Guitar Built-in Octave Effect?

[ShadowSpectre]

Hey

would it be possible to, in a guitar, install a preamp, and right after it split the signal chain into three. one would be dry, one would encounter a diode followed by a capacitor to block DC ( i think ) and the third would encounter two such diode-capacitor chains, then blend all three together with blend knobs? this would theoretically allow a musician holding a note/chord to turn up the levels of the octaves and down the fundamental, thereby achiveing a mediocre approximation of standing in front of an amp which has been cranked to hell?

Now that i think about it, it seems kinda trivial/dumb, but could it be done nonetheless?

[Tim37]

schematic?

[Geo]

What do you expect to get from running your signal through a diode? That turns it into DC. The cap will not block all of it, as it's still pulsating DC, but I just don't understand how you expect to get an octave effect out of this. Are you thinking of how diodes rectify 60hz AC into 120 hz DC in a power supply? Because that's more involved than just tacking a diode somewhere. You need a ground reference... a full-wave bridge might accomplish this w/ a guitar signal, but you need four diodes arranged specifically (google that on the image search).

[fookgub]

What do you expect to get from running your signal through a diode? That turns it into DC.

Not exactly. A single diode will clip off the one half of a sine wave (half wave rectification), but it is still essentially an AC signal. You would indeed get second harmonic generation from this, but it's not quite as simple as one may think. For one, silicon diodes have a turn on voltage of about .7V. Before that voltage they will not conduct much forward current, so it's difficult to get a diode to conduct directly with a guitar signal. You need to boost the signal level first.

I've played around with passive distortion before, and I can tell you that the best you can reasonably expect is a slightly gritty sound when playing hard. You won't be able to get the levels of distortion and compression needed to approximate a distorted amp.

[weezerboy]

so a boss DF-2 then......

[Skiye]

would the addition of a signal boost be required when trying to install any effect directly into the guitar?

i am thinking of installing a sustain, octaver, or phaser directly into the guitar body.

Edited July 4, 2008 by Skiye

[ShadowSpectre]

Hmmm.. i'm sorry, i should have been more clear. Yes i was referring to rectification, not just putting a typical solid state diode in the signal path, but i didnt know that a capacitor wouldnt block all of it... if there were a reference to ground... hmm.. anyways i guess its not the best idea. also, i have active pickups in my guitar and i use 12s so i can put out about 2 or so volts (i've measured).

[Geo]

Per fookgub's post, it sounds like it WOULD do what you want.

Here's what I was referring to...

http://images.google.com/imgres?imgurl=htt...l%3Den%26sa%3DG

The "ground reference" would be the bottom in and out lines. It looks like this would give you octave generation, although now there is positive voltage swing only, and I'm not sure how that would "sound." (All right, I'm a musician, not an engineer! )