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mlr
06-22-2007, 10:28 PM
Hi!

I have a pair of Carvin 4x12 guitar cabinets that each run 4-16ohm Celestions. These are very early '70's vintage, with exceptional versions of Celestions, and heavy, sealed cabinets. They have a fantastic sound when wired to 4 ohms and used in stereo, and a mean heavy crunch at 8ohm (sum/2 16ohm cabs) in bridged mono. However, it's a bit time consuming stopping to rewire the cabinets especially during a gig...ha ha.

Can someone lay down the skinny on how to wire these so that I could switch each cabinet from 16ohm, to 8ohm, or to 4ohm? I had a Randall 2x12 cabinet that had a switch that allowed one to change from 8ohm to 4 ohm at will, so I know it's possible, just beyond my technical level to figure out.

If possible, I'd like to have the capability to select (via a switch/switches on each) each cabinets ohm rating at my discretion depending on how I want to configure (ie: both cabinets running in stereo, split mono, bridged mono, or using only 1 cabinet). It doesn't matter to me how many switches it would take, although, if possible, I'd prefer to avoid having to switch from one speaker jack to another (on the cabinets... obviously this would be required if running both in series).

If it's possible, it would also be cool to be able to flip a switch and split a single cabinet from 4x12's, to 2 2x12's and use a single cabinet in stereo. Of course that would require an additional speaker jack for connection to the amp.

If someone could help me out with this I would appreciate it immensely. A simple wiring diagram would greatly aid in the chance of success on my part as well. Any input would be great. Thanks very much in advance.

Regards,
Mike

Mr. Widget
06-22-2007, 11:33 PM
If you wire four 16 ohm woofers in parallel you will have a 4 ohm load.

If you wire two pairs of your 16 ohm woofers in parallel and then wire these two pairs together in series you will have a 16 ohm load.

Or...

If you wire two pairs of your 16 ohm woofers in series and then wire these two pairs together in parallel you will have a 16 ohm load.

A quick google search yielded this:

http://colomar.com/Shavano/speaker.html

Hope this helps.

Widget

Fred Sanford
06-23-2007, 06:18 AM
Keep looking around on that site, more stuff for your purposes:

http://www.colomar.com/Shavano/4speaker.html

http://colomar.com/Shavano/stereocab.html

...wiring/switching all the permutations you desire at once would be pretty complex, but the diagrams on these sites give you guidance for the mono/stereo configs at the least.

je

mlr
06-23-2007, 06:29 AM
Hi Mr. Widget, and thanks.

Yes your info helped. Not so much in regards to my question, but regarding my failure to grasp how efficient 'google' actually is. My wife keeps bugging me to enter the 21st century, but it's a tough climb for a fellow trying to acclimate himself to the 20th! HA HA.

Anyhoo... I know how to achieve a specific load by wiring the speakers, what I don't know how to do is wire them with a switch/switches so that I might shift the load from one level to another by flicking the switch.

I just tried 'googling' the phrase: "flicking the switch" but all I got was "does your mother know your playing with the computer?".. and I'm fairly certain that somewhere deep in 'geek squad' HQ there's a big map on the wall with a blinking red light, a sign indicating a change to 'def con 2', and some big shot yelling "will someone please turn off that damned alarm!". HA HA!

Thanks all the same. I appreciate you taking your time to try and help me with this.

Regards,
Mike

boputnam
06-23-2007, 10:06 AM
It doesn't matter to me how many switches it would take...Well, it seems you stumped the forum, Mike!

The problem I'm having with one switch, is the need to completely disconnect say, series connections to go to parallel. There may be a clever solution but I'm thinking you need one switch per speaker (or a ganged switch) which seems not a great deal "smarter" than re-wiring each time.

I posted the two configurations to help visualize this question - maybe it will give someone an idea...

toddalin
06-23-2007, 11:25 AM
Well, it seems you stumped the forum, Mike!

The problem I'm having with one switch, is the need to completely disconnect say, series connections to go to parallel. There may be a clever solution but I'm thinking you need one switch per speaker (or a ganged switch) which seems not a great deal "smarter" than re-wiring each time.

I posted the two configurations to help visualize this question - maybe it will give someone an idea...

A 4pdt switch could be used with a little creative wiring.

Mike Caldwell
06-23-2007, 03:01 PM
Hello
If you wanted to install a speaker connector called a speakon you could do it just by connecting the appropriate cable for the total cabinet impedance needed. You would need to use the Speakon NL8 connectors.
The NL8 has a total of 8 connections, each speaker would be wired directly to the connector on the back of the cabinet. All of the series parallel connections would take place in the mating connector on the speaker cable by jumpering the speakers together in different combinations for the desired impedance. You would have different pre made speaker cables for each impedance desired, just by plugging say the 16 ohm cable into the cabinet you would have a 16 ohm cabinet change cables to the 4 ohms and it's a 4 ohm cabinet.

I have never been a fan of switches for selectors in high power speaker cabinets. The speakon connector would be a far more solid connection.

If your interested I could make up the cabling and connectors for you.

Mike Caldwell

boputnam
06-23-2007, 04:23 PM
I have never been a fan of switches for selectors in high power speaker cabinets. That is a great suggestion Mike - and I agree with the concerns.

:thmbsup:

glen
06-23-2007, 06:37 PM
The problem I'm having with one switch, is the need to completely disconnect...

Don't completely disconnect everything, only what needs to change.

What's wrong with the setup below? one Double pole double throw switch
(shown in the 4 ohm position, all speakers in parallel)
Flipping the switch puts the left pair in series with the right pair, giving a 16 ohm impedance.


Am I forgetting something?

boputnam
06-24-2007, 10:40 AM
Flipping the switch puts the left pair in series with the right pair, giving a 16 ohm impedance.Yea, but that idea, cool as it is, will not allow the drivers to be individually all in series (or individually all in parallel...).

That is the challenge of this...

scott fitlin
06-24-2007, 11:23 AM
That is a great suggestion Mike - and I agree with the concerns.

:thmbsup:Yes, I agree too.

:)

Mike Caldwell
06-24-2007, 05:59 PM
Hello
I case anyone is curious as to what the Speakon Connector is that I am talking about here are a couple of pictures. There made by Neutrik.

Mike Caldwell

mlr
07-09-2007, 02:27 PM
Well fella's, it would figure that the one thing I hoped to do was not possible.
..... but I just know I saw an article on how it would be possible in the year 1993. It was the same issue that said we'd all be cruising around in flying cars, and that long before that we'd have grown bored of scooting around in our personal JetPacks... you guys don't remember that issue huh? Bummer.

I poked around the website ya'll suggested and I'll probably just settle for 1 4x12 cab wired to 8ohms, and the other at 8ohms, but with a switch to allow split to stereo. That way I can at least go with choices of using both cabs in stereo at 8ohms, split mono at 8ohms, or bridged mono at 4ohms. Plus have the option to just lug 1 4x12 and still get stereo in 8ohms with the switch.

If you ever figure out how to wire the 'ol switch-a-roo so that I might go from old-fat bald guy w/ear "dreads", to cool-sexy young guy with long hair, and platform shoes send me the diagram most rikki-tik! Until then I'm gonna just run with "beeeeg fadddt saxxy mannn" (gat in ma belly!) HA HA HA!

Ok so, anyhoo...... I really do appreciate the generousity you brainiacs have demonstrated by using up your free time pondering my problem. It was very nice of you. Should you ever get stuck on some problem I can help with, like.... "how to become a chick magnet" I'll be all over it for ya! Anything else will likely yield a sort of lower frequency, sustained "duhhhhhhh", followed by one of those startled sideways jumps, and a "wo did you just see that" flashback dealio's. HA HA HA!

Seriously though, many thanks mates!
Mike

JBL 4645
07-09-2007, 06:42 PM
Don't completely disconnect everything, only what needs to change.

What's wrong with the setup below? one Double pole double throw switch
(shown in the 4 ohm position, all speakers in parallel)
Flipping the switch puts the left pair in series with the right pair, giving a 16 ohm impedance.


Am I forgetting something?

What is this “sesame street”:D just stick a big yellow bird in there with a high squeaky voice that drawing was charming you’re a natural.:)