Amp Head watts vs Cabinet Watts

AndrewM · #1 02-10-2013, 12:08 PM

Okay, so I just purchased a new Ampeg PF-350 head with the Ampeg PF115he cab, and I love the tone I'm getting! I do have a question, however. The Cab is rated for 450w I believe, and the head is only 350w. Does this mean that I could turn the volume on the head up basically all the way without fear of damaging the cabinet, since its rated for 450w? Please help me out here, I've never been too smart with understanding technology

Shardik · #2 02-10-2013, 12:19 PM

I don't know that cab too well. Does it have a tweeter?

mattbass6945 · #3 02-10-2013, 12:26 PM

in theory, yes. although, i wouldn't advise it. let your ears be your guide, if the speaker starts to distort, you've gone too far. i believe that cab is rated at 8 ohms, so you should be safe (the head should only be putting out about 250?), but if you need more volume, i would suggest adding a second matching pf115he.

mattbass6945 · #4 02-10-2013, 12:27 PM

to clarify, with a second 8 ohm cab, you would be running the head at 4 ohms. for more clarification, look into the sticky's at the top of the amp forum.

AndrewM · #5 02-10-2013, 12:38 PM

Quote:

Originally Posted by Shardik

I don't know that cab too well. Does it have a tweeter?

Yes, it does have a tweeter.

And thanks everyone for the informative and quick replies :P

Shardik · #6 02-10-2013, 01:09 PM

Well, if you are overdriving your amp into heavy distortion, especially hard solid state clipping, you may actually harm a tweeter, even if you play with an amp with lower max effect than the rated cab power. The reason is that normal instrument signals have only a fraction of the effect in the tweeter frequency range. But clipping a signal means introducing high frequency components of much more effect, and that may actually destroy a tweeter. 'Use your ears' is a good advice.

mattbass6945 · #7 02-10-2013, 01:14 PM

or don't use tweeters.......

JimmyM · #8 02-10-2013, 01:26 PM

Ya, turn the tweeter off if you use distortion. It not only can damage your tweeter, but it just plain doesn't sound good.

mattbass6945 · #9 02-10-2013, 01:30 PM

i turn the tweeters and women off regardless.

Bass_Pounder · #10 02-10-2013, 01:48 PM

No, you can't turn it up all the way........

Cabs are rated at the point of voice coil melting, NOT the mechanical limits of the speaker which is often around half the thermal rating depending on your use of low end EQ.

Additionally, amps can put out almost double their clean wattage rating when overdriven.