Neovibe Bright/Modern switch mod

[ItsGiusto]

Hello everyone. I'm going to be attempting to build a Neovibe. I know it'll be a difficult build but I can't help but already think of one mod I know I'd like to have in my finished pedal, and it might help to be able to work it into my build.

Many vibe pedals these days feature a "bright" or "modern" switch, to change from vintage sound to a more up-front one that makes the phasing/throbbing effect more obvious. The Fulltone Mini Deja Vibe and the Drybell Vibe Machine come to mind. Does anyone know how this sort of mod might be accomplished in a Neovibe?

[R.G.]

I haven't messed with the Neovibe much since the Vibe in a Crybaby Shell days. I'm guessing it's a feedback path to enhance the notches and peaks.

If you can post a schemo of either of the ones you mention, I can tell you what to do.

[bean]

A JFET input buffer is another way to do a "modern" switch. It would replace the 22k/47k voltage divider at the input. The result is it gets a bit brighter and louder. I like it quite a bit.

[ItsGiusto]

Thanks Bean! Shortly before you posted, I decided to try tracing my mini deja vibe to get an answer. I think the deja vibe's switch is a lot more simplistic than the JFET input buffer, though I'm not sure if what I've found makes sense.

The vintage/modern switch is a SPDT switch. The center lug is connected to ground. The two other lugs are each connected to a resistor on the board, which are connected to each other right afterward, when I follow the trace on the pcb. So basically this switch is just swapping out one resistor for another of a different value. The one that is "on" when the pedal is in "vintage" mode measures 33.8k on my DMM, and the one that corresponds to "modern" mode measures 73.9k.
What follows on the trace is a capacitor, and a 22k resistor, after which it goes to the input. It's really confusing to talk this all out, so I'll post a picture of the small amount of the circuit that I've traced.



To me, this seems to indicate that the switch is swapping out resistor R3 (in the Neovibe circuit) for a higher valued resistor. Is this a good diagnosis? It would definitely make the effect louder, but not necessarily brighter, unless I'm missing something. It would make sense to me that the schematic that Bean posted is more logical. But this seems to be my findings, regardless. Does it make sense that it might produce the intended effect?

[Jaicen_solo]

http://www.geofex.com/article_folders/univibe/univtech.htm