Just picked up a Kustom K 250-4 head and cabinet.
Doesn't have the original speakers.
Inside I found 4 12" Celestion Rocket 50's.
Seeing that the head's 250W and the speakers add up to 200W, I'd be afraid of blowing one or more out.
Anyone have experience with the Celestions?
stevem Messages: 4728 Registered: June 2004 Location: NY
Senior Member
The amp is 250 watts peak.
The tag on the rear of the amp if it is still there states 125 watts rms and this is into a 4 ohm load, so if your Celestions are 8 ohm models and are wired up for a 8 ohm load(serise parallel) the amp will only out put 75 watts rms and 150 watts peak.
If they are 16 ohm drivers and wired that same way the overall impeadance will be 16 ohms and the amp will output 1/2 of what I posted in the alst paragraph.
rodak Messages: 511 Registered: October 2001 Location: Georgia
Senior Member
Keep in mind that any amp can be pushed well beyond it's rated output if you drive it hard enough. At that point, you're into clipping, which sends square waves to the speakers. Speakers do NOT like square waves. So you can blow a 200watt speaker with a 50 watt amp if you push it hard enough. Conversely, you can safely drive a 50 watt speaker with a 200watt amp if you don't push it too hard. The type of signal figures into it, too. I think it would be almost impossible to blow a speaker if you were only playing a flute through it, but guitar fuzz and distortion boxes also produce nasty square-ish waves that speakers don't.
I think of amp and speaker wattage ratings as general guidelines, or rules of thumb. Too often people get caught up in using precise numbers (Oh, no, my amp is rated at 101 watts, my speakers are only rated for 100w!), and wind up missing the forest for the trees.
"I think it would be almost impossible to blow a speaker if you were only playing a flute through it, but guitar fuzz and distortion boxes also produce nasty square-ish waves that speakers don't."
Hey Rodak - I'm not sure that I agree with that.
I think a flute sample played on a synthesizer would be easy on speakers, but a flute through a microphone without a compressor could be pretty nasty to a speaker if the volume was set too high.
.. uh oh, I feel a story coming on ... different instrument - but I once sold a beautiful Kustom combo to a guy who blew the speakers immediately with a mandolin. He "only had it on 4" - but we know that 3 or 4 is full clean volume on most Kustoms and you can overdrive the amp into distortion even at that setting. How many previous owners over the years never hurt those vintage speakers with their guitars - but his mandolin destroyed them in seconds.
pleat Messages: 1452 Registered: June 2004 Location: Belding, Mi
Senior Member
I don't think the celeston Rocket 50's are ava. in a 16 ohm version. So 4 speakers in the cab are going to give you a either a 8 or 2 ohm depending how you wire the cab. I'd suggest a Series and Parallel wiring to get the 8 ohm.
pleat