Mesa Boogie Stiletto Replacement Footswitch

Cacofonix

unless the plate is acting as an earth - but there isn't an obvious connection to any of the lines and the jack is otherwise isolated.

ICBM

No, there must be a not very visible ground trace! It simply would not work otherwise, since if both circuits were in series the amp could not detect which footswitch was closed, and there would be no need for a TRS jack anyway.

All other Mesa 2-button switches work like that. There are no diodes inside the switches and there's nowhere else for them to be.

Just because you appear not to be able to see a ground connection does not mean it's not there, it's probably not visible because that end of the board is not well lighted due to the shadow of the jack and so appears less translucent.

Mesa don't go in for clever sensing systems like Fender with their diode/LED circuit that works with a mono cable.

Cacofonix

Edit:  ICBM is right.

Cacofonix

Having considered all things, I figured out (unsurprisingly) that ICBM had to be right, as there had to be a non-permanent connection to sleeve.



So here it is.

On reflection, it makes sense to have an extra circuit trace rather than a cv system, with several additional diodes and resistors, at a cost equalling that of a home mixing desk.

Kudos to @ICBM for standing by his story.

camf

Nice detective work.

ICBM

camf said:

Nice detective work.

"How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth?" - Sherlock Holmes




Don't credit me, it was that logic and nothing more!

Cacofonix

But I still forgot to check which way round the diodes were.