[sdiy] Simple clickless FET mute switch?

[nicolas]

The clickiness isn't really so much affected by what technology you use to switch as to when and how fast you switch.

To avoid the click it needs to be either zero-crossing.  Or be a gradual fade over at least 10ms.  10-20ms won't be heard as a fade.  A vactrol will do this naturally (especially if you have it hooked up so high resistance is the off rather than the on), but may actually be somewhat longer and be hearable as a fade.

So when you hook up the fets, try just putting an RC on the control voltage to give you that 10ms of smoothing.  Or even better a current source plus cap to give you a defined slew limiter.  But if you're wanting to keep it cheap and cheerful, the RC option with a CV swing that takes you somewhat beyond where you _need_ to go for off/on will be just as good.

Cheers,
Nicolas


--- On Tue, 16/9/08, Paul Perry <pfperry at melbpc.org.au> wrote:

> From: Paul Perry <pfperry at melbpc.org.au>
> Subject: RE: [sdiy] Simple clickless FET mute switch?
> To: synth-diy at dropmix.xs4all.nl
> Received: Tuesday, 16 September, 2008, 1:04 PM
> Maybe always leave the inputs connected, but have it go to a
> voltage divider
> consisting of a 100K resistor & a fet.
> And switch the fet either fully off, or fully on.
> 
> Mind you, if a signal is switched on or off aren't
> there going to be at
> least some artifacts, unless you switch when it is crossing
> zero?
> 
> paul perry Melbourne Australia
> 
> 
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