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Analog Switches

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9/5/2004 10:57 AM
anonymous	Analog Switches Anyone have any experience using analog switch IC's for bypass switching?

9/7/2004 10:44 AM

Plenty. They work fine for some things and applications, and not so fine for others. The nicest thing about mechanical switches over CMOS/analog switches is that they need no buffering, contribute no hiss or other noise, and work fabulous after the battery dies or the wallwart supply gets accidentally knocked out of the wall.

On the other hand, analog switches can accomplish some very delicate tasks easily that might require an extremely expensive and bulky mechanical switch to do (e.g., switching cap values to make a phaser a univibe), are cheap and effective, and often do not require any buffering to make them work the way that FET-based switches do.

If a person wanted the best of all possible worlds (i.e., hissless power-failure immunity), I'd say make yourself loop-selector box with mechanical switches to remove groups of pedals out of the signal path, and use analog IC's for individual pedals where feasible.

9/9/2004 7:40 AM

Thanks for the input Mark.
I'm pretty clear on functionality. I'm interested to learn more about implementation experiences with devices like these:

http://www.alldatasheet.com/datasheet-pdf/pdf/AD/SSM2412/datasheet.pdf

http://www.alldatasheet.com/datasheet-pdf/pdf/AD/SSM2404/datasheet.pdf

The data sheets are pretty clear but I’m sure you will agree that real world experience is very valuable.

For stomp box switching, I'm pretty happy to use a 3PDT switch such as the one offered by Fulltone. But I'm also interested in exploring the use of these IC device types in remote switching applications such as you might see in a rack or amp-top mounted circuit.

So your implementation experiences with any IC packages is of interest to me.

How did you enable?
Did you need/use a NAND Gate debouncer?
Any noise issues with that?
Any noise issues overall?
Power issues?
Decoupling issues?
What was the insertion loss - if any?
Did you buffer the I/O?

Thanks,
Steve

10/27/2004 7:19 AM
Artie	This doesn't refer to the exact part #'s you mention, but it's still a great primer. Covers the basics: http://www.geofex.com/Article_Folders/cd4053/cd4053.htm

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