Home Forums Help/Technical Questions New EH4800 Issue (Small Stone)

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    My brand new EH4800 (black with orange and red swirly Small Stone script) stopped working.

    I use an MXR Mini ISO power supply. When I put the EH4800 on my pedal board initially, I removed the included battery from the Small Stone, and used a lead from my MXR Mini ISO – it worked fine (though the pedal did add some noise when engaged) – the phaser effect was nice.

    I redid my pedal board, adding another MXR Mini ISO, because I needed more power jacks – and when I went to try the pedal out – the light comes on when engaged, but no sound at all – except if I turn the dial all the way I hear some clicking – disengaging the pedal, the dry signal comes through clear and clean.

    I put the battery back in removing AC adapter and just went direct from my guitar into the pedal and from the pedal into the amp – and the behavior is the same.

    I setup a return/replacement with the company I bought the pedal from but would like to avoid this in the future, in case I caused the issue.

    I understand there is AC/DC, volts, mA, and polarity. I used 1 of the 4 9v 300mA outputs on the MXR ISO Mini power supply and I think I used one of the supplied power cables.

    MXR says: Included cables use industry standard 5.5mm x 2.1mm positive barrel, negative center polarity plugs

    I’m not sure if I used the new MXR Mini ISO or my existing one when I noticed the problem. I’m wondering if a cable could have done this (perhaps wrong polarity) or maybe if I used my new MXR mini ISO and it has an issue?

    I’m not using the switchable 9/18v jacks on these MXR supplies yet.

    Thanks for any help!

    • This topic was modified 2 years, 8 months ago by specialmonkey.

    It doesn’t sound like you did anything wrong. The polarity on all outputs of the Mini ISO-Brick are center-negative which is what the Small Stone requires. Do you have any special cables that might reverse the polarity?

    The Small Stone can definitely be damaged if the voltage at the power jack exceeds 15V so possibly that is what happened in this case?


    Thanks for the response.

    I don’t believe I’m using any cables other than what arrived with the MXR ISO mini – and I’m only using the 9v / 300mA outputs – (not using the switchable 9/18v output – and both are currently on 9v anyway) – would a cable using the wrong polarity cause something like this? The issue continued when using only the included battery.


    Yes it could or if the voltage was wrong…

    Andre Hage

    I have the same problem with mine. I only used the 9.6 V 200 mA power supply from EHX. The s/n is 202110082834. I will send it back to the retailer for repair.


    Sorry please write the techs at info@ehx.com

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