Adapser - Super simple 2 stages phaser

[Crontox102098]

Hi guys, i'm here again to introduce a new little desing that i've been testing some weeks ago.
It's a little, simple and very adaptable phaser/vibrato and with some LDR can be a tremolo.

I cannot record some clips because my soundcard it's broken, but in phaser mode with C9 and C11 sounds like the MXR Phase 45 and with C4 and C11 taste like the UniVibe.



Cheers!  

[Mark Hammer]

Interesting.  Is the LFO intended to provide something close to a sine wave?

[Crontox102098]

Interesting.  Is the LFO intended to provide something close to a sine wave?

Exactly  .

[StephenGiles]

Interesting, I wonder to what extent a dry signal phase shifted through 2 static sections (the word has gone - senior moment!!) would affect the sound?

[Crontox102098]

Interesting, I wonder to what extent a dry signal phase shifted through 2 static sections (the word has gone - senior moment!!) would affect the sound?

You mean to add 2 stages more?

[StephenGiles]

No replace dry signal with 2 static stages.

[~arph]

*fixed* 

[Mark Hammer]

If the stages are fixed, AND there is clean blended in, what you have is a notch filter, suitable for taming feedback howl.

Using two different cap values would likely make the notch produced wider and shallower, such that it becomes a sort of tunable Varitone sort of thing.

[lapsteelman]

Looks like a cool circuit!

Why does the phase/vibrato switch tie to the VC line? Wouldn't you just want to switch off the clean signal for vibrato?

[Crontox102098]

Looks like a cool circuit!

Why does the phase/vibrato switch tie to the VC line? Wouldn't you just want to switch off the clean signal for vibrato?

I relied primarily in the John Hollis EasyVibe desing... So far, it does the job and is deadly quiet talking about noises.

[mth5044]

Looks like a cool circuit!

Why does the phase/vibrato switch tie to the VC line? Wouldn't you just want to switch off the clean signal for vibrato?

The VC is a reference voltage, so it's basically turning off the clean blend and biasing the the vibrato signal to half voltage.

[Davelectro]

I relied primarily in the John Hollis EasyVibe desing

Thanks for sharing.

Now, I could be wrong but the LFO section looks different from the Easy Vibe. Where did you take it from?

[Crontox102098]

I relied primarily in the John Hollis EasyVibe desing

Thanks for sharing.

Now, I could be wrong but the LFO section looks different from the Easy Vibe. Where did you take it from?

From an image that Frequencycentral's has posted a long time go modifing all the values until get the oscillation i wanted, something close as a sine wave.
This is the image:

[Mark Hammer]

Two things to consider:

1) If you absolutely know what the resistance range of the LDRs will be, then you have the freedom to simply use them on their own.  Many phasers made with JFETs (and on occasion, LDRs) will use a fixed resistor, in parallel with whatever the variable resistance element is going to be, to set the maximum resistance to ground.  That makes it easier to determine what sort of response one will get, and where any notches will be located in the spectrum, with the caps one has decided to use.

2) If you are using homebrew optoisolators (LED+photocell in a relatively light-resistant package), it is not a big deal, or "wrong" to have one LED driving two LDRs, if they are positioned well.  That gives you the freedom to use the circuit as it is shown, but mount one of the two LEDs on the control panel as a speed indicator.