ALM Stem Ripper Thru (2025–)

A tiny, passive expander that solves one of Eurorack's more annoying cable tangles.

Overview

Say you're routing your main outputs through a mixer and a recorder at the same time, and you end up with a nest of stacked cables that won't stay put. The ALM Stem Ripper Thru doesn't fix your whole rack, but it does fix that. It's a 2HP passive module, an add-on to the ALM Stem Ripper. Its entire job is to duplicate the eight input signals to a second row of outputs, unbuffered and direct. No processing, no power. Stacked cables tend to wiggle loose at the worst possible time, and this means you don't have to rely on them.

It doesn't expand the recording capabilities of the Stem Ripper itself. The main module still handles that. The Thru module connects to the Stem Ripper with a ribbon cable and presents a second row of jacks that mirror the inputs. You patch your sources into the Stem Ripper as normal and record your stems directly to SD card. Then you use the Thru's outputs to send those same signals elsewhere, maybe to a mixer, a compressor, or a second recording chain. That avoids overloading the input jacks and avoids dropouts from poor contact in stacked cables.

Owners report that the build quality is consistent with ALM's usual standards: clean silkscreen, sturdy jacks, and a compact 3U x 2HP footprint. This is a passive expander, not an active one. There's no buffering, no gain stage, and no protection from impedance mismatches. That keeps it simple and reliable, but the signal integrity depends on the passive pass-through design. In practice this works fine in most setups, especially if you're not driving long cable runs or splitting to multiple destinations beyond what the Thru provides.

Specifications

Manufacturer	ALM Busy Circuits
Production Years	2025–
Original Price	$80 / £60 / €70
Module Type	Eurorack Expander
Width	2HP
Depth	32mm
Power Requirements	Passive (no power draw)
Power Connector	Ribbon cable to Stem Ripper (no direct power connection)
Inputs	None (passes through signals from Stem Ripper)
Outputs	8x unbuffered thru outputs (1:1 with Stem Ripper inputs)
Signal Type	Audio (passive pass-through)
Impedance	Unbuffered, high-impedance pass-through
Compatibility	ALM Stem Ripper (ALM050) only
Mounting Type	Standard Eurorack 3U
Panel Material	Aluminum
Color	Silver with black silkscreen
Weight	Approx. 50g
Country of Origin	England

Key Features

Passive Signal Duplication Without Power Draw

The Thru module requires no power. Because it's a direct, unbuffered pass-through, it doesn't draw any current from your power supply. That matters in a Eurorack system where every milliamp counts, especially on crowded power rails. A short ribbon cable connects it to the Stem Ripper and carries the eight input signals to the rear of the Thru module. There's no active circuitry and no op-amps, so there's no risk of added noise or coloration. What goes in comes out, just duplicated.

Eliminates Stacked Cables at Critical Points

Stacking patch cables is a common point of failure. Jacks can become unreliable, signals drop out, and the physical strain on the module can lead to long-term wear. The Thru module sidesteps this by giving you a dedicated second set of outputs. Instead of stacking a second cable onto the Stem Ripper's input jacks, you patch into the Thru's outputs. This keeps the original inputs free and stable, reduces mechanical stress, and makes your patch more reliable during live use or transport.

Compact and Skiff-Friendly Design

At just 2HP wide and 32mm deep, the Thru module is very space-efficient. It needs no additional power connectors or external cabling beyond the internal ribbon link to the Stem Ripper. That suits skiff builds and compact cases where every millimeter matters. It mounts flush with the Stem Ripper. The silver panel matches ALM's standard look, so it blends in.

Historical Context

The ALM Stem Ripper Thru arrived in 2025 as a companion to the Stem Ripper, a compact 8-channel recorder that answered a growing demand for in-rack multitrack recording. Standalone recorders like the Zoom L-6, or field recorders with ADAT I/O, could handle the job, but they required external power and cabling, and often broke the flow of a modular session. The Stem Ripper brought that functionality inside the case. The Thru module addressed a practical limitation: how to access those recorded signals without compromising the patch.

At the time, competing solutions like the Half Time Modular 8TR offered higher bit depths and sample rates, but they didn't include a dedicated thru solution out of the box. ALM's approach was modular, incremental, and focused on workflow. The Thru module reflects a broader trend in Eurorack design: utility expanders that solve specific, niche problems rather than trying to be all-in-one solutions. It's not a standalone product, and it's not meant to be.

Collectibility & Value

The ALM Stem Ripper Thru isn't a collectible in the traditional sense. There are no limited editions, no alternate panels, and no aftermarket premium beyond its original MSRP. It sells for $80 new, and used units typically trade for $50 - $65 depending on availability. Because it's passive and has no active components, failure rates are extremely low. The most common issue reported is ribbon cable disconnection, usually from rough handling during module removal, but that's easily fixed with a reseat or replacement cable.

When buying used, check that the ribbon cable is intact and that all eight output jacks are securely mounted. Since the module relies on direct signal pass-through, any cold solder joints or damaged traces would show up immediately as dead channels. Such failures are rare. The bigger concern is compatibility. This module only works with the ALM Stem Ripper. It won't function with any other recorder or interface, so don't expect to repurpose it later. Without the main module, it's useless.

There's nothing to restore on the Thru module. It's built to last, and ALM continues to support the Stem Ripper ecosystem with firmware updates and spare parts. The included ribbon cable is proprietary but replaceable, and ALM's documentation is thorough enough to guide repairs if needed.