FET relay configuration

May 28, 2007 4 Replies

Hey all;



This is kind of picked up from the 'can I do this with a uProcessor' thread. Eeyore got talking about using JFETs as a replacement for relays. This is what I've come up with, but I'd be glad to know of a better way, since I have 4 effects to switch in and out of the signal path, thus putting a fair amount of noise and resistance in the path:


bypass comp bypass flanger in o-----------------o----------------o ---------oo-------------o | | | | | |-+ |-+ | |-+ |-+ | | | | | o ->|-+ o->|-+ | o->|-+ o->|-+ | | | | | | | | | etc | | | o | | o | o | | | | | | | | | | |-----------|----o---| | o--------|----o | | | | | | | | | | | | | | | | | | | | | ___________ ___________ control v control v control v control v


What do you think? There would be 2 more sets of 2 FETs for the remaining effects.



Thanks


(created by AACircuit v1.28.6 beta 04/19/05

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Ohhhhh the horror! :P

Is that some sort of analog multiplexer? I think the only good application I've had for JFETS is for DC current sources..

Maybe go mixer style with VCA's...

D from BC

Probably the intention is to make a clickless switch (by filtering the control voltage signals). Yep, VCAs or transconductance amplifiers, like LM13700 and the late SSM2017, are the slick way to do this.

Or CA3080; I see that's now obsolete. Pity, there were some nice uses for 'em. The newer designs (LT1228) seem like overperformers, far pricier and faster than I like.

Why not use the bog standard 4016 or 4066 bi-lateral switches? Cheap as chips !

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Long ago I heard of THAT Corp. VCA's.. D from BC

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