Quick 4x12 cab wiring question

[TimWaldvogel]

existing existing cab is going from 4-16ohm speakers to 4-8ohm speakers. 
How do I wire this so I can get 2-4ohm loads in stereo or one 8 ohm load in mono without any problems?

I know I can do two 4-ohm loads by putting two in parallel. I just can't think of how to connect the 2-4ohm loads in series

[earthtonesaudio]

                        ==


Above is ASCII art symbolizing four speakers wired in series-parallel.

You can wire two pairs in series, then wire the resultant two in parallel, OR you can wire two pairs in parallel, and the resultant two in series.  Both give you a total of 8 ohms.

[8*8/(8+8)+8*8/(8+8)] = [(8+8)*(8+8)/(8+8+8+8)]

[Thomeeque]

 Maybe is Tim asking how to wire output jacks to get automatic mono/stereo switching..?

[petemoore]

  two speakers wired together equal half or double ohmage. Series wiring of resistors add to sum resistance. Parallel wiring of 2 equal value resistors = 1/2 the resistance.
  2x 8ohm in series = 16 ohms.
  2x 8ohm in series = 16ohms [say..a second set of two speakers].
   You now have 2 circuits, each with 2 speakers, each 2 speaker circuit = 16ohms.
  Consider the 1... two speaker series wiring as 'a' speaker.
  Consider the other two speaker siries wired circuit as 'a' speaker.
   The two 16ohm loads [each one now ='s two speakers] can be wired in series or parallel.
  I'd wire 'em in parallel...2x16ohm load in parallel divide by two to become 8ohm cabinet.
   Resistors of equal value can be used as substitutes for speakers as a way to test series, parallel, series/parallel or parallel/series wirings of resistances.
   Think of the two speakers wired together as an ohmage 'subgroup' or ''a'' speaker load, which can then be combined with another subgroup of two =ohmage speakers.
  No recommendation for wiring mismatched ohmage speakers in a circuit unless load-mismatch is desired.

[TimWaldvogel]

Yes sorry, I want mono/stereo in my 4x12 cab like it has now. Hut my old speakers are junk, and my replacement ones are 8 ohm.

I understand how to wire the 2-8 ohm speakers in parallel for 4-ohms. But idk how to wire two parallel loads in series.

All my amps only have 4 and 8 ohm taps. So I want 2-4 ohm loads in stereo. With a switch to put the 2 loads in series. I just don't know how to safely

[Henry89789]

I think you simply take the positive lead from one parallel load and connect it to the negative lead from the other parallel load then connect the resulting positive and negative leads to jacks in the normal way.  Try it  then test with a DMM before using it.

[Thomeeque]

 You could do something like this:



I'm pretty sure there are smarter ways*, but this should do the job. You just have to be careful not to switch speaker to the MONO mode when plugged for stereo (amps may not like it).

* E.g. "smart" J2 with lot of switched contacts maybe could replace S1 (then the speaker would be switched automatically from MONO to STEREO mode when cable plugged into J2 and vice versa), but I don't know what jacks are available for you.

T.

[TimWaldvogel]

I also posted this in get klutz and this I what I was told by someone tree. And now I think it's making sense to me. Can someone confirm?

Tim-
 
You could do it as follows:
 
You'll have 2 1/4" jacks, and one dpdt switch.
 
One jack will be left/mono, the other right.
 
On the left/mono jack, attach the positive speaker terminals of the two associated speakers to the tip, and attach the two negative terminals to the common lug on one pole of the dpdt switch.  Attach one of the throws to the sleeve of the left/mono jack.  Connect the other throw to the same throw of the other pole on the switch.
 
On the right jack, attach the positive speaker terminals to the tip, and attach these to the common lug on the second pole of the dpdt switch.  There will be no connection to the remaining throw.  Finally, wire the negative terminals to the sleeve.
 
CAUTION:  Be sure that the switch is set to stereo if you running two amps into the cabinet, otherwise the outputs of the two amps will be hooked together.  I'm not sure what would happen if you did that, but I don't think it would be good...

ALSO sorry I could not view the picture you posted prior to this

[Thomeeque]

ALSO sorry I could not view the picture you posted prior to this

Are you saying that you don't see picture from my previous post? Try this link then..

T.

[TimWaldvogel]

Sorry that one dent work either. Just a weird 404 error

[Thomeeque]

Sorry that one dent work either. Just a weird 404 error

Damn, my fault, they do no allow hotlinking. So, open http://hidemyass.com/, copy-paste image link http://thmq.mysteria.cz/diystompboxes.com/4x12_speaker_switching.gif to the address field (where is http://google.com preset by default) and click Hide My Ass! button..

Good luck, T.

[TimWaldvogel]

Your old image is on here now. As of this morning for me anyways. Thank you :-)

[TimWaldvogel]

Ok would this work right or am I connecting it wrong in my head

http://www.gearslutz.com/board/geekslutz-forum/650653-4x12-cab-mono-stereo.html

The post from me at the bottom shows the picture I drew. I couldn't figure how else to upload it from my iphone


[QUOTE from gearslutz previously] Tim-
 
You could do it as follows:
 
You'll have 2 1/4" jacks, and one dpdt switch.
 
One jack will be left/mono, the other right.
 
On the left/mono jack, attach the positive speaker terminals of the two associated speakers to the tip, and attach the two negative terminals to the common lug on one pole of the dpdt switch.  Attach one of the throws to the sleeve of the left/mono jack.  Connect the other throw to the same throw of the other pole on the switch.
 
On the right jack, attach the positive speaker terminals to the tip, and attach these to the common lug on the second pole of the dpdt switch.  There will be no connection to the remaining throw.  Finally, wire the negative terminals to the sleeve.
 
CAUTION:  Be sure that the switch is set to stereo if you running two amps into the cabinet, otherwise the outputs of the two amps will be hooked together.  I'm not sure what would happen if you did that, but I don't think it would be good...

[Thomeeque]

 Either I don't get it right or there is one connection missing for mono mode (negative terminal of the right pair leads to nowhere) plus use of dual switch makes no sense this way..

Have you tried circuit I did draw for you?

T.

[TimWaldvogel]

I was trying to figure it out. For some reason dpdt and 3pdt switches confuse me on schematic diagrams. Even for my 3pdt pedals I still had to use Beavis's diagram on their site

[Thomeeque]

For some reason dpdt and 3pdt switches confuse me on schematic diagrams.

Oh, OK, here's version with S1 pinout, maybe it will help..



Good luck, T.

[TimWaldvogel]

thank you SOOOO much. that is so simple now. thank you for taking your time out to do that for me

[TimWaldvogel]

I'll probably post a couple picture in the "custom built amps and cabs" thread in the pictures section