hedge

I am trying to decide between two amps. I have purchased an 40x4 Alpine amp from a local retailer (MRP F250). I have now found a listing on a local forum for it's bigger brother (MRP F550) which is 90x4. I can buy the 550 for about the same price but it's been used for 6 months.

My speakers (Polk DB751) call for 60w RMS, 180 peak.

1. Will this be too much for my speakers? I've always heard amps should be a bit over the RMS, but it seems to be that 90 is quite a bit more than 60.

2. Are used amps reliable? Am I just better off with a new one

Thanks for any help.

Jo-Psyko

iTrader: (1)

just cause an amp makes 90 doesnt mean you have to have it put out that much... you can turn it down... as far as new vs used... if you buy an amp and hook it up it is now used... so yeah whatever... more personal preference, unless the used is banged up and missing parts....

silverbane

iTrader: (1)

The Gain **** is NOT a volumn control. Buy the correct amp for the application.

SteveDempsey

A speaker will always handle more than its rated power so long as that power is distortion free and does not clip.

Think of it like this....you have a Corvette and a Kia Rio, your trying to get them to go 200 KMH...the Corvette with the larger mortor will hit this speed all day long and not break a sweat, however the Kia Rio might make it to 200 KMH (if it's lucky) but it will really be straining to achieve this goal, and if kept trying to reach this speed over & over again, will likely fail before too long. This same logic applies to amplifier power as well.

You will be fine with the more powerful amp so long as you properly adjust your gain settings.

Haunz

iTrader: (3)

a voice coil does not care if it passes distortion harmonics through it's windings... you are misinformed...





To the OP... there are too many factors to list.. but if you keep the gain **** down you'll be fine... and if set up properly you can only expect extra headroom....

SteveDempsey

Alright smartass, well as long as it doesn't clip then....how about that, are you satisfied now that you have shown your superior intellect?

Jo-Psyko

iTrader: (1)

i know its not a volume ****... im just saying it can be used to lower the output to the speakers...

Haunz

iTrader: (3)

guy, I'm not trying to be a smartass... when you 'clip' an amp it's creating odd harmonics of the fundemental it's supposed to produce.... (harmonic distortion)

the topic has A LOT of aspects..... but as far as this thread goes I'm sure the OP will be fine......

SteveDempsey

Well when an amp "clips" it holds the speaker either all the way in or all the way out and burns out the voice coil as it's doing so, thereby destroying the speaker. If the amp doesn't clip, then there should be no reason for the speaker to destroy itself... I'm talking about a reasonable amount of headroom here....90 watts on a 60 watt speaker is perfectly fine. You know perfectly well what point I was trying to get across, in order to help the guy out, but you felt the need to chime in and shoot me down. Congratulations, you're an audio guru.

Haunz

iTrader: (3)

Guy..... I am not trying to shoot you down or do anything other then present the facts.... you clearly have no idea what you are talking about as far as clipping and distortion goes..... but at least we agree the OP will be fine with 90watts/ch.