For analog switching different components (not 3pdt) how do you avoid pops?

[acehobojoe]

not true bypass, but what if you were wanting that pop from switching out a component in a circuit to stop?

For example, changing the input capacitor, or adding a cap to the source of a JFET, or maybe switching diodes in clipping stages,

In my experience they've always popped, and I don't much mind, but is there a way to avoid it?

[R.G.]

You avoid it by making sure that the circuit stays at the same DC conditions before and after the switch changes.

For caps, the simplest way is to put a largish (1M or more) resistor in series with the cap that will be added/removed, so it stays charged to the same DC level before and after the switch "shorts out" the series resistror.

For resistors, you put a BFC in series with the resistor, of a value suitable to make sure that the resistor  being switched does not upset the DC conditions - and that the cap is not suddenly charged/discharged.

For active devices, this gets much harder. You have to know your devices.

Finally, you can use a circuit that clamps the output to mute is slightly (~ 1mS) before and after the switch change, exchanging an instant of silence for a big pop.

[acehobojoe]

Is that what a precision clamp is? or is that completely different..

Is there some sort of device that can do the muting?

Also, The BFC is a big cap, just before the resistor and connected to the switch?

And you also were saying a resistor could be put in series with a cap, obviously, you don't mean that a 1m goes before the cap, Maybe you meant tied from the cap to the ground? or tied to one of the lugs of the switch to GND?..

Either way. this is great info!

[Eddododo]

Is that what a precision clamp is? or is that completely different..

Is there some sort of device that can do the muting?

Also, The BFC is a big cap, just before the resistor and connected to the switch?

And you also were saying a resistor could be put in series with a cap, obviously, you don't mean that a 1m goes before the cap, Maybe you meant tied from the cap to the ground? or tied to one of the lugs of the switch to GND?..

Either way. this is great info!

For the cap, i think RG was speaking about a cap shunted to ground.  For a signal-series cap i would do this in parallel with the cap:
10meg resistor -> new cap
Put a 2throw switch with the 10meg leads attached to the outside lugs, middle lug is 'input', parallel to the input of original cap.

[Eddododo]