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Hi Bill,
Isn't the RMS Power rating of an audio amp much lower than its=20
peak output capability? When I was in high school drooling over
high-end stereo amps, I recall magazines like Stereo Review would
rate audio amplifiers in terms of their peak output capability=20
as well as RMS output. The really good amps were capable of=20
deliverying something like 3 or 4 times their RMS rating on music=20
peaks without clipping. I think they used the term "dynamic=20
headroom" when comparing RMS to peak output capability. =20
Mike, W4EF............................................
----- Original Message -----=20
From: William Fuqua=20
To: amps@contesting.com=20
Sent: Thursday, June 28, 2001 5:49 AM
Subject: Fwd: [AMPS] RMS Power
There is no mathematical notation for "RMS POWER".
If you calculate voltage from average power and load resistance you =
get RMS volts.
Like wise if you calculate current from average power you get RMS =
amps.
Look at the definition of RMS voltage or current. Put it into =
the equation for=20
Power. What you get is the formula for Average Power!!!!!
This RMS power stuff started in the 60's with the stereo equipment =
manufacturers.
They invented "RMS Music Power". This is equivalent to PEP, low% =
duty cycle power.
It allowed them to come up with large wattage ratings for short burst =
of audio. This was necessary
due to the fact that their equipment had weak power supplies and low =
power dissipation capability.
RMS power is a meaningless term.
73
Bill wa4lav
X-Originating-IP: [12.41.226.194]
From: "Billy Ward" <billydeanward@hotmail.com>
To: amps@contesting.com
Subject: [AMPS] RMS Power
To: <amps@contesting.com>
Date: Thu, 28 Jun 2001 05:32:16 -0000
X-OriginalArrivalTime: 28 Jun 2001 05:32:16.0893 (UTC) =
FILETIME=3D[B175B2D0:01C0FF93]
Sender: owner-amps@contesting.com
X-Sponsor: W4AN, KM3T, N5KO & AD1C
[WC6W]
The Bird 43 (without a peak reading module) is an average reading
meter.
[Billy]
I thought that the Bird 43 was an RMS meter without the peak reading =
module. RMS and average are not the same?
Billy
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<DIV><FONT face=3D"Courier New" size=3D2>Hi Bill,</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3D"Courier New" size=3D2>Isn</FONT><FONT face=3D"Courier =
New"=20
size=3D2>'t the RMS Power rating of an audio amp much lower than its =
</FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2>peak output capability? When I =
was in high=20
school drooling over</FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2>high-end stereo amps, I recall =
magazines=20
like Stereo Review would</FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2>rate audio amplifiers in terms =
of their=20
peak output </FONT><FONT face=3D"Courier New" size=3D2>capability =
</FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2>as well as RMS output. The =
really good amps=20
were capable of </FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2>deliverying something like 3 or =
4 times=20
their RMS rating on music </FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2>peaks without </FONT><FONT=20
face=3D"Courier New" size=3D2>clipping. I think they used the =
term=20
"dynamic </FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2>headroom" </FONT><FONT =
face=3D"Courier New"=20
size=3D2>when comparing RMS to peak output capability. =
</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3D"Courier New" size=3D2>Mike,=20
W4EF............................................</FONT></DIV>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: =
0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A href=3D"mailto:Wlfuqu00@pop.uky.edu"; =
title=3DWlfuqu00@pop.uky.edu>William=20
Fuqua</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
href=3D"mailto:amps@contesting.com"=20
title=3Damps@contesting.com>amps@contesting.com</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Thursday, June 28, 2001 =
5:49=20
AM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Fwd: [AMPS] RMS =
Power</DIV>
=
<DIV><BR></DIV> </X-TAB>Th=
ere=20
is no mathematical notation for "RMS POWER".<BR>If you calculate =
voltage from=20
<B>average power</B> and load resistance you get RMS volts.<BR>Like =
wise if=20
you calculate current from <B>average power</B> you get RMS=20
amps.<BR> =
<X-TAB> </X-TAB>Look at the=20
definition of RMS voltage or current. Put it into the equation for=20
<BR>Power. What you get is the formula for Average =
Power!!!!!<BR>This=20
RMS power stuff started in the 60's with the stereo equipment=20
manufacturers.<BR>They invented "RMS Music Power". This is =
equivalent to PEP, low% duty cycle power.<BR>It allowed them to =
come up=20
with large wattage ratings for short burst of audio. This was =
necessary<BR>due=20
to the fact that their equipment had weak power supplies and low power =
dissipation capability.<BR><BR>RMS power is a meaningless=20
term.<BR><BR><BR>73<BR>Bill wa4lav<BR><BR><BR><BR><BR><BR>
<BLOCKQUOTE class=3Dcite cite type=3D"cite">X-Originating-IP:=20
[12.41.226.194]<BR>From: "Billy Ward"=20
<billydeanward@hotmail.com><BR>To: =
amps@contesting.com<BR>Subject:=20
To: <amps@contesting.com>
[AMPS] RMS Power<BR>Date: Thu, 28 Jun 2001 05:32:16=20
-0000<BR>X-OriginalArrivalTime: 28 Jun 2001 05:32:16.0893 (UTC)=20
FILETIME=3D[B175B2D0:01C0FF93]<BR>Sender:=20
owner-amps@contesting.com<BR>X-Sponsor: W4AN, KM3T, N5KO &=20
AD1C<BR><BR><BR>[WC6W]<BR>The Bird 43 (without a peak reading =
module) is an=20
average reading<BR>meter.<BR><BR>[Billy]<BR>I thought that the Bird =
43 was=20
an RMS meter without the peak reading module. RMS and average =
are not=20
the=20
=
same?<BR><BR>Billy<BR><BR>_______________________________________________=
__________________<BR>Get=20
your FREE download of MSN Explorer at=20
http://explorer.msn.com<BR><BR><BR>--<BR>FAQ on=20
=
WWW: &nb=
sp; =20
=
http://www.contesting.com/FAQ/amps<BR>Submissions:  =
; =20
amps@contesting.com<BR>Administrative requests: =20
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amps-REQUEST@contesting.com<BR>Problems: &nb=
sp; =20
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