Connecting cabs of different Ohm ratings?

Discussion in 'Amps and Cabs [BG]' started by TCollins, Feb 5, 2002.

1. TCollins

Apr 4, 2000
I have a 2x15 (4 Ohms) and will be getting a
2x10 rated at 8 Ohms. I have a Basis M-2000 that
has speaker outputs for 2, 4, & 8 ohm connections.
My question is which speaker output on the amp should
I connect to if I use both of these cabs?

Thanks!

2. Christopher

Apr 28, 2000
New York, NY
Amps typically are endangered when they face a load that is lower than the one that they are rated for. The combined load of the two cabs in parallel is 2.67 ohms.

I don't know the specifics of the amp that you have, but my guess is that it would be safer to connect to the 2 ohm posts.

3. ShowdownSupporting Member

Jan 21, 2002
Honolulu, Hawaii
The formula for caculating total Ohms, with X being the first cab and Y being the second is:

1/(1/X)+(1/Y)

Christopher is right that a 4 Ohm and a 8 Ohm cab in parallel = 2.67 Ohms. And I agree the 2 Ohm input is the one you should use.

4. Matthias

May 30, 2000
Vienna, Austria
1/((1/X)+(1/Y))
to be correct...

you can also use (X*Y)/(X+Y)

Matthias