how do i add a volume controll to easyvibe?? Still need help

[Bron-Y-Aur-Stomp]

how do i add a volume control to easyvibe??
UniVibe has a third knob, volume, and i like to have that too on my easyvibe stompbox.

how do i add one and get the best results out of it?

here is the debug schematic as a reference:

http://i30.photobucket.com/albums/c345/stompbox_layouts/Easyvibe/Easyvibe_debug.gif


thx

[jrc4558]

nice drawing.
Make R3 value X and replace R4 with a potentiometer of value X*2.
E.g.: R4 - 10Kohm Log taper potentiometer, then R3 - 4.7kohm

[Bron-Y-Aur-Stomp]

nice drawing.
Make R3 value X and replace R4 with a potentiometer of value X*2.
E.g.: R4 - 10Kohm Log taper potentiometer, then R3 - 4.7kohm

okey i'll do that, thanks Constantin

[Bron-Y-Aur-Stomp]

In my search of improvements of the all ready great easyvibe circuit i found this after some searching on the forum:

"Change the 47k-100k negative feedback network in the first op-amp, that takes the signal from the input 0.001mF capacitor. Replace it with a 22mF/470ohm (to ground) combo and a 1kB potentiometer in the feedback loop. The fidelity of the signal improved dramatically and now the volume can be controlled with a knob. The tone is smoother and warmer.

It's just like Constantin just mentioned, but i don't understand what to do with the capacitor?
The 22uF capacitor, where should i attach it?

The fidelity of the signal improved dramatically and now the volume can be controlled with a knob. The tone is smoother and warmer. Sounds very interesting!! 

all help is welcome 

here is the debug schematic as a reference:

http://i30.photobucket.com/albums/c345/stompbox_layouts/Easyvibe/Easyvibe_debug.gif

[lovric]

this recent post gives another solution:
http://www.diystompboxes.com/smfforum/index.php?topic=43904.msg318322#msg318322


find:"I also changed the 47k resistor on the first opamp section (the one for the sound signal that doesn't have an LDR on it) to a 100k, I noticed this increased the overall volum, I then added a 500k pot (I used that value just because it was the first one I grabbed) to the input to set the volume.  Now I can have it quieter or louder then the clean signal."

[Bron-Y-Aur-Stomp]

Yes, i really know that stuff.
I like to know more about the 22uF capacitor placement. (recon it's not 22mF cause that's very high)

Bump 

[Bron-Y-Aur-Stomp]

Bump 

[slacker]

You'd connect R3 and the 22uF cap like this



but you don't need the cap, just changing R3 and R4 like Constantin said gives you the same result.