hey vero guys... brazillian edition of elektor "octave up"

[GFR]

this is where this came from, before extracting it from the CHM file it was in:

http://wayback.archive.org/web/20040226072053/http://www.gfrhpg.hpg.ig.com.br/CCDB/oitavador.chm

definitely a brazillian site. it was on a page listing all of the CDDB stuff made for mutantes by cesar dias, so i downloaded it.

spanish? portugese? beats me, i can barely speak english.

Well, gfrhpg @ hpg.ig.com.br, that site was mine I still have the magazine with the CCDB octaver, if you can't find it online I can scan it again. But the circuit in the first post (with the text in Spanish ) has nothing to do with it.

[tubegeek]

...have to say I did not feel the slightest qualm about cannibalizing it for parts afterwards.

Mark, is there anything about this PARTICULAR circuit that would make adhering to the .82 uF cap spec important? I was planning on trying it with the lowest valued 1 uF's I could select to see what it does. But I guess I could bother paralleling .47's with .33's if it's actually important to get close.

My question stems from the fact that there are so MANY of them - I was wondering if there was an important multipole rolloff being applied by those caps that would be important to keep.

[GFR]

BTW the CCDB phaser is a MXR phase 90 with some mods, the CCDB sustainer is a MXR Dynacomp with a 10V power supply and a 1M sustain pot, etc. The CCDB octaver in my opinion is the most original and cool CCDB effect.

[tubegeek]

So - this?

link to a pdf on munky's Geocities site

[Mark Hammer]

Mark, is there anything about this PARTICULAR circuit that would make adhering to the .82 uF cap spec important? I was planning on trying it with the lowest valued 1 uF's I could select to see what it does. But I guess I could bother paralleling .47's with .33's if it's actually important to get close.

I think you'll be fine with the 470nf or 680nf units you likely have in your parts bin.  If you plan on using it with bass then maybe use 1uf electrolytic, but I can't see hanging onto as much low end as possible critical in this application.

My question stems from the fact that there are so MANY of them - I was wondering if there was an important multipole rolloff being applied by those caps that would be important to keep.

The circuit blends clean and full-wave rectified signal.  The doubling is produced by the op-amp stage with diodes.  I suppose a more "natural" sound might be had if you keep bass content on the clean side, and forfeit some bass on the octave side.  So, if you had 680nf on the clean side and 330nf on the rectified side, I imagine you'd be fine.

I don't know how critical the matching of diode forward voltage is, but I suppose it wouldn't hurt to aim for similar Vf.

I don't know if I like the connection of P1 to both C2 and C3.  P1 sets the gain of A1 (from a little more than 2x to 101x) but its setting changes nothing about what's reaching the mixing node via C3.  My gut sense is that P1's connection shown in the schematic is a drawing error, since there is no need for C2 and C3 to be tied together when P1 is set to minimum gain.  If you want to adhere as much as you can to the drawing, then run a 1M fixed resistor from C3 to ground, but don't connect P1's outside lug to C3.

Who knows.  Maybe that was the reason I was so unimpressed with it.  Like I said, I built it exactly as shown, and lacked the knowledge to "fix" any errors made in the drawing or PCB layout.  And since Elektor was one of those magazines that did not regularly show up on the newsstand, I might have missed a subsequent issue where the error was mentioned and corrected.

[pinkjimiphoton]

this is where this came from, before extracting it from the CHM file it was in:

http://wayback.archive.org/web/20040226072053/http://www.gfrhpg.hpg.ig.com.br/CCDB/oitavador.chm

definitely a brazillian site. it was on a page listing all of the CDDB stuff made for mutantes by cesar dias, so i downloaded it.

spanish? portugese? beats me, i can barely speak english.

Well, gfrhpg @ hpg.ig.com.br, that site was mine I still have the magazine with the CCDB octaver, if you can't find it online I can scan it again. But the circuit in the first post (with the text in Spanish ) has nothing to do with it.

cool, i had no idea what the hell it was, i just found it and figured out it was an octave box. i only really know a couple bad words in spanish, but can read it a little bit. poorly.



i didn't know if this had anything to do with CDDB or not, but i'm loving the regulus style fuzz i built, and was curious to see what the other stuff was like.

[pinkjimiphoton]

So - this?

link to a pdf on munky's Geocities site

that's the gizmotron, right there i believe. funny, i couldn't find a working link to nab it!!

wonder how hard it will be to vero?

[tubegeek]

funny, i couldn't find a working link to nab it!!

Your google-fu is no match for my sophisticated Crane Style!

[pinkjimiphoton]

google fu'd up.

and i'm usually pretty good at hacking thru them robot.txt files..