cabinet wiring help please!

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cabinet wiring help please!

Postby djhollowman on Sat Aug 10, 2013 6:19 pm

Hi all, please help a noob!
I've built a cab to house a pair of 16 ohm 75 watt Celestion G12T-75 speakers, which I want to wire exactly like a Marshall 1922 cab, ie selectable mono or stereo performance with mono being 8 ohms impedance and stereo being 16 ohms. I ordered a real Marshall 1922 socket plate which achieves these options with only two sockets - one socket is switched. I have since been told that there could be a problem in getting the Marshall plate delivered, so my question is this:
Is there another way to install and wire up a socket plate to achieve the same selectable mono/stereo configuration?
This is DIY build, and the cabinet back is blank at the moment so I'm open to any ideas, however I'm a total noob so please be very specific!
Thanks a lot!
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Re: cabinet wiring help please!

Postby Kid on Sun Aug 11, 2013 3:38 pm

Hello,
I must warn you that I am by no means an expert, but I googled a little
http://www.wikihow.com/Power-Two-Speake ... hannel-Amp and learned that speakers in parallel half the impedance. This would get your 8 Ohm mono out of the two 16 Ohm speakers. The 16 ohm stereo connection I assume is pretty straightforward. Made this little sketch for ya.
Image
I think this may be the simplest way to accomplish your goals.

A regular Stereo Jack shown on the right (2ch. @ 16 Ohm).

A Mono switching jack placed in the MIDDLE of the blue connection that must BREAK the positive connection when nothing is inserted. Vice-Versa it will CONNECT the Parallel 8 Ohm mono Channel when you Jack in.

Hope this helps.....
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Re: cabinet wiring help please!

Postby Kid on Sun Aug 11, 2013 4:27 pm

Simplify the wiring even more - eliminate the negative wire shown between the two speakers. Jumping from Jack to Jack will give the same connection, saves a little wire.....
:cheers:
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Re: cabinet wiring help please!

Postby gusfinley on Mon Aug 12, 2013 3:58 am

I built something like this for my 2 x12 cab when I had it. I had a jack plate with two jacks. One Jack went to each speaker. Then I installed a switch between them to wire them in parallel, so they could both be used. My purpose was to isolate the speakers for recording.

To eliminate error/confustion, I think it would be best to have three jacks: one for 8 Ohm Mono, one for 16 Ohm Left, one for 16 Ohm Right. Plug in one cable and you have three options (8 Ohm Mono, 16 Ohm Left, 16 Ohm Right). Plug two cables into ANY two Jacks and you will ALWAYS get 16 Ohm Left and Right.)

If you want to copy the Marshall 1922 approach, here are a few pics from the web:

Image

Image
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Re: cabinet wiring help please!

Postby Papa Dog on Sat Aug 17, 2013 8:48 pm

gusfinley wrote:I built something like this for my 2 x12 cab when I had it. I had a jack plate with two jacks. One Jack went to each speaker. Then I installed a switch between them to wire them in parallel, so they could both be used. My purpose was to isolate the speakers for recording.

To eliminate error/confustion, I think it would be best to have three jacks: one for 8 Ohm Mono, one for 16 Ohm Left, one for 16 Ohm Right. Plug in one cable and you have three options (8 Ohm Mono, 16 Ohm Left, 16 Ohm Right). Plug two cables into ANY two Jacks and you will ALWAYS get 16 Ohm Left and Right.)

If you want to copy the Marshall 1922 approach, here are a few pics from the web:

Image

Image


The above picture is the correct way to wire that cab. The only issue is that thew numbers are wrong. It should say 8 ohms mono and 16 ohms x 2 sterio.
Last edited by Papa Dog on Sun Sep 01, 2013 7:29 pm, edited 2 times in total.
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Re: cabinet wiring help please!

Postby djhollowman on Tue Aug 20, 2013 6:27 am

Hi all, and thanks for the helpful replies!
I actually got the Marshall plate in the end, and it's wired up and working well.
I can post pics of the completed project later for anyone interested?
Thanks,
DJ
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Re: cabinet wiring help please!

Postby Kid on Tue Aug 20, 2013 3:15 pm

Don't know how helpful I was, am a novice bassist. Don't really know anything about gear. Good to hear that you got it sorted. :cheers: I'll certainly check it out if you post some pics, as I am building a cabinet myself.
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