small stone

[shawsofhell]

hey i just finished modding my small stone (tonepad design) and when i ground the filter caps it doesnt sound like it wahs up and down like people have said it does. it seems to just act like a tremelo pedal where the volume just swells up and down? any ideas whats wrong?

Also i was thinking about putting a 50k pot in series with a 20k resistor in place of the 27k resistor where the dry and wet signals meet. Will this allow me to control the depth?

[shawsofhell]

bump

[puretube]

are you sure you grounded the correct side of the caps;
and you disconnected that side from where it used to be hooked to?

[shawsofhell]

i'm certain i have the right side grounded. ill try swapping sides and see what happens also does anyone know if my depth mod will work?

Also how do you get rid of the volume drop when you turn it on? Mine seems to be slighlty louder when colour is turned off then when it is on is this normal?

[Mark Hammer]

Take a look here at the datasheets for the SSM2040.
http://www.synthdiy.com/files/1/20011030/ssm2040.pdf

Scroll through it and you will see how the relocation of the capacitor results in different sorts of filters.  Each of the big "G" triangles, and little "B" triangles is effectively equal to a CA3094, half a 13600, or one of the OTA+Darlington circuits used to replace them in the various Small Stone clones.

Use that to guide you as to whether you've got the correct end of the cap moved.

And yes, the pot you describe (in series with the wet-side mixing resistor) will help you to adjust the intensity of the effect.  You may want to use 100k instead of 50k.  I'm not sure 50k will give you quite the range of effect reduction you want.  Note that this will have NO effect on the width of the sweep, but WILL have an effect on the depth of the notches created since maximum cancellation requires a 50/50 mix.

Of course, the control will function a little differently should you install a wet-only dry-lift switch for vibrato effects.

[moosapotamus]

Also how do you get rid of the volume drop when you turn it on?

Here's what I recommend... an external volume control...
http://www.generalguitargadgets.com/v2/index.php?option=displaypage&Itemid=124&op=page&SubMenu=

I recently added this to a modded smallstone that I did for a friend... on it's own little piece of perf wired between output from the circuit board and the stompswitch. Bango slick!

~ Charlie