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  • January 19, 2020 at 1:32 pm #86113
    Hels.Yeah
    Member

    I’ve inherited a hefty black Big Muff Pi (made in Russia) and am looking for info on suitable replacement pots. The pot on the right turns 360° with a small click at the max point.

    Also, the output is very quiet (running a synth through it). I’ve read that this is often the case with the older pedals, but to what extent?

    Fresh battery from the shop this morning.
    Lovely noise though :)

    January 19, 2020 at 4:36 pm #125748
    The EH Man
    Moderator

    Does turning the pot make any change in the sound?

    January 19, 2020 at 4:50 pm #125749
    Hels.Yeah
    Member

    It does, it works as is expect until the click, at which point out switches to low. Almost like there’s a latch or something in the pot that’s gone

    January 19, 2020 at 6:27 pm #125750
    The EH Man
    Moderator

    There is a stop in the pot to prevent 360 degree turning. You need to find a miniature 100k linear pot with a 1/8″ shaft. Not easy, but they do exist. If you can’t find one, let me know.

    January 20, 2020 at 7:24 am #125756
    Hels.Yeah
    Member

    Thank you so much Ron, I’ll get on the hunt.

    January 21, 2020 at 12:12 am #125760
    j_flanders
    Participant
    Quote:
    It does, it works as is expect until the click, at which point out switches to low. Almost like there’s a latch or something in the pot that’s gone

    The ‘tab’ that limits the rotation probably broke of.
    http://www.geofex.com/article_folders/potsecrets/potscret.htm
    [img]http://www.geofex.com/article_folders/potsecrets/pot4.JPG[/img]

    Trying to repair the ‘broken’ pot is doable but a gamble as there’s a good chance you will break it beyond repair and then what?
    Since it still works, I would just use it as it is. Now you can go from min to max or vice versa with only 60° rotation instead of 300°. :)

    Happy hunting for a new pot.

    Normally, for these niche items I’d suggest Smallbear but even he doesn’t have them for sale, so it’s going to be really hard to find one.
    He does list a pot you could use after a tedious amount of modding to both pot and enclosure:
    http://smallbear-electronics.mybigcommerce.com/poteniometer-for-russian-big-muff-work-alike/
    http://smallbear-electronics.mybigcommerce.com/electro-harmonix-sovtek-spares-1/?sort=featured&page=3
    [img]https://cdn10.bigcommerce.com/s-sxoup5r/products/3762/images/6147/Russian_BMP_Pot__93201.1523243561.1280.1280.jpg?c=2[/img]

    With the volume up, the pedal should not be quiet or any quieter than other Big Muff Pi’s. So there might be other issues. This has nothing to do with old or new.

    Black Russian BMP uses linear pots though, so you have to turn the volume up more, compared to a lot of other versions of the BMP which use log pots, to get the same output volume.
    But with volume at max on both, they’re pretty much equally loud.

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