
External Controls
1
5
4
6
3
1 WHITE LED indicates good input power connection
2  Four 9V DC outputs
3  One switchable 9V/18V DC output
4  9V/18V switch sets voltage output level of 9V/18V output 
(indicated by green LED)
5  INPUT jack 18V @ 2000mA power
6  GREEN LEDs indicate good output power connection 
2
M239 | Mini Iso-Brick 2

Basic Operation
Operation
Connect included AC adapter into M239’s 18V INPUT jack.
Plug AC adapter into wall outlet; white INPUT LED indicates  
good connection.
Connect up to four pedals requiring 9V power to the four 9V  
OUT jacks using the included barrel-to-barrel cables. 
Connect another pedal to the switchable 9V/18V output. Use 
9V/18V slide switch to match pedal voltage (indicated by green 
LED).
Included splitter cable can be used to connect two pedals to a 
single output. Connect straight end to M239 output and rightangle ends to pedals’ power inputs.
Whether connecting single pedal or multiple pedals via splitter 
cable, always be sure pedal mA ratings do not exceed output  
mA ratings. 
WARNING: Some pedals may be damaged if powered using 
voltage that exceeds level required by the manufacturer, e.g. 
powering a 9V pedal with 18V. We highly recommend staying 
at or below manufacturer’s stated voltage requirement. Dunlop 
assumes no responsibility or liability for equipment damage 
caused by misuse of M239.
Power
The Mini Iso-Brick Power Supply requires an 18V 
regulated power supply rated at 2000 mA, with   
5.5mm x 2.1mm positive barrel, negative center plug. 
The included power adapter can utilize a wide range 
of wall power, from 100–240V at 47–63Hz. Comes with 
switchable US/Japan, UK, EU, and Australian plugs.
M239 | Mini Iso-Brick 3

Basic Operation
Connection Notes
Included cables use industry standard 5.5mm x 2.1mm positive 
barrel, negative center polarity plugs.
Each output features a green LED. When lit, this LED indicates 
a good connection. If short-circuited or overloaded, this LED 
will turn off.
M239’s four 9V outputs can handle up to 300mA each. 
M239’s 9V/18V output can handle up to 800mA.
All outputs may be used simultaneously for a total power 
output of 17.1 watts.
The M239’s foldback current limiting circuit (FBCL) provides 
ultimate protection against power shorts and overloads. Even 
at full load, the M239 operates coolly and quietly as a fully 
regulated power supply.
Troubleshooting
The power LED fails to light.
Dead AC outlet. Try plugging into another outlet, or test 
the outlet with another device like a lamp.
Faulty connection. Double check plugs to make sure  
they are inserted securely.
Short-circuited output. Disconnect the cable from the 
output whose blue LED is off. 
Wait 5 to 10 seconds for the unit to reset, indicated when 
the blue LED comes on. 
Power provided to some effects, but not others.
Incompatible power plug. Check that the dimensions  
and polarity of the pedals are compatible with the 
provided cables.
Faulty cord. Check by swapping the power cable with 
another known good cable. 
Faulty jack on Iso-Brick Power Supply DC output jack. 
Check by plugging the power cable into a different DC 
jack.
Faulty jack on the pedal. Test by running the pedal off 
battery power.
M239 | Mini Iso-Brick 4

Specifications
Input 18V At 2 Amps regulated supply (positive barrel negative center 
5.5mm x 2.1mm plug)
Outputs  9-18V @ 800mA (switched)
(4) 9V @ 300 mA
(all positive barrel negative center 5.5mm x 2.1mm)
*Note: Using a split cable allows you to share one output with two devices. Remember 
the straight plug is the end that goes into the Mini Brick DC output and the two 90° to 
the effects (this helps minimize ground return current noise). position.
M239 | Mini Iso-Brick 5