4ms Row Power 45 (2020)

It doesn't make a sound, but if your Eurorack system crashes mid-performance, this little black module suddenly becomes the loudest thing in the room.

Overview

The 4ms Row Power 45 isn't glamorous. It doesn't glow, sequence, or filter. But ask any modular synth builder: power is everything. Released in July 2020, the Row Power 45 (also known as RP45) is a 4HP module. Its job is delivering clean, stable power across your rack with minimal noise and maximum flexibility.

What sets it apart isn’t flash but function: independent regulation on each rail (+12V, -12V, +5V), protection circuitry to prevent cross-talk, and a daisy-chain design that lets you link multiple units from a single power brick. That last bit is key for larger systems, where running separate supplies becomes a cable spaghetti nightmare. The Row Power 45 keeps things tidy, letting you scale your setup row by row without rewiring the whole rack.

Under heavy loads it needs watching. Owners report that it runs cool under recommended specs, but pushing it near its 45-watt ceiling, especially on the +12V rail, can make it run hot. A few have also noted occasional audible noise, like a faint buzz or beep, under certain conditions. These aren't dealbreakers. It also needs an external power brick, specifically a 15-20V DC unit like the 4ms 90W Power Brick, sold separately. No brick, no juice.

Specifications

Key Features

Independent Regulation, Real Protection

Each voltage rail (+12V, -12V, and +5V) is independently regulated and protected. That means digital modules won't inject noise into your analog oscillators, and a short in one row won't take down your entire system. Cross-talk between rows is ultra-low, so FM patches stay clean and sequencers clock steadily.

Daisy-Chaining Done Right

The dual 5.5mm x 2.1mm barrel jacks on the front panel let you daisy-chain multiple Row Power units from a single power brick. You can mix them with other Row Power modules or 4ms Pod enclosures. The on/off switch doesn't interrupt the daisy-chain, so you can power down one row for maintenance while the rest of the system keeps running.

Hot-Swappable Rows, Custom Distribution

The Row Power 45 supports hot-swapping, so swapping a module or reconfiguring a row doesn't mean powering down the whole rack. Its dual 16-pin headers work with flying bus cables, bus sticks, or custom bus boards. For something bespoke, there are solder holes for MTA156 headers or 14 AWG wire.

Monitor What Matters

Pair it with the 4ms Row Power Shield or Power Watcher BT (sold separately) and you can monitor current draw and rail voltages via Bluetooth. Real-time power usage lets you catch an overloaded rail before it overheats, and spotting a voltage dip early can save a performance.

Collectibility & Value

The 4ms Row Power 45 isn't a collector's item in the traditional sense. It's a working module, not a museum piece. Current resale prices hover between $165 and $173, though exact pricing varies by condition and seller. Given its 2020 release date, most units on the market are in good working order, but buyers should watch for signs of thermal stress, especially if the module was regularly run near its 2.0A +12V limit. Overheating has been reported under maximum load, and a small number of users have noted audible noise, buzzing or beeping, possibly from components under strain. These aren't widespread failures, but they're worth testing for if buying used. Original MSRP remains unconfirmed, and there's no official word on whether production has ended.

eBay Listings

4ms Row Power 45 Eurorack Power Supply

$165

4MS ROW POWER 45 MODULE : NEW : [DETROIT MODULAR]

$165

4MS Row Power 45 Power Solution for Eurorack Systems, Black

$165

4MS Row Power 45 Power Supply Modular EURORACK - NEW - PERFE

$165

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