Author Topic: Smoothie 2020: vibe mod on a toggle switch?  (Read 489 times)

sjaustin

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Smoothie 2020: vibe mod on a toggle switch?
« on: July 19, 2020, 06:50:06 PM »
I'd like to do the "Univibe" mod on a toggle switch, but I'm not totally sure what to do. The instructions say:

Quote
• There are two pads outlined next to Q2. You can ignore these. I had intended this to be a mod for a “Univibe” switch but in my haste to complete the layout I accidentally attached them to the wrong cap. D’oh!
• If you want to do the Univibe mod make C2 10n and C3 100n.

Would I have to wire one switch to toggle both of those caps between these Univibe values and the stock values? Having trouble picturing how to do that.

madbean

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Re: Smoothie 2020: vibe mod on a toggle switch?
« Reply #1 on: July 19, 2020, 07:04:38 PM »
For a Univibe mod you want to have the phase stages at a 10:1 ratio. So, C2 and C3 need to be 10:1. Or 1:10. It doesn't matter which order it's in. When I put those extra pads in I was blazing through the design and didn't realize until later I put them on the wrong caps!

The easiest way to achieve the mod on the Smoothie is to switch out C2 for a 4n7. Or, you could toggle b/w 4n7 and 47n using a mini SPDT switch.

sjaustin

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Re: Smoothie 2020: vibe mod on a toggle switch?
« Reply #2 on: July 20, 2020, 09:02:46 AM »
For a Univibe mod you want to have the phase stages at a 10:1 ratio. So, C2 and C3 need to be 10:1. Or 1:10. It doesn't matter which order it's in. When I put those extra pads in I was blazing through the design and didn't realize until later I put them on the wrong caps!

The easiest way to achieve the mod on the Smoothie is to switch out C2 for a 4n7. Or, you could toggle b/w 4n7 and 47n using a mini SPDT switch.
Ah, so when the two caps are the same value, the effect acts like a phaser, and when they're 10:1, the effect acts like the vibe—so toggling one of them between equal and 10x (or .1x) is the way to have access to both sounds. I think that makes sense.

Wouldn't I need a DPDT, though? One cap on each end, with the common row wired to the PCB? BTW, I'm putting this in a multi-effect box, so space is not a concern.

madbean

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Re: Smoothie 2020: vibe mod on a toggle switch?
« Reply #3 on: July 20, 2020, 09:55:55 AM »
No, you only need an SPDT.

There are actually three different ways you can do the switch mod but this one is the more common, I think. The two 2M2 resistors are only if the switch pops when you toggle it (they help keep all the switch contacts at approximately the same voltage levels).