Boss OC-2 Volume Mod

Discussion in 'Effects [BG]' started by bass.bert, Feb 1, 2014.


  1. bass.bert

    bass.bert

    Joined:
    Dec 27, 2009
    Hi folks,
    some people complain about the slight volume drop when using just the -1oct without dry/-2oct on the mighty oc-2.

    If you never need the dry signal or -2oct, you can simply take these pots out of the signal chain and get more output on the -1oct pot. You just have to desolder one resistor for each pot you don't need.

    If you sometimes need the dry signal it's still possible to just take away the -2oct and leave the dry in. But the increase of volume won't be as much as when taking out both.

    Here is what i did in particular:

    I opened up my oc-2 an took out the mainboard (it's linked to the box with some cables, so you can't take it out completely).

    Under the mainbord there is a smaller board attached to the casing right under the pots for dry and -2oct.

    In front of each pot (the green cubes, see the pix) you'll find one resistor for each pot. They're labeled "r60" and "r59" on my unit.

    By disconnecting one side of the resistor i made the corresponding pot useless, but the overall output is now slightly higher. I desoldered only one side of the resistor and left the other side in. so it's easy to connect it again, just in case i will need it again.

    With the mod (i just left the -1oct and took the others out) i have unity gain at about 1 or 2 'o clock now. I didn't notice any difference in tone at normal levels. When i turn up -1oct completely, it breaks up/distorts slightly, but it's way over unity gain then. When i set it at 12 'o clock it's about the same output like without the mod and just -1oct soloed.

    Here are some pix from the guts:

    OC-2_vol-mod.jpg
  2. sillyfabe

    sillyfabe keeping the low-end silly since '06 Supporting Member

    Joined:
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    Sub'd as I never use the dry pot anyways. (I just did the mod but opted to remove the direct pot and resistor completely.) I have since then added a DPDT switch and have found two mods just by messing around with it. I'll take some pictures later as I can never explain I just find these by wiring across different parts of the board. The first is an overdrive type sound that somehow gives me a direct signal but slightly crunchy (also works when bypassed too....) and the other mod sounds like the synth mod but even more aggressive/low-end friendly (if the switch is on the mod when bypassed a high pitched whines comes out...maybe a feedback mod?)

    Sorry but I have to wait for the little one to wake up to record!
  3. Larmer

    Larmer

    Joined:
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    Location:
    Helsinki, Finland
    Thanks. Is this for the Taiwanese or Japanese one?
  4. bass.bert

    bass.bert

    Joined:
    Dec 27, 2009
    I think mine is MIT (labeled "octave" on the outside), but i guess it will also work with the MIJ version, given that the circuit is the same (never heard anything else).

    Gastric posted some pictures of a MIJ oc-2 in his synth mod thread where you can see some resistors next to the pots. These could be the ones, but i don't know exactly. Maybe they are located somewhere else...
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  6. gregmon79

    gregmon79 Supporting Member

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    This is interesting. I never use oct 2 but I do use the dry. I need it to get that volume back. Wondering if I should do this or not. Hmmmmm. Intriguing indeed. I guess if I don't like it, it'd be easy to put back the way it was wouldn't it?
  7. bass.bert

    bass.bert

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    Dec 27, 2009
    I thought the same and never went back! ;)
  8. gregmon79

    gregmon79 Supporting Member

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    So I opened mine up. It doesn't look like the pics at all. It says OC2 ver 2 on it, not 3 like in the pic. What now........
  9. gregmon79

    gregmon79 Supporting Member

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    I do see three caps on that little board though. Like one for each pot..... Trying to upload a pic to show you guys but photobucket sucks
  10. gregmon79

    gregmon79 Supporting Member

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    This is what the inside of my birds looks like. This little board. The only caps are right here:

    [​IMG]
  11. gregmon79

    gregmon79 Supporting Member

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    Can anyone help me out with this??? Are these the two I need to snip?
  12. gastric

    gastric Professional product tester for hire Supporting Member

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    Looks like a Japanese PCB and pot sub-board.

    Please take a picture of the underside so we can see the traces of which resistor goes to which pot.
  13. gastric

    gastric Professional product tester for hire Supporting Member

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    Can probably just cut one of the legs on the OCT2 and DRY pot to remove them from the circuit. Though I'm not the one to say which one, or if that'd even work.
  14. gregmon79

    gregmon79 Supporting Member

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    Will this help? If not I can take a better one when I get home.

    [​IMG]
  15. sunbeast

    sunbeast Supporting Member

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    You can see that the middle leg of each pot goes to a resistor- it appears that the two outside resistors are for "Direct" and "Octave 2"
  16. gregmon79

    gregmon79 Supporting Member

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    So I follow those "trails" from the cap to the pot??
  17. sunbeast

    sunbeast Supporting Member

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    I can't personally speak to how it will work, but based on the OP, disconnecting one side of the resistor of the voice you want to remove should do the trick by cutting the pot out of the circuit. Makes sense to me- give it a shot with the Octave 2 resistor and see if you get a volume boost as a result. It should be an easily reversible mod should you want to!

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