Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: goldstache on July 02, 2015, 11:28:44 pm
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Having a Brain-Fartimus-Maximus on how to wire 3-2X12" cabs together.
Here are the speakers on hand.
4-16ohm vintage 30's
2-8 ohm vintage 30's
2-16ohm cream backs
Can't wrap my head around it (not surprising)
The amp has taps for 4,8,16 spkr outs
Series parallel????
Parallel 2 cabs and one in ........series????
Cabs have 2-3/8" holes for jack connections if needed.
Anybody willing to walk me through it, is it even possible with the speakers I have? Since its fuzzy for me, I'm leading towards improbable.
Thanks!
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Hmmm, a head scratcher...
In order to keep each speaker carrying an equal load, I'd wire two 16ohm in series in each 2x12 cabinet, and then plug the three 32 ohm cabinets all parallel. 2x32 ohm cabinets make 16, and another one makes 10 ohms, close enough to 8 for me.
I don't know another way to combine them that would lead to anything above 4 ohms. If you do each pair parallel, effectively all paralleled, then each pair would be 8 ohms, and the total of three would be 2.66 ohms. You don't have a 2 ohm output available?
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2 16ohm creamback in parallel = 8ohm
2 16ohm vintage in parallel = 8ohm
these two cabinets in parallel = 4ohm
2 8ohm vintage in parallel = 4ohm
wire the two 8ohm cabinets parallel, now wire those then in series with the 4 ohm cabinet, the total load is then 8 ohms. the problem is the 2 cabinets with the 16ohm speakers in parallel are doing half the work and third cabinet with the 2 8ohm speakers are doing the other half of the work. maybe put the 2 8ohm cabinet in the middle of the stack or turned backward?
--pete
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Thanks for replies!!!
Pete that was my initial idea too!
Let you know how it goes.
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Why three?
That's always going to give an odd answer.
Four good Twelves ought to be enough for anything short of a stadium. Put two 16r V30 per cab. Each cab wired parallel for an 8r cab. Both cabs together parallel make a 4r load.
Going from 4 to 6 will not be a huge difference in air-paddle effectiveness and leads to odd-number loading or power imbalances. You could load a third cab and stack it for "looks", but of course it will look the same with black paper behind the grille and much easier to hoist.
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You guessed it PRR. It's for a NAMM booth. Purely cosmetic, and operated at very low volume at the show. More of an eye catcher than a functional stage rig.
Thanks everyone.