Resistor Controled Wah (Twin T Wah)

[moisho]

Hi all.
Some spanish friends and I are trying to build some kind of sequencer-wah...
We managed quite well with the Geofx articles... they are great and very detailed (useful when somebody like me doesn't know anything about electronics)

But I have a couple of questions: I would like to use the Twin T Wah circuit... and I don't know the driver resistor value... How much should it be?

There is another think. I can't find the transistors (2N5129) in my usual stores... Could anybody suggests some "more usual" replacements?

[Paul Perry (Frostwave)]

This chart http://modecideas.com/faq91.html suggests a BC338, which would be commoner in your country.
Or you can buy 2N5129 from Banzai Effects in Europe, I think.

[moisho]

This chart http://modecideas.com/faq91.html suggests a BC338, which would be commoner in your country.
Or you can buy 2N5129 from Banzai Effects in Europe, I think.

Thanks a lot Paul!!!
This BC is available in my usual place.
In fact I use to buy in Banzai once a month minimum, but as I said we are developing this project almost from scratch, and I'm very excited right now... I can't wait for the shipping..  :wink: (I will add those parts in my next order, of course)

[moisho]

Hi again... yesterday I buid my Twin-T... using BC399 and 2N3903... I'm pretty sure it's because those transistors, but I only apreciate a small diference changing the control resistor betwen 0 and infinite (you know, with or without contact)....
Any mod in other values to increase the sensitivity or I can forget it and order the right trannies??
I need a simple resistor controled wah.... any other option suggested?

[spudulike]

Use Tim Escobedo's "IdiotWah" ...

http://www.geocities.com/tpe123/folkurban/fuzz/snippets.html

Scroll to the bottom of the page. Uses a single MPSA13 darlington tranny (or 2x2N5088's back-to-back) and sounds pretty good to my ears.

[moisho]

Use Tim Escobedo's "IdiotWah" ...

http://www.geocities.com/tpe123/folkurban/fuzz/snippets.html

Scroll to the bottom of the page. Uses a single MPSA13 darlington tranny (or 2x2N5088's back-to-back) and sounds pretty good to my ears.

Thanks a lot... and simpler!!!
It's just what I'm going to do.