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From: "Ian Buckner"
Subject: Re: 'Current Dumping' Amplifier Circuits ?
Date: Wed, 4 Dec 2002 10:45:46 -0000
Organization: Agilent Technologies
References: <firstname.lastname@example.org> <email@example.com> <3debaeec.2879341@News.xtra.co.nz> <86$6IEAG7I79EwxN@jmwa.demon.co.uk>
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"Phil Allison" wrote in message
> "John Woodgate" wrote in message
> > I read in sci.electronics.design that Phil Allison
> > wrote (in ) about
> > Dumping' Amplifier Circuits ?', on Wed, 4 Dec 2002:
> > >** I service and test these buggers for a living, John.
> > I never doubted it for a moment.
> > >
> > > The THD figures I see are nearly always better than
> > >at just below clipping into 8 ohms. Some are down to 0.005 % at
> > >( Yamaha 2200)
> > Yes.
> > >
> > > Go 0.5 dB more an the figure is 5% THD. Nothing crazy
> > Well, 0.5 dB in power terms is a 12.2% increase. In heating terms,
> > can easily take a voice coil over the magic 260 C that spells
> > And amps are often driven up to 10% THD in the field. Is your
> > of fried drivers different?
> ** I am not with you here, John.
> The average power delivered into the speaker over some
> time is what may overheat it - the THD of the amp is just not
> This average may be enhanced by amplitude compression as a result of
> PA amps have had low to very low THD figures ever since they
> using valves.
> ................. Phil
ISTR that one problem is that running into clipping generates large
of high frequecies, which fries the tweeters, as they are not designed
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