Help with sub and amp

[puss puss]

Hey, this random girl of msn is selling me a amp ( she didnt even kno what it was) a kenwood jobbie 2/3/4channel i think. for 25 notes o.0!

Well i read it up, and it could put out about 220watt rated, if i bridged it to one channel.

The jbl gt4 sub i think it is can handle about 250 watts rated i been told, so all sounds good atm.

Yet the amp puts out 220 watt at 2ohms i belive it is.

But the sub wants 250watts are 4ohms!

so would this amp be able to run this sub ? am a little bit confussled with the whole Ohms thing. I know that it is resistance but am not sure if it will damage either the sub or the amp.

Thanks for any replys Nathaniel

[Jack]

Can the amp handle 4Ohm resistance? Often find they can do multi resistance (but it'll be a different power output); may also depend on how the sub is wired up to the amp.

If the amp can handle the higher resistance it'll just output a different power; if it can't then it could damage the amp or sub. A kid on the local kroooze forum recently broke his amp by apparently trying to run a 4Ohm sub on a 1Ohm amp.

Have you got a model number for the amp so we can look up manuals for specific specs?

[bump]

IIRC if the amp can handle a 4ohm load then the power output will halve.

[puss puss]

urgh if so what amp would u say i should get for that sub it is a jbl gt4 12inch sub =P

[philly]

anything really with atleast 600 watt rms or even max power

if you manage to get a jbl gt0 amp rated at either 600 and 800 it will make the best difference.

[Jack]

NO! 600WRMS is far too much for a 250WRMS sub!

GT4-12 is 250WRMS/1000WPMPO @ 4Ohms. Ignore the max power output figure, the RMS is the important one (also shows how limp JBL stuff is if its only 250W continuous power, but thats beside the point )

You need an amp that can match those figures - The Alpine MRV-T320 can be bridged to mono and puts out 1x 240WRMS @ 4Ohms when running on 14.4V (i.e. with the engine running).

[Lucky Luke!]

One of the most common reasons that subs blow is not through being overpowered but by being underpowered.

If you have a 250w rms sub with a 200w rms amp then most people think that you cant blow the sub cause the power rating is higher so they crank the amp right to the max. in actual fact this is what blows the sub, when you crank an amp over about 3/4 the amp starts to distort, its this distortion that leads to the overall destruction of the sub.

i would personally recommend about a 280w rms amp to run the 250w rms sub just dont turn the amp over 3/4.

[focus_neil]

Im with Luke on this one, alwys get an amp thats slightly more powerfull than the sub. This way the amp doesnt need to work mega hard to get decent quality

[puss puss]

ok thanks for all ya help, ill jus use that amp to run my front speakers den hehe, ill go with jack and get that amp

[mikey14sr]

All multi channel kenwood amps are 4ohm stable, but the one you describe will only put out about 100w rms bridged into a 4ohm load, the 220 into 2ohms qouted will be a peak figure.
I have a little 529 which says 250watts on the badge, but the only way to get that out of it is into a 2ohm load when bridged (and turned right up), In stereo mode it can just about manage 2x70w rms @4ohms.