[sdiy] idea for "almost true bypass"

[jhaible at debitel.net]

As we all know, one can make true bypass for an FX box with a 2p2t switch, which
routes the signal completely around the device when in "off" position.

The same is possible with a relay with 2p2t contacts. I often do it that way, because
you can control the relay with a flip flop from a momentary contact, and because
the relay will automatically go to bypass at power-off.

Now if I don't want to use a relay, I could use FET switching. This is often done in 
Guitar stomp boxes with "electronic" switching. But this also means that the switch
won't work properly when the power is switched off. (In stomp boxes, they often use
switching on the output only, anyway.)

What about this idea: Build a 2p2t switch from 2 JFETs and two MOSFETs,
with the JFETs forming the bypass path. Then, when the power for the FX
box is off, the JFETs will conduct (Gate floating, or connected with high impedance
to S or D) and the MOSFETs will be off.

Not true bypass, but the few hundred ohms might not hurt.

Does this work? Has anybody used it yet?

JH.