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MXR Blue Box Pedal Octave/Synth - MXR Blue Box Pedal Octave/Synth

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1 Answer

I have a used synth, and want to use it as a controller keyboard for GarageBand and other programs.

Dec 09, 2014 | Music

1 Answer

Growl knob not working mxr 288

I would get a can of good electrical contact cleaner and open the unit, spray the cleaner into the back of the controls while rotating them back and forth quickly. This will somewhat clean the control contacts inside eliminating most dust and corrosion. If the control is too old and dirty, it may not work but, I would definitely try. It probably has a special made potentiometer that would be hard to find and replace. They usually have special legs attaching them to the board. I am almost positive that the control is bad or dirty, though. If the sound gets loud when almost all the way up, it does indeed work, just not in a dirty position. That already proves it.

Mar 25, 2014 | MXR M288 Bass Octave Deluxe

1 Answer

My pedal oc3 does the octav , but it makes not at the same time I play

A very slight delay would be normal as it takes the pedal electronics time to acquire and creae the second harmonic. The ear is sensitive to about 1/1000 second. You haven't said how much delay it is causing... If it is over 1/20 of a second there is a problem.

May 05, 2011 | Roland Boss OC-3 Pedal Octave/Synth

1 Answer


I don't know what you mean by "DC Brick"...

The MXR Stereo Chorus unit requires a special 18 Volt power adapter. The common 9 volt pedal power adapters will NOT work with this device. If you have batteries in the unit, when you plug in an incorrect adapter, the unit disconnects from the batteries and the caps discharge so the light will fade.

You will need to use: ECB-004 18-volt AC Adapter Best to use the manufacture's exact device for this one.

Jan 12, 2011 | MXR Stereo Chorus Pedal Guitar

1 Answer

How do I fix a mxr phase 90 (overvoltaged!with 12V universal)

My first guess would be that the zener diode is probably shorted. Also check the 2N4125 transistor for a short. Start there and update this with your results.


Apr 30, 2010 | MXR Phase 90 Pedal

1 Answer

MXR Phase 90 doesn't phase only clean signal. The oscillator is working and I have changed the BJT's.

sounds like a switch contact problem, try some surgical alcohol. (for the MXR not for you!!!)

Dec 31, 2009 | MXR Phase 90 Pedal

1 Answer

Mxr phase 90 block logo and the 9v power jack not working

These break and SOMETIMES the circuit board gets cracked.

Open up and inspect for damage. If board is cracked, bridge broken traces by soldering wires around the break.

If the solder is broken, resolder it.

If the connector is damaged or weak spring, replace the connector.

Sep 12, 2009 | MXR Phase 90 Pedal

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