Questions about my amp setup/ Different amperage/ohm ratings

HeavyMrEd19 · #1 05-18-2011, 05:26 AM

Okay, so this has been bothering me for a little while... and up until now I've been able to 'fake it', so to speak. But I really need to know a few things about my amp setup.

Currently I'm running:
-Kustom Deep End 300 head (300 Watts @ 4-Ohms)
-Kustom DE 1x15" (250 Watts @ 8-Ohms)
-Kustom DE 4x10" (400 Watts @ 8-Ohms)

and I used to run a Kustom Groove Bass 600 (600 Watts @ 2-Ohms) as the head for the same cabinet stack.

(The 600 was my first head and these cabs were my first cabs... I wasn't aware they weren't the same series/ potentially mismatched. I bought out of necessity, just got the power I needed, and got the cabs the guy at the store told me to. Dumb move, really

)

THIS IS THE STORY. ROLL DOWN TO THE NEXT BOLD PART TO SEE THE QUESTIONS

When I was running my 600 into that 15 and 4x10 stack, for some reason I had to practically crank my head full over to get loud enough for my band to hear me (let alone feel the bass)... and I was thinking '600 watts and this is all I get? This is bad'

Then one night, my 600 bit it. Right in the middle of a show (But nobody was really paying attention, so it wasn't a total loss). When I got home, I figured it was just after all the strain I put on the amp to get it as loud as it was getting... so I sent it out to get repaired and sought out to buy another amp.

Then I got the DE300 since I got into a quieter band (so I thought) and plugged it into my two trusty cabinets. Immediately, I noticed how much friggin' louder it could get. After a solid hour of testing the cabs and dialing in my tone, I sat down and scratched my head-

"Why the hell is my 300 packing more power than my 600 did? That makes no sense." So then I started looking over both spec sheets for the heads. Maybe it was the difference of speakon cables to the cabs instead of quarter inch cables? Maybe it was the lack of a tube? Maybe 600 watts doesn't indicate the power but the draw? I had no clue. Then I looked at the Ohms spec and noticed the heads had different ratings there. Maybe that was something. I confirmed my suspicion that it had something to do with the ohm rating... but I'm still clueless as to what that does, exactly.

The Questions

Why does a 600w@ 2 ohm head have more power than a 300w head @ 4 ohm?

Would running a single cable to a cab, and then another cable between the two cabs make a difference between running a cable from the head to each cabinet separately? If so, what difference? and would the order of the 15 and the 4x10 change anything?

Sorry for the boring and obnoxious story

-HME19

FunkDragon · #2 05-18-2011, 06:19 AM

The 600 Watt head will only run 600 Watts when it has a 2ohm load.
Meaning to get full power out of that head you would need to run 2 x 4ohm cabs.
When you run 2 cabs together you actually halve the ohm's.
That means 2 x 8ohm cabs = 4ohm load
& 2 x 4ohm cabs = 2ohm load.

I would assume both your cabs are 8ohm cabs (should be written on somewhere on cab) which would mean that the 600 Watt head would be running around half power, whereas the 300 Watt head would be running full power.
That's why you would find yourself turning the 'more powerful' head up so much more.

DRafalske · #3 05-18-2011, 06:53 AM

FunkDragon is correct.
Also, most speaker cabinets have their input jacks wired in parallel, just like most amps with dual speaker jacks. You can plug both cabs into the head, or daisy chain the cabs and the amp will see the same load. Makes no difference what order if you chain them.
D

HeavyMrEd19 · #4 05-18-2011, 07:44 AM

Thanks for the help, FunkDragon and DRafalske