Ok, so here's a question for the more experienced out there.

The formula for matching different ohm ratings is (I'm going to use 4 and 8 as an example here, they are the most common)

4 + 8 = 12
4 x 8 = 32

32/12 = 2.6

So the ohm rating would be 2.6, here's my question.
What would I need to power this?

Do you go lower than that number or higher?
I'm going to assume it's higher, but I can't find a definite answer anywhere.
You'd need a 2 ohm amp to be safe.
Yamaha TRB1006
Fender MIA jazz bass
Hora Hybrid double bass
Hartke lh 500
Ev 606L
Epiphone les paul
Well...

That formula's not too bad, but the percise one is 1/R = 1/R1 + 1/R2 ; R being the impendance of the speaker configuration.
The impendance rating on the amp says "Minimum impendance x ohms" which means you can connect ANY cab configuration that will have an impendance rating HIGHER than the amps minimum, but capable of handling the wattage output (Which is invertedly proportional to the impendance). So, if you, for example have 4 and 8 ohm cabs, you are in need of a 2 ohm amp.
Last edited by nesveikuolis at Jan 3, 2010,
Thanks guys, much appreciated.
I actually remember your formula from GCSE technology
I had never made the connection from those resisters to amplification before.

This is all hypothetical by the way, I was just wanting to educate myself slightly.
Thanks guys, much appreciated.
I actually remember your formula from GCSE technology
I had never made the connection from those resisters to amplification before.

This is all hypothetical by the way, I was just wanting to educate myself slightly.

Yea, physics is awesome Actually, I learned this from a radio blueprint in physics class a while back. I can't remember exactly, but we were told that speaker impendance is also calculated that way. This is atually one of the things that I didn't notice in the Bass Forum FAQ - how to calculate impendance.
Well its hardly difficult and i believe in the faq their is a section on it including the basic ohm configurations.
Yamaha TRB1006
Fender MIA jazz bass
Hora Hybrid double bass
Hartke lh 500
Ev 606L
Epiphone les paul
So, with a 2 ohm capable amp, ANY combination above 2 ohms wont hurt my amp at all?
I could hook up four 8 ohm speakers, or two 8 ohms and a 4ohm, or an 8 and a 4, or three 8 ohm cabs...
Just making shure.
...it was bright as the sun, but with ten times the heat
Yep
Yamaha TRB1006
Fender MIA jazz bass
Hora Hybrid double bass
Hartke lh 500
Ev 606L
Epiphone les paul
Lets say I have two cabs. One is 8 ohms, the other is 4. I can bridge my amp to get 1000 watts at 2 ohms and I have two outputs. So Output 1 goes to cab, and output 2 goes to the other cab?
Sorry if this seems stupid...
...it was bright as the sun, but with ten times the heat
Presuming each cabcan handle it,

Unless you have a bridge mode no. Are their 3 outputs on the back, left right bridged.
Yamaha TRB1006
Fender MIA jazz bass
Hora Hybrid double bass
Hartke lh 500
Ev 606L
Epiphone les paul

Speaker 1 output (low freq.)
Bridge output
Bridge outout
Speaker 2 output (High freq.)
And I just realised, Its 1000 watts at 4 ohms so I couldnt bridge with a 4 and 8 ohm combo, but how about two 8 ohm cabs that both run at 500 watts or more.
...it was bright as the sun, but with ten times the heat
Last edited by c3powil at Jan 3, 2010,
Yes you can bridge then but i would take advantage of your bi-amp feature. Using it on both sides at 2 ohms will proably give you more like 1200 watts.
Yamaha TRB1006
Fender MIA jazz bass
Hora Hybrid double bass
Hartke lh 500
Ev 606L
Epiphone les paul