Fantastic new audio amp !
TTman
a 500AHr. single nicad then, with a 2C charger.
Its true !
http://www.audiumsemi.com/
Jan Panteltje
<someo...@ntlworld.com> wrote in <PPONm.21138$2E....@newsfe20.ams2>:
Links to:
http://www.audiumsemi.com/news002.php
100 W *peak* power output.
That would be 100 mW normal RMS?
Dave Platt
>>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/
>Links to:
> http://www.audiumsemi.com/news002.php
>100 W *peak* power output.
>That would be 100 mW normal RMS?
Something like that, I suspect. The footnote on their October 9th
news article says:
[1] Normal listening level is defined as 73dBC sound pressure level
(SPL) at a distance of 1 metre, with a speaker sensitivity of 89dBC/W
at 1 metre.
Quiet background music, from relatively efficient speakers located
only a few feet from you. -16 dBW, or only 25 milliwatts of audio
delivered to the speakers.
Let's see... "up to 10 months on a set of four C batteries, playing
for up to three hours per day." That's 300 days, 900 operating hours,
45 watt-hours (assuming 100% efficiency), or 15 amp-hours at 1.5 volts.
According to The Great Dubious Reference (WikiPedia) alkaline C
batteries have a nominal capacity of 8530 mAh. Four of them in
parallel would have about 35 amp-hours of energy, which is
quite a bit more than the 15 amp-hours which would need to be
delivered to the speakers. Required "battery in to audio out"
electrical efficiency would be around 40%.
So, it seems to me that their claims don't necessarily violate the
laws of physics... assuming high efficiency in the amp, the sound
level and speaker sensitivity that they assert, and the "up to 10
months" and "up to three hours per day" boundaries. They don't seem
to specify frequency response, distortion, or noise levels.
They'd need a *very* different power supply arrangement in order for
the "100 watt" number they quote to be even slightly relevant and
believable.
Seems as if it may be an interesting niche product.
--
Dave Platt <dpl...@radagast.org> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!
Ralph Barone
"TTman" <someo...@ntlworld.com> wrote:
And also "is 20 times more efficient than competing devices, such as
Class D amplifiers...". Well, that spec is obviously not measured
anywhere within 13 dB of full power, since Class D amps are near 100%
efficient at full power. Reading further, it seems that they do power
rail switching (a la Class G) to get their claimed high efficiency at
low power output. The big question is of course, "So what?".
The first product on their product listing is the AS2001 50 WPC stereo
amp. Let's assume that at power levels below 1 WPC, that they have
higher efficiency. However, any decent product built with this part
will need a power supply capable of > 100 W, or energy storage capable
of delivering ~ 100 W for some reasonable amount of time. Once you've
done that, who cares whether you can save 0.5 W dissipation when you're
listening really, really quietly?
fitlike min
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.
D from BC
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
ChrisQ
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
Tony
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
ChrisQ
>>
> 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
christofire
"ChrisQ" <me...@devnull.com> wrote in message
news:_wtOm.18019$492....@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)
Jim Thompson
<chris...@btinternet.com> wrote:
[snip]
>
>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)
>
I was always fond of touting my amplifier as 400W CONTINUOUS RMS, as
opposed to those nutcases who spout "music power" or "peak power" ;-)
...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
ChrisQ
> "ChrisQ" <me...@devnull.com> wrote in message
> news:_wtOm.18019$492....@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:
>
That was a bit of an own goal, but to be honest, just searched for an
article as an explanation, without reading it in full :-(.
Doesn't change the fact that rms measurement of power is just as valid
and accurate for power as a true rms voltmeter is as valid as an average
reading voltmeter, depending on what you are trying to measure. A true
rms measurement takes into account waveform shape, whereas an average
reading meter is calibrated for a given waveform shape, usually sine
wave, at calibration time. It will be in error with anything else. Thus,
a true rms measurement is more usefull in practice...
Regards,
Chris
Vladimir Vassilevsky
Jim Thompson wrote:
> I was always fond of touting my amplifier as 400W CONTINUOUS RMS, as
> opposed to those nutcases who spout "music power" or "peak power" ;-)
Agreed. The real power, not bullshit power, tells a lot about the
design. However, there is one more parameter: for how long the amp can
sustain that power level undistorted.
Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com
Jim Thompson
In my case "CONTINUOUS" meant exactly that ;-)
krw
No it isn't. RMS is valid for voltage and current because the square
is useful for calculating power. The square, thus the root of the
mean square, of power is meaningless. "Average" power says it all,
regardless of waveform. Any other sort of power is bogus.
ChrisQ
> On Mon, 23 Nov 2009 09:25:10 -0600, Vladimir Vassilevsky
> <nos...@nowhere.com> wrote:
>
>>
>> Jim Thompson wrote:
>>
>>
>>> I was always fond of touting my amplifier as 400W CONTINUOUS RMS, as
>>> opposed to those nutcases who spout "music power" or "peak power" ;-)
>> Agreed. The real power, not bullshit power, tells a lot about the
>> design. However, there is one more parameter: for how long the amp can
>> sustain that power level undistorted.
>>
>>
>> Vladimir Vassilevsky
>> DSP and Mixed Signal Design Consultant
>> http://www.abvolt.com
>
> In my case "CONTINUOUS" meant exactly that ;-)
>
> ...Jim Thompson
Right, not '1 minute duty' like you see on some motors, but continuous,
24/7 if required and stay within spec :-)...
Regards,
Chris
ChrisQ
>
> No it isn't. RMS is valid for voltage and current because the square
> is useful for calculating power.
Umm, isn't that what we are trying to measure ?.
> The square, thus the root of the
> mean square, of power is meaningless. "Average" power says it all,
> regardless of waveform. Any other sort of power is bogus.
Why do you think all pro audio gear is specified in terms of rms power
output ?...
Regards,
Chris
Spehro Pefhany
<To-Email-Use-Th...@My-Web-Site.com> wrote:
>On Mon, 23 Nov 2009 09:25:10 -0600, Vladimir Vassilevsky
><nos...@nowhere.com> wrote:
>
>>
>>
>>Jim Thompson wrote:
>>
>>
>>> I was always fond of touting my amplifier as 400W CONTINUOUS RMS, as
>>> opposed to those nutcases who spout "music power" or "peak power" ;-)
>>
>>Agreed. The real power, not bullshit power, tells a lot about the
>>design. However, there is one more parameter: for how long the amp can
>>sustain that power level undistorted.
>>
>>
>>Vladimir Vassilevsky
>>DSP and Mixed Signal Design Consultant
>>http://www.abvolt.com
>
>In my case "CONTINUOUS" meant exactly that ;-)
>
> ...Jim Thompson
Notwithstanding the PMPO type of lies, I have seen serious audio work
(new patents and technology etc.) being done to maximize the music or
vocal performance from a fixed amount of power input.
krw
>krw wrote:
>
>>
>> No it isn't. RMS is valid for voltage and current because the square
>> is useful for calculating power.
>
>Umm, isn't that what we are trying to measure ?.
No, you said that you were measuring power.
>> The square, thus the root of the
>> mean square, of power is meaningless. "Average" power says it all,
>> regardless of waveform. Any other sort of power is bogus.
>
>Why do you think all pro audio gear is specified in terms of rms power
>output ?...
The same reason that Monster Cables are so popular; audiophoolery.
christofire
It isn't!
A popular manufacturer of professional audio power amplifiers is QSC and,
for example, the specifications of their CX-series of PA amps
(http://www.qscaudio.com/products/amps/cx/cx2/cx2.htm) give the output
powers in W ... not W RMS, just watts. However, they do use RMS, correctly,
in their specification of input signal _voltages_ (sensitivity and clipping
threshold).
Chris(tofire)
Jim Thompson
You _have_ to know... if _I_ built a 400W audio amplifier, it used a
transformer, not a switcher, and had heat sinks with fans... took two
people to carry it ;-)
Spehro Pefhany
<To-Email-Use-Th...@My-Web-Site.com> wrote:
I bet it did. The technology did not exist to build these things at a
reasonable price even a decade ago. Maybe if you had BJTs made from
resublimated thiotimoline. ;-)
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
sp...@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
Rich Grise
"Fantastic" as in "a fantasy?"
Thanks,
Rich
Jim Thompson
<spef...@interlogDOTyou.knowwhat> wrote:
That 400W amplifier was around 1975-ish, for the neighbor kid who I
tutored in Algebra, applying a little bribe... get "A" and we'll build
you a 400W guitar amplifier ;-)
He got an "A", and I got a swimming pool for around 1/2 price... his
father was president of Anthony Pools ;-)
Joel Koltner
news:pan.2009.11.24....@example.net...
> "Fantastic" as in "a fantasy?"
Yep. They say 100W "peak power" output, which of course means nothing at all.
It's the same hyperbole many companies release today... they may well have
some improvement that make their amplifiers a bit better (notice that nowhere
to they talk about something as simple as the power *efficiency* of their
designs), but they have to come up with all sorts of hype to get anyone to pay
attention... or so they think.
The whole "use a low voltage except when you start getting peaks at which
point you switch on a boost converter and have it track the peaks" is
well-known (and pretty obvious to anyone "skilled in the art") technique for
high-power RF amplifiers; I have to imagine the audio guys have known about
such things for decades too.
---Joel
Vladimir Vassilevsky
Spehro Pefhany wrote:
> Notwithstanding the PMPO type of lies, I have seen serious audio work
> (new patents and technology etc.) being done to maximize the music or
> vocal performance from a fixed amount of power input.
Simply put, audio signal has Gaussian distribution of amplitude.
Providing ~12dB backoff for peaks, for the same max. output swing, the
average audio power is going to be somewhat 1/8 of the undistorted
sinusoidal RMS power. So, there is little advantage in sustaining high
power at sinusoid, however the amp should be able to handle peak
loads. This allows for saving $$$, especially as audio market is VERY
sensitive to cost. The consideration applies to linear amps and Class D
as well, because the efficiency of Class D is not so good at low power.
There are, however, quite many folks who like to drive amps deep into
clipping and all that matters is loudness. If the amp is overheating, it
turns down the party. The amps for those folks are rated in watts per
dollar, and they should sustain full swing square wave operation. This
is entire special area and the design approach is different.
Vladimir Vassilevsky
Joel Koltner wrote:
> "Rich Grise" <rich...@example.net> wrote in message
> news:pan.2009.11.24....@example.net...
>
>>"Fantastic" as in "a fantasy?"
>
>
> Yep. They say 100W "peak power" output, which of course means nothing at all.
>
> It's the same hyperbole many companies release today... they may well have
> some improvement that make their amplifiers a bit better (notice that nowhere
> to they talk about something as simple as the power *efficiency* of their
> designs), but they have to come up with all sorts of hype to get anyone to pay
> attention... or so they think.
"Power efficiency" is politically correct way of saying "saving on the
heat sink metal".
> The whole "use a low voltage except when you start getting peaks at which
> point you switch on a boost converter and have it track the peaks" is
> well-known (and pretty obvious to anyone "skilled in the art") technique for
> high-power RF amplifiers; I have to imagine the audio guys have known about
> such things for decades too.
Audio is very sensitive to cost; lots of different things could be done,
however the art is about getting it cheap and simple while keeping
reasonable performance.
Dave Platt
Vladimir Vassilevsky <nos...@nowhere.com> wrote:
>> Notwithstanding the PMPO type of lies, I have seen serious audio work
>> (new patents and technology etc.) being done to maximize the music or
>> vocal performance from a fixed amount of power input.
>
>Simply put, audio signal has Gaussian distribution of amplitude.
>Providing ~12dB backoff for peaks, for the same max. output swing, the
>average audio power is going to be somewhat 1/8 of the undistorted
>sinusoidal RMS power.
Unfortunately (for my ears, at least) the width of the distribution
has been narrowing quite a lot over the past couple of decades. A
great many commercial CDs being released these days have very little
dynamic range - their peak-to-average ratio has been squashed down
into a paper-thin wafer. It seems to be that the "race to be loudest"
(on average) has won out over any sort of dynamic range or
expressiveness.
It's even worse if you're listening to music on the radio... most
stations take the already-squashed material, and squash it down even
further.
Audio amps designed to play this sort of music will have to deal with
a regime in which they just won't see significant changes in
output power level over time, unless somebody actually grabs the
volume control knob and twists it.
JosephKK
<pNaonSt...@yahoo.com> wrote:
>On a sunny day (Sat, 21 Nov 2009 09:56:56 -0000) it happened "TTman"
><someo...@ntlworld.com> wrote in <PPONm.21138$2E....@newsfe20.ams2>:
>
>>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/
>>
>>
>
>Links to:
> http://www.audiumsemi.com/news002.php
>100 W *peak* power output.
>That would be 100 mW normal RMS?
Pretty much. For those old enough it seems a lot like the return of
PMPO. And the other amplifier appears to be class A instead of class
D.
JosephKK
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/
>
>>Links to:
>> http://www.audiumsemi.com/news002.php
>>100 W *peak* power output.
>>That would be 100 mW normal RMS?
>
>Something like that, I suspect. The footnote on their October 9th
>news article says:
>
>[1] Normal listening level is defined as 73dBC sound pressure level
> (SPL) at a distance of 1 metre, with a speaker sensitivity of 89dBC/W
> at 1 metre.
>
>Quiet background music, from relatively efficient speakers located
>only a few feet from you. -16 dBW, or only 25 milliwatts of audio
>delivered to the speakers.
>
>Let's see... "up to 10 months on a set of four C batteries, playing
>for up to three hours per day." That's 300 days, 900 operating hours,
>45 watt-hours (assuming 100% efficiency), or 15 amp-hours at 1.5 volts.
>
>According to The Great Dubious Reference (WikiPedia) alkaline C
>batteries have a nominal capacity of 8530 mAh. Four of them in
>parallel would have about 35 amp-hours of energy, which is
>quite a bit more than the 15 amp-hours which would need to be
>delivered to the speakers. Required "battery in to audio out"
>electrical efficiency would be around 40%.
>
>So, it seems to me that their claims don't necessarily violate the
>laws of physics... assuming high efficiency in the amp, the sound
>level and speaker sensitivity that they assert, and the "up to 10
>months" and "up to three hours per day" boundaries. They don't seem
>to specify frequency response, distortion, or noise levels.
>
>They'd need a *very* different power supply arrangement in order for
>the "100 watt" number they quote to be even slightly relevant and
>believable.
>
>Seems as if it may be an interesting niche product.
The target audience may be people who are dissatisfied with how loud
their mp3 players get.