AMSynths AM997 (In Production)

A 4HP module that solves one of the Behringer System 55's trigger compatibility problems for little money and little rack space.

Overview

Modern gear speaks V-Trigger. The 911 envelope generators in a Behringer System 55 want S-Trigger. Patch one into the other and nothing fires. No envelopes, no percussion, just silence where the punch should be. The AM997 from AMSynths was built to fix that. It doesn't make noise, it doesn't modulate, and it doesn't even have a knob. Once it's installed, you forget it's there until you try to live without it.

The AM997 Dual Trigger Converter does what the name says. It has two independent channels of V-Trigger to S-Trigger conversion in a 4HP Eurorack module. It's not flashy, but you need it if you're bridging modern gear with Behringer's Moog-accurate S-Trigger architecture. The Behringer 961 interface module takes up 16HP and does a lot more than most people need. The AM997 strips the job down to one thing, converting a +5V gate into a proper S-Trigger pulse, in a fraction of the width.

AMSynths is a small UK-based builder that has handcrafted modules in Sussex since 2010. The AM997 is part of their "Modular III" line, a series of no-nonsense analog utilities. There's no firmware, no menus and no hidden functions. It's hand-soldered circuits on a 2mm black anodised aluminium panel. In 2024 they upgraded the finish to a sharper black and silver look.

Owners report it slots into their System 55 builds without fuss. One reviewer, John Rofrano, called it "indispensable," noting it delivered "solid triggering" and giving it a full recommendation. Another, Steven Wilkinson, wrote: "This module does exactly what I need without taking up major space. Excellent build quality."

Specifications

Key Features

Two Independent Conversion Channels

The AM997 gives you two complete, isolated V-Trigger to S-Trigger conversion paths. Each channel accepts a +5V gate or V-Trigger signal and outputs the S-Trigger pulse that Moog-style envelope generators, like those in the Behringer 911 modules, need. You can trigger two separate envelope sections at once, say one for a bass line and one for a lead, without crosstalk or timing drift. It's straightforward, but it matters for polyphonic or layered patches where precise triggering counts.

Front and Internal S-Trigger Outputs

Each channel gives you three outputs. Two S-Trigger signals are available on the front panel via 3.5 mm jacks, for patching to nearby modules or sending triggers to other systems. There's also an internal S-Trigger output per channel, meant for interfacing with other AMSynths modules, like the AM993. The internal routing keeps critical timing signals off the patchbay, which cuts clutter and potential noise pickup.

Compact, Efficient Design

The AM997 is only 4HP wide and draws 5 mA from the +12V rail, with zero draw from -12V and 5V. It doesn't hog space or strain your power supply. The module ships with a standard Doepfer power cable and M3 mounting hardware. The 35 mm depth fits most cases, even shallow ones.

Visual Feedback with Red LEDs

Each channel has a red LED that lights whenever a V-Trigger signal is detected at the input. That makes troubleshooting easy. If your envelope isn't firing, you can see right away whether the gate signal is reaching the module. If the LED flashes but the S-Trigger output doesn't work, the source isn't the problem. If the LED stays dark, check your sequencer or keyboard output.

Hand-Built in England

Every AM997 is hand-built and tested in Sussex, England. The front panel is cut from 2mm thick black anodised aluminium, which gives it a solid feel for a modest price. The 2024 revision brought a refined black and silver finish.

Historical Context

The AM997 exists because Behringer chose to stay true to the original Moog System 55's S-Trigger design, even though most modern Eurorack gear uses V-Trigger (positive-going gate) signals. That leaves a compatibility gap, and the AM997 is one of the cleanest, most affordable ways to bridge it. It was designed as a direct, space-saving alternative to the Behringer 961 Interface module, which offers similar conversion in a much larger 16HP package, with additional features many users don't need.

The AM997 sits in AMSynths' "Modular III" product line, which is focused on practical analog utility modules. AMSynths launched its Eurorack range in 2010 and has built a reputation for reliable, no-frills modules.

Collectibility & Value

The AM997 is currently in production and available new from the manufacturer at £39.00 (inc. tax). It's a utility module and a recent introduction, so it's not a vintage collectible in the traditional sense, and it's not likely to appreciate in value. Builders and integrators still seek it out because of its place in the Behringer System 55 ecosystem. One unit was recently listed on Reverb as part of a 16-module lot, described as "mint condition" and "bought new recently and only gently used."

There is no data on common failures or long-term maintenance needs, likely because the circuit is simple and passive. With no moving parts or complex ICs, it's expected to be highly reliable. As with any module relying on precise voltage thresholds, users should make sure their power supply is stable and their gate sources are within spec.

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