Special Sauce [Chorus, Doubler, Slap Back, Vibrato]

[Aleph Null]

Special Sauce is for when your tone needs a little something extra. It's a PT2399 based delay with envelope controlled pitch modulation that does chorus, vibrato, doubling, or slap-back delay.





The enclosure is a Love My Switches limited run. The face plate is a one-sided aluminum PCB from JLCPCB.





This circuit is tuned for short, bright delays ranging from 30–150ms or so. The short delay time meant I could use the first CMOS stage of the PT2399 as an input buffer instead of for filtering. A Mosfet at the output supplies 0—35dB of gain. The boost cuts frequencies below 140Hz or so. At the lowest setting, there is no frequency cut. The boost gets "brighter" as the gain is increased. This keeps things tight when boosting into an overdrive or dirty amp.The real trick here is using the voltage on pin 8 as an envelope follower (as discovered by DeadAstronaut). Instead of applying the pin 8 voltage directly to pin 6, I used it to control a 2N5089 set up as a voltage sink. This makes the pitch bending much more pronounced, especially at shorter delay times.

Here's a demo of my original vero build.

I have extra PCBs and face plates. If anyone is interested in building this, please DM me.

[Mark Hammer]

Not meant as a slight, but I couldn't resist.  Nice work BTW.

[Aleph Null]

Not meant as a slight, but I couldn't resist.  Nice work BTW.

Thanks! That was kind of the joke. I think most guitarists know that double tracking or a little delay make any guitar part sound better—it's not much of a secret.

[sethwitz]

Wow, that sounds great, and I'd love to build one! I'll send you a message.