octave down?

[Joe Kramer]

Stephen,

I guess the thing I should have asked was, is it really a sined guitar that comes out, or is it only a sort of p-v conversion that then controls a sine?  If it's p-v, that can be done with an MS-20 or other, but then it's not really guitar is it?  And also, again if it is p-v, I guess the question would still remain, can the output of a guitar actually be shaped into a sine?

Joe

[snap]

why not?

[StephenGiles]

It's a sined guitar as you put it. It is then squared by the 311 and fed to a 4030 frequency doubler and then to the clever bit with a 4047, a VCO that tracks the guitar at twice the frequency of the note played which creates the control voltage for the other two VCOs. My tracing of the full circuit is on Mark Hammer's site.
Stephen

[jmusser]

It was bugging me, so I got the Octup Blender out again, and tried to figure out what I was listening to. What it seems to have, is a very good mix of one octave up, and one octave down. They are blended so well, it's hard to tell where one stops and one starts. The way the harmonics are blended in there, gives you the feeling that the octave up is happening on all over the fretboard, but it's mostly octave down. The octave down is always there, but as you would guess, from the 12 fret on up, the up octave over powers the down octave. Needless to say, it makes for a thick, synthy sound, that's not like any other effect I've built to date, especially when the fundamental is added in. When you get rid of the fundamental the tone gets down right weird, and really synthy sounding. I have no idea if this was what Tim was going for, or whether this is some sort of oddity due to me using a LM324 chip, and not three separate op amps.

[petemoore]

If the above is true, would it not infer that a fat stiff string [like on a bass guitar] would produce octave pitches lower than from a guitar?
 Anyone tried this?

[StephenGiles]

Yes, I once put the top three bass guitar strings on my strat and used a ordinary bottom E for the top string. It sounded fine.
Stephen

[school]

what about in that octave down distortion pedal from danelectro? licorece or something?  anyone know what octave circuit gets switched on when you flip the octave switch?

[puretube]

pop-up

[Mark Hammer]

I'm not all that familiar with the Dano pedal in question, but if it is a "traditional" mono octave down pedal, then it will likely have a 4013 or similar flip-flop in it, which can provide a divide-by-2 and/or divide-by-4 function (two octaves down).  Chances are pretty good the switch you speak of selects between those two options.

The MXR Bluebox works similarly, except that it ONLY provides divide-by-4.  Some folks have modded theirs to permit switching between F/2 and F/4.

[puretube]

information lost...

[StephenGiles]

I've had an hour or two to spare (keeping out of my wife's office space while she does pre holiday paperwork!) soI've done a pruned down version of the EH guitar to sine wave circuit from the Guitar Synthesiser. [A] is the input and the sine wave appears at bottom right at the output of the adaptive filter formed around the 1458, 74 and the 2 x CA3094.

IN accordance with EH convention, upward arrow = +12v, downward arrow = -12v and 0v is a triangle with a line through it.

Have a good build, I'm off to Argentina.
   

http://img.photobucket.com/albums/v317/StephenGiles/EH_sine.gif
Stephen

[puretube]

a real pearl!


bon voyage!


& happy easter!

[Joe Kramer]

Excellent Stephen!  Many many thanks!   Ditto the Bon Voyage!

Sine-ing Off,
Joe

[StephenGiles]

I could have redrawn it in the time it has taken us to get to London Heathrow! 3hours to do 50miles.
Stephen

[puretube]

information lost...

[puretube]

information lost...
:shock: