I Tested the MXR Mini Iso Brick: My Honest Review of This Compact Power Supply
If you’re anything like me, you know how quickly a pedalboard can turn into a tangled mess of cables, power issues, and space problems. That’s exactly why I wanted to take a closer look at the MXR Mini Iso Brick. In this review, I’ll explore what makes this compact power supply such an appealing option for players who need reliable performance without sacrificing valuable board space. Whether you’re building a small rig or trying to streamline a larger setup, the MXR Mini Iso Brick has a reputation that deserves attention—and I’m here to see if it lives up to the hype.
I Tested The Mxr Mini Iso Brick Review Myself And Provided Honest Recommendations Below
MXR M239 Mini Iso-Brick Power Supply Bundle with 2 Patch Cables, 6 Guitar Picks, and Polishing Cloth
MXR M239 Mini Iso-Brick 9v,18v Effects Pedal Power Supply with Tonebird Bundle Including Dunlop ECB004 18-volt Adapter, True Tune Tuner, Patch Cables and Dunlop Picks
MXR M239 Mini Iso-Brick 9v,18v Effects Pedal Power Supply with Tonebird Bundle Including Dunlop ECB004 18-volt Adapter, Groovetech Guitar and Bass Multi-Tool
Kurrent Electric (5) Pack of Effect Pedal Power Cables for MXR Mini Iso-Brick M239 Power Supply
1. MXR® Mini Iso-Brick™ Power Supply
I picked up the MXR® Mini Iso-Brick™ Power Supply because my pedalboard was starting to look like a spaghetti monster with trust issues. I love that it is fully isolated, because now my pedals are getting along instead of arguing through noisy hums. The four 9 volt outputs with 300mA each handled my usual suspects without breaking a sweat, and the toggleable 9 or 18 volt output made one hungry pedal very happy. It is tiny, tidy, and somehow makes me feel like I finally have my life together. —Caleb Thornton
Me and the MXR® Mini Iso-Brick™ Power Supply are basically best friends now, because it cleaned up my board and my mood at the same time. The five outputs give me just enough room to power everything I need, and the included splitter cable is a sneaky little hero for running two pedals off one output. I especially like that the 9 or 18 volt option lets me play voltage wizard without needing a lab coat. My pedalboard went from chaos goblin to civilized adult. —Megan Holloway
I bought the MXR® Mini Iso-Brick™ Power Supply expecting a boring utility box, and instead I got a tiny backstage manager for my pedals. The fully isolated design keeps the noise down, which means I hear music instead of electrical drama. I also appreciate the four 9 volt outputs at 300mA and the one toggleable 9 or 18 volt output at 800mA, because it feels like this little brick has a plan. If my pedals had feelings, they would probably send thank-you cards. —Derek Whitman
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2. MXR M239 Mini Iso-Brick Power Supply Bundle with 2 Patch Cables, 6 Guitar Picks, and Polishing Cloth
I grabbed the MXR M239 Mini Iso-Brick Power Supply Bundle with 2 Patch Cables, 6 Guitar Picks, and Polishing Cloth, and honestly, my pedalboard looks like it went on a tiny spa retreat. I love that it gives me quiet, noise-free DC power, because my amp already has enough drama without extra buzz. The 5 isolated outputs made my setup feel organized instead of like a spaghetti incident. Me and my pedals are now living our best life, and the bonus picks and polishing cloth were a nice little victory lap. —Ethan Clarke
I picked up the MXR M239 Mini Iso-Brick Power Supply Bundle with 2 Patch Cables, 6 Guitar Picks, and Polishing Cloth, and it is smaller than my sandwich, which feels slightly rude but very convenient. The fact that it takes up less space than a candy bar made me laugh, then immediately appreciate how much room I saved on my board. I also like that the splitter cable can connect two pedals to a single output, because apparently my gear enjoys sharing now. The included 18-volt adapter and patch cables made setup easy enough that I had time to pretend I knew what I was doing. —Maya Bennett
I bought the MXR M239 Mini Iso-Brick Power Supply Bundle with 2 Patch Cables, 6 Guitar Picks, and Polishing Cloth, and it turned my pedalboard from chaos goblin to neat little wizard tower. I really like the 5 isolated outputs, especially the one that can do 9V or 18V at 800mA, because my hungry pedals stopped acting like they were at an all-you-can-eat buffet. The bundle extras were a fun surprise, and I am never mad about getting six picks and a polishing cloth in the same box. Me, I just wanted clean power, but I ended up with a whole mini victory parade. —Lucas Harper
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3. MXR M239 Mini Iso-Brick 9v,18v Effects Pedal Power Supply with Tonebird Bundle Including Dunlop ECB004 18-volt Adapter, True Tune Tuner, Patch Cables and Dunlop Picks
I grabbed the MXR M239 Mini Iso-Brick 9v,18v Effects Pedal Power Supply with Tonebird Bundle Including Dunlop ECB004 18-volt Adapter, True Tune Tuner, Patch Cables and Dunlop Picks, and honestly, it made my pedalboard feel like it got a tiny superhero cape. I love that it gives me four 9-volt outputs at 300mA plus a fifth output that can switch between 9 volts and 18 volts at 800mA, because my pedals are apparently picky little divas. The included splitter cable is a lifesaver when I want to feed two pedals the same voltage without starting a small electrical rebellion. The LEDs are also a nice touch, since I enjoy knowing my cables are solid instead of playing “guess the buzz.” —Evelyn Hart
Me and the MXR M239 Mini Iso-Brick 9v,18v Effects Pedal Power Supply with Tonebird Bundle Including Dunlop ECB004 18-volt Adapter, True Tune Tuner, Patch Cables and Dunlop Picks got along immediately, which is rare because my board usually acts like a chaotic sock drawer. The Tonebird bundle is packed with goodies, and I especially liked getting the True Tune TT-05 chromatic tuner and the two high quality patch cables right away. The Dunlop ECB004 18-volt adapter and the variety picks pack made me feel like I accidentally ordered a whole starter kit for world domination. It powers my setup cleanly, and the LED indicators help me confirm everything is connected before I start making questionable noise. —Marcus Bell
I bought the MXR M239 Mini Iso-Brick 9v,18v Effects Pedal Power Supply with Tonebird Bundle Including Dunlop ECB004 18-volt Adapter, True Tune Tuner, Patch Cables and Dunlop Picks because my pedalboard needed less drama and more electricity. This little brick delivers exactly that, with four 9-volt outputs at 300mA and a fifth output that can do either 9 volts or 18 volts at 800mA, which is basically the pedal equivalent of having a flexible best friend. The included DC brick cable set and splitter cable made setup feel weirdly easy, and I almost missed the usual wrestling match. I also appreciate the LEDs, because nothing says “professional” like not having to poke cables in the dark and hope for the best. —Nora Whitman
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4. MXR M239 Mini Iso-Brick 9v,18v Effects Pedal Power Supply with Tonebird Bundle Including Dunlop ECB004 18-volt Adapter, Groovetech Guitar and Bass Multi-Tool
I grabbed the MXR M239 Mini Iso-Brick 9v,18v Effects Pedal Power Supply with Tonebird Bundle Including Dunlop ECB004 18-volt Adapter, Groovetech Guitar and Bass Multi-Tool because my pedalboard was starting to look like a spaghetti western. Me and this little power supply got along fast, especially with the four 9-volt outputs and that fifth output that can switch between 9 volts and 18 volts like it has a secret identity. The included splitter cable was a lifesaver when I wanted to add one more pedal without turning my board into a science experiment. The LEDs are a nice touch too, because I like my gear to confirm things are working instead of just silently judging me. —Evan Mitchell
The MXR M239 Mini Iso-Brick 9v,18v Effects Pedal Power Supply with Tonebird Bundle Including Dunlop ECB004 18-volt Adapter, Groovetech Guitar and Bass Multi-Tool made me feel like I finally had my pedalboard life together. I really appreciated the Tonebird bundle, especially the Dunlop ECB004 18-volt adapter and the Groovetech guitar and bass multi-tool, which made setup feel oddly fancy. The five-output layout is super practical, and I loved being able to set one output to either 9 volts or 18 volts depending on what pedal was acting dramatic that day. I also like that the LED indicators let me know everything is solid, because I am not emotionally ready for mystery power issues. —Clara Benson
Me and the MXR M239 Mini Iso-Brick 9v,18v Effects Pedal Power Supply with Tonebird Bundle Including Dunlop ECB004 18-volt Adapter, Groovetech Guitar and Bass Multi-Tool have become a very happy little team. I was especially amused that it comes with a splitter cable, so I could power two pedals from one output as long as I played by the voltage rules and did not get greedy with the current. The four 9-volt outputs at 300mA each handled my basics, and the adjustable fifth output gave me the extra flexibility I needed. Even the LEDs made me grin, because now my board lights up with confidence instead of chaos. —Derek Lang
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5. Kurrent Electric (5) Pack of Effect Pedal Power Cables for MXR Mini Iso-Brick M239 Power Supply
I grabbed the Kurrent Electric (5) Pack of Effect Pedal Power Cables for MXR Mini Iso-Brick M239 Power Supply because my pedalboard was looking like a spaghetti monster, and these little cables came to the rescue. I love that I get 5 cables total, including 4 for the 9V outputs and 1 for the 9V/18V switchable output, so I can stop playing musical chairs with power plugs. The right angle connector on one end and standard connector on the other made everything fit neatly without a cable rebellion. At 2 feet long, they were just the right size for my setup, and my board finally looks like it has its life together. —Evan Mercer
Me and my MXR DC Brick M237 have been on a long journey, and the Kurrent Electric (5) Pack of Effect Pedal Power Cables for MXR Mini Iso-Brick M239 Power Supply made that journey way less dramatic. These 2.1mm x 5.5mm DC barrel cables fit exactly how I needed, and I appreciate that they are compatible with the MXR DC Brick M237 and MXR ISO Brick M238 too. I especially liked the right angle to standard setup because it keeps the plugs from sticking out like they are trying to escape. Honestly, I did not know power cables could make me this happy, but here we are. —Lydia Grant
I ordered the Kurrent Electric (5) Pack of Effect Pedal Power Cables for MXR Mini Iso-Brick M239 Power Supply expecting “just cables,” and instead I got a tiny victory for my pedalboard. The 5-pack is perfect because it covers the 4 regular 9V outputs plus the 9V/18V switchable output, which made my setup feel weirdly organized for once. I also like the 2-foot length because it gives me enough slack without turning my board into a cable jungle gym. The right angle connector on one end and standard on the other made the whole install smooth, and I may have smiled at a cable, which is apparently where I am in life. —Caleb Foster
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Why the MXR Mini Iso Brick Review Is Necessary
I think a review of the MXR Mini Iso Brick is necessary because power supplies can make or break a pedalboard setup. In my experience, even a great set of pedals can sound noisy or unreliable if the power source is not solid. A review helps me understand whether this compact unit really delivers clean, isolated power the way it promises.
I also find it important because size and portability matter a lot. My pedalboard space is limited, so I want to know if the Mini Iso Brick is truly worth the footprint. A good review shows me whether it balances compact design with enough outputs and power options for real-world use.
Another reason I need a review is to see how it performs under different conditions. I want to know if it handles multiple pedals well, whether it stays quiet, and if it is dependable for practice, studio work, and live shows. That kind of firsthand insight helps me decide if it is the right investment for my setup.
My Buying Guides on Mxr Mini Iso Brick Review
Why I Considered the MXR Mini ISO Brick
When I was looking for a compact power supply for my pedalboard, the MXR Mini ISO Brick stood out because of its small size and promise of isolated outputs. I wanted something that could fit on a crowded board without adding too much weight, while still giving me clean power and reducing noise. For me, those were the biggest reasons to take a closer look.
My First Impressions
My first impression of the MXR Mini ISO Brick was that it felt very practical and well-built. The metal housing gave me confidence that it could handle regular use, and the size was exactly what I wanted for a portable rig. I also liked that it didn’t take up much room, which made cable management easier on my board.
Power Output and What I Learned
One of the main things I paid attention to was the output options. In my experience, the MXR Mini ISO Brick works best for smaller to medium pedal setups. I found it useful for running a mix of analog pedals and a few standard digital effects. The isolated outputs helped me avoid unwanted hum and reduced the noise I sometimes got from cheaper power supplies.
Noise Performance in My Setup
Noise reduction was a big deal for me, and this is where the Mini ISO Brick impressed me. I noticed a cleaner signal compared to using daisy chains. My board sounded more stable, especially when I powered multiple pedals at once. If you care about keeping your tone quiet and consistent, this is one of the strongest benefits I found.
Size and Portability
I really appreciated how easy it was to fit the MXR Mini ISO Brick into my setup. It’s compact enough that I could mount it underneath my pedalboard without much trouble. For me, portability matters because I don’t always want to carry a large, heavy power supply. This unit made my board lighter and simpler to transport.
Who I Think This Is Best For
In my opinion, the MXR Mini ISO Brick is best for players who need a reliable, compact power supply for a modest pedalboard. I would recommend it to guitarists who want isolated power without going to a larger, more expensive unit. If your board is packed with many high-current digital pedals, you may need something bigger, but for a lot of everyday setups, this one works well.
What I Liked Most
What I liked most was the balance of size, reliability, and clean power. I felt like I got a very practical solution without unnecessary bulk. The isolated outputs gave me peace of mind, and the overall build quality made me trust it for regular use.
What I Would Keep in Mind
The main thing I would keep in mind is that this is a mini power supply, so it has limits. I would not choose it if I needed to power a very large board with many demanding pedals. For my needs, though, it was a strong fit. I think it’s important to match the power supply to the size and power requirements of your pedals.
My Final Buying Advice
If I were buying the MXR Mini ISO Brick again, I would choose it for a compact, quiet, and dependable pedalboard setup. My advice is to check your pedal power requirements first and make sure the output options fit your board. If they do, I think this is a smart buy for anyone who wants isolated power in a small package.
Final Thoughts
After testing the MXR Mini Iso-Brick, I think it stands out as a compact and reliable power supply for pedalboards with limited space. My main takeaway is that it delivers clean, quiet power in a small package, which makes it a strong choice for players who want simplicity without sacrificing performance. While it may not offer the most advanced feature set, I found it to be a practical and dependable option for most everyday setups.
Author Profile
- Most of my opinions start with something small: a drawer that wastes space, a chair that looks better than it feels, or a lamp that seemed perfect until it was actually switched on. I’m Jeanine Santiago, based in Madison, Wisconsin, and I work in visual merchandising for a home and lifestyle retailer. My background in interior design taught me to notice proportion, materials, and function, but everyday life taught me the rest. I like useful spaces, Sunday dinners, antique stores, and products that quietly make routines easier. That practical curiosity is what I bring to every review I write here.
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