Getting more intense 'wah' from ghost dance?

[shawsofhell]

I built the Ghost DAnce from the circuit snippets site http://www.geocities.com/tpe123/folkurban/fuzz/ghostdance.gif. It seems to be very subtle and I was wondering if there is anyway to make the effect more intense?

I checked all my cap and resistor values before putting them in and they were all within about 1%

[puretube]

don`t load the output too much with a low impedance (?)

[gez]

As Ton notes, the high output impedance makes inverters a poor choice for wahs.  However, all is not lost!

I built a CMOS inverter fuzz wah once and used a T-filter at the output.  I directly coupled the output of the inverter to the gate of a JFET buffer (drain goes to 9V and source to ground via a 10k resistor), lifted the arm of the filter with the two caps and variable resistance off the inverter's output, and connected it to the source of the JFET instead.  I ran the CMOS chip at 5V so there was no clipping of the JFET as it was run off the full 9V (bypassed the regulator).

As Tim has used a primitive form of regulation here (not a slight I hasten to add), you could probably do the same with this circuit.  Can't guarantee you won't have to tweak a few values, but it's a simple fix and the wah I got was superb (sounds like two cats srapping* with the fuzz kicked in)!

*= fighting (in case of dirty minded!)  

[shawsofhell]

so basicly your saying i need a low impedence after the effect? i only tried it straight into the amp so far. Sorry gez but I found your post a little confusing are you basicly saying you put a jfet buffer on the output?

[puretube]

no: - plug into a high impedance - like a tube amp...

[gez]

Sorry gez but I found your post a little confusing are you basicly saying you put a jfet buffer on the output?

More or less, just with a slight twist:



Presumably pin 14 of the CMOS chip will be at a lower voltage than the 9V supply due to the primitive regulation, so it would be unlikely that the JFET would clip.  

The above arrangement gave more quack with my own build and prevented loading.  I dare say you'll have to mess about with values if you try it with Tim's circuit though.  Breadboard and tweak it empirically, see what you think (it's all subjective)...

[shawsofhell]

i already ran it straight into my tube amp? ok i will try your circuit gez, thanks for your help

[Eric H]

*= fighting (in case of dirty minded!)  

...hard to tell the difference, with cats.

[puretube]

hey gez: do you happen to know why the 2 series-caps in the twin-t
are different (5n & 1n5)?
(maybe the Q would be too high otherwise?)
(or a typo...?)
And why is the C-member hooked to the left of the input-cap,
and not to the right, like the R-member?

[gez]

hey gez: do you happen to know why the 2 series-caps in the twin-t
are different (5n & 1n5)?
(maybe the Q would be too high otherwise?)
(or a typo...?)

Don't think it's a typo Ton, I've seen unequal cap values in a few schematics.  It would shift the range slightly, and I should think alter the Q, as you suggested.

And why is the C-member hooked to the left of the input-cap,
and not to the right, like the R-member?

No idea!  

[puretube]

tnx!
so I suggest, that Shaw... tries out swapping the left cap to .0015µ for comparison,
and edits the topic of this thread such,
that "ghost dance" appears in capital letters in the title. (UPPER CASE).

this might attract Tim E. ...  :wink: