[sdiy] Boss OBD-3 distortion ( was Re: Bass synth update... sorta.)

[Dave Magnuson]

-----Original Message-----
From: Tom Wiltshire [mailto:tom at electricdruid.net] 
Sent: Monday, January 16, 2012 3:13 PM
To: Dave Magnuson
Cc: 'Kyle Stephens'; 'Ian Smith'; synth-diy at dropmix.xs4all.nl
Subject: Boss OBD-3 distortion ( was Re: [sdiy] Bass synth update... sorta.)

That OBD3 is pretty complicated for a fuzzbox. What does it do? I notice
there's two paths through it - is one a suboctave or something?

Thanks,
Tom (another fan of crunched-up synths)

On 16 Jan 2012, at 19:49, Dave Magnuson wrote:

> 
> 
> I have a ProCo Rat II, and I think it's OK on synths.   My favorite by far
> is the Boss OBD-3 (bass overdrive).   The low end is ridiculous in
> comparison to the Rat (which sounds a bit thin on really low end stuff).
> The Rat is great for an edgy high-end lead, though.
> 
> http://www.indyguitarist.com/schematics1/boss/boss%20odb-3%20schematic
> .jpg
> 
> My favorite combo is the Crumar Spirit -> OBD-3 -> Ampeg SVT II preamp 
> - > Mixer.  BOOM
> 
> Dave Magnuson
> 
> 
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Hi Tom,

It's a fairly "normal" sounding overdrive with a few added features.   I
would assume it's based on the OD-3 guitar pedal, although I've never
verified that.    The "Balance" pot is essentially a wet/dry mix, which I
like a lot.  Leaving a bit of dry signal makes it sound "tighter" usually.
Notice that there's back-to-back red LEDs for clipping near the bottom of
the schematic rather than the traditional 1N4148, etc.   Not sure how much
of an impact this has the tone, but I know a lot of people swap LEDs into
their distortion pedals

There are also 2 bands of EQ (controlled via concentric pot) which allows
you to boost low and high independently. This opens up the possibility of it
having a scooped mid frequency (both controls boosted) or a mid-frequency
bump (both controls cut) for a bit more tonal variety.    I like that I can
boost the bass without losing the highs unlike a traditional single tone
knob where it's an "either/or" situation

But yes, a bit more involved to build from scratch than a Rat.   

Dave Magnuson