Robovox Build Report

[marmora]

Thanks to Marcos for having this project on his site.  I used the PCB layout.
First impressions: Not as robotic as I would have hoped.  However, it is still fun and entertained me on guitar as well.
This circuit is noisy, but it's really simple to build.  I didn't use shielded cable and it isn't boxed up, so those things should be taken into consideration.  Marcos told me people were having noise problems with common bypassing methods and recommended I hook up the input and output directly.  The clean (unaffected) sound comes by placing a SPST (on/off) switch between pins 11 and 13 of the IC.  I connected it to the 10nf/0.01uf cap that connects these pins.  However, using this method, there is still some audible noise when the effect is off.
For vocals, the effect was a bit subtler than I hoped.  With the depth pot maxed, you got the most noticeable robot voice.
On guitar, the Robovox works like a ring modulator.  This was a lot of fun for me because I've never really used one before.  I tried the trick where you use the neck pickup and roll down the tone and it worked well, but I also found some interesting sounds with the bridge pickup and the treble all the way up.
Hope this helps someone with this rarely mentioned circuit.