MXR M239 ISO Brick Mini Power Supply

I bought this because I heard it fits nicely under a PedalTrain Metro board and it does. So well, in fact, that after I bought the first one, I bought another immediately after so I can power up to 12 pedals.Feels really robust, is really simple to use. I'd never realised that a few of my pedals (e.g. my Boss RV-5) weren't getting enough power.The only downside for me is that the power cord has a bigger plastic bit on it that feels like it's always in the wrong place for my pedal board and that it might get crunched under the weight, but that's up to me to affix it properly in a way that it won't.

A really well made piece of kit from MXR,compact,light but sturdy.It works really well and is silent in use even with high gain pedals............highly recommended.

No nonsense, tiny, solid and comes with all the leads you need.I've rehearsed and gigged with this and it's been spot on.Totally recommended .

Yes, I know it says mini-brick right on the box, but I still wasn’t prepared for how dinky this power supply is, I’ve only ever owned a couple of cheaper pedal power supplies, and though they did work, I’ve was never truly convinced they were ‘isolated’ or indeed that ‘safe’.When my last £30 one overheated the PSU when it was powering four pedals out of a claimed max of eight (with the aroma I hadn’t enjoyed since the 1970s Scalextric era!) I thought maybe I should invest in something that wasn't made so cheaply for a change. And here I am!Initial impressions are it is very nicely made, especially for something that is most likely going to be hidden away. All brushed aluminium and Apple inspired packaging. The dimensions are fantastically miniature, as the photo shows, and a lot smaller than the army of pedal clone PSUs all over your Amazon search.I suppose it is expensive for what it is. And there are definitely even more solid options at a slightly higher price that don’t use an external power supply, this point might be a deal breaker for some. But for me, a bedroom musician, it’s perfect, unobtrusive, silent, and gives me a little assurance that I won’t be frying my favourite pedals. Very pleased.

Firstly the good: Before I got an amp modelling pedal, it was great! It was easy to install under my nano+ board with hook and loop tape, and the cables supplied were just the right length and of nice quality. There was no noticeable noise with delay, reverb and chorus pedals - and it powered my RC-5 looper without any fuss. The problem started 3 weeks after I installed it, when I got a UAFX dream 65 amp modelling pedal. This needs 400ma, so I used the only output capable of this (other outputs 300ma) which is the switchable voltage one also used for adding another iso mini brick. This was obviously set to 9v. The UAFX had noticeable pickup whine, high pitched - it only stopped when the strings were held. I tried swapping guitars, adjusting the pickup height etc - I was convinced it couldn’t be the power supply because the MXR iso is supposed to be isolated and designed for this purpose. In the end I tried a Boss 500ma charger straight into the UAFX and it totally solved the problem. I’m no where near the milliamp limit for the iso brick, so it must be either faulty or not fit for purpose. So back it to Amazon it went, which I hate doing. It has been replaced by a Cioks SOL- which is totally noiseless - but around £50 more in price. The MXR is a nice looking and compact piece of kit - it’s such a shame about the noise on my example

This is a perfect power supply for small boards I really like it, only issue I came across was when using vintage style fuzz pedals especially units with silicone transistors, I’ve found if you use the 18v outlet for any pedal on the board it introduces a siren type sound to my fuzz pedal when I switch it on, i run my fuzz on battery! the only way to eliminate the sound is to disconnect the 18v/9v output completely which is annoying as it’s one less pedal on the board.It’s a great unit so I’m happy to live with that minor issue.

Got this to power a pedal board. I had hoped this would fix some noise issues I had with a set of pedals that I won, but it made no difference. However used for my main pedals, Boss, Digitech, and it is fine. Small enough for a medium sized board. Leads provided to power up to 6 pedals. I would probably try a cheaper brand next time to see if there is any difference, but it is certainly a good quality item.

I've owned quite a few different pedal power supplies (Cioks, Strymon, TrueTone, T-Rex etc) and this is the worst I've had. Maybe I just got unlucky with the specific unit I received but I did a side by side comparison of this with a TrueTone OneSpot and this sounded terrible. Simple pedalboard with good quality pedals but lots of hum induced. Sending back for a refund.