PIC based silent switching switch matrix

[R.G.]

I'm unsure what you mean here. Let me see if I've got this straight:
D = 0v
S = 0v - so do you ground the drain and source (through a 1 meg or so resistor I'm assuming)?

Correct.

Should this read 'pulling the gate up ...' or 'pulling them up....' (as in the drain and source)?

Gate.

If gate is the answer, you basically use these the same way I was trying to use the MOSFETs, only with reverse logic? IOW:
D = 0v
S = 0v

G = 0v for on
G = 5v for off.
Is that right?

Yes.

If so, could this type of JFET be driven directly from a PIC?

If and only if you use a P-JFET with a Vgsoff of less than 5V. Otherwise the PIC can't pull the gate high enough to turn the channel off reliably.

And, with the drain and source at 0v (instead of at 1/2 V+) is there any clipping of the incoming signal?

This is **exactly** the same as using N-channel JFETs biased at +4.5V or +9V or +50V); any clipping is a result of using signals on the same order as the Vgsoff voltage of the JFET. Low Vgsoff of 2-5V is desirable for making them easy to use in a 9V circuit, but high Vgsoff is desirable for good off isolation. Yep, the two objectives are diametrically opposite and you have to make compromises.

That said, it works fine with guitar signals and Vgsoff of 4-5V.

Is it possible to ask so many questions in the same post?

Yes. Actually, it's possible to ask more. 

On the other hand, it's also possible to use relays dead quietly. I've both done it and seen it done. There is something else you don't understand going on in your switcher. But you knew that already.

[MoltenVoltage]

On the other hand, it's also possible to use relays dead quietly. I've both done it and seen it done. There is something else you don't understand going on in your switcher. But you knew that already.

Try using a relay all by itself and you will see that it is possible.  You won't even need the diode if you use a battery without a common ground.  Just connect the jack tips to the relay switch and the connect the audio grounds (sleeves) together.

Once you get that piece of the puzzle solved, add more parts until you find your mistake.

[R.G.]

Try using a relay all by itself and you will see that it is possible.  You won't even need the diode if you use a battery without a common ground. 

If you mean the diode on the coil, actually you will still need it. The stored energy in the coil is perfectly capable of killing the driver unless there's a catch diode there to shunt the coil energy harmlessly away from the driver.

[MoltenVoltage]

Try using a relay all by itself and you will see that it is possible.  You won't even need the diode if you use a battery without a common ground. 

If you mean the diode on the coil, actually you will still need it. The stored energy in the coil is perfectly capable of killing the driver unless there's a catch diode there to shunt the coil energy harmlessly away from the driver.

Good point.

I wasn't talking permanently, just for the sake of proving that relay switching can be silent.

[tempus]

On the other hand, it's also possible to use relays dead quietly. I've both done it and seen it done.

I'm sure it is. However, since I need to rebuild my board anyway, I thought I'd look at other options. Let's face it, electronic switching is cool. So at home already I've got:

SPDT relays
DPDT relays
mosfets to drive relays
ULN2003 to drive relays
CMOS analog switches

I need to order a uP from Mouser, so I figure I may as well order some JFETs and give those a try as well.

From a very basic "where is that pop coming from" perspective, let me ask this: If you are using relays, or JFETs or whatever, and you just touch a wire that has the control voltage on it to the relay driver control or JFET gate, do you get a click in the signal?

Maybe this will help me chase down my clicks and pops and hopefully prevent repeating my previous mistakes.

Thanks