Soldering help - never seen an input jack like this

[fourstr00]

My Carvin’s jack is getting scratchy so I ordered a standard stereo Switchcraft jack to replace it. I (wrongly) assumed I could just solder like to like and be done with it.

When I pulled the old jack, I found this:

 

[fourstr00]

For reference, here’s what I was expecting. Any idea on which posts correlate?

 

[Michedelic]

For reference, here’s what I was expecting. Any idea on which posts correlate?

View attachment 3780408

One thing at a time; the ‘scratchy’ is more likely to be from dirt in the pots, not the output jack, unless it occurs when you wiggle the 1/4” jack at the end of your cable. The black heatshrink covered connctions, by the looks of it, are not solder points, but this kind of clip...

which slip onto the tab of the jack. More often seen on speaker cable ends, with the heatshink surrounding it, it should remain a solid connection. So, that covers the green and white lines. The two black/ground wires seem to be both soldered to a common termination point, but it looks like it might be a little too close to the contact point for the ‘tip’ of your cable jack(the curved part), which might cause some shorting issues. I’d have to see more photos, but it looks like the original is a switching jack, the replacement is not. Is the bass active?

 

[fourstr00]

Thanks - Bass is active (Carvin AC40, semi-hollow with a piezo). The jack does introduce noise, although the pots are next on the list. Connections are fairly oxidized and patch cables don’t sit tightly.

I’m not familiar with switching jacks but that would make sense.

 

[El Güero]

It's an output jack, btw. Signal out.

 

[Bill Staudt]

It does look like a switching stereo jack. It also looks like two lugs are jumpered together, so your new jack might still work.

 

[ctmullins]

It does look like a switching stereo jack. It also looks like two lugs are jumpered together, so your new jack might still work.

It looks to me like a switching mono jack.

I see four conductors. Two of them are straightforward:

• Signal (tip connector)
• Ground (sleeve connector)

The other two are the ones that do the switching. On your original jack, when you fully insert the cable, the tip of the cable plug pushes against that small plastic disc, causing the two arms to make contact, and complete the circuit. I'm guessing that the circuit that they complete is the ground path for the battery negative.

The usual way to do this is with a stereo jack, with the battery negative connected to the ring connector; the sleeve of a two-conductor tip-sleeve (TS) cable plug connects the ring terminal to the sleeve, which completed the battery ground circuit.

 

[robert43]

Its a switch stereo jack like Bill said is the same that Rick used for there Rico sound

 

[ctmullins]

Its a switch stereo jack like Bill said is the same that Rick used for there Rico sound

Not a stereo jack.

 

[fourstr00]

Thank you! So I’m thinking:

black wires to ground
Green to tip
White to ring

does that sound right?

 

[ctmullins]

It's hard to tell from your photos, but it looks like your current jack has:

• White to tip
• Black to ground
• Green to switched contact

Which would translate to, for the Switchcraft stereo jack:

• White to tip
• Black to ground
• Green to ring

Double-check me on this, though, please!

 

[fourstr00]

Since the tip and ring are just completing a circuit to turn on the preamp, does tip or ring matter?

 

[ctmullins]

Since the tip and ring are just completing a circuit to turn on the preamp, does tip or ring matter?

PLEASE be careful.

Tip is signal hot, not ground.

Please don't connect your tip to ground. Best case you get no sound; worst case you could damage the preamp.

 

[JeezyMcNuggles]

For reference, here’s what I was expecting. Any idea on which posts correlate?

View attachment 3780408

I dont see the difference

 

[Jeff Scott]

Its a switch stereo jack like Bill said

Todd is correct, it is a mono jack with a switch. Quite obvious, too, as there is only one signal tang.

 

[byacey]

It's a mono jack with an isolated set of switching contacts. It can be used for switching current on and off without being referenced to ground, unlike the typical TRS jacks usually used for switching the negative battery lead to ground. With such a jack, you could switch the positive lead on the battery while leaving the preamp ground permanently connected.

The advantage is you don't get a full 9 volt signal pop should a plug get pulled with the amp level turned up.

 

[AndyPanda]

Without a schematic (or without tracing the circuit out) you just don't know what the switch does. Most instruments use the ring connector of a stereo jack (like the one you pictured as what you expected to find) to short the battery negative to ground. But the isolated switch on the jack you found in the instrument doesn't necessarily connect the battery negative to ground... for all you know it connects the battery positive to the preamp.

Jacks like that don't really need to be replaced often, just clean it and put it back in. If you have some deoxit contact cleaner just clean all the contacts.

 

[ctmullins]

Good point, @AndyPanda - my earlier comment about the switch controlling the battery negative was an assumption that needs verification.

 

[Ewo]

I don't have the bass anymore, but my SB5000 had an output jack like that--there's two spring contacts that get shorted together when the plug is inserted. The innermost leaf with the plastic pad rides the sleeve of the plug, and gets pushed into the outermost leaf. When I received the bass (used), the switch was cranky and made popping noises if I touched the guitar cord.

It was easy to fix. First I cleaned all the contact points with Deoxit D5 on a cotton swab. Then I bent the outermost leaf inward just a teeny bit, so they made firmer contact.

Worked on mine, anyway.

 

[Michedelic]

My Carvin’s jack is getting scratchy so I ordered a standard stereo Switchcraft jack to replace it. I (wrongly) assumed I could just solder like to like and be done with it.

When I pulled the old jack, I found this:
View attachment 3780403 View attachment 3780404

It looks to me like a switching mono jack.

I see four conductors. Two of them are straightforward:

• Signal (tip connector)
• Ground (sleeve connector)

The other two are the ones that do the switching. On your original jack, when you fully insert the cable, the tip of the cable plug pushes against that small plastic disc, causing the two arms to make contact, and complete the circuit. I'm guessing that the circuit that they complete is the ground path for the battery negative.

The usual way to do this is with a stereo jack, with the battery negative connected to the ring connector; the sleeve of a two-conductor tip-sleeve (TS) cable plug connects the ring terminal to the sleeve, which completed the battery ground circuit.

That above explains it better than I could, but in the long run, if you need to, you should contact Keisel and talk to them about what’s going on. In the unlikely event that you would have to replace that output jack, you should get it from them. Yes, you should get some D4 to spray out not only the pots but the jack with all of its contact points, but since an electronics store probably won’t be open right now, get some contact cleaner from Home Depot or Lowes, usually found where all the wiring supplies are.
Do it outside or in a well-ventilated area, if you can spare some latex gloves, wear ‘em, don’t get that stuff on your skin. If you do, wash your hands immediately. With that jack disassembled as in the pix, as you spray insert the cable jack, in/out a few times.
Another thing to do, very carefully, is to gently bend the ‘hot’ prong, the one with the curled end where the plug tip settles in and ‘clicks’, in toward the center, but not too far. Use a pair of pliers at the base, down at the ring, but once again, easy does it. Over the years, repeated in-and-out of cable plugs push that outward, decreasing the tension holding the plug in place, and decreasing the angle of the sleeve portion of the plug, diminishing or making loosey goosey the contact with the ring portion of the output jack, which is the ground.
One last thing...for better communication, I would refer to that extra replacement jack as TRS, ‘tip/ring/sleeve’(or 3-conductor); while yes, it can be used as a stereo audio out, that’s just one function, and use of the word ‘stereo’ has led to a lot of confusion here. I looked online at the AC40 specs, and nowhere did I see mentioned that was “stereo out”. You use a standard(2-conductor)audio/guitar cable, right? The jack that’s in the bass is a tip/sleeve(2-conductor) switching output, ‘switching’ to disrupt the battery circuit when not plugged in.