ADDAC 816 (2025–)
At just 5HP, it's a VCA with a snappy, saturating bite and a built-in envelope that cuts the patch cable clutter.
Overview
The ADDAC816 Percussion VCA is a Eurorack module built for immediacy. ADDAC System introduced it on August 19, 2025. It turns any incoming audio signal into a percussive event without an external envelope generator. It combines a standard exponential-response VCA with an internal AD envelope, so a single trigger input produces a shaped, transient-rich output. The attack is fixed and fast, just enough to eliminate the harsh click that often plagues gate-controlled VCAs. The decay is fully adjustable with a front-panel knob. A second knob controls the envelope's gain, which sets how hard the VCA is driven. According to available documentation, the internal VCA can be overdriven into saturation, adding grit and presence when pushed. That makes it a tone shaper as well as a utility.
This isn't a module for subtle dynamics or long, evolving swells. It's for kicks, snares, claps, and stabs - anything that needs a quick hit and immediate release. It's not trying to replace a full envelope generator or a clean linear VCA. It's reportedly useful for processing external sounds, drum samples, or even modulating noise into tight percussive bursts. It will also be available as a full DIY kit, so ADDAC appears to be targeting both ready-to-use buyers and builders who want to work on the circuit directly.
Specifications
| Manufacturer | ADDAC System |
| Product type | Eurorack module |
| Width | 5hp |
| Depth | 40mm |
| Current draw | 80mA @ +12V, 80mA @ -12V, 0mA @ +5V |
| VCA type | Standard VCA with exponential response, saturating |
| Envelope type | Integrated AD envelope with fast attack and adjustable decay |
| DIY Availability | Available as full DIY kit |
Key Features
Integrated AD Envelope with Fixed Fast Attack
The ADDAC816's envelope is not a full ADSR, and it isn't meant to be. The attack is fixed at a short duration, set just long enough to avoid the audible click that occurs when a gate signal directly opens a VCA. That removes a common annoyance in percussive patches without extra slew circuits or complex routing. The decay is fully variable with a front-panel knob, so users can shape how quickly the sound fades after triggering. Speed and reliability matter more here than flexibility.
Saturating Exponential VCA
At its core, the module uses a standard exponential-response VCA, which naturally emphasizes the perception of loudness and punch. That suits percussive material. It can also be overdriven into saturation. When the envelope gain is turned up, the VCA begins to distort, adding harmonic content and a sense of weight. The saturation behaves differently depending on the input signal level, so the interaction between source and module becomes part of the sound design.
Compact 5HP Design with Full Front-Panel Control
The ADDAC816 occupies only 5HP, which makes it one of the more space-efficient ways to get a VCA with an envelope. Despite the narrow width, the front panel gives access to the essential parameters: decay time and envelope gain. It has inputs for the audio signal and for the trigger that starts the envelope, plus outputs for the processed audio. The module draws 80mA from both the +12V and -12V rails, with no +5V requirement. That's standard for analog VCAs, but useful for power supply planning. Its 40mm depth fits most cases, even shallower ones.
Collectibility & Value
The ADDAC816 launched with a manufacturer-stated price of 205 USD plus shipping, though retail pricing varies. It is available new from multiple dealers, with prices ranging from $149.00 to $209.00. At Reverb Finland, it lists for €165.60, while Perfect Circuit notes it as in stock and immediately available. The module is sold in brand-new condition and is also offered as a full DIY kit, which may affect secondary market availability. No data exists yet on long-term reliability, common failures, or maintenance needs, given its 2025 introduction. As a new release, it has not yet entered the vintage market, and collectibility remains speculative.
eBay Listings
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.