Harmony Central Forums
Announcement Announcement Module
Collapse
No announcement yet.

Can you help me wrap my brain around wiring some jacks?

Page Title Module
Move Remove Collapse







X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts

  • Can you help me wrap my brain around wiring some jacks?

    I'm wiring some jacks on the inside and outside walls of my little recording booth (for being able to have a sound-proof pass-through for cables) and am having a very difficult time wrapping my brain around which terminals get soldered to which terminals. Each wall will have 2 male and 2 female XLR jacks (for close-field monitors and microphones), 2 female 1/4" jacks (for my vintage microphones that use 1/4" plugs, as well as for instruments), a double-ended VGA cable with one end mounted on each side (for the computer monitor), and will need to have 3 female USB jacks (trackball, keyboard and Behringer control surface) -- unless it's possible to have 3 different USB devices share the same USB line (in which case -- 1 USB jack on each side).

    Here's the problem: I can't figure out which pins on the back of the XLR jacks need to be wired to which pins on their corresponding partner on the other wall! There are 3 on each, of course, but should they be mirror images of each other (when back-to-back), or directly across, or what? And what the heck is wrong with my brain, to not be able to figure that out?!

    Also, for the 1/4" jacks -- I could use either regular 2-contact phono jacks, or T-R-S, or 2-contact phonos that have the extra do-hickey on them that opens a contact when a plug is in place (a ground for bypass?). None of my instruments use T-R-S jacks, so I don't see how T-R-S would be an advantage, but then again, what do I know? And either way, do tips get soldered to the sleeves of their corresponding jacks across the wall, or tips-to-tips? Brains...Must get brains.

    Can anyone advise?

    Thanks!

  • #2
    As for the 1/4" I would try standard jacks to begin with. I haven't worked with XLR other than to just plug the things in. Use an ohm meter to determine which pin is which. Then wire them up.
    It's 4am woman make up your mind. EITHER SPIT IT OUT OR SWALLOW IT!!!

    Comment


    • #3
      Some jacks have very small numbers molded into the plastic base to identify each contact. If you don't have those, just put some numbers on yourself. Lay the jacks out side by side and wrap some masking or "writable" tape around the body and number each contact in sequence - do every jack the same. Regardless of how you orient them, #1 goes to #1, 2 goes to 2, etc..

      I'm not sure about the 1/4" vs phono plug question. If you need shielding, and you're not going to be plugging / unplugging them all the time, the phono will probably do better. If you don't need a shielded (coax) line and/or they will pulled and plugged all the time I'd use 1/4". They will take a lot more abuse.

      Tip to tip, sleeve to sleeve.

      Comment


      • #4
        The easiest way is to pull the cover off a mic cable that would plug into th jack Write down the connections to the pins. The pins are numberd on your better switchcraft type jacks. You can wire the jacks by the numbers if they have them.

        If not heres the connections if you face the soldering side of the wall jacks.

        Hold the jack so the center pin is on top. The left pin will be a clear wire. The center the red, the right the ground. Wire both jacks the same when facing them from the soldering side.

        In case the core wires are different colors, you can substitute the two core wires and use say a black wire on both lefts, and clear for both centers. just keep the grounds on the right of both.

        The 1/4" jacks stay tip to tip, ground to ground, and ring to ring if you're using the third wire.

        For the USB, I'd use an extension cable mounted in the wall through a hole and forget about trying to solder in jacks. Just plug into the extension cable.

        I personally would get a wireless keyboard and mouse or track ball. They were a godsend in my studio and can operate over a long distence. (At least as far as you can see the monitor screen.

        Comment


        • #5
          I don't know what happens when the length is too long but VGA cables have a maximum distance (which is related to the resolution being used). I discovered that when I wanted to use the VGA input on the LCD television to connect the laptop's VGA output. I bought a VGA extension cable and although it worked, I know it exceeded the max length for the 800x600 I was using it at, and I did have funny scanlines scrolling every so often, much like you see when you are watching television and there is a CRT monitor being shown, you see the scrolling lines because the camera picked them up when filming it. It may have been a coincidence for me or may have been related to the excessive cable length. So factor that in when adding a VGA port. Too bad it's not HDMI or something. My newest motherboard has HDMI and I'd be using that if I were doing anything like this.

          Comment


          • #6
            Thanks!

            As for the 1/4" I would try standard jacks to begin with. I haven't worked with XLR other than to just plug the things in. Use an ohm meter to determine which pin is which. Then wire them up.

            Comment


            • #7
              Ah! I hadn't seen those tiny numbers, but under a magnifying glass, they're there! That'll help a lot. And thanks for clearing up the connection sequence.

              Some jacks have very small numbers molded into the plastic base to identify each contact. If you don't have those, just put some numbers on yourself. Lay the jacks out side by side and wrap some masking or "writable" tape around the body and number each contact in sequence - do every jack the same. Regardless of how you orient them, #1 goes to #1, 2 goes to 2, etc..

              I'm not sure about the 1/4" vs phono plug question. If you need shielding, and you're not going to be plugging / unplugging them all the time, the phono will probably do better. If you don't need a shielded (coax) line and/or they will pulled and plugged all the time I'd use 1/4". They will take a lot more abuse.

              Tip to tip, sleeve to sleeve.

              Comment


              • #8
                Thank you for all the good advice! It'll make me a lot more confident in soldering the jacks up.

                The easiest way is to pull the cover off a mic cable that would plug into th jack Write down the connections to the pins. The pins are numberd on your better switchcraft type jacks. You can wire the jacks by the numbers if they have them.

                If not heres the connections if you face the soldering side of the wall jacks.

                Hold the jack so the center pin is on top. The left pin will be a clear wire. The center the red, the right the ground. Wire both jacks the same when facing them from the soldering side.

                In case the core wires are different colors, you can substitute the two core wires and use say a black wire on both lefts, and clear for both centers. just keep the grounds on the right of both.

                The 1/4" jacks stay tip to tip, ground to ground, and ring to ring if you're using the third wire.

                For the USB, I'd use an extension cable mounted in the wall through a hole and forget about trying to solder in jacks. Just plug into the extension cable.

                I personally would get a wireless keyboard and mouse or track ball. They were a godsend in my studio and can operate over a long distence. (At least as far as you can see the monitor screen.

                Comment


                • #9
                  I ended up getting a 20-foot VGA cable and, in lieu of being able to find VGA wall jacks, I took a 3-foot VGA cable and attached the connector at each end to one of the jack plates, with the cable coiled up inside the wall. Connecting the workstation to the outside "jack" is another 6-foot VGA, so a total run of under 30 feet. Hopefully that won't be a problem. Frankly, given the rest of my half-assed set-up, "funny scanlines scrolling" would be the least of my worries! As long as the screen is readable, I'll be happy.

                  Thanks for the info!

                  I don't know what happens when the length is too long but VGA cables have a maximum distance (which is related to the resolution being used). I discovered that when I wanted to use the VGA input on the LCD television to connect the laptop's VGA output. I bought a VGA extension cable and although it worked, I know it exceeded the max length for the 800x600 I was using it at, and I did have funny scanlines scrolling every so often, much like you see when you are watching television and there is a CRT monitor being shown, you see the scrolling lines because the camera picked them up when filming it. It may have been a coincidence for me or may have been related to the excessive cable length. So factor that in when adding a VGA port. Too bad it's not HDMI or something. My newest motherboard has HDMI and I'd be using that if I were doing anything like this.

                  Comment


                  • #10
                    OK, now I've got both mounting plates set up with the jacks, and the jacks wired together. The 1/4" jacks are T-R-S, and I have the tip and ring terminals wired to their corresponding jacks on the opposite side (the sleeve terminals are unused), but unfortunately, when I plug anything into either of the jacks, and the other end into an amp, I get a hellish hum.

                    Is there some way to knock out the hum -- perhaps grounding the jacks to something?

                    Comment


                    • #11
                      If this is just a short "through the wall" run, my first thought would be to go back and check to be absolutely sure you didn't reverse a connection somewhere. Are you getting any audio, or is it hum only? If it's hum only I'd suspect the bad connection. If the audio is there with hum over it you may have to look at the kind of cabling your using, length of cables, etc..

                      edit: If you have a multimeter, check your cable runs, as far as is possible with everything plugged up. Check for continuity on each wire as close as possible between the source and the termination point.

                      Comment


                      • #12
                        yes it does sound like a bad ground or the guitar jacks in the wall are reversed. as some other thoughts, the wire in the wall to connect the two jacks must be shielded like guitar cable, and the hot tips of the jacks themselves cant be touching anything or it will add hum like you get touching the tip of a hot guitar jack.

                        The other thing that comes to mind is having a CRT cable near the mic and guitar jacks. Its going to generate a huge amount of EMF hum. Running the CRT cable 5' or more away from the guitar jacks might be the best solution there. (or putting a grounded led glass window and having the monitor on a shelf in front of the window)

                        Are you running two video cards so you dont have to swap wires inside or outside the booth?

                        Comment

                        Working...
                        X