clip — running on a standard 9V supply but internally generating 18V headroom for maximum clean boost capability when that's what the situation demands.

Signal Chain Note: In lo-Z mode (side button not pressed in), use the 424 MKII first in the signal chain for best results. In buffer mode (side button pressed in), it can be placed anywhere in the chain.

Ideal For

• Players who want the raw, grimy, characterful distortion texture of a classic cassette 4-track recorder preamp in a portable pedal format
• Tone enthusiasts and experimenters who want a pedal that interacts with guitar pickups in a fundamentally different way than conventional high-impedance distortion circuits
• Players who want the versatility of two genuinely different tonal characters from one pedal — lo-Z mode for authentic 4-track pickup interaction and buffer mode for full-range distortion and boost applications
• Lo-fi, indie, alternative, and experimental guitarists who want the kind of characterful, imperfect, organic distortion that conventional boutique pedals often smooth away
• Guitarists in Idaho Falls looking for one of the most original and tonally distinctive distortion pedals Benson Amps has ever produced

Key Features

Classic Cassette 4-Track Preamp Circuit
A direct adaptation of the 424 channel strip preamp — capturing the raw, grimy, characterful distortion texture of classic cassette 4-track recorder op-amp designs in a portable pedal format.

Low Input Impedance — Loads the Pickup
The circuit's dazzlingly low input impedance loads down the guitar pickup in a way that conventional high-impedance pedal inputs don't — producing the core tonal character that makes the 424 MKII sound like nothing else.

Switchable Input Buffer
The side button engages a high-impedance buffer before the preamp circuit — opening up the tonal range from clean boost through warm overdrive to chaotic grind, and allowing the pedal to be placed anywhere in the signal chain.

Gain and Trim Controls — Authentic Gain Staging
Recreate the gain staging of the original 4-track preamp with control tapers that match the original's unusual feel — kept authentic rather than corrected for conventional pedal expectations.

Treble and Bass EQ Controls
Broad, usable EQ controls that cover a wide range of tonal flavors from the original 4-track circuit — from clean boost village through the forests of distortion and up fuzz mountain.

18-Volt Internal Headroom
Internal voltage doubling provides 18V headroom on a 9V supply — maximum clean boost output capability and amp-punishing headroom when the situation demands it.

What's Included

• Benson Amps Portable 424 MKII Distortion Pedal
• Free standard shipping

Note: 9V DC center-negative power supply required, sold separately. Do not exceed 9V DC input. Battery operation supported (activated when cable is plugged into input with no DC power connected).

Technical Specifications

Get Your Hands on This Pedal Today

The Benson Amps Portable 424 MKII is available now at No Limit Guitar Co in Idaho Falls. Stop in to hear both modes in person and discover what loading a pickup like it owes it money actually sounds like — or reach out online to arrange your purchase. Simple, rattley sounding, and really fun.