ADDAC System ADDAC804 Audio Integrator (2010s?)
Plug your iPhone into your modular rig and turn your apps into synth modules.
Overview
The ADDAC804 Audio Integrator isn't a Eurorack voice or filter. It's a bridge between iOS and a patchable modular system. iPhones and iPads were becoming serious tools for sound design, and ADDAC System saw no reason to treat mobile apps as isolated islands when they could be full citizens in a modular setup. The 804 sends audio from your modular system into an iOS device, say to run a signal through a granular app, and brings it back out again, all in real time, with no extra gear. It also extracts envelope followers from whatever iOS app is making sound. That gives you two voltage-controllable triggers with adjustable sensitivity and decay, so the amplitude of your iPad synth can fire envelopes in your rack. That opens up feedback loops and hybrid workflows.
It ships with a custom iOS duplex audio cable, the kind that works with the extended headphone jack protocol Apple used before the Lightning era. You don't have to hunt for obscure adapters. It draws only 20 mA from the +12V rail and works with both ±12V and ±15V power systems, so it fits nearly any case. It's 8 HP wide and 15 mm deep, small enough for even a crowded skiff. It isn't a sound generator, and it won't filter or modulate your signal in the traditional sense. It's a utility, and it turns your iOS device into whatever app you load into it.
Specifications
| Manufacturer | ADDAC System |
| Format | Eurorack |
| Width | 8 HP |
| Depth | 15 mm |
| Current Draw | 20 mA +12V |
| Power compatibility | compatible with ±12v and ±15v power supplies |
| Bus board cable | 8 × 2 idc (doepfer style) connector |
| Features | 2 independent inputs, 2 independent volume knobs, 2 independent outputs, 2 independent envelope knobs to set trigger levels, 2 envelope decay knobs |
| Included accessory | ios duplex audio cable included |
Key Features
Two-way audio integration with iOS
The idea is simple. Send audio from your modular synth into an iOS device, process it in any app (Moog Model 15, GarageBand, or even a field recording tool), then return the processed signal to your rack. The ADDAC804 handles this two-way flow with two independent input/output pairs. On the output side, sending to iOS, there are two volume-controlled signals that feed the iOS device through the included duplex cable. On the input side, receiving from iOS, two separate audio outputs bring the iOS signal back into your modular system, ready to be mixed, filtered, or processed further.
Envelope followers with full control
The 804 also listens. It analyzes the incoming iOS audio and generates control voltages with two envelope followers. Each has its own level knob to set the trigger threshold, which is handy when apps output at wildly different volumes, and a decay knob to set how long the envelope lingers. These CV outputs can trigger envelopes, gates, or sequencers in your rack, so the dynamics of your iPad synth can drive physical modules. You could, for example, use an iOS granular app to generate texture, extract an envelope from it, and use that to modulate a filter on a hardware synth, all without leaving the patch.
Built-in iOS connectivity
Cabling is one of the biggest headaches in integrating mobile devices into modular setups. The ADDAC804 gets around it by including a dedicated iOS duplex audio cable. It isn't a standard headphone cable. It's wired for simultaneous input and output through the advanced audio jack found on iPhones and iPads of the era (pre-Lightning, and not compatible with the iPhone VS1, as noted in the design docs). No additional adapters or USB interfaces are needed. The module acts as a dedicated audio interface for your iOS device, in Eurorack format.
Historical Context
The ADDAC804 appeared during a surge of interest in mobile music-making, when iOS devices became capable platforms for serious audio applications. ADDAC System positioned the 804 as a way to dissolve the boundary between app-based and hardware synthesis. It's part of the ADDAC800 series, a line focused on bridging external gear with modular systems. The exact release year isn't documented in the available sources, but its design philosophy fits the early to mid-2010s, when Eurorack was expanding beyond traditional synthesis into hybrid and experimental workflows.
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