On Fri, 07 Jan 2005 16:12:31 -0500, Spehro Pefhany
wrote:

On Fri, 07 Jan 2005 20:53:13 GMT, the renowned Howard Eisenhauer
wrote:

On Fri, 07 Jan 2005 05:49:13 GMT, "Leo Lichtman"
wrote:


"Howard Eisenhauer" wrote: Is that watts RMS? (clip)
^^^^^^^^^^^^
Howard, I hope you did that on purpose. "Watts RMS," a term popular in
advertising audio amplifiers, has always galled me. I can see no way for it
to have any meaning, considering what RMS stands for, and what it is used
for. :-)



On the contrary actually, I consider RMS to be the most meaningful
measurement of power, but that may be specific to the areas I use it
in.

"RMS watts", although mathematically possible to compute, would have
no useful *physical* meaning that I can think of. Usually they are a
misnomer for "true power".

I can see your point however once you're away from DC or working
outside narrow specialty fields where it's assumed everybody knows
"Whats Watt" the term "watts" by itself can be mis-leading. If you
say watts RMS everybody (at least in my experience) knows what you're
talking about. For commercial power situations where you can run into
power factor issues "VA" is a better concept. For audio I just buy
the biggest amp I can afford & say the heck with the rest.

So, anytime I set the power output on an AM or FM transmitter the ol'
Bird 43 sez "Watt RMS". Same thing on the HP power meter when I'm
doing micro wave links, except that when measuring at the directional
coupler it generally comes out in "milli-watts RMS". And thats not
even using the BIG Bucks "True RMS" meters they sell. SSB is, of
course, Not to be Talked About Here .

Anytime I set or measure a level on an analog audio line using a test
tone I'm usually looking for a given level of dBM, where 0 dBM is, by
definition, equal to 1 mW, RMS .

I recently designed an oil heater with a non-inductive load (duh). I
calculated, using the resistance of the element and the 115 V RMS
line level, the RMS power disapation in watts which I then cleverly
converted (Convert.EXE- Gotta Luv It!) into calories to figure out how
long it would take to heat up the oil under given conditions. When I
actually tried the thing out I was pretty damn close :0.

In point of fact, I find RMS usefull every day of the week, &
sometimes twice on Sundays .


As far audio goes I'd be more interested in THD, peak power/dymanic
range & whether or not the dual isolated power supplies were built
using oxygen free silver buss bars .

H.

You don't want to spend $500 on a wooden knob that prevents
"microvibrations" from entering the delicate signal path? ;-)


Only if it's one thats been lovingly hand crafted from select cuts of
rare imported Outer Pangorian Swamp Palm. Anybody with half an ear
can tell that a set of knobs made from it perceptually add to the
acoustic colour depth as well as mellowing the harmonic relationships
;.


Best regards,
Spehro Pefhany


Back At'cha,

H.