A/B/A-then-B switching using CMOS logic?

[easilyamused]

I have an idea I need to switch as the title suggests: Effect A, or Effect B or Effect A then B. Note this is not the "standard" A/B/Y switch as I don't want the a parallel "both"...

By the way this is for a single stompbox containing two circuits (Vibracaster, and Boobtube). At the risk of running afoul of purists I'm thinking that a cool way to do this is with a couple of 4053 ICs (triple SPDT analog switch). I would send a logic signal in the form of a 2-bit binary (00 = bypass, 01=effect A, 10=effect B, 11=effect A then B) to trigger the appropriate routing. This trigger would be created using a 4027 (dual J-K Flip Flop) to count up based on a SPST switch input.

I think the following might work... Any thoughts? Or is there a dead simple way I'm missing? I know I could just use two 3PDT's and wire it up point to point, but I kind of like the elegance of the CMOS switching, and toggling through the modes with a soft SPST might be nice...

https://www.dropbox.com/s/eb1qltckyvfzlq5/ABAPLUSB.jpg




References include: http://www.geofex.com/article_folders/cd4053/cd4053.htm

[PRR]

I trust your logic.

All your in/outs seem to have significant DC voltage, and it is rude (sometimes bad) to have DC on audio interconnects.

If you can't go for bi-polar supply (can be battery since the current demand of pure CMOS is near zero), then you want a lot of signal capacitors. Much as shown in the page you linked:

http://www.geofex.com/article_folders/cd4053/cd4053-1.gif

"the analog inputs and outputs need to be held somewhere near the middle of their power supply. ....The simplest thing to do is to AC couple the in/out pins and bias them to the middle of the 4053's power supply. In a +9V system, this only needs a two resistor divider and a cap, then a resistor and capacitor per in/out pin.
"Yes, this is a pain, eats up board space, and is complicated. It works, though. When biased this way, the CD4053 has little or no distortion and no perceptible switching pops - exactly what we want."

[easilyamused]

PRR - many thanks for pointing this out. My next step is to breadboard it, so I'll make sure to put in such caps/voltage dividers before I do anything rude

I trust your logic.

All your in/outs seem to have significant DC voltage, and it is rude (sometimes bad) to have DC on audio interconnects.

If you can't go for bi-polar supply (can be battery since the current demand of pure CMOS is near zero), then you want a lot of signal capacitors. Much as shown in the page you linked:

http://www.geofex.com/article_folders/cd4053/cd4053-1.gif

"the analog inputs and outputs need to be held somewhere near the middle of their power supply. ....The simplest thing to do is to AC couple the in/out pins and bias them to the middle of the 4053's power supply. In a +9V system, this only needs a two resistor divider and a cap, then a resistor and capacitor per in/out pin.
"Yes, this is a pain, eats up board space, and is complicated. It works, though. When biased this way, the CD4053 has little or no distortion and no perceptible switching pops - exactly what we want."