Boss - OD-3 Overdrive  [schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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nooneknows
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Post by nooneknows »

Hi,
My attempts to modify the od-3 to remove some of the bass and improve the clarity were a failure.
I've seen MonteAllums has some, any idea of the kind of substitution of these mods (except the the insert of the opa2134...)?
thx
M

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CHEEZOR
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Post by CHEEZOR »

http://indyguitarist.com/forum/index.php?topic=210.0

The 2nd to last post down has some ideas. I have never tried any of these though as I dont own the pedal. I do usually own at google though. lol

I hope this helps! :) Happy modding!

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nooneknows
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Post by nooneknows »

Very interesting. C14 was one the thing I changed but maybe I've made a mistake doing them all together, so I probably exceed in something...
thenk you very much
ciao

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sevinisthenumber
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Post by sevinisthenumber »

I would like to build one of these... Can anyone point me to a pcb layout??
"The man who says he knows everything will never know the truth"
C.S. Lewis

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sevinisthenumber
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Post by sevinisthenumber »

One came by me the other day... Can anyone point me to a stripped down pcb layout?
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"The man who says he knows everything will never know the truth"
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sevinisthenumber
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Post by sevinisthenumber »

Can anyone do a PCB for this???
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"The man who says he knows everything will never know the truth"
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Ben N
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Post by Ben N »

PurplePeopleEater wrote:I've had a couple OD3's. I like them because they have a lot more low end than tube screamers, and sound more like natural amp overdrive to me. Everyone has their own opinion, but mine is that the OD3 is one of the best Boss ODs made.
That's my experience, too, with two of them. Very amp-ish, with dynamics and touch-sensitivity like a pushed vintage amp. But I haven't played out with them, and I can see Nooneknows' point, too--the lack of tone shaping could be an issue trying to cut through. I would use it in conjunction with a boost anyway, so that might be the solution.

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monkeyxx
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Post by monkeyxx »

great pedal. Just got it so honeymoon I guess, but, I immediately love it. Very smooth and never harsh, big bass!! I like overdrives like that, tube screamers get thin for me most of the time. Totally worth the $45 shipped I paid used, saves me all that build time as well, great value! Just buy one!! there is something about the better Boss dirt pedals.... an evenness of tone with this slight hair or grit to it, just lovely with the right ones (SD-2 Turbo Distortion my other favorite of the ones I've tried so far). Clearly superior to the SD-1 to me, all of which I have I've modified. No need here.

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Post by TubeDude22 »

There is one mod that I did to my OD-3. That was removing D6 & D7. My OD3 is my #1 dirt pedal.
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Boss OD-3 Schematic
Boss OD-3 Schematic

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Post by sanfi4u »

It seems Boss OD-3 Service Notes is the best kept secret in the world. I'm interested in the exact OD-3 schem (with power circuit, trigger etc.). Can anybody share one?

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Post by george giblet »

It seems Boss OD-3 Service Notes is the best kept secret in the world. I'm interested in the exact OD-3 schem (with power circuit, trigger etc.)
I've never seen one.

The pics a few posts back in post "by sevinisthenumber » 25 Mar 2010, 17:40" has enough info to fill in the JFET switching flip-flops. To me it looks like the stuff in the bottom right hand corner, C1, R1 and all that stuff. Use another Boss schematic as a guide for the schematic and just change the part designators to match the OD-3.
This pic,
download/file.php?id=6846&mode=view

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roseblood11
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Post by roseblood11 »

Is there a verboard layout for the OD-3 with true bypass?

I only found a simplified version.

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Post by PCN »

There are 3 versions of the 2sk184, each with a different Idss value:
Y - 1,2~3 mA
GR - 2,6~6,5 mA
BL - 6~14 mA
The original pedal has GR, but would any of 3 work?
It seems that 2sk117 is a direct replacement for the 2sk184 (same specs), but could be used in place of the 2sk118 too?

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Manfred
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Post by Manfred »

If you use the GR or BL type, it is necessary to adjust the connected components,
Without adaptation, the operating points and the stage gains are shifted and the stages no longer work properly.
Yes, the 2SK117 is identical except for the pinout and as I see this must be installed rotated by 180 °.

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masajinobe
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Post by masajinobe »

Can someone take photos of new OD-3 on SMD?

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CheapPedalCollector
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Post by CheapPedalCollector »

What year did they move to SMD ?

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Post by masajinobe »

CheapPedalCollector wrote: 16 Jul 2022, 20:23 What year did they move to SMD ?

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Post by CheapPedalCollector »

Recently then?

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Post by masajinobe »

CheapPedalCollector wrote: 17 Jul 2022, 06:28 Recently then?
Yes. I think quite recently.

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Post by george giblet »

For a long time I've wanted to do a re-trace of the Boss OD-3 OverDrive.
20 years have past since Luja/Axiom Drift posted his tracing.

The parts not on the Luja schematic are the footswitch flip-flop, power supply,
and also an addtional buffer in bypass path (that's where wampler's C18 mod comes in.)

I started tracing and found some errors in the the power supply section on the Luja schematic.
I just about got to the end after resolving a lot of part designators from pics and was
stuck on the voltage of the zener D13 as there were no clear pics. I could see "6B" or 68 on
one of the pics. Was it 5.6V or 6.8V? whatever the case it was clear is the power rails
for the overdrive section are somewhat lower than the 9V on the Luja schematic.

To cut the story short, I was hunting down pics trying to get a pic showing D13
and I found a Japanese blog with a very accurate tracing.
The tracing correctly shows all the power supply details and also has
correct part designators matching the PCB. The guy did a great job.

So here it is:
boss_od3_schematic - kanengomibako_dec_2021.png
boss_od3_overlay - kanengomibako_dec_2021.jpg

Boss OD-3 OverDrive schematic
kanengomibako
Dec. 2021

Boss OD3 Tracing, 1998 model
https://drugscore.blog.fc2.com/blog-entry-279.html
https://blog-imgs-132-origin.fc2.com/d/ ... ematic.png
https://blog-imgs-132-origin.fc2.com/d/ ... _2od3B.jpg

Additional info:
C24, C33 are tantalums
C17 located on Level/Tone pot board

Variants:
2017 Model:
- R3, R5 10k
(- it's possible the R3, R5 change also implies different IDSS category JFET switches.)
- C1 47n
- C25 100uF
- D13 larger package, black

Wires:
1 V footswitch
2 GY footswitch gnd
3 O LED+
4 GN LED-
5 W Output
6 BU 0V in (to input socket switch)
7 R +9V (to battery)
8 BR Input
9 GR GND (from input socket)
10,11,12 Level pot, Tone pot board
13,14 Drive pot board

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