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ampeg stack, head and cabinet questions

H

hecTr0n

Jan 6, 2011
44
0
#1
Hello all !
I own a 100wat combo amp and im looking to upgrade to a stack.
ive been eyeballing the Ampeg PF-500 Portaflex and PF-115HE Stack (ill put a link at the bottom of this post). anyways, i wanted to know, i see the cabinet can handle 450watts and the head is 500 watts so, will the cabinet be able to give out the full 450watts ? if so or not, why or why not?

ive never owned a stack before and the whole ohms thing and getting the full wattage of a cabinet is new to me.

i understand youre supposed to get a cabinet that is either equal to or greater than the heads ohms, is this correct?

also, if the ohms on the cabinet are greater than the heads ohms... i hear that maybe the cabinet will only be able to give off half of what the cabinet is rated for? if thats true, in this specific stack im looking to get, will the cab only be able to give off around 275watts (because the cab is 8ohms and the head is 4ohms). if so, whats the point of being rated for 450watts?

anyways, im confused...lol. heres the link:

Invalid Link Removed
 
#2
The single PF-115HE cab is 8 ohms, this means the PF-500 will only output 350 watts (@ 8 ohms load) If you added a second 8 ohm cab the total load for two 8 ohm cabs would be 4 ohms and the PF-500 would output 500 watts (@4 ohms load).

Speakers don't "make" watts, they have a rating of maximum safe INPUT from an amp head. With a 450 watt INPUT rating they "can" handle an amp more powerful than the PF-500.

SS amps put out more "power" the greater the load (lower number in ohms) up to the minimum designed load. Go lower than the minimum number (like a 2 ohm load with a 4 ohm minimum rated amp) and amp failure will result.
 
#6
hecTr0n said:
anyone care to be the tie breaker? one reply says he cab wont give he full 450watts (which with the explanation he gave, i believe more) the other says it will...
Click to expand...
That is not what I said.

CL400Peavey said:
Have no worries. The PF-500 will drive that cab to its limits. If you need to be louder add a second matching cab.
Click to expand...

The RMS rating on the PF-115HE is a thermal rating, and has little to do with how much power it will handle before it reaches its mechanical limits. The 300 or so watts the PF-500 will put out will push the PF-115HE right up to its limits. ie. you are not going to gain any more volume out of the cab by throwing more power at it.
 
#7
The cab can't "give" 450 watts, it can't "give" any watts :). It will receive 350 watts FROM the PF-500. CL400Peavey was just trying to say you are good to go with that rig and the 350 watts will likely drive the cab to it's actual max (don't put a lot of stock in the 450 watt input rating on the cab).
 
#8
hmmm, thermal rating, watts and the mechanical limits of the cab goin up to 300watts or so. im confused...any links that are dummy proof? like i said im new to this all. i wanna understand better.
 

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