Skip to main content Skip to footer

MXR Logo

MXR M238 ISO-Brick Power Supply Unit

  • Write a Review

The MXR Iso-Brick Power Supply is small and light with tons of quiet, noise-free DC power on tap ready to run a wide range of pedal types without cro...Click To Read More About This Product

In Stock & Ready To Ship


  • Shipping (48 Contigous U.S. States)
    FREE WITH FIRST CHAIR REWARDS
  • Your Price :
    $149.99
Add to Cart
SKU 
J19629000000000
Add to Wish List

Earn up to 750 reward points.

OVERVIEW

Power your pedals without any hassles and save some much-needed space on your pedal board.

The MXR Iso-Brick Power Supply is small and light with tons of quiet, noise-free DC power on tap ready to run a wide range of pedal types without crowding or weighing down your pedal board.

Each of the Iso-Brick Power Supplys 10 outputs is fully isolated, eliminating gig-ending ground loop noise. Whether analog or digital, positive or negative ground, this power box has you covered. The MXR team broke down these 10 outputs to accommodate a variety of voltage and current requirements: two 9V outputs at 100mA, two 9V outputs at 300mA, two 9V outputs at 450mA, two 18V outputs at 250mA, and two variable outputs adjustable from 6V to 15V at 250mA. The two variable outputs can be used to emulate voltage sag, a drained battery effect sought by many vintage tonechasers.

On top of all that, the Iso-Brick Power Supply comes in a small, lightweight housing thats built like a tank. Features power on/off and connection status LEDs. Put this little box on your pedal board to make sure it runs reliably and quietly gig after gig.

FEATURES
  • Pedalboard-friendly size
  • 10 fully-isolated outputs
  • Quiet, noise-free operation
  • Powers a wide range of pedal typesdigital and analog, positive and negative ground
  • (2) 9V outputs @ 100mA, (2) 9V @ 300mA, (2) 9V @ 450mA, (2) 18V @ 250mA, and (2) variable outputs adjustable from 6V to 15V @ 250mA
  • Variable outputs can be used to emulate drained battery effect
  • On/off and connection status LEDs

Order today!

Reviews
Questions & Answers View All
Loading....

Review Snapshot

by PowerReviews
MXRM238 ISO-Brick Power Supply Unit
 
4.6

(based on 7 reviews)

Ratings Distribution

  • 5 Stars

     

    (4)

  • 4 Stars

     

    (3)

  • 3 Stars

     

    (0)

  • 2 Stars

     

    (0)

  • 1 Stars

     

    (0)

100%

of respondents would recommend this to a friend.

Pros

  • Good value (6)
  • Good power output (3)
  • Reliable (3)

Cons

No Cons

Best Uses

No Best Uses
    • Reviewer Profile:
    • Quality oriented (7)
    • Primary use:
    • Personal (7)
    • Was this a gift?:
    • No (6)

Reviewed by 7 customers

Displaying reviews 1-7

Back to top

(7 of 7 customers found this review helpful)

 
4.0

Good for the price, minor issues with some pedals

By Andrew Meyer

from Oak Lawn, IL

About Me Quality Oriented

See all my reviews

Verified Reviewer

Pros

  • Good Value
  • Powerful

Cons

  • Inconsistent Performance

Best Uses

    Comments about MXR M238 ISO-Brick Power Supply Unit:

    I got mine brand new on eBay (most sites won't have them in stock for at least a month), had it about a week now. I mainly got it because I added an MXR 10-band to my board and didn't want to deal with a separate 18v power supply on top of my old One-spot. Pros: this thing puts out a lot of power for the price; the 10 inputs are well thought out, and provide a lot of flexibility. It's smaller than I was expecting, and could easily mount underneath my pedalboard. My One-spot wasn't incredibly noisy, but the Iso-brick seems to have cut out some of the little hisses and squeals I would get when running a lot of effects.

    As for the cons, they don't have to do with the unit itself so much as the adapter and DC connectors. The cord on the adapter is only about 5 feet long, which means I'll have to run an extension cord out to my pedalboard in most gigging situations. It also feels pretty flimsy; nothing like the beefy cord on my One-spot. If it actually were a decent length, I'd probably worry constantly about it getting damaged. The DC connectors feel just as flimsy as the adapter cord, and don't seem to fit the inputs on my Boss and Electro-Harmonix pedals; when running them right into these pedals, the LEDs light up very weakly and the pedals are very noisy, if they work at all. I've currently got my One-spot's daisy chain running from the Iso-brick to remedy this, as it seems to make a more solid connection. I'll probably be buying better connectors in the future.

    Overall I'd still say it's a good buy; just be prepared to replace the DC connectors as they may not fit all pedals perfectly.

    • Primary use:
    • Personal
    • Was this a gift?:
    • No

    (3 of 3 customers found this review helpful)

     
    5.0

    Excellent product on first impressions

    By KDMD

    from Corvallis, OR

    About Me Quality Oriented

    See all my reviews

    Ask me a question

    Pros

    • Good Value

    Cons

      Best Uses

        Comments about MXR M238 ISO-Brick Power Supply Unit:

        I just picked this up from my local music store. I'd been waiting for it to be released for some time now as it looked like a great value and on first impressions it would appear to be as expected. I had some concerns that it might be too tall to be mounted under a pedaltrain board, but that is no problem. I have it mounted under a pedaltrain PT JR with the stock mounting brackets and it fits fine. The bracket only had to be bent very slightly to get the bracket to screw down flush to the underside of the board as they're designed for the slightly shorter voodoo lab power supplies. Screwing it in was all the force needed to bend it down. It holds the unit in place snugly. I would technically give this a 4.5 star rating because of only two complaints. On the pedaltrain board, once mounted, the upper row of plugs are too close to the board rail to use the straight plugs on the cords, so you have use the right angle side on the unit and the straight plugs into your pedals. The lower row is clear to use either, though.

        The only other complaint is the power cords seems a bit flimsy, not a robust, rubberized cord but rather just a thin wire AC adapter. Doesn't seem to be a bid deal, though, as I am running seven pedals on it currently and I get no noise and reliable powering of all of my pedals. Bottom line, I'm glad I waited on this unit to be released (my backup plan was a voodoo lab 4x4) which thus far seems to be an excellent value.

        • Primary use:
        • Personal
        • Was this a gift?:
        • No

        (1 of 1 customers found this review helpful)

         
        5.0

        power to spare

        By MCL

        from Longmont, CO

        About Me Quality Oriented

        See all my reviews

        Verified Buyer

        Pros

        • noise reduction
        • Powerful

        Cons

          Best Uses

          • perfect power source for pedal junkies
          • running a lot of pedals at once

          Comments about MXR M238 ISO-Brick Power Supply Unit:

          I had about 7 pedals all running off of a Godlyk power adapter and daisy chain, one 18v pedal and two other 9v pedals which require higher voltage than the godlyk could handle. All were plugged into a power strip mounted to the inside of the case I built to house my pedals. That left only one usable outlet left in my power strip, not to mention it was very messy looking. I began to notice more and more unwanted noise being produced by my board, so I started looking for solutions. I probably created a ground loop by putting too much onto one daisy chain and adapter. Enter the ISO brick. Now all of the pedals that need an isolated power supply can get all the clean power they need. Instant reduction in unwanted noise. The ISO brick has more power outlets than the voodoo power supply, plus it has two 18v ports so one doesn't need to use up 2 9v ports to get an 18v port. Two of the 9v ports have a sag knob, so pedals can be run from 6v-15v to simulate low battery power, and I can report that doing so does change the character of my pedals. Just another cool feature to get some different sounds without changing your gear. I have all my distortion pedals daisy chained with the old godlyk cable which was compatible with the MXR cables that are included with the ISO brick. Quiet. All other pedals are powered by their own isolated ports. In total, I have 13 pedals powered by the ISO brick, and my board is quieter than it has ever been, and all of the pedals are getting the adequate amount of power they require. I still have 3 unused ports left in the ISO brick. So now all that is plugged into the power strip that powers my board is the 18v adapter that is included with the ISO brick. Looks much cleaner than the rats nest it looked like before, and I have 4 usable outlets left on the power strip. The ISO brick comes with 10 power cables, each has a 90 degree plug on one end and a straight plug on the other. Also included is the unit itself and an 18v adapter. AWESOME!

          • Primary use:
          • Personal
          • Was this a gift?:
          • No
           
          5.0

          No Complaints

          By Jomi

          from Los Angeles, California

          About Me Quality Oriented

          Verified Reviewer

          Pros

          • Good Value
          • Reliable Performance

          Cons

            Best Uses

            • Having Around The House

            Comments about MXR M238 ISO-Brick Power Supply Unit:

            This item was purchased to finally avoid having to worry about 9v batteries. After doing some browsing around i decided to go with MRX, never having purchased anything by them. I really wanted to finally be able to use my Minifooger Drive pedal, which came with a 9v battery but is only powered by a power adapter so that was funny... a pricey pedal was just piling dust somewhere but i finally got to use it and i love it, it goes great with my Dunlop XL Volume/Expression pedal, it becomes a sick wah. I only play for hobby so i can't attest to its stage performance but it works great for my 8 pedal rig. It's very compact but like everyone says, the power cord is a little flimsy and kind of short, even for my home setup. No noise so far but ive had it less than a week and can't wait to change signal paths up and since it has enough slots for 10 pedals, I can't wait to add two more and see if it can take them all.

            • Primary use:
            • Personal
             
            5.0

            A pedal boards best friend!!!

            By Gary L GRG GUITARS

            from STATEN iSLAND NY

            About Me Quality Oriented

            Pros

            • Good Value
            • Long Lasting
            • Powerful
            • Quiet operation!
            • Reliable Performance

            Cons

            • doesnt come with a 500ma output
            • doesnt come with a 9v battery converter cable

            Best Uses

            • A pedal boards best friend
            • Having Around The House
            • Portable Electronics
            • Travel

            Comments about MXR M238 ISO-Brick Power Supply Unit:

            I was concerned that I might experience an awful hiss when I purchased my iso brick and yes I read many reviews, To my surprise I didnt experience any unwanted noise and i am using nine of my favorite gadgets! I have had it for over a year and I play a minimum of an hour a day. Most days I at least 2 hrs and I hope I dont put the whammy on myself however I havnt had a single issue thus far. I am actually on right now to purchase a second one. I am totally honest in my reviews and would never recommend anything I felt was junk nor would I be purchasing a second one. Most important than not experiencing a hiss I get no loss in my signal. I am a stickler when it comes to my tone. I do wish it did have at least one input that was 500 ma to accommodate one of my multi effects processors and it would be nice if it came with an adapter cable that would work with my vox wah which doesnt have a dc input only runs on a 9v battery, Tho not a reason not to buy it. If you run into this issue you can buy that cable separately. Hope this helps, Rock on!!!

            • Primary use:
            • Personal
            • Was this a gift?:
            • No
             
            4.0

            Works well but I'm cautious

            By Paul C

            from Winchester virginia

            About Me Quality Oriented

            See all my reviews

            Verified Buyer

            Pros

            • Good Value

            Cons

              Best Uses

                Comments about MXR M238 ISO-Brick Power Supply Unit:

                The first one I bought died in the middle of the first gig. Returned and had a second one shipped - based on reviews, I'm assuming I just got a bad one, and MXR is known for reliability so, I'm sure it was a one-off situation. That said, I am cautious. Cautious not to overload the unit, put too many pedals on it, use all the available outputs, etc. currently it is running a digitech Jamman, freqout, and drop pedal - all semi-high power pedals. Two of the units are using combined outputs via a voodoo labs y-cable. While it works great so far, I'm afraid to put my overdrives or my m5 on it, so I have them on a caline cp-05 (not the m5) for the moment (which is not isolated), since I'm just not sure where the limit is on power for the mxr. That said, it is quiet, small, and seems to stay cool. I'd recommend it, but only after tallying up your power requirements and making sure you aren't overburdening the brick. I might be wrong in my caution, and possibly the br4ick can handle whatever, but I cant have another o0ne die off at a gig.

                • Primary use:
                • Personal
                • Was this a gift?:
                • No
                 
                4.0

                Great power supply

                By John

                from Colorado Springs, CO

                About Me Quality Oriented

                See all my reviews

                Verified Buyer

                Pros

                • Good Value
                • Reliable Performance

                Cons

                • Main power cord is thin

                Best Uses

                • Great for pedals
                • High-End Equipment
                • Portable Electronics

                Comments about MXR M238 ISO-Brick Power Supply Unit:

                Great product. Powers my pedal board with ease and no noise. The main power cord is a wall wart and the cable is thin which bother some people. It work for me though. Yes the power cable is a bit shorter that others but that is not a deal breaker. The only thing I wish were different would be the ability to change the 18v outputs to 9v if desired.
                I had tried more than one Voodoo supply but it induced AC noise when mounted under the pedalboard if any of my pedals were near it.

                • Primary use:
                • Personal
                • Was this a gift?:
                • No

                Displaying reviews 1-7

                Back to top

                Questions & Answers

                © Woodwind & Brasswind. All rights reserved.     Terms & Conditions | Privacy Policy | Accessibility Statement

                Bizrate reviews (opens in new window)
                You are changing the Ship-To country.

                Our product catalog varies by country due to manufacturer restrictions. If you change the Ship-To country, some or all of the items in your cart may not ship to the new destination.