ADDAC 305 (2017–)

Name: ADDAC System 305
Brand: ADDAC System

Eight toggle buttons that work as manual gate generators and signal switchers.

Overview

The ADDAC 305 Manual Latches doesn't make sound, shape it, or sequence it. It gives you direct, latching control over gates and signals. Each of the eight illuminated buttons toggles between 0V and +5V, sending a steady gate high or low depending on position. There's no holding down and no spring return. Press once to turn on, press again to turn off, like a light switch. That makes it handy for toggling envelopes, arpeggiators, or looping sequences without tying up a sequencer step. Four of the eight latches also have signal inputs, so you can use them as manual on/off switches for audio or CV paths. Plug in a drone, flick the switch, and it's in or out of the mix. Route a clock through it and you've got stop/start control.

The 305 fits into 8 HP, with a black or red aluminum faceplate and white legends. The buttons have a mechanical click, and the LEDs glow red when active. It draws 10 mA on +12V and nothing on -12V, so it won't strain even a small power supply. It has no voltage control and no MIDI sync. There are no menus, no screens, no firmware updates. Just switches. Live performers and minimalists like it for that reason.

Specifications

Manufacturer	ADDAC System
Production Years	2017–
Original Price	€105 / $106
Format	Eurorack
Width	8 HP
Depth	25 mm
Current Draw +12V	10 mA
Current Draw -12V	0 mA
Current Draw +5V	Not specified
Gate Output	0 to +5 V
CV Input	±10 V
Number of Channels	8
Latching Switches	8
Signal Inputs	4
Signal Outputs	8
Bus Board Connector	8-pin Doepfer-style IDC
LED Indicators	8 (red, per channel)
DIY Kit Available	Yes

Key Features

Latching Action, Not Momentary

The 305 latches. Press a button and it stays. Momentary switches, like those on the ADDAC 304, only send a gate while held. That makes the 305 suited to sustained functions: turn on a drone oscillator, enable a feedback loop, or activate a modulation path and leave it running. Once engaged, the circuit holds until you change it, so nobody has to keep a finger on a button. The feel is firm but not stiff, with a clear tactile bump when the switch actuates. Each switch is illuminated, so a glance at the case shows which paths are live.

Hybrid Gate Generator and Signal Router

Four of the eight channels double as signal pass-throughs, which turns the module from a simple gate source into a manual patch bay. With a jack in one of these inputs, the matching output mirrors the incoming signal when the switch is engaged. When off, the output drops to 0V. To mute a filter sweep mid-performance, patch it through a 305 channel and flick the switch. To toggle between two LFOs, use two channels to gate their outputs and switch manually. It's also useful for testing, since you can bypass a noisy module or mute a runaway oscillator without repatching. Some users report minor bleed-through in the off state, especially with high-impedance or hot signals. That is generally low-level and expected in passive switching designs. This isn't a relay-based muter. It's a simple transistor switch.

Minimalist Design, Maximum Utility

The 305 has no trim pots, no mode switches and no hidden functions. It has eight switches, eight LEDs and eight outputs. The faceplate is labeled with channel numbers and input indicators. Build quality is consistent with ADDAC's reputation: milled aluminum, crisp silkscreening and reliable PCB construction. It ships fully assembled or as a DIY kit (€69, excluding VAT), the latter aimed at builders comfortable with SMD and through-hole components. The kit includes everything needed, and ADDAC provides an assembly guide online. Given the passive switching, there's little that can go wrong in normal use. There are no delicate ICs and no complex power regulation.

Historical Context

The ADDAC 305 emerged in 2017, as Eurorack was shifting from boutique curiosity to mainstream adoption. Cases were growing larger and patches more complex, and demand for utility modules, especially ones that improved physical interaction, was increasing. Modules like the Intellijel Pal or Mutable Instruments Links offered smart clock distribution or voltage manipulation. The 305 answered a more basic need: turning something on and off with a finger. It joined a wave of minimalist utility modules from makers like ALM, Doepfer, and Intellijel. ADDAC positioned the 305 as part of their "Expressive Controls" line.

Collectibility & Value

The ADDAC 305 has never been rare, since ADDAC has kept it in steady production since its release, but it has never been common either. On the used market, prices range from $80 to $130, depending on condition and whether it's assembled or a kit. Fully built units in good condition typically sell for $100-$120, while DIY kits go for $60-$80. Original retail was €105 (about $106 at the time), so resale holds value reasonably well, especially for those who dislike soldering. Failures are uncommon, and when they occur they're usually tied to incorrect power connection or PCB damage during installation. The module draws no current from the -12V rail, so a reversed or missing negative supply won't damage it, but incorrect polarity on the +12V can fry the board. There are no known widespread design flaws, though some builders report minor bleed-through on the switched channels when off. This is typically below -40 dB and not an issue for gate signals, but may be noticeable with high-level audio. Before buying used, check that all LEDs illuminate and that switches click cleanly. A multimeter test for continuity on the switched paths can confirm proper operation. With its passive design and no moving parts beyond the switches, a working 305 should last indefinitely.