Ross Vibrato Mod question

[jimbob]

This is for the Ross vibrato mod=

Mark wrote, "How to accomplish this?  One way is to take the 27k resistor out completely, and install two wire leads to the pads for that resistor.  Solder a 27k resistor to one of the lugs of a SPST switch (toggle, slide or stomp), put some heat shrink around the resistor and lug to secure it and prevent it from snapping during installation, and you're done.  Naturally, the unshrunk heat shrink needs to be slipped over the wire BEFORE you solder it to the free end of the resistor."

I did this and I cant seem to notice a difference in sound? Is it supposed to be like this? It seems to phase either way I toggle it. I did just as the mod explains. I took the 27kresistor that sits below the 470k and placed 2 wires in those pads. From there I put a 27k between the lud and the wire and connected the other remaining wire from the other pad to the other lug of the spst switch.

[Mark Hammer]

Well, just to make sure you have a reference to recognize the vibrato when it happens, just completely pull the 27k resistor under discussion and listen.  You should get a wobbly sound.  Best if you turn down the resonance for that listening test.

[jimbob]

This might be a dumb question but - does it matter of the switch Im using is a spst on/off switch?

[Mark Hammer]

Dumb is charging ahead without being sure, my friend.  You know the old adage about measure twice, cut once?

Yup, a SPST is precisely what the doctor orders.  You CAN use other switches, but two contacts is all you really need.

[jimbob]

great thanks!