# Mixing a 4-ohm cab with an 8-ohm cab?

Discussion in 'Amps and Cabs [BG]' started by Skel, Feb 13, 2006.

1. ### Skel

Jun 19, 2005
Sorry if this has been beat to death in previous threads, but I couldn't find this exact scenario. I know the formula for calculating impedance, but if ran a 4-ohm cab and an 8-ohm cab in parallel, and set my amp's impedance to 2 ohms - I'm pretty sure it would be safe for the amplifier(?), but would the result be that the amp just wouldn't drive the cabs quite as hard as they need to be? Put differently, is this (1) safe, and (2) a bad/good idea tone wise?

Thanks - Skel

2. ### barthanatosInsert witty comment here

Feb 8, 2006
South Carolina
From http://ampeg.com/faq.htm

Q5) - Can I combine cabinets of different impedances?

It can be done, but it will cause a mismatch of levels. This is not recommended

Q6) What is the impedance of an eight ohm cabinet combined with a four ohm cabinet?

2.7 ohms. This is not recommended

Sorry I can't offer more than that, but at least it's relevant.

3. ### Figjam

Aug 5, 2003
Boston, MA
I think that would be safe, since at 2 ohms you can run two 4 ohm cabs, and an 8 ohm would be fine in its stead. ALthough as mentioned above....

4. ### Skel

Jun 19, 2005
Yea, I think I'll just stick to recommended configurations. Thanks for the quick responses.

Skel

5. ### Mcrelly

Jun 16, 2003
Minnesota, USA
just to be clear...does your amp say it can run 2 ohm loads? if yes you'll be safe in the "blow up your amp" dept.

if your amp is mono or dual mono (meaning you can't adjust individual volumes for two speaker outputs) then you will probably have the 4ohm cab over powering (volume wise) the 8ohm cab. still safe, but not might sound the best.

6. ### Plain Old Me

Dec 14, 2004
If you are running a SS amp that can go to 2 Ohms, it would be fine, but keep in mind that the 4 Ohm will get 2x the power as the 8. On a tube amp, it depends on the amp. Some can handle a slight mismatch, most can handle up to 100% of a mismatch with some loss of power. I run an 4 and 8 on my Mesa 400+, one through the 2 Ohm and one through the 4.

Jun 19, 2005