Boss ODB-3 mods (and Behringer clone)

A forum devoted to mod, tips and suggestions for upgrading and rehousing your VERY CHEAP commercial stompbox to near boutique excellence.
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rvargas
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Post by rvargas »

Hi all,

I have in my hands a Behringer BOD400, which, AFAIK is a clone or very similar circuit to the Boss ODB-3. I am looking to mod it and get something decent out of it, or at least, heaver :wink:

I have found the same ODB-3 schematic over and over the internet, which looks to be ok, and also a mod for the Boss pedal:

c10: 1uf
r31: 1k
c8: .001uf
for more smoother compressed tone, change d2 and d3 to 1n4148's

Now, the thing is that this schematic does not have components identified. Since I dont have the actual Boss one, I don't know exactly how to identify those components mentioned. Also , since Behringer pedal has a different layout (it is SMD) things will be located elsewhere and with other numbers.

Any of you guys have this pedal, or know more about it?

I will be posting the BOD400 pictures tonight, but wanted to get a headstart here..

EDIT: Now taking a closer look, C8 is close to the clipping LEDs, so it seems to be the 330pF cap before those LEDs in the schematic. It seems the resistors around C10 (R21 and one below it) are 4.7K. The only ones in the schematic are close to the end of the distortion part (after the clipping LED's), so C10 seems to be that 33nF cap. However.. they are too far away from the LEDs so unless there is a big connection below there.. I cant see exactly where the R31 is. Just wanted to start shooting and then get the comments.


Thanks
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ODB-3 mods.JPG
boss odb-3 schematic.jpg

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showoutdoor
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Post by showoutdoor »

Thanks

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cropec
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Post by cropec »

Few days ago I got BOSS ODB-3 to mod it (True Bypass, Toggle Eq)

Schematic posted above got few lacks and mistakes. Most disturbing for me was that noninvertive opamp input is connected with both Bass and Treble Pots.

Unfortunatelly I didn't have time to check whole schem and correct it, but it's always better to spot one mistake than none ;)

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TubeDude22
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Post by TubeDude22 »

I've been spending some time modifying a Boss ODB-1 and rather than starting a new topic, I'll just add to this one. The common schematic on the web does not list part reference numbers. So, as I make progress I'll attach a marked up one.

The Wampler book mods have always sounded good to me so I started there by changing C8 from 300 pf to .001 uf. Using a Telecaster into a Deluxe Reverb amp gave nice results. The .001 uf cap yielded much improved tone but, the dirty tone is still too buzzy. Next, I swapped out the two LEDs for a single 2N7000 MOSFET for softer and asymmetrical clipping. It was a big improvement but that buzzy voice is still dominant. I bypassed R19 with a capacitor decade box in an attempt to tame the buzz but the result was lackluster. Values that helped the buzz made the pedal sound muffled.

My goal is bluesy dirt that I can blend with a nice sounding Tele. Any suggestions on achieving this are appreciated. I want to modify the distorted section without affecting the clean section. Unfortunately the pedal shares a common EQ circuit with both sides which complicates things.

For reference, the Wampler changes are:

Change C10 from .033uf to 1uf or 2.2uf
Change R31 from 3.3K to 1K
Change C8 from 300pf to .001uf
Change D2 & D3 from LED to 1N4148
Change C2 from .1uf to .001uf

First marked up schematic below. I'll update it as I progress.
Attachments
ODB-1 COMPONENTS.jpg

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astrobass
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Post by astrobass »

The stock clipping LEDs contribute to the harshness of this one substantially. I'd recommend two silicon diodes in series to replace each one. Try a 1N4001 instead of the usual 1N914/4148, or a mix of types.

The Wampler mods are all great, though the "more mids" one can muddy things up depending on what you're using with it.

I never tried the mod that makes it better for guitar. I can definitely say that while the Wampler mods and some diode experimenting has turned this into one of my go-to pedals for grit or even fuzz on bass, it's still not useful on guitar.

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Bernardduur
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Post by Bernardduur »

cropec wrote:Few days ago I got BOSS ODB-3 to mod it (True Bypass, Toggle Eq)

Schematic posted above got few lacks and mistakes. Most disturbing for me was that noninvertive opamp input is connected with both Bass and Treble Pots.

Unfortunatelly I didn't have time to check whole schem and correct it, but it's always better to spot one mistake than none ;)
Please, adjust the schematic! I've made it a long time ago but had some time issues so I can't really say I've checked it thoroughly.
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Bernardduur
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Post by Bernardduur »

ODB-3.JPG
'No more....... loud music.......'
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CheapChip
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Post by CheapChip »

Bernardduur wrote:
BOSS ODB-3 (FSB).JPG
Is that schematic right, please?

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