D.I. jack insertion relay trigger

[moamps]

And why not use 9 pin TRS with two isolated switches?

 

[Voyager10]

That one looks like the sleeve terminal (9) will be connected to the panel it is mounted on. If you're trying to keep 'signal ground' separate from 'protective earth' (a popular talking point, I understand) you won't want this type of socket.

 

[atavacron]

shield normal as logic pull-down contact. no voltage on the tip during insertion or retraction. TS/TRS agnostic. see post #20 with amphenol types.

rotary switch drawn is just one deck of multiple, with an example number of contacts. point is that DI is only enabled during certain operating conditions. as @Voyager10 noted, the input to the ULN200x could be the base of a 2N3904, collector to the coil, emitter to ground. same concept.

 

[moamps]

That one looks like the sleeve terminal (9) will be connected to the panel it is mounted on. If you're trying to keep 'signal ground' separate from 'protective earth' (a popular talking point, I understand) you won't want this type of socket.

If the sleeve needs to be insulated, these washers should be used.
https://www.tubedepot.com/products/isolation-washers-for-1-4-input-jack-flat-shoulder

 

[abbey road d enfer]

And why not use 9 pin TRS with two isolated switches?

View attachment 128396View attachment 128397

Yes, with that type of socket, there is almost no limit to the switching possibilities, no risk of damaging the source or corrupting ground, except what post #22 exposes.
I'm not sure about reliability, though, compared to the rusticity of the original Cliff (now Neutrik) design. Thousands of Vox AC30 are a testimony to that.

 

[Newmarket]

Nasty because it briefly connects the battery -ve to the tip of the incoming plug, and battery +ve (via the circuitry) to the sleeve. I'm sure a million guitars survive this treatment every day, so it's probably fine in practice.

Not getting the perceived problem here. Connecting battery / power negative to plug tip is not a problem with a guitar given that is a floating source. Sleeve connection is either no connect or to battery/power negative.

 

[abbey road d enfer]

When you insert the jack, there is a moment where the sleeve connects to the socket's sleeve and the tip of the plug hits the ring of the socket.
When it happens, the socket's sleeve is positive, due to circuit being connected to battery +.