#1
OK if I have 2 250w cabs ran parallel do I still need 250 watts or do I need 500?
Gear:
Mesa Boogie Tremoverb And Recto cab
Peavey 5150 and cab
Peavey classic 2 12
Agile Intercepor pro 7
Jackson soloist sls
Jackson RR3
Ibanez 7321
Washburn Dimebolt 333
#2
i don't think it matters just get ur ohms right and u should be good
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#3
I understand the Ohms must match.
Gear:
Mesa Boogie Tremoverb And Recto cab
Peavey 5150 and cab
Peavey classic 2 12
Agile Intercepor pro 7
Jackson soloist sls
Jackson RR3
Ibanez 7321
Washburn Dimebolt 333
#4
well what wattage are u talking about? because i mean u need a head to power the cab. what exactly are u asking?
Deacon of Zeppelinism PM TheHeartbreaker to join
speed demon of the UG Jeepers
Member of the Neutral Milk Hotel club PM Hamish5178 to join~
#5
i mean like ur wattage is gonna depend on ur impedence or ohms anyways.
Deacon of Zeppelinism PM TheHeartbreaker to join
speed demon of the UG Jeepers
Member of the Neutral Milk Hotel club PM Hamish5178 to join~
#6
ok if 2 250w 8 ohm cabs were in parallel would I need 250w at at 4 ohms or 500w at 4 ohms per side?
Gear:
Mesa Boogie Tremoverb And Recto cab
Peavey 5150 and cab
Peavey classic 2 12
Agile Intercepor pro 7
Jackson soloist sls
Jackson RR3
Ibanez 7321
Washburn Dimebolt 333
#8
but wont underpowering hut the speaker and I want to get optimal performance>
Gear:
Mesa Boogie Tremoverb And Recto cab
Peavey 5150 and cab
Peavey classic 2 12
Agile Intercepor pro 7
Jackson soloist sls
Jackson RR3
Ibanez 7321
Washburn Dimebolt 333
#9
As long as your head is not over 250 watts, your cabs should work fine.
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I think he just endorses them because he likes sacks of money
#10
yea that 250 just means it can handle the wattage up to 250 watts. Cabs dont need to be saturated like tubes in amps do.
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#11
if your cab power total > amp's output power

then you're fine.
Call me "Shot".

ShotRod Guitar Works

Custom Hand-wired Amplifiers and Effect Pedals.

Est. 2007


Source to everything I say about Guitars, Pedals, and Amplifiers: I make them.


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#12
so I dont need more power for paralled cabs
Gear:
Mesa Boogie Tremoverb And Recto cab
Peavey 5150 and cab
Peavey classic 2 12
Agile Intercepor pro 7
Jackson soloist sls
Jackson RR3
Ibanez 7321
Washburn Dimebolt 333
#13
If your output is 4 ohms and the cabs are 4 ohms each and wired in parallel, it's still 4 ohms. Is that what you mean?

edit: hmmm...according to the equation, it's .5 ohms...
Last edited by Invader Jim at Jan 29, 2008,
#14
Quote by Invader Jim
If your output is 4 ohms and the cabs are 4 ohms each and wired in parallel, it's still 4 ohms. Is that what you mean?

if the cabs were 4 ohms each wired in parallel wouldn't it be 2 ohms...?
Call me "Shot".

ShotRod Guitar Works

Custom Hand-wired Amplifiers and Effect Pedals.

Est. 2007


Source to everything I say about Guitars, Pedals, and Amplifiers: I make them.


UG's Best DIY PedalBoard
#15
No "ok if 4 250w 8 ohm cabs were in parallel, 2 per side would I need 250w at at 4 ohms or 500w at 4 ohms per side?"
_______
Gear:
Mesa Boogie Tremoverb And Recto cab
Peavey 5150 and cab
Peavey classic 2 12
Agile Intercepor pro 7
Jackson soloist sls
Jackson RR3
Ibanez 7321
Washburn Dimebolt 333
#16
just worry about the ohms. if you are somehow using four 250w cabs, then you're definitely fine. just worry about the impedance.
Call me "Shot".

ShotRod Guitar Works

Custom Hand-wired Amplifiers and Effect Pedals.

Est. 2007


Source to everything I say about Guitars, Pedals, and Amplifiers: I make them.


UG's Best DIY PedalBoard
#17
Ok let's see....now even I'm confused...

If one cabinet is 8 ohms, 250 watt handling capability, that means it can handle 250 watts at 8 ohms. Put two of those together wired parellel and it would be the same 250 watts power handling capability, but would now operate at 4 ohms. I may be wrong here, with a pair of 250 watt cabinets, it might handle 500 watts total, but I think it would stay 250.

But a 30 watt 4 ohm amp would still work with it. My Fender Champ, 6 watts would work with it. I've run it through my Kustom 2x12 cabintet that handles the 130 watt Peavey MX just fine, and has for 15 years. The 6 watt Champ will still run it. But I couldn't run an amp that puts out 200 watts, it might onbly handle 150. I'm not sure just how much the speakers can handle, but I know they can do 130...

For your situation it sounds like you're trying to figure how to rig 2 cabinets, each 250 watt handling capability at 8 ohms into your amp. If it has two output jacks, labeled 4 ohm, it's probably wired parallel, so one cab plugged into each output would total 4 ohms. If you wire the cabinets themselves parallel (the way I would prefer because I can be sure) it would be 4 ohms and you can check it with a multimeter to be sure. Then you have one speaker cable to the amp, 4 ohm load, another to the second cabinet wired parallel. Don't worry if it checks 5 ohms, or even 6, lots of times they are not exact. The Fender Champ is labeled 3.2 ohms, I've never seen a 3.2 ohm speaker, 4 ohms works great. One 4 ohm speaker I checked was 5.2 ohm, another 3.8 ohms. It varies. Amps will tolerate that much, some up to 50% but I wouldn't push it.

The 250 watts is the maximum it can handle, not the required wattage to run it. If the speakers are efficient, 1 watt will run the cabinet. As long as your amp is not putting out 250 watts continuous, you're fine, just make sure you match the impedance, 4 or 8 ohms, whichever the amp is labeled. Parallel, divide it by the number of cabinets, series, add them together.

8 ohm x 2 parallel = 4 ohm.
8 ohm x 2 series -= 16 ohm.

Forget the wattage, if you're running an amp that will damage a 250 watt cab, I don't wanna be in the building...
Hmmm...I wonder what this button does...
#18
Parallel will up the wattage handling; series will keep it the same.
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#19
but how much? Would it double?
Gear:
Mesa Boogie Tremoverb And Recto cab
Peavey 5150 and cab
Peavey classic 2 12
Agile Intercepor pro 7
Jackson soloist sls
Jackson RR3
Ibanez 7321
Washburn Dimebolt 333
#20
Quote by killdie
but how much? Would it double?


Yes. If you connect two equal impedance, equal wattage loads in parallel, the overall impedance (ohms) will be cut in half, and the overall power handling capability will double.

Think of it this way. If you have only one cabinet connected, that's only one path for current flow. Adding another cabinet in tandem adds another path for current. If you add another path for current, that means more current can flow, right? Well, that turns into decreased resistance, as resistance is opposition to the flow of current.

And because the amount of total power a circuit can handle is directly related to current, if you add another path for current, you'll also increase the amount of power a circuit can handle.
#21
resistance in parallel is

1 / R = (1 / R1) + (1 / R2)
so for two 4ohm speakers

(1 / 4) + (1 / 4) = 1 / 2 (2 quarters = 1 half)
if 1 / R = 1 / 2, then R = 2

in series they just add up
#22
Impedance will change, wattage won't.
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#23
Your speakers should also have a power wattage handling 1.5 times what your amp's rated output is. Some people like the sound of cones distorting, but you'll blow through speakers pretty quick if you don't know what you're doing.
American Ash Deluxe Tele
Squire Standard Strat w/ Texas Specials
'65 Fender Deluxe Reverb RI
'53 Fender Deluxe 5C3
California Dreamer
Valve Junior
2X12 Avatar w/ V30's