Where can I find a cool A/B box Schematic?

[Hiwatt25]

I'm still fairly new here so please forgive me if I'm asking a silly question but I did do a bit of searching (without much luck) before I decided to post. 

What I'd like to build is a pedal that will allow me to switch between two amps (one dirty, one clean) while playing a single guitar.  I'd like to have two LED's on it because they're neat looking.  I should be able to tell what amp I'm playing by hearing it LOL 

Also, I've read a little about silent switching by means of a resistor.  Is that something that can be added to such a pedal?

So, does anyone know of such a schematic and where I could buy the parts for such a thing?

Thanks in advance.   

[LyleCaldwell]

http://fulltone.com/PDfFiles/AB_switcher.pdf

[Hiwatt25]

Thanks for the reply but unfortunately that link did not open for me.  Any other suggestions?

[LyleCaldwell]

That's the circuit you want.  Install Adobe Acrobat Reader and try it again.

[delbowski]

hey...

make sure that you have a program like adobe acrobat reader that can open a pdf.  also make sure your browser is set to open pdf files with it.  i ran in to trouble getting firefox to open pdfs with adobe, but i just had to change the settings.  i say this because the link is to a simple a/b box and if you're just starting out it should be an easy build. hope this helps!

del

[Hiwatt25]

Duh!  Thanks guys.  I just formatted my hard drive this weekend and forgot that I hadn't reinstalled Adobe.  Oops. 

[brett]

Hi.
With that box, you might want to keep the signal lines away from the power to the LEDs.  Otherwise, you might get a "click" as the LEDs turn on and off.
cheers

[343 Salty Beans]

Out of curiosity, what advantages do buffered AB boxes have over this one?

[LyleCaldwell]

Depends on the quality of the buffer.  But you could put a buffer in front of this A/B design and it would sound the same.

The real advantage is with a buffered circuit with isolated outputs, so you could make an ABY pedal with no impedance loading or ground loops.

But for straight AB the Fulltone is a good circuit.