Fantastic new audio amp !
in [Design]
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From: D from BC on 22 Nov 2009 02:38 On Sat, 21 Nov 2009 23:03:18 -0800 (PST), fitlike min <killwhang(a)googlemail.com> wrote: >On Nov 21, 10:56�pm, "TTman" <someone...(a)ntlworld.com> wrote: >> 100Watts, runs from a 1.5V battery . Yes, that's correct ! So that would be >> a 500AHr. single nicad then, with a 2C charger. >> Its true !http://www.audiumsemi.com/ > >It quotes peak output power. I switched off then. Only amateurs use >peak power or fraudsters. >Power is defined as average power or instantaneous. > >F. I use peak power in amp design but I kinda call it 'clip power' over here. It's the power at the peak of the signal. When clipping is audioable at the lowest common audio frequency, I call that the peak power or clip power. It can depend on load, frequency and waveform. It's also the max instantaneous power Ipeak^2*Z =Peak power. Or perhaps your thinking peak music power... :P
From: ChrisQ on 22 Nov 2009 13:58 fitlike min wrote: > On Nov 21, 10:56 pm, "TTman" <someone...(a)ntlworld.com> wrote: >> 100Watts, runs from a 1.5V battery . Yes, that's correct ! So that would be >> a 500AHr. single nicad then, with a 2C charger. >> Its true !http://www.audiumsemi.com/ > > It quotes peak output power. I switched off then. Only amateurs use > peak power or fraudsters. > Power is defined as average power or instantaneous. > > F. In the uk, the power output is usually specified as the rms value of a continuous sine wave into a resistive load just below clip level and is usually less than instantaneous power due to power supply sag... Anything else is a lie, though quite common in the specmanship world... Regards, Chris
From: Tony on 23 Nov 2009 01:43 On Sun, 22 Nov 2009 18:58:01 +0000, ChrisQ <meru(a)devnull.com> wrote: >fitlike min wrote: >> On Nov 21, 10:56 pm, "TTman" <someone...(a)ntlworld.com> wrote: >>> 100Watts, runs from a 1.5V battery . Yes, that's correct ! So that would be >>> a 500AHr. single nicad then, with a 2C charger. >>> Its true !http://www.audiumsemi.com/ >> >> It quotes peak output power. I switched off then. Only amateurs use >> peak power or fraudsters. >> Power is defined as average power or instantaneous. >> >> F. > >In the uk, the power output is usually specified as the rms value of a >continuous sine wave into a resistive load just below clip level and is >usually less than instantaneous power due to power supply sag... > >Anything else is a lie, though quite common in the specmanship world... > >Regards, > >Chris > Not that this hasn't been done to death many times, but there's no such thing as "rms power", and the "rms value of a continuous sine wave" isn't really quite explicit.enough to be useful. AFAIK the fictitious term "rms power" means something like V^2/R, where R is the nominated load resistance, and V is the RMS voltage of a sine wave that the amp can be sustain into such a load resistance without clipping. Cheers, Tony
From: ChrisQ on 23 Nov 2009 05:32 Tony wrote: >> > Not that this hasn't been done to death many times, but there's no such thing as "rms > power", and the "rms value of a continuous sine wave" isn't really quite explicit.enough > to be useful. > Sure there is and what's not explicit enough ?. An amplifier can be seen as a voltage generator and can have it's continuous power expressed in terms of rms value. > > AFAIK the fictitious term "rms power" means something like V^2/R, where R is the nominated > load resistance, and V is the RMS voltage of a sine wave that the amp can be sustain into > such a load resistance without clipping. > > Cheers, Tony Fictitious ?. Ok, here's a wiki article on it: http://en.wikipedia.org/wiki/Audio_power Even the us makers specify rms now, when in the old days, they specified peak or some variation. Jap quality hifi manufacturers always specified rms, fwir, as did uk builders. There have to be standards. Some domestic and auto amplifiers have in the past claimed Kw, when you can tell just by looking at the size of the box that it's bs. Some strange runes and arithmetic may have got them there, but it ain't engineering. Here, such claims go into the same bin as tinfoil hats and o2 free copper cable :-)... Regards, Chris
From: christofire on 23 Nov 2009 07:07
"ChrisQ" <meru(a)devnull.com> wrote in message news:_wtOm.18019$492.10435(a)newsfe18.ams2... > Tony wrote: > >>> >> Not that this hasn't been done to death many times, but there's no such >> thing as "rms >> power", and the "rms value of a continuous sine wave" isn't really quite >> explicit.enough >> to be useful. >> > > Sure there is and what's not explicit enough ?. An amplifier can be seen > as a voltage generator and can have it's continuous power expressed in > terms of rms value. > >> >> AFAIK the fictitious term "rms power" means something like V^2/R, where R >> is the nominated >> load resistance, and V is the RMS voltage of a sine wave that the amp can >> be sustain into >> such a load resistance without clipping. >> >> Cheers, Tony > > Fictitious ?. Ok, here's a wiki article on it: > > http://en.wikipedia.org/wiki/Audio_power You didn't spot the bit: 'In common use, the terms "RMS power" or "watts RMS" are erroneously used to describe average power.' then? Or the references: a.. The so called "RMS Power" a.. Meaningless RMS Power - Why there is no such thing as 'RMS watts' or 'watts RMS' and never has been Unfortunately, the Wiki gnomes don't manage to weed out all the dross and they've left in stuff like: 'The peak power of a sine wave of RMS value X is ?2*X; ' which is wrong for the same reason. Chris (a different one) |