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Boss OC-2 issue (it’s ASA)

Attym

Attym

Apr 3, 2015
264
269
#1
I just picked up a Japanese OC-2 Octave pedal. It’s from 1988 and is ASA power supply. I’ve tried it with a 9v power supply, a 9v power supply daisy chained with another pedal and with a 9v battery. It slightly turns on but the light is dim and the effect feels “slightly on”.
I had another OC-2 with ASA power supply that worked perfectly when daisy chained. Also, the button doesn’t click. Any trouble shooting suggestions?
 
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#4
Attym said:
I just picked up a Japanese OC-2 Octave pedal. It’s from 1988 and is ASA power supply. I’ve tried it with a 9v power supply, a 9v power supply daisy chained with another pedal and with a 9v battery. It slightly turns on but the light is dim and the effect feels “slightly on”.
I had another OC-2 with ASA power supply that worked perfectly when daisy chained. Also, the button doesn’t click. Any trouble shooting suggestions?
Click to expand...
If it’s malfunctional with a fresh 9V battery then thats the easiest way to test it’s working right- it will need 12V with any external power. My first thing to try would be to replace all electrolytic capacitors inside then go from there.

Agreed with the other comment that Boss switch relays don’t “click”. Modding one of these for direct 9V is very easy since internally they run at 9V anyway. ACA pedals just took 12V external power and used a diode network internally to drop it down to 9V and many old Boss pedals have already been modded for this over the years so it’s possible your other old OC-2 was.
 
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#5
sloppy_phil said:
@Attym Do you mean ACA, or PSA power? As far as I can see, "ASA" doesn't exist. If it's ACA power, you need to give it 12v, not 9, despite what the pedal may say.

Not sure how to help if it's a PSA power OC-2 and exhibiting the problems you mention, apologies.
Click to expand...
The dim light is very much characteristic of an ACA pedal only getting 9V.
 
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#8
JazznFunk said:
My OC-2 is a late 80s and uses ACA. I use batteries.... I've never been able to find a plug/supply that I felt 100% comfortable trying without risking ruining the pedal. I just have to remember to unplug the input when I'm done so it doesn't drain.
Click to expand...
Here’s a tutorial of a couple ways to mod ACA pedals for regular 9V. This is easy to do since all these pedals run at 9V anyway (or the battery wouldn’t be sufficient!), they just take that 12V external power and drop it down to 9V. Modifying old Boss ACA pedals to PSA specs – stinkfoot.se
 
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#9
sunbeast said:
Here’s a tutorial of a couple ways to mod ACA pedals for regular 9V. This is easy to do since all these pedals run at 9V anyway (or the battery wouldn’t be sufficient!), they just take that 12V external power and drop it down to 9V. Modifying old Boss ACA pedals to PSA specs – stinkfoot.se
Click to expand...
It's beyond my desire or capabilities to mod myself, but I appreciate the info for sure! If I used it all the time, I might consider doing that in the future.
 
#10
JazznFunk said:
It's beyond my desire or capabilities to mod myself, but I appreciate the info for sure! If I used it all the time, I might consider doing that in the future.
Click to expand...
It’s totally worth it IMO, and quite easy and reversible (if you ever wanted to)! If you do it I’d recommend adding a sticker pointing it out for future users though- I’ve had a few ACA-era Boss pedals come through that had already been modded for 9V (including my first OC-2) but I’d never have known if I hadn’t looked inside. Most likely most of these pedals could handle the extra voltage if I were to feed a 9V-modded pedal 12V, but it’s nice to know what you’ve got!
 
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#15
Attym said:
Sent it back, what little it was working turned into no response at all. Found a black label MIT for the same price. I'll have to get over that it doesnt say made in japan.
Click to expand...
Sounds to me like an electrolytic cap had probably gone out of spec in the power supply. I have an early OC-2 with the Japanese circuit board and a much later 90s one and they sound basically the same to me (and both sound very close to the MXR Vintage Octave FWIW), so I wouldn’t worry about it too much!
 
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#17
Attym said:
I never use it, does it help when you just use octave 1? Any links to how to do this?
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I’m not sure how it does it, but removing the 2nd octave gives more volume to the clean and sub. I can’t find the link but there’s a lot of info of tb. Just look up oc2 mods.

I never used the 2nd octave so this was well worth it. Run it at 12v and it’s a much better pedal.
 
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#18
Attym said:
I never use it, does it help when you just use octave 1? Any links to how to do this?
Click to expand...
Disconnecting any of the unused voices will raise the volume of the remaining ones slightly, it can help counteract the volume drop that happens if you ever solo the -1 octave. Basically the 3 voices are mixed using a simple resistance mixer so they all lose some gain due to parallel mixing. The 3 potentiometers are connected to a circuit board that also has 3 corresponding mixing resistors, and if you follow the traces from the -2 pot you will find its resistor. You just need to desolder and lift one leg of the resistor to cut the -2 octave voice. You can also unsolder the pot itself or cut one of its legs, but lifting the resistor is the easiest way to make it reversible.
 

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