Date: Wed, 27 Apr 2005 07:02:25 -0400 From: Malt_Hound <Malt_Houndnospamm*yahoo.com> Subject: Re: I think I blew my amp??!!
James Sweet wrote: > > Actually it's more the rating of the *speaker* that's the issue. A 140W > speaker will not handle 140W anywhere near continuously, that rating is > music power, which assumes that the average RMS power is much lower. When an > amplifier clips hard the output is much closer to DC at the *peak* power of > the amplifier which is substantially higher than the RMS. No it's not. When an amplifier clips hard it produces a multitude of odd harmonic frequencies of the original. It doesn't produce DC. Other failures of amps can cause DC, but not clipping. > > If you don't believe me, take a speaker rated at 140W, assuming it's 4 ohm, > connect it to a 24V DC source (which will cause it to draw about 140W) and > see how long it takes the voice coil to smoke. You probably won't get more > than 10-15 seconds out of it. Tweeters usually go first, but I've seen > *many* speakers damaged by an underpowered amp clipping, if you open one up > the voice coil is blackened. > You are comparing apples and oranges. The power rating of a speaker is based on its impedance, not its DC resistance. They are very different things. When using a DC coupled amplifier, it is quite common for the amp to fail and produce a DC voltage. As you noted, this is very bad for the speakers' voice coil, which is a pretty fine piece of wire, and they burn out almost instantly. -Fred W