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power amp and 15 driver...sounds really low

hi all, i got a question, i decided to go with a poweramp, bass preamp instead of a pre-made bass head. i havent got my bass preamp yet but i got my poweramp (575 watts per channel@4 ohms and bridged-1570 watts at 4ohms.) and plugged it to my 15" cab. the 15 is a carvin 600watt driver at 4ohms. and i have my bass is an active ibanez soundgear. i didnt know what to expect but i expected to be loud with no eq of course, but its not loud. i tried both, on one side stereo and on bridged and i got just about the same low volume. am i just missing the preamp or do i simply need another cab of speakers??help...
 
You are missing the preamp to step up your signal to the correct level. As you noticed, an active bass can put some signal into the poweramp, just not nearly enough.

yup, this. Even though your bass has a preamp, it's a preamp that just boosts the signal a bit into another preamp. Onboard preamps are pretty much universally not hot enough to properly drive a power amp
 
Dude, hate to break it to you, but if that cab takes anymore than 200-250w without either exploding or sounding like a fartbox, consider yourself lucky. 600w is the wattage it takes to blow the voice coil. You can count on losing at least half that due to other factors like box size, port tuning, and how much lows you're pushing. Seen a lot of people blow cabs and say, "Well they told me I could do it!"

Common sense goes a long way when running your gear, and if it sounds like it will explode, I don't care what they tell you it'll handle, it will explode.
 
Yep, you don't want a bar of bridging.

When you get it all set give it all it can take until it farts out, then lower the bass eq and see how much more it will take. If you lower the bass eq enough you should have enough amp power available to get into trouble with heat instead, at that point you will be hearing little increase in volume as you wind on the loud knob. Capiche?