Author Topic: help with running 3 cabinets and proper ohms / series?  (Read 5415 times)

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Offline 57classics

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help with running 3 cabinets and proper ohms / series?
« on: February 17, 2011, 11:36:01 am »
Hello everybody, I have been google searching all week to find some answers.  Maybe you guys can help me out.

I am currently playing a Laney Pro Tube Aor 100watt through a late 60's sunn sceptre 4x12 at 8ohms(tall cab)
I want to add 1 or 2 sunn cabs to the mix.  At first I was thinking about getting an empty sunn 4x12 and load it with 8ohm greenbacks.
So that means I will run 2 8ohm cabs and set my amp to 4ohms right?

Then I thought about also adding a vintage sunn 2x15 at 8ohms as well. So Whats the best way to do this? 2-4x12's and 1-2x15.
I read up a little on running cabs in series and I think I got it figgured out but I want to find out if this is ok.

Can I run my sunn 4x12 8ohms and a sunn 2x15 8ohms in series to get a 16ohm load in one of the amps speaker jacks?
And then get another 4x12 loaded with 16ohm greenbacks and run it to the second amp speaker jack?
And set my amp at 8ohms?

Will this work?  Is this a common configuration?  And what are the plus's and negative's to running a 4x12 @8ohms in series with a 2x15 @ 8ohms?
Ive read that those original sunn transducers can blow if pushed too hard. So is running those cabs in series harder on the speakers?

Any help, advice and experience with this configuration would be greatly appreciated. Thank you

Offline 57classics

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Re: help with running 3 cabinets and proper ohms / series?
« Reply #1 on: February 18, 2011, 12:07:32 pm »
No one can help me with this?  Help a fella out!

Offline shibbz

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Re: help with running 3 cabinets and proper ohms / series?
« Reply #2 on: February 18, 2011, 12:21:43 pm »
You could try one of these guys. Super cheap. You'll spend more time in radioshack that it takes to put it together.
http://sunn.ampage.org/sdp/index.php/topic,5502.0.html

Offline Greg_M

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Re: help with running 3 cabinets and proper ohms / series?
« Reply #3 on: February 18, 2011, 01:27:07 pm »

3 is always a bugger
Here's a handy page that will help with the calculations

http://www.bcae1.com/spkrmlti.htm

and another here

http://www.1728.com/resistrs.htm

Offline 57classics

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Re: help with running 3 cabinets and proper ohms / series?
« Reply #4 on: February 18, 2011, 01:51:07 pm »
Thank you guys!  I think that is my best bet.  I am pretty much ready to purchase some greenbacks but I wasnt sure if I should get 16ohm or 8ohms.  One more question, if I use one of the box's to run a 2x15 and a 4x12 in series, does that mean I can only use the cabs together?  Im not even 100% sure If I would like adding the 2x15.  Is it possible to set up all 3 cabs to have the option of running series or paralell?  That way I can play through 1 cab, 2cabs, or 3 without having to rewire anything?

Sorry for the stupid questions, all this stuff is super confusing to me.

Offline Greg_M

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Re: help with running 3 cabinets and proper ohms / series?
« Reply #5 on: February 18, 2011, 02:00:07 pm »
You could set up a switch(s) in your cabinets that would switch from series to parallel, but it would be a mess.

Offline loudthud

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Re: help with running 3 cabinets and proper ohms / series?
« Reply #6 on: February 18, 2011, 04:19:02 pm »
Running cabinets in series usually doesn't work very well. Use a gizmo like this:

https://taweber.powweb.com/store/wzc100.jpg

Connect all three 8 ohm cabinets in parallel and connect to the 2.6 ohm tap. Connect the amp to the tap matching it's output. Order the gizmo here:

https://taweber.powweb.com/store/magnetic.htm

Offline stanner

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Re: help with running 3 cabinets and proper ohms / series?
« Reply #7 on: February 18, 2011, 07:56:11 pm »
sorry-this has nothing to do w/ your problem here. i have a steadfast rule-one amp=one cab.
and i use multiple amps for my shows. it gives you clarity of signal-headroom-and most important, the cab reflects the characteristics of the amplifier. when you start adding  cabs to one amp-you get a distasteful coloration that i dont like. YMWV
http://stanosaur.com/
AMPSSOUNDBETTERLOUDER

Offline 57classics

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Re: help with running 3 cabinets and proper ohms / series?
« Reply #8 on: February 19, 2011, 11:18:45 am »
Thanks stanner,  I was actually wondering about that too.  Theres allot of info on series and parallel out there but no one ever talks about the tone characteristics.  Also, what does that do to the amp?  is it harder on the tubes to run cabs in series?  Is it harder on the speakers?

I play allot of 50's rock (chuck berry), 60's stuff like hendrix,cream, and zep but I also like to play some heavy stoner/sludge type stuff like Sleep.
Do any of you guys play really heavy stuff with original sunn transducer speakers like the ones in a sceptre cab?

Ive read that you can fry those speaker fairly easy but most of that info was from bass players.

Maybe I will start a new topic on what an original sunn transducer can handle.

Thanks again for all your input guys. 

Offline xsolarusx

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Re: help with running 3 cabinets and proper ohms / series?
« Reply #9 on: February 19, 2011, 03:30:33 pm »
I play through transducers in two 612 cabs (running a 1st Gen T and a concert lead into each) while running a Rat, and have yet to find anything wrong with the speakers.

However, I was playing the Rat through a JCM 900 (4100) into a Crate 412, and apparently blew some fuses in the head and killed the speakers in the cabinet.

So, for what it's worth, Sunn cabs should do you well.
(2) 73 1st Gen Model T
Late 70's Marshall JCM 800 1960B cab