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) It’s a 4HP module—small in footprint, big in responsibility—tasked with 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.

It’s not a “set it and forget it” module under heavy loads, though. Owners report that while it runs cool under recommended specs, pushing it near its 45-watt ceiling—especially on the +12V rail—can make it run hot. A few have even noted occasional audible noise, like a faint buzz or beep, under certain conditions. These aren’t dealbreakers, but they’re the kind of quirks you only learn after living with the gear. And yes, it needs an external power brick—specifically a 15–20V DC unit like the 4ms 90W Power Brick, sold separately. No brick, no juice. Simple as that.

Specifications

Key Features

Independent Regulation, Real Protection

Each voltage rail—+12V, -12V, and +5V—is independently regulated and protected. That’s not just marketing fluff; it means digital modules won’t inject noise into your analog oscillators, and a short in one row won’t take down your entire system. This kind of isolation is what turns a functional rack into a reliable one. The result? Ultra-low cross-talk between rows, so your delicate FM patches stay clean and your sequencers clock steadily.

Daisy-Chaining Done Right

The dual 5.5mm x 2.1mm barrel jacks on the front panel aren’t just for show. They let you daisy-chain multiple Row Power units from a single power brick, which is a godsend when expanding your system. You can mix and match with other Row Power modules or 4ms Pod enclosures, building a modular setup that grows with you. And because the on/off switch doesn’t interrupt the daisy-chain, you can power down one row for maintenance while the rest of your system keeps humming.

Hot-Swappable Rows, Custom Distribution

Need to swap out a module or reconfigure a row? The Row Power 45 supports hot-swapping—no need to power down the whole rack. Its dual 16-pin headers work with flying bus cables, bus sticks, or custom bus boards, and if you’re building something bespoke, the solder holes for MTA156 headers or 14 AWG wire give you full control over your distribution. It’s modular power with modular flexibility.

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. That’s not just cool—it’s practical. Seeing real-time power usage helps you avoid overloading rails before they overheat, and catching a voltage dip early can save a performance. It’s like giving your rack a dashboard.

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. But in the Eurorack world, reliability has value. 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 Supply Modular EURORACK - NEW - PERFE

$165

As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.

Related Models

• 4ms Row Power 25
• 4ms Row Power 35
• 4ms Row Power 40
• 4ms Row Power
• 4ms Ping
• ADC 27
• 2hp LPG V2
• ALM Busy Circuits MS-014
• ALM AXON-2
• AMS DMX 2000