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Need To Replace An Oddball Jack

Posted: Thu Mar 01, 2018 5:32 pm
by Stargazer735
I'm in the process of rewiring a 1977 CM-140 and, just when I thought I had everything I need, I've stumbled across a bit of an issue: it looks like one of the jacks is pretty hard to find.

Apparently, these used a special variation of L11 jacks that were 3 terminals instead of 2, and allowed for switching between mono and stereo whenever the 2nd jack was plugged in. It's 3 terminals, but not a conventional stereo jack.

See the diagram below for reference:
http://www.carvinmuseum.com/decade/imag ... iring.html

For the life of me, I can't find this type of jack anywhere on the web. Does anyone know where I might obtain one?

Thanks!

Re: Need To Replace An Oddball Jack

Posted: Thu Mar 01, 2018 7:37 pm
by spudmunkey
Huh... I never thought much about it, but I guess I always just assumed that the mono summed to stereo split happened because of how the jacks were wired, and completing or breaking circuits, rather than a special type of Jack. :think:

Re: Need To Replace An Oddball Jack

Posted: Fri Mar 02, 2018 7:56 am
by Stargazer735
Yeah, they're special transfer jacks.

Switchcraft makes one called an L12A, but apparently, it's not the same thing.

I sent a ticket into Kiesel, but no response yet. :(

Re: Need To Replace An Oddball Jack

Posted: Fri Mar 02, 2018 12:00 pm
by UnexplodedCow
Do you have a picture of the physical jack in need of replacement?

That component layout picture looks like a regular mono switching jack (IE: the L12A).

Maybe the 14B jack will work? It's a stereo dual switching type.

Or the 13A? It's a dual switcher for mono. The positive connector either hits the ground, or passes to another output. Might be what you need. (link: https://www.mouser.com/ProductDetail/Sw ... 0UzOgSc%3D
Here's another link with more pictures: https://www.parts-express.com/switchcra ... --093-1003)

I typically use the 12A style for adding an external speaker jack to a combo amp, so it switches to the internal speaker normally, and then shuts it off to run external, so it could be used in an alternative wiring scheme that would otherwise have no sonic difference.