# 3 8 ohm cabs = How many ohms?

Discussion in 'Amps and Cabs [BG]' started by Ty McNeely, Mar 9, 2002.

1. ### Ty McNeely

Mar 27, 2000
TX
What would the impedence of 3 8 ohm cabs be (1 cab out of one input, then another cab out of the other daisychained to a 3rd).

2. ### Rockin John

Dec 20, 2000
Leicestershire, UK.
I'm not quite sure what your question means.

Nevertheless, you can work out the vaue of any number of resistances parallel connected by the formula:-

1 / (1 / R1 + 1 / R2 + 1 / R3)

The answer to 3 x 8 Ohm cabs in parallel = 2.66 Ohms.

John

3. ### Ty McNeely

Mar 27, 2000
TX
See the attachment to see what I meant. I was tired when I wrote that

So in other words I can run 3 cabs as long as I don't mind running my head at 2 ohms?

4. ### Mark Reccord

The three 8 Ohm boxes in that configuration will give 2.67 Ohms if the two output jacks are from the same amplifier (ie a mono amplifier). If it's a stereo amp (like the Eden 800) the two outputs could be from different amp channels. This would create a different impedence situation. For mono amps, if there are two speaker outs they're just paralleled internally.
Go for it if your amplifier is rated to drive 2 ohm loads. If it doesn't specifically say it can drive 2 ohms don't do it.....

5. ### leftybassdogSenior Supporting Member

spacegoat is right, look at the the back of your amp and it should be marked with the mimimun ohms the amp can handle,3 8ohm=2.66 or 2.5 most amps are set for a mimimun of 4 ohms but eden,swr,ampeg,and some others can drop down to 2 ohms, example swr 350, two ohms is the lowest,but the swr 750 will only drop to 2.5 or 2.66, be sure to check if you dont it can burn up your amp,

6. ### Ty McNeely

Mar 27, 2000
TX
Its a Sunn and it does go down to 2 ohms.

7. ### Mark Reccord

All tube?
Anyway, you should be all set then! Have fun....

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