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I have a 1x12 wedge cabinet I'm repurposing into a guitar speaker cab. It has a jack plate with two 1/4" mono jacks. What I'd like to do is reset the jack plate in such a way that it can:

  1. Run directly to the onboard 12" speaker with one input cord jacked in.
  2. Run a signal to a second cabinet via the other 1/4" jack.

Both the wedge speaker and the satellite cabinet speaker are 8 ohms and the amp powering this can do 8- or 16-ohm output.

My first thought was to wire in a switched 1/4" jack that can either run a series circuit between both cabinets (16-ohm load to the amp output) or the wedge speaker by itself (8-ohm load to the amp output.) I'm not going for a stereo rig here; one cab will serve as a stage monitor and the satellite can be miked for FOH or serve as a second monitor elsewhere on the stage plot.

Can anyone offer advice (and possibly a simple wiring diagram) that might accomplish this?

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    \$\begingroup\$ You're using a lot of what appears to be audio engineer jargon here. What is a "wedge cabinet", "wedge speaker", "satellite cabinet speaker", "stage monitor", or "jack plate", and what on earth does "the satellite can be miked for FOH" mean? \$\endgroup\$
    – Hearth
    Oct 5, 2023 at 15:02
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    \$\begingroup\$ @Hearth: A stage monitor (often called a wedge) is a speaker cabinet placed on a stage in front of, and facing, the performer so they can hear themselves and the rest of the band. FOH is Front of House - the audience. \$\endgroup\$ Oct 5, 2023 at 15:29

2 Answers 2

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You find easily jacks which have a switch which shorts the jack if there's no plug. Such jacks are used to silence unused sensitive inputs so that they do not catch noises from the air. One Switchcraft type:

enter image description here

To one of your speaker boxes:

Wire 2 such jack in series with the onboard speaker. Label one jack to "input" and the other to "aux speaker" Actually the aux jack only need to have a switch. The speaker is between the tip contacts.

enter image description here

Hopefully neither of your speaker boxes have an amp inside and switches can stand the current A metallic jack mounting plate would work and the jacks could well be of the shown type. But having a switch in both jacks do not make them equal. Swapping the cables reverses the speaker polarity which can be extremely harmful - bad total freq.response, bass vanishes.

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  • \$\begingroup\$ That is now the plan. The jack plate is steel, but I found isolated switched mono jacks that have nylon bushings at plate contact. \$\endgroup\$
    – kkitchen63
    Oct 5, 2023 at 20:45
  • \$\begingroup\$ After getting all the parts together and soldering it up, EUREKA!! Did a standard Switchcraft mono jack for the input and a tip-shunted mono jack for the output to the second speaker cabinet. Both jacks are mounted to the plate with isolation washers. Tested the run with a multimeter after I had it mocked up. Impedance was read at 7.2 ohms from the input jack by itself and 14.2 ohms with the second speaker cabinet jacked in at the output jack. \$\endgroup\$
    – kkitchen63
    Oct 9, 2023 at 20:50
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I would simply wire the two jacks in parallel.

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    \$\begingroup\$ Can't do a parallel circuit. It would result in a 4-ohm resistance load at the amplifier and the amp can't do 4 ohms. It can do 8 or 16. A series circuit with two 8-ohm cabinets hits the amp with a 16-ohm load it can push. Current thought is a combo of an unswitched mono jack for amp input and a switched/shunted jack for the output cable to the second speaker cabinet. \$\endgroup\$
    – kkitchen63
    Oct 5, 2023 at 18:14

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