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From: ray@utcsrgv.UUCP (Raymond Allen)
Newsgroups: net.audio
Subject: Re: High power amps are sometimes useful - (nf)
Message-ID: <1473@utcsrgv.UUCP>
Date: Tue, 7-Jun-83 12:29:19 EDT
Article-I.D.: utcsrgv.1473
Posted: Tue Jun  7 12:29:19 1983
Date-Received: Tue, 7-Jun-83 16:15:34 EDT
References: <1089@hp-pcd.UUCP>
Organization: CSRG, University of Toronto
Lines: 20


	Actually, your speakers must not be very efficient.  If you were to try
to reproduce a symphony orchestra recording at concert hall volume levels (where
the musical peaks could exceed 100dB) then, on these peaks, your amplifier would
have to produce instantaneous power on the order of 5000 to 10000 watts!!!
Although there is little likelyhood that an attempt to produce such power would
destroy your amplifier (since the transients are of very short duration) some
simple mathematics would indicate that to produce 5000 watts across 8 ohms
requires 200 volts.  Very few commercial amplifiers use a power supply of this
high of a voltage (dare i say none?).  The result?  Your amplifier will simply
clip, and thus distort the output.

	To be perfectly fair, it is important to note that i have never seen an
audio power amp which has power meters which actually give a true indication of
the power that the amplifier is producing.  All the amps that i see just use a
voltmeter on the output with a scale that is calibrated for watts which assumes
that the amp is driving an 8 ohm resistive load.  Most real-world speakers are
quite reactive and, thus, this type of meter is less than useless.  The only
thing that you can be sure of is that the actual power is less than or equal to
(if the load is a pure resistance) the reading on the meter.