Single-staged Univibe / Easyvibe for novice builders?

[aeiou]

Is a passive (similar to an original 60s vibe) single stage univibe feasible? I'm looking for a light, subtle phasing sound and a quick simple build for a beginner like myself. I'm looking at a few schematics right now and trying to narrow them down to just a single stage but having some difficulty -- I do have the light (LFO) working a treat though.

Maybe someone could recommend a particularly simple build (or draw up a quick schematic!), and help me narrow it down to a single stage. I'll can return with a qualitative report on the sound of a simplified, single stage vibe/phaser.. Thanks much all

[aeiou]

another thing -- does anyone know the 'polarity' of the univibe? ie, when the light goes dark, does that mean the circuit runs 'clean', and when the light goes on, that engages the 'phasing sound'?

for the intent of my project, i need it to engage the 'phase' when the light turns on -- thanks.

[aeiou]

heres an interesting chestnut --



looks like heres a phase circuit with as many or as few stages as i'm comfortable with, all laid out and easy to understand --

now how do i get this to work with my LDR? specifically -- clean on light off, 'phase' when light on.

[artifus]

http://www.geofex.com/article_folders/univibe/univtech.htm

[Havaden]

heres an interesting chestnut --



looks like heres a phase circuit with as many or as few stages as i'm comfortable with, all laid out and easy to understand --

now how do i get this to work with my LDR? specifically -- clean on light off, 'phase' when light on.

Im no expert on phasers yet.
Though i think the ldr should go somewhere between the 1N4148 diodes and ground?
I can't see an lfo in this circuit..?

Can some circuit guru verify that im right or wrong on this?

[Kipper4]

Take a look here at reply #9

http://www.diystompboxes.com/smfforum/index.php?topic=114633.0


This might answer some of your questions.

"Though i think the ldr should go somewhere between the 1N4148 diodes and ground?"

My ldrs go from the +input to V/2.

All of which was plagurised from Crontox's little worker phaser.

Search and you shall find.


I am no Expert.

[R.G.]

I'm a bit confused by the question. You need a non-passive (i.e. has amplifiers in it) circuit to do a reasonable phaser. And a reasonable sounding phaser needs at least two phase stages.

By your description of what you want, you are looking for something very similar to the Phase 45. Give that one a look.

[Mark Hammer]

The principal difference between a Univibe, and any 4-stage phaser, apart from the LFO waveshape differences between a bulb+LDR and other forms of modulation, is that the Vibe produces a pair of wide and shallow dips, rather than two pronounced and focussed notches.  In some respects, mixing a clean signal with an opposite-polarity low-Q (i.e., gentle slope, not so obvious peak) bandpass ought to achieve a simple vibe-like sound.  Many auto-wahs will use a bandpass filter whose centre-frequency is dictated by a photocell or transistor.

The major difference between that and simply adapting a Phase 45, is that lifting the clean signal in a Phase 45 will yield subtle vibrato.  Lifting the clean signal in the configuration I described would yield a swept gentle bandpass/wah sound.  Could be interesting, I suppose.