Home › Forums › Help/Technical Questions › Bad Stone wiring help?

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  • May 30, 2009 at 3:57 am #78321
    devnulljp
    Participant

    I bought an old Bad Stone off ebay, and it’s completely shot (I have many many choice words for the seller and their “cosmetic blemishes but in working condition”).
    There’s a broken capacitor and two disconnected wires — one from the ON/OFF switch and one from the bottom of the board.
    I found a schematic, but that doesn’t mean a whole lot to me.
    anyone have one of these and can tell me where these wires go? Or post a gutshot so I can trace your wiring?

    Here’s the cap
    th_dsc_0066-1.jpgth_dsc_0064-1.jpgth_dsc_0067-1.jpg

    Here’s the board with the broken wires:
    th_board.jpgth_plug-wire.jpgth_switch-wire.jpg

    Are those three nasty looking trimmers soldered onto the board stock or has it been badly modded ?

    May 30, 2009 at 1:11 pm #97175
    The EH Man
    Moderator

    The trimmers are stock. I’ll have to see if I can put a diagram together for the wiring.

    May 30, 2009 at 6:21 pm #97180
    devnulljp
    Participant

    OK, got one of the wires; the one from the bottom of the board goes to one of the battery clips (clumsy, I didn’t notice it was broken).
    Just the one from the switch to go — should go to the negative voltage pad on the board? Where’s that/how can I tell?

    Here’s the component side of the board.

    th_componentside_0002.jpgth_componentside_0001.jpg
    and another of the trace side
    th_rearboard.jpg

    Thanks Ron

    May 30, 2009 at 8:17 pm #97186
    The EH Man
    Moderator

    The Bad Stone works on a dual power supply: +9 and -9. The red wire of the positive supply goes to the switch then to the board. The black wire of the negative supply goes to the switch then the board. Both remaining leads are tied together at ground.
    The positive supply goes to pin 4 of the LM324 op-amps, the negative to pin 11. You should be able to trace them on the board.

    May 30, 2009 at 9:39 pm #97190
    devnulljp
    Participant

    Got it, thanks!
    Lifted out one dead electrolytic to be replaced as soon as I can get anew one, quick solder and it’s (kinda) working now.

    EDIT: Quite a volume drop on engaging the pedal. Is that normal (like the old Small Stone)? I modded my old Small Stone — is there a similar mod for this one?

    May 31, 2009 at 11:40 pm #97217
    devnulljp
    Participant
    Quote:
    The trimmers are stock. I’ll have to see if I can put a diagram together for the wiring.

    Thanks for all your help — got it working…sort of. Any advice for those trimmers?
    There’s a 500k JFET BIAS control trimmer, ad two 100k trimmers — one for depth and the other for mix (?)
    I’m tweaking by ear, but is there a range of readings I should be looking for to set them with a DMM?

    Setting the Rate pot in the last third of its range gives a quite unpleasant metallic warble; it’s better in the lower part of the range but the phase doesn’t sound symmetrical…the phase goes wump–WUMP…wump–WUMP…like it’s got a limp :-)
    The profile sounds like a drumlin rather than Mt. Fuji — does that make sense?

    This:
    800pxdrumlinplsvg.th.png
    Not this:
    7550300421b644fa.th.jpg

    Is that normal or is something knackered?

    EDIT: The clips I found online (of a slightly different version…same enclosure but different board) have a very symmetrical phase effect.
    Would a knackered op-amp cause the phase to be lopsided?

    June 2, 2009 at 7:23 pm #97256
    azrael
    Participant

    Here’s a link to reverse-engineered Bad Stone:
    http://topopiccione.atspace.com/PJ05EHBadStone.html

    I suggest you simply learn how to read a schematic. It will help you figure out where each wire goes. It’s not hard. Here’s a link on how to get started:
    http://www.generalguitargadgets.com/index.php?option=com_content&task=view&id=31&Itemid=27

    June 2, 2009 at 7:45 pm #97258
    devnulljp
    Participant
    Quote:
    Here’s a link to reverse-engineered Bad Stone:
    http://topopiccione.atspace.com/PJ05EHBadStone.html

    I suggest you simply learn how to read a schematic. It will help you figure out where each wire goes. It’s not hard. Here’s a link on how to get started:
    http://www.generalguitargadgets.com/index.php?option=com_content&task=view&id=31&Itemid=27

    Thanks for the links — I definitely do need to learn to read a schematic (although the people who wrote those pdfs on GGG need to learn to write: they’re unintelligible in places). That reverse engineer page looks cool too, but it’s for a different version to mine.
    Is Electronic Projects for Musicians by Craig Anderton any good for learning this stuff?

    September 25, 2010 at 8:47 pm #111664
    gil2003
    Member

    Funny. There must be a ton of inconsistencies with these bad stones. I have a 2-knob version with a circuit board that has the exact same components as above, but the traces are slightly different, and the layout is subsequently different. Also, my circuit board isn’t labled at all. It only has a faint, repeating “TC” printed in red on the component side. No “5800” on mine.

    May 15, 2012 at 4:15 am #117555
    JimmyZ
    Member

    Great forum first off !
    I had been searching the internet for wiring a Bad Stone phase shifter that was given to me.
    Noticed first off the positive wire was disconnected…easy to figure out.
    Still not working,so decided to take it apart and do a thorough check.
    Found another blue wire disconnected that goes to the foot switch which has 3 wires total.
    Have no clue where it goes and looking at various schematics,none seem to be this particular
    model.This also has only one 9v battery holder.
    Hope these photos are good enough for someone to help me out.They were taken on the fly.
    Is there a specific schematic available for this model?
    Looking forward to hearing this again after many years.
    JimmyZ

    [img][/img]123.jpg
    http://i430.photobucket.com/albums/qq22/N2NXZ/DSCF0014-4.jpg
    http://i430.photobucket.com/albums/qq22/N2NXZ/new-1.jpg
    Above shows top red line pointing to blue wire (disconnected) and bottom shows connection to Foot switch (3 wire).Where does it go?
    [img][/img]DSCF0025-1.jpg
    http://i430.photobucket.com/albums/qq22/N2NXZ/DSCF0018-6.jpg

    May 16, 2012 at 12:27 pm #117566
    JimmyZ
    Member

    Wow.just noticed this thread is 2 years old !!!

    May 17, 2012 at 11:24 pm #117570
    JimmyZ
    Member

    Disregard my question…finally after hours of looking online,found one photo locating wire location.
    http://www.pedalarea.com/images/EH_bad_stone_03.jpg

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