Needed wiring info for amp cabinet(s).....

Jerry Hayes R.I.P. · Post by **Jerry Hayes R.I.P.** » 3 Apr 2006 10:33 am

I've ran into a problem with wiring a couple of of Kustom speaker cabinets. I bought an old Kustom 250 piggyback rig with one cabinet that didn't have any speakers in it. The guy gave me a Peavey 4-12 cabinet that had Shefields in it that I could transfer into the Kustom Cabinet. A friend of mine saw the blue sparkle tuck and roll rig and said he and a matching cabinet that I could have which only had two speakers in it and two open holes for speakers. I found a couple of 8 ohm speakers for that cabinet. Today I started to put the whole thing together and I removed the speakers from the Peavey cabinet and found that they were 16 ohm. What my dilema is, is that I have two 4-12 Kustom cabinets and 4 each, 16 ohm speakers, and 4 each, 8 ohm speakers. How can I wire this up so that each cabinet would have 8 ohms at the jack on the back. would I put all the 16 ohms in one cabinet and all the 8 ohms in the other, or mix them or what? Also how would the wire have to be routed to each speaker? Thanks in advance..........JH in Va.

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Don't matter who's in Austin (or anywhere else) Ralph Mooney is still the king!!!

James Quackenbush · Post by **James Quackenbush** » 3 Apr 2006 11:40 am

Jerry,
I don't think you can do it, but I could be wrong ....I did the figures for your cabinets wired in Parallel, Series , and in Series /Parallel but could not come up with 2 sererate cabinets with the same ohms , never mind seperate cabinets running 8 ohms .... Maybe some of our speaker Pro's have a way ??....Sorry I couldn't be of more help .....Jim

Jon Light (deceased) · Post by **Jon Light (deceased)** » 3 Apr 2006 12:30 pm

You can get your 4--8ohm speakers to 8 ohms but I don't see a way to get 4--16's to 8 ohms. 4 ohms or 16 ohms is the only way I can see it.

Bob Knight · Post by **Bob Knight** » 3 Apr 2006 12:38 pm

Wire 1 pair 16 ohms in paralell =16ohms
wire the other pair paralell =16ohms.
wire the 2 pairs in series and you should have 8 ohms.??

Bill Crook · Post by **Bill Crook** » 3 Apr 2006 12:41 pm

Bob is correct !!!!!

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Jon Light (deceased) · Post by **Jon Light (deceased)** » 3 Apr 2006 12:43 pm

1 pair 16ohm in parallel = 8ohms

Bob Knight · Post by **Bob Knight** » 3 Apr 2006 6:44 pm

Jon,
You better listen to Bill.

David Doggett · Post by **David Doggett** » 3 Apr 2006 8:04 pm

Two 8 ohm speakers in series = 16 ohms. Run that circuit in parallel with one 16 ohm speaker and you get an 8 ohm 3-speaker cab. I can't figure any way to get 4-speaker 8 ohm cabs.[This message was edited by David Doggett on 03 April 2006 at 09:42 PM.]

John Daugherty · Post by **John Daugherty** » 4 Apr 2006 10:24 am

Bob, Jon is correct. (2) 16 ohm speakers in parallel is 8 ohms. You better listen to Jon.

Jerry Hayes R.I.P. · Post by **Jerry Hayes R.I.P.** » 4 Apr 2006 11:14 am

I'm a dummy in electronics and such but good with a soldering iron. What does it mean "in parallel"? Is that when you have two speakers and go to the positive terminal, out the ground to the positive of the other speaker and out the ground of the second speaker and then back to the jack, or what? Can someone tell me exactly how the wireing would go as I'm not sure what the correct terminology is....Thanks, JH in Va.

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Don't matter who's in Austin (or anywhere else) Ralph Mooney is still the king!!!

Michael Holland · Post by **Michael Holland** » 4 Apr 2006 11:22 am

Here's a page I googled, Jerry. It explains series and parallel wiring.
http://www.rocketroberts.com/techart/spk_wire.htm

David Doggett · Post by **David Doggett** » 4 Apr 2006 11:24 am

Run two 16 ohm speakers in parallel = 8 ohms. Run two 8 ohm speakers in parallel = 4 ohms. Run the 8 ohm circuit in parallel with the 4 ohm circuit and you get a 2.67 ohm 4-speaker cab (I originally said 6 ohms, which is wrong). If you run the two 2.67 ohm cabs in parallel, the amp sees 1.34 ohms, which is too low for a 4 ohm amp. Run the two 2.67 ohm cabs in series and you get a 5.33 ohm load on the amp, which I think is tolerable for most 4 ohm amps. But that's just my surmise from what I've read here on the Forum. Check with a real electronics guru like Ken Fox or Brad Sarno before trying this.[This message was edited by David Doggett on 04 April 2006 at 04:26 PM.]

Donny Hinson · Post by **Donny Hinson** » 4 Apr 2006 11:24 am

This'll explain it...
http://www.termpro.com/articles/spkrz.html

Jon Light (deceased) · Post by **Jon Light (deceased)** » 4 Apr 2006 11:47 am

Bob--you better listen to John.

David---I'm on thin ice here because I don't really "know" a lot of this stuff. I've only learned it...a small distinction....but I used to make the same mistake but was corrected: your final step of running 8 and 4 in parallel to yield 6ohms is a natural brain twist that is not correct. I believe the actual result is 2.666ohms
Zt = (Za x Zb) / (Za + Zb)

This graphic covers the same ground as Michael Holland's link:

[This message was edited by Jon Light on 04 April 2006 at 12:53 PM.]

David Doggett · Post by **David Doggett** » 4 Apr 2006 3:19 pm

Okay, back to the drawing board. According to my physics book the total resistance of 8 ohms and 4 ohms in parallel is: 1/R = 1/8 + 1/4, and R = 2.67 ohms. So, no you wouldn't want to run two 2.67 ohm cabs in parallel (1.34 ohms) into a 4 ohm amp. You could run the cabs in series for 5.33 ohms, which would be okay with most 4 ohm amps. I guess I better go back and correct everything above so nobody gets the wrong idea.

[This message was edited by David Doggett on 04 April 2006 at 04:21 PM.]