ohms

Discussion in 'Amps and Cabs [BG]' started by Pthump, Jun 27, 2005.

1. Pthump

Nov 18, 2004
I have no idea what this means Im looking into getting an avatar cab, dunno whether to get a 4 or 8 ohm. My head is a SWR workingmans 400 watt.. I plan to add another cab later, so which do i want.

2. Plain Old Me

Dec 14, 2004
Do a search. I think there is a tech page on here somewhere as well. If you want to add another cab later, get 8 Ohms.

3. LowtonejoeSupporting Member

Jul 3, 2004
Pasco, WA
You need to know your amps nominal impedance. They can all do 8ohms, most do 4ohms and some can do 2ohms. If your amps nominal impedance is 4 ohms you may use 2-8ohm cabs or 1-4ohm cab.

Joe.

4. oldfcleferlow ended

May 5, 2005
Southern Ohio
If you add a cab, add the impedence of both cabs and divide by 4. If the answer is less than the recommended minimum impedence your amp is specified to run, you can harm the amp. If the answer is greater, you should be fine.

Oct 22, 2002
Maple Grove, MN
A huge discussion of ohms and everything related is here:

Ohms FAQ

For a somewhat less technical discussion check here:

How Ohms Work

6. oldfcleferlow ended

May 5, 2005
Southern Ohio
My formula works for two cabs.

7. GetLow

you want an 8 ohm cab. it will not get the maximum amount of power from the amp, but it will allow you to add another (8ohm) cab later on.

8. Richard Lindsey

Mar 25, 2000
SF Bay Area
Only if they're the same impedance. By your formula, 8 + 4 = 3, but the accurate answer is 2.67. Close, but no cigar. (Actually, close enough for most practical purposes.)

9. oldfcleferlow ended

May 5, 2005
Southern Ohio
Yes, yes, now I remember. In ohms, it's product divided by sum for parallel cabs.
Sorry for the mistake.
Reviving this thread to dispel disinformation.
Thanks for pointing it out.