Colorsound Supa Octivider (1978) - was it ever sold?

[Rob Strand]

Found this the other day when I was looking at the versions of the Colorsound Tremolo,

http://www.bigmuffpage.com/images/Tonebender%20Images/Colorsound_1978_leaflet.jpg

1978,  Colorsound Supa Octivider.   In the text it claims to work with chords (but not produce an octave for each note in the chord.)

Did it ever exist?
Was it just a rebadged Colorsound Octivider?

(FYI, There was another weird on posted on the forum a few years back, the Colorsound Diphonizer.  That did exist.)

[Mark Hammer]

Not a Supa, but Colorsound nonetheless, with a brief demo around the 19:40 mark here:

Hard to imagine it handles chords.

[Rob Strand]

Not a Supa, but Colorsound nonetheless, with a brief demo around the 19:40 mark here:

The scary thing is, while sorting out my old stuff I actually discovered I had traced the (non Supa) Colorsound Octivider back in 2003!   I forgot all about it but once I saw the schematic I rememebered doing it - if that make sense.

It is very much like the Shin-EI OB-28 Octave Box.   Few part changes here and there.

Hard to imagine it handles chords.

The way I understood the brochure is it will track when you play chords.  It supposed to play the octave of the lowest note.  It doesn't claim to generate the octave for the each note of the chord.

So my reading of that was is it has better tracking than the standard unit.    Having seen the standard Octivider I was interested to see what they did.    Perhaps it didn't end-up working any better than the standard unit.   Everyone knows those analog sub-octave units end-up mistracking and bobbling at some point.

[bms19]

Could ypou post the schematic?

Regards
BEn

[Rob Strand]

Could ypou post the schematic?

After I sorted all my stuff out I packed it up and it's not easy to get to.

Unfortunately I can't remember differences between  Shin EI and the Colorsound, other than they were small.
IIRC, the forum member Duck Arse said that thing didn't track so well.

There's a few links on the web for the Shin-EI OB-28 Octave Box but I'm assuming you already have those.

[11-90-an]

Fredrik (aka Freppo) did a layout some years ago... if you wanna trace the vero, go ahead...

https://www.parasitstudio.se/stripboard-layouts/colorsound-octivider
https://www.parasitstudio.se/building-blog/colorsound-octivider

This guy seemed to do some chords...

[Rob Strand]

f you wanna trace the vero, go ahead...

It wouldn't be too hard.  You can use one of the schematics I posted as a guide and just tick-off the parts.
You are only looking for a few part value differences.

[11-90-an]

Searched: https://www.diystompboxes.com/smfforum/index.php?topic=54797.0

Links there don't work, but here's the relevant one...

https://www.aronnelson.com/gallery/main.php/v/Martys-layouts-and-photos/colorsound_octivider_v11.gif.html

[Rob Strand]

LOL! Well done.  That *is* my schematic.

[11-90-an]

LOL! Well done.  That *is* my schematic.

From the scem... this pedal *isn't* true bypass right? It seems to pass through Q4 and associated components...

[Rob Strand]

From the scem... this pedal *isn't* true bypass right? It seems to pass through Q4 and associated components...

Yep, sure looks like it.   I don't remember it but it probably wasn't too hard to trace given it follows the Shin EI fairly closely.

For the schematics in that era I did make an effort to document what was there (good or bad).   For uncertain stuff I added notes so it was easy for someone else to fill in the blanks or check.    There might a few dumb-ass mistakes as well  .

[11-90-an]

But why does the colorsound octivider handle chords (but not octave all the notes,) but not the boss oc2? Is it the fact that the octivider's flipflop'ed signal is blended straight in and the oc2's is only used to power a jfet? Or the filtering types?

[Rob Strand]

But why does the colorsound octivider handle chords (but not octave all the notes,) but not the boss oc2? Is it the fact that the octivider's flipflop'ed signal is blended straight in and the oc2's is only used to power a jfet? Or the filtering types?

I haven't spent enough time going over that one so I can only guess.    First three stages remove high frequency junk which would otherwise corrupt the zero crossings.   Then the low-pass filter before Q5 presents a strong slope with frequency across the frequency range of the fundamental.   What that does is emphasize the lowest harmonic and suppresses the second and third harmonics (that includes higher frequency stuff from the other notes in chords).     That way of emphasizing the fundamental does work but like most filters (including the OC2) it's a tricky balance.  Considering the number of variables to tune, it's a pretty good job - and done back in the early 70's.   Someone might have spent a lot of time on it.

[11-90-an]

Hmm ok that makes sense...

Just thought about something... what would happen if the output of that flipflop will be fed into a jfet to invert the signal every blah blah yada yada... ....just like the oc2? Would there be some tracking errors, glitchy stuff, etc. ?

[Rob Strand]

Would there be some tracking errors, glitchy stuff, etc. ?

The bobbling type tracking errors are determined at the flip-flop output so what you do after that can't affect the tracking.   What you do with the output of the flip-flop will affect the buzziness of the sound.   Most designs will need some filtering after the final octave signal to reduce any harsh buzz.