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  #41   Report Post  
Paul Vina
 
Posts: n/a
Default Clean Power?

That's very true. When we first built our new store we level matched
everything (well, as close as you can in a retail environment) and all of a
suuden Crossfire amps were our new best sellers. All of our other brands
were sliding because people couldn't hear a difference, or at least not a
big enough of a difference to justify twice as much money on a more
expensive amp, unless it was the other features they wanted.



Paul Vina




"Scott Gardner" wrote in message
...
On Sun, 4 Jan 2004 10:40:48 -0500, "Mark Zarella"
wrote:

What I have found with so called cheap amps such as Profile, Jensen and
Pyramid is that you have to crank the hell out of them to get deep

bass.
Where
more costly amps such as Orion, Kicker, PPI and MTX seem to produce

deeper
bass at lower volume levels. I also found that these cheaper amps seem

to
run
a lot hotter. The only reason for this that I can think of is an

inadequate
power supply.


No, that's not a problem. Every "cheap" amp I've ever tested has a flat
frequency response down to 20 Hz (lower in fact). This is well

documented
actually. What you're undoubtedly experiencing is a lack of power. Use

a
bigger "cheap" amp and you won't run into this.


Yep - it's amazing how many sonic "differences" between amplifiers
disappear when they're level-matched before the comparison. Anyone
that sells amplifiers using an in-store display will tell you that a
customer will always favor the slightly louder setup, even if it's
only a dB or two.

Scott Gardner



  #42   Report Post  
Captain Howdy
 
Posts: n/a
Default Clean Power?

I don't understand how this could be a wattage issue, since this is an
auditable difference at low volume levels. A few years ago I was running a
1200 watt 4 channel Pyramid bridged in to a pair of 4ohm 12's and it powered
them nice and loud, but there just wasn't any low bass at low volume levels.
Then I replaced it with a Kicker IX704 amp which had loads of grindage at low
volume levels. But oddly enough it did not hit as hard at high volume levels.
It's not just the Pyramid, I have a pair of Profile amps here that act the
same way.


In article , "Mark Zarella"
wrote:
What I have found with so called cheap amps such as Profile, Jensen and
Pyramid is that you have to crank the hell out of them to get deep bass.

Where
more costly amps such as Orion, Kicker, PPI and MTX seem to produce deeper
bass at lower volume levels. I also found that these cheaper amps seem to

run
a lot hotter. The only reason for this that I can think of is an

inadequate
power supply.


No, that's not a problem. Every "cheap" amp I've ever tested has a flat
frequency response down to 20 Hz (lower in fact). This is well documented
actually. What you're undoubtedly experiencing is a lack of power. Use a
bigger "cheap" amp and you won't run into this.


  #43   Report Post  
Pug Fugley
 
Posts: n/a
Default Clean Power?

John Andreen. The only SANE person (besides myself) that I've seen in this
newsgroup yet. You guys spouting out advice and acting like you know
everything should listen to Mr. Andreen. Trust me, you'll learn something.



"John Andreen" wrote in message
news:tMXJb.26126$i55.5289@fed1read06...
Mr Zarella

You are correct, there is always a trade-off between a "clean" amplifier

and
a "dirty" amplifier. But the "dirty" amplifier will always loose in terms
of reliability, distortion, sound quality etc. All at the expense of good
Engineering practices and a handful of parts.

On a side note, what would you rather be driving, a Yugo or a Mercedes?

Ok,
not the same, but how about a Yugo or a Ford Focus? But if your life
depended on its proper operation all the time, which would you choose?

Here is another case in point. Old school PPI amplifiers. Some of these
amplifiers are over 15 years old and they are still operating and making
great sound. In fact, these units are still highly sought after. Can you
say the same for an equally aged Pioneer or Sony? I think you are perhaps
using a shifting baseline as to what is "clean" today.

Could you also be confusing distortion with noise? They are not the same.
You should do some investigation on these subjects. What you say is a
measurement of distortion is actually called "THD +N" a.k.a. Total

Harmonic
Distortion + Noise. Then to make matters worse, some audio companies use
filters (read A-weighted) to make there units appear to have low THD+N.

To
add even more confusion into the mix, this "THD+N" is almost always
computationally measured using FFT methods. There are more than a dozen
FFT windows ( read measuring envelope ) that can be used to make the
measurement. Each will give a return a different value for "THD+N". There
is one more thing about measuring "THD+N". One must also specify the

power
of the signal being measured. One can measure at 1W, 5W, Full rated

power,
etc. "THD+N" is not constant at all power levels. It is usually higher

at
very low power levels and very high power levels. At very low power
levels, the major component comes from "noise". At very high power

levels,
the major component comes from "THD". Really "clean" amplifiers have "TH
+N" values nearly equal at all power levels under clipping.

I can take even the "dirtiest" amplifier and measure extremely low values

of
distortion. On the order of 1/1000 of a %. That is, if I can choose my
own method and power level of distortion measurement.

There is also harmonic distortion caused by the sum and difference of two
signals. Let's say a 40 kHz square wave from a power supply and a 1 kHz
sine wave. There will be strong harmonic distortion at 39 kHz and 41 kHz.
There are also artifacts called sub-harmonics of these two signals that
will be present. These are the artifacts that can appear down in the

audio
spectrum. I would also like to point out that music isn't just 1 kHz, but
a plethora of frequencies.

I have told this group many times not to be concerned with "THD+N" as a
figure of merit when buying an amplifier. The human ear doesn't mind even
1-3% THD. It is a "Marketing Tool" designed to sway the masses. Go

listen
to a high quality pure tube amplifier and a high quality transistorized
amplifier of the same output power specifications. Do this test blindly.
I am absolutely certain that you will always pick the tube amplifier over
the transistorized one as having the better sound. But, that tube
amplifier will have distortion figures SEVERAL HUNDRED TIMES WORSE than

the
transistorized amplifier. Instead, try to buy an amplifier that has Low
"TIM" and low S/N. TIM stands for Transient Intermodulation Distortion.
Good audio distortion analyzers can find this kind of distortion using the
"IMD" settings.

Now, onto the subject of noise. Noise is ever present in the audio world.
It comes from the amplifiers SMPS. It comes from the Automobiles charging
system. It comes from solar wind. It comes from the power transmission
lines. In short, it comes from just about everywhere. In my last post, I
stated several things that make for a "clean" amplifier. Those things are
the items or methodologies used to eliminate or diminish the ingress of
noise into an amplifier. I forgot one them. Decoupling capacitors. Once
again, do not do any or all of those items, and more effective noise will
make it into the audio path. Do all of them right and you will diminish
the ingress of noise into the audio path and have a "clean" amplifier.

I have measured and tested amplifiers from many of the "top" car audio
companies. Some had signal to noise ratios of -50dB, some had signal to
noise ratios greater than -100dB. In other words, the best amplifiers S/N
was 64 times better than the worst. The reason, one amplifier was more
"clean" than anothers. Once again, you can fudge these numbers too. S/N
is different depending upon the position of the gain pot. At max gain,

S/N
to noise will be different than min gain. The difference, a handful of
parts and good Engineering practices. QED

John Andreen


Mark Zarella wrote:

There is such a thing as "clean" and "dirty" power. A perfect case in

point
would be to run your amplifier with a cheap battery charger as its B+
supply. You will hear a tremendous amount of "hum". In other words,

it
is
"dirty" power. At the other extreme, hook up a whole bunch ( maybe

10 )
of
automotive batteries in series. Tap the "GND" from the connection
between
battery 5 and battery 6. Tap the amplifiers output rails (+/-) from

the
the top and bottom posts. to do this, you must eliminate the SMPS
section
and some other items. The Rectifying diodes and the bulk rail

capacitors
to be exact. You now have "clean" Power for your 400W/ch RMS

amplifier.

Many things can affect just how "clean" an amplfier is. Power supply
topology, filter capacitors, Inductors, ferrite beads, transformer

type,
board layout, star grounding, trace capacitance, trace inductance, PCB
layers ( e.g. 1, 2, 4 ). Do all these things right, and you have a

"clean"
power amplifier. Do any one or all these things wrong and you now have

a
"dirty" power amplifier. There is even an extreme case where when the
output rails do not have enough bulk capacitance, the output feedback
circuit goes "open loop" for just a microsecond or so. In this time,

the
output transistors modulate or "burst" at their peaks causing audible
distortion. Lots of cheap amplifiers will do this just before clipping
at full power.

Not all things are created equal. Power is one of them.

If you want a mechanical analog, how about a V-8 piston engine and a

jet
turbine



That's all well and good, but the important thing to examine here is
whether
the results are significant during normal operation. Hint: by
significant,
I mean audible. While there are several ways to lower distortion
(sometimes at the expense of noise, or at the expense of reliability, or
at the expense of other forms of distortion, and so forth), there is of
course a threshold at which further reduction is not warranted, nor is

it
necessarily recommended since there's almost always a tradeoff in some
manner or another.

So your engine analog holds true, but if your application is to just

drive
down a road, then either one will perform as well as the other.




  #44   Report Post  
Pug Fugley
 
Posts: n/a
Default Clean Power?


"Paul Vina" wrote in message
news:h7YJb.123849$VB2.354905@attbi_s51...
I bet the commision based sales people at your local car audio store get

quite
excited when you walk into their store.

Nick



I know I did. Sounds like the kind of guy that would come in and evertime

I
showed him something would ask "Is this competition?"! LOL! GOD, I hated
those guys. Yo man, I want some Rocksford (yes, they said it with the "s"
in there) Fosgate competition subs that bump! That's one of the things

that
makes me glad I got out of retail.


Yep. Guys like that, and guys like Zarella (think they know EVERYTHING) are
the reasons why I got out of retail also. You can only beat the hell out of
them so often before the cops get sick of coming to get them from your
store.


  #45   Report Post  
Pug Fugley
 
Posts: n/a
Default Clean Power?

That's mainly a product of the power supply. But Zarella seems to think that
ALL amps have the same exact power supplies in them for some reason.



"Captain Howdy" wrote in message
...
I don't understand how this could be a wattage issue, since this is an
auditable difference at low volume levels. A few years ago I was running

a
1200 watt 4 channel Pyramid bridged in to a pair of 4ohm 12's and it

powered
them nice and loud, but there just wasn't any low bass at low volume

levels.
Then I replaced it with a Kicker IX704 amp which had loads of grindage at

low
volume levels. But oddly enough it did not hit as hard at high volume

levels.
It's not just the Pyramid, I have a pair of Profile amps here that act the
same way.


In article , "Mark Zarella"
wrote:
What I have found with so called cheap amps such as Profile, Jensen and
Pyramid is that you have to crank the hell out of them to get deep

bass.
Where
more costly amps such as Orion, Kicker, PPI and MTX seem to produce

deeper
bass at lower volume levels. I also found that these cheaper amps seem

to
run
a lot hotter. The only reason for this that I can think of is an

inadequate
power supply.


No, that's not a problem. Every "cheap" amp I've ever tested has a flat
frequency response down to 20 Hz (lower in fact). This is well

documented
actually. What you're undoubtedly experiencing is a lack of power. Use

a
bigger "cheap" amp and you won't run into this.






  #46   Report Post  
Jimmy Deam
 
Posts: n/a
Default Clean Power?

On Sun, 04 Jan 2004 10:12:23 -0700, John Andreen
wrote:

Mr Zarella

You are correct, there is always a trade-off between a "clean" amplifier and
a "dirty" amplifier. But the "dirty" amplifier will always loose in terms
of reliability, distortion, sound quality etc. All at the expense of good
Engineering practices and a handful of parts.

On a side note, what would you rather be driving, a Yugo or a Mercedes? Ok,
not the same, but how about a Yugo or a Ford Focus? But if your life
depended on its proper operation all the time, which would you choose?

Here is another case in point. Old school PPI amplifiers. Some of these
amplifiers are over 15 years old and they are still operating and making
great sound. In fact, these units are still highly sought after. Can you
say the same for an equally aged Pioneer or Sony? I think you are perhaps
using a shifting baseline as to what is "clean" today.


http://silverpioneer.com/


Could you also be confusing distortion with noise? They are not the same.
You should do some investigation on these subjects. What you say is a
measurement of distortion is actually called "THD +N" a.k.a. Total Harmonic
Distortion + Noise. Then to make matters worse, some audio companies use
filters (read A-weighted) to make there units appear to have low THD+N. To
add even more confusion into the mix, this "THD+N" is almost always
computationally measured using FFT methods. There are more than a dozen
FFT windows ( read measuring envelope ) that can be used to make the
measurement. Each will give a return a different value for "THD+N". There
is one more thing about measuring "THD+N". One must also specify the power
of the signal being measured. One can measure at 1W, 5W, Full rated power,
etc. "THD+N" is not constant at all power levels. It is usually higher at
very low power levels and very high power levels. At very low power
levels, the major component comes from "noise". At very high power levels,
the major component comes from "THD". Really "clean" amplifiers have "TH
+N" values nearly equal at all power levels under clipping.

I can take even the "dirtiest" amplifier and measure extremely low values of
distortion. On the order of 1/1000 of a %. That is, if I can choose my
own method and power level of distortion measurement.

There is also harmonic distortion caused by the sum and difference of two
signals. Let's say a 40 kHz square wave from a power supply and a 1 kHz
sine wave. There will be strong harmonic distortion at 39 kHz and 41 kHz.
There are also artifacts called sub-harmonics of these two signals that
will be present. These are the artifacts that can appear down in the audio
spectrum. I would also like to point out that music isn't just 1 kHz, but
a plethora of frequencies.

I have told this group many times not to be concerned with "THD+N" as a
figure of merit when buying an amplifier. The human ear doesn't mind even
1-3% THD. It is a "Marketing Tool" designed to sway the masses. Go listen
to a high quality pure tube amplifier and a high quality transistorized
amplifier of the same output power specifications. Do this test blindly.
I am absolutely certain that you will always pick the tube amplifier over
the transistorized one as having the better sound. But, that tube
amplifier will have distortion figures SEVERAL HUNDRED TIMES WORSE than the
transistorized amplifier. Instead, try to buy an amplifier that has Low
"TIM" and low S/N. TIM stands for Transient Intermodulation Distortion.
Good audio distortion analyzers can find this kind of distortion using the
"IMD" settings.

Now, onto the subject of noise. Noise is ever present in the audio world.
It comes from the amplifiers SMPS. It comes from the Automobiles charging
system. It comes from solar wind. It comes from the power transmission
lines. In short, it comes from just about everywhere. In my last post, I
stated several things that make for a "clean" amplifier. Those things are
the items or methodologies used to eliminate or diminish the ingress of
noise into an amplifier. I forgot one them. Decoupling capacitors. Once
again, do not do any or all of those items, and more effective noise will
make it into the audio path. Do all of them right and you will diminish
the ingress of noise into the audio path and have a "clean" amplifier.

I have measured and tested amplifiers from many of the "top" car audio
companies. Some had signal to noise ratios of -50dB, some had signal to
noise ratios greater than -100dB. In other words, the best amplifiers S/N
was 64 times better than the worst. The reason, one amplifier was more
"clean" than anothers. Once again, you can fudge these numbers too. S/N
is different depending upon the position of the gain pot. At max gain, S/N
to noise will be different than min gain. The difference, a handful of
parts and good Engineering practices. QED

John Andreen


Mark Zarella wrote:

There is such a thing as "clean" and "dirty" power. A perfect case in

point
would be to run your amplifier with a cheap battery charger as its B+
supply. You will hear a tremendous amount of "hum". In other words, it

is
"dirty" power. At the other extreme, hook up a whole bunch ( maybe 10 )

of
automotive batteries in series. Tap the "GND" from the connection
between
battery 5 and battery 6. Tap the amplifiers output rails (+/-) from the
the top and bottom posts. to do this, you must eliminate the SMPS
section
and some other items. The Rectifying diodes and the bulk rail capacitors
to be exact. You now have "clean" Power for your 400W/ch RMS amplifier.

Many things can affect just how "clean" an amplfier is. Power supply
topology, filter capacitors, Inductors, ferrite beads, transformer type,
board layout, star grounding, trace capacitance, trace inductance, PCB
layers ( e.g. 1, 2, 4 ). Do all these things right, and you have a

"clean"
power amplifier. Do any one or all these things wrong and you now have a
"dirty" power amplifier. There is even an extreme case where when the
output rails do not have enough bulk capacitance, the output feedback
circuit goes "open loop" for just a microsecond or so. In this time, the
output transistors modulate or "burst" at their peaks causing audible
distortion. Lots of cheap amplifiers will do this just before clipping
at full power.

Not all things are created equal. Power is one of them.

If you want a mechanical analog, how about a V-8 piston engine and a jet
turbine



That's all well and good, but the important thing to examine here is
whether
the results are significant during normal operation. Hint: by
significant,
I mean audible. While there are several ways to lower distortion
(sometimes at the expense of noise, or at the expense of reliability, or
at the expense of other forms of distortion, and so forth), there is of
course a threshold at which further reduction is not warranted, nor is it
necessarily recommended since there's almost always a tradeoff in some
manner or another.

So your engine analog holds true, but if your application is to just drive
down a road, then either one will perform as well as the other.


  #47   Report Post  
Mark Zarella
 
Posts: n/a
Default Clean Power?

Mark,

Why the A/D/S amplifiers? It is because they are well made according to
Engineering practices and very high quality parts. I know, some of my
"work" is in that amplifier.


John, I run the a/d/s/ P840 for my front set because it supplies an adequate
power distribution to my a/d/s/ 641is set allowing me to triamp them and
level control the individual drivers, and it has built-in crossovers that
allow me to bandpass the midbass and midrange speakers and highpass the
tweeters, all with continuously adjustable xover points. Also, its flat
depth means it can be installed up in the rear deck. These features, along
with great support I've had with JD and Directed so far with my other a/d/s/
equipment, and decent reliability is why I bought this amp. Oh yeah, and it
only cost me $220.


  #48   Report Post  
Mark Zarella
 
Posts: n/a
Default Clean Power?

I don't understand how this could be a wattage issue, since this is an
auditable difference at low volume levels.


"Deep bass" tends to require more power to reproduce. This follows the 1/f
"rule". If there were differences at lower volume levels, then one of four
things must be true: 1) tone controls and boosts were active in one case but
not the other; 2) the difference in gain settings were causing a difference;
3) one of the amps was faulty; 4) the power of suggestion is powerful.

A few years ago I was running a
1200 watt 4 channel Pyramid bridged in to a pair of 4ohm 12's and it

powered
them nice and loud, but there just wasn't any low bass at low volume

levels.
Then I replaced it with a Kicker IX704 amp which had loads of grindage at

low
volume levels. But oddly enough it did not hit as hard at high volume

levels.
It's not just the Pyramid, I have a pair of Profile amps here that act the
same way.


Have you measured their frequency response? If something's wrong with that,
including at low volume levels as you suggested, then it's time to send them
in for repair.


  #49   Report Post  
Soundfreak03
 
Posts: n/a
Default Clean Power?

John Andreen. The only SANE person (besides myself) that I've seen in this
newsgroup yet. You guys spouting out advice and acting like you know
everything should listen to Mr. Andreen. Trust me, you'll learn something.


Pug, he didnt ever agree with you you know? Besides you probably were not able
to even understand most of his post, your poor reading comprehension and lack
of electronics knowledge keeps you from that.
Oh and again, where do you work and what competitions have you won? You dropped
it out there by saying your shop drove the others out of business and that you
were winning competitions so lets hear it, when and where did all of this
happen? Oh but wait could it be that none of it happened so thats why your not
telling.

Les
  #50   Report Post  
Mark Zarella
 
Posts: n/a
Default Clean Power?

That's mainly a product of the power supply.

Please elaborate. You keep dodging this question.




  #51   Report Post  
Mark Zarella
 
Posts: n/a
Default Clean Power?

Mr Zarella

You are correct, there is always a trade-off between a "clean" amplifier

and
a "dirty" amplifier. But the "dirty" amplifier will always loose in terms
of reliability, distortion, sound quality etc. All at the expense of good
Engineering practices and a handful of parts.


I have to disagree with you on this point. But I suppose much of it depends
on what you're referring to exactly when you use the term "dirty". I assume
you're talking about distortion and noise, and maybe frequency response.
Much of the distortion characteristics of an audio amplifier are due to the
input stage circuitry, even moreso than the components. You can further
reduce harmonic distortion trhough additional circuitry, however statistical
reliability is sacrificed by doing so. PSRR methods are usually sufficient
in even the simplest IPS designs, and noise is rarely an issue. The biggest
issue to tackle is linearity when compensating for freq response
imperfections. But I don't know of any modern-day class AB amplifiers that
don't perform adequately in this respect.


On a side note, what would you rather be driving, a Yugo or a Mercedes?

Ok,
not the same, but how about a Yugo or a Ford Focus? But if your life
depended on its proper operation all the time, which would you choose?


You're talking about reliability concerns I think, which I haven't disagreed
with anyone on in this thread. The analogy when applied to sound quality
does not apply, unless of course you're talking about driving 5 MPH down the
road, in which case you wouldn't notice a difference. The reason I modify
your analogy is because it completely neglects the measuring device: that
is, the human brain.

Here is another case in point. Old school PPI amplifiers. Some of these
amplifiers are over 15 years old and they are still operating and making
great sound. In fact, these units are still highly sought after. Can you
say the same for an equally aged Pioneer or Sony? I think you are perhaps
using a shifting baseline as to what is "clean" today.


Not sure what reliability has to do with "clean"/"dirty".


Could you also be confusing distortion with noise? They are not the same.
You should do some investigation on these subjects. What you say is a
measurement of distortion is actually called "THD +N" a.k.a. Total

Harmonic
Distortion + Noise.


There are several sources of distortion (but the resulting types of
distortion can most easily be narrowed down to harmonic distortion,
intermodulation distortion, and phase distortion), and I don't believe I've
narrowed it down to any of them. I've generally been referring to
distortion, noise, frequency/phase response as a whole in the discussion of
sound quality.

Then to make matters worse, some audio companies use
filters (read A-weighted) to make there units appear to have low THD+N


Are you referring to the amplifier designs or the testing methodologies?

To
add even more confusion into the mix, this "THD+N" is almost always
computationally measured using FFT methods. There are more than a dozen
FFT windows ( read measuring envelope ) that can be used to make the
measurement. Each will give a return a different value for "THD+N".


The estimation procedure is not vital in this case. A confidence interval
can be derived from any estimation procedure, and if the sample size is
large enough (and given the limited bandwidth in audio) it's quite easy to
limit the bias and variance to negligible levels, especially with proper
windowing when applicable.

There
is one more thing about measuring "THD+N". One must also specify the

power
of the signal being measured. One can measure at 1W, 5W, Full rated

power,
etc. "THD+N" is not constant at all power levels. It is usually higher

at
very low power levels and very high power levels. At very low power
levels, the major component comes from "noise". At very high power

levels,
the major component comes from "THD". Really "clean" amplifiers have "TH
+N" values nearly equal at all power levels under clipping.


Right. Distortion levels vary significantly with different power levels.
Good distortion measurements (like the kind I use ) take this into
account by performing the analysis at different power levels and with
different signals. Harmonic distortion is easy. It's IMD where you start
having to make seemingly arbitrary (though not necessarily incomplete)
decisions.

I can take even the "dirtiest" amplifier and measure extremely low values

of
distortion. On the order of 1/1000 of a %. That is, if I can choose my
own method and power level of distortion measurement.


That's why it's important to use representative techniques and keep them
uniform.


There is also harmonic distortion caused by the sum and difference of two
signals. Let's say a 40 kHz square wave from a power supply and a 1 kHz
sine wave. There will be strong harmonic distortion at 39 kHz and 41 kHz.
There are also artifacts called sub-harmonics of these two signals that
will be present. These are the artifacts that can appear down in the

audio
spectrum. I would also like to point out that music isn't just 1 kHz, but
a plethora of frequencies.

I have told this group many times not to be concerned with "THD+N" as a
figure of merit when buying an amplifier. The human ear doesn't mind even
1-3% THD.


Well, that can depend on a number of other factors, but your point is well
taken.

It is a "Marketing Tool" designed to sway the masses. Go listen
to a high quality pure tube amplifier and a high quality transistorized
amplifier of the same output power specifications. Do this test blindly.
I am absolutely certain that you will always pick the tube amplifier over
the transistorized one as having the better sound. But, that tube
amplifier will have distortion figures SEVERAL HUNDRED TIMES WORSE than

the
transistorized amplifier. Instead, try to buy an amplifier that has Low
"TIM" and low S/N. TIM stands for Transient Intermodulation Distortion.
Good audio distortion analyzers can find this kind of distortion using the
"IMD" settings.


I agree completely. But note that the discussion at hand is picking apart
the difference, rather than the more "pleasing" sound. Several reports have
demonstrated that many listeners actually prefer even order harmonics, which
tend to be especially high in tube designs. However, other reports say
quite the opposite, and asymmetrical clipping which often results in high
even order harmonic content is generally viewed as unfavorable. The most
telling paper I've read on the subject is Farrimond, Perceptual and Motor
Skills,1990,70. He found that in the subjective evaluation of audio
components, it was quite easy to implement paradigms where the users could
tell the difference between two sounds but could not reliably label which
was more or less distorted.


Now, onto the subject of noise. Noise is ever present in the audio world.
It comes from the amplifiers SMPS. It comes from the Automobiles charging
system. It comes from solar wind. It comes from the power transmission
lines. In short, it comes from just about everywhere. In my last post, I
stated several things that make for a "clean" amplifier. Those things are
the items or methodologies used to eliminate or diminish the ingress of
noise into an amplifier. I forgot one them. Decoupling capacitors. Once
again, do not do any or all of those items, and more effective noise will
make it into the audio path. Do all of them right and you will diminish
the ingress of noise into the audio path and have a "clean" amplifier.


I don't know of any modern amplifiers where the inherent noise is a problem.
In fact, the noise resulting from less-than-stellar installation tends to be
much larger than that which cannot be overcome in the amplifier. I said
earlier in the thread however that some amplifiers are more prone to noise
than others, but the significant portion can be eliminated with good
installation techniques. It wasn't too long ago that -70dB to -80dB was
considered good. And IMO, in the car that still is perfectly sufficient.
Now people quibble over the difference between -100dB and -92dB. Again,
it's inconsequential.


I have measured and tested amplifiers from many of the "top" car audio
companies. Some had signal to noise ratios of -50dB, some had signal to
noise ratios greater than -100dB. In other words, the best amplifiers S/N
was 64 times better than the worst. The reason, one amplifier was more
"clean" than anothers. Once again, you can fudge these numbers too. S/N
is different depending upon the position of the gain pot. At max gain,

S/N
to noise will be different than min gain. The difference, a handful of
parts and good Engineering practices. QED


Our disagreement isn't in the electrical aspect of the amplifier. We agree
on just about all of it. Rather, it's the psychophysical end of things.
Pushing distortion down past the noise floor is unnecessary. Trying to
obtain -100dB noise levels is unnecessary. Trying to minimize freq
response dips to below 1dB is unnecessary. This can all be demonstrated in
psychophysical experiments. And these so-called "dirty amplifiers" (even
when, in many cases, the cheaper amplifier is actually "cleaner" than the
more expensive one), do not exhibit deficiencies in any of these categories
that can be detected by us listeners, especially in an electric and acoustic
noise box like a car.


  #52   Report Post  
John Andreen
 
Posts: n/a
Default Clean Power?

This NG is called rec.audio.car. Your picture is of a home amplifier. Not
even close to the same environment. Car=harsh environment. Home=not harsh
environment. There is lots of good old home equipment available, I find and
sometimes buy it at the local good will stores. I have owned Sony and
Pioneer amps way back in the late 70's, but fish paper PCB's do not hold up
all that well in the long term. They all gave out and the cost to diagnose
and repair was prohibitive.

JA
  #53   Report Post  
John Andreen
 
Posts: n/a
Default Clean Power?

Mark

I can also tell you that A/D/S pretty much made extremely good units except
for a few choice "dogs". I can only currently think of only one. I can't
remember the model, but it had several DSP processors on board. Also had
5, yea 5 separate power supplies. Each one "yanking" the amplifiers ground
all over creation. They also had a rather good Audio Engineer's ( Ed
Meitner ) pre-driver stage that was particularly good at rejecting Power
supply noise or any "common-mode" noise for that matter. It was partly
their saving grace. I think that your P840 shares this pre-driver
technology. If you can get your hands on a schematic of your P840, look
for the pre-driver stage. If you see some OPAMPS whose output pins are
tied to GND and has JFETS between the +/- 15 volt rails and the OPAMPS
input +/- supply pins, then you are indeed fortunate. This type of driver
section is usually only used in audiophile grade home amplifiers. Ed
performed a miracle and got it to work for a car amplifier. Those amps
also typically us Burr-Brown Audio grade OPAMPS as well.

I was working at A/D/S when we made great product, I was there when we
knowingly made crap and I was there when we started to make good product
again. I was there when good Engineers left, I was there when bad
Engineers came in and I was there when these bad Engineers either left or
were fired. Those bad Engineers "talked the talk" but didn't "walk the
walk". FYI, a couple of those bad Engineers were really marketing guys who
were Engineering wannabe's. IMHO, Engineers cogitate and marketing types
scheme. The real downfall of PPI/ADS/ORION was pretty much due to these
guys lack of skill and knowledge when it came to Audio Engineering. On
another side note, these same Engineers had a little something to do with
making bad ORION product as well. Bad PPI products also came about around
this time frame as well due to a person who was in "New Products
Development" ( read Marketing ). It was his scheming and back door dealing
( Engineering was left out of the loop ) that created the first gen of the
PCX amplifier. This line was a year late, poorly thought out and had many
issues. This is what you get when you have Marketing telling offshore
firms how to make an amplifier. This new line of PCX amplifiers was even
approved for production after only visually inspecting the prototype
models. Hell, they "looked" great. The marketing man was pleased. Little
did he know.........

In short, That amp of yours and it's next of kin the P850 are indeed great
amps. Just stay away from Constant Bass. This function was implemented
incorrectly. If it were done right, it would be a blessing. But, it was
implemented wrong and kills your sound stage. Engage this feature and
listen to a "sound staging" test CD. You will indeed hear the loss of your
soundstage.

JA


Mark Zarella wrote:

Mark,

Why the A/D/S amplifiers? It is because they are well made according to
Engineering practices and very high quality parts. I know, some of my
"work" is in that amplifier.


John, I run the a/d/s/ P840 for my front set because it supplies an
adequate power distribution to my a/d/s/ 641is set allowing me to triamp
them and level control the individual drivers, and it has built-in
crossovers that allow me to bandpass the midbass and midrange speakers and
highpass the
tweeters, all with continuously adjustable xover points. Also, its flat
depth means it can be installed up in the rear deck. These features,
along with great support I've had with JD and Directed so far with my
other a/d/s/
equipment, and decent reliability is why I bought this amp. Oh yeah, and
it only cost me $220.


  #54   Report Post  
Mark Zarella
 
Posts: n/a
Default Clean Power?

I can also tell you that A/D/S pretty much made extremely good units
except
for a few choice "dogs". I can only currently think of only one. I can't
remember the model, but it had several DSP processors on board. Also had
5, yea 5 separate power supplies. Each one "yanking" the amplifiers

ground
all over creation. They also had a rather good Audio Engineer's ( Ed
Meitner ) pre-driver stage that was particularly good at rejecting Power
supply noise or any "common-mode" noise for that matter. It was partly
their saving grace. I think that your P840 shares this pre-driver
technology. If you can get your hands on a schematic of your P840, look
for the pre-driver stage. If you see some OPAMPS whose output pins are
tied to GND and has JFETS between the +/- 15 volt rails and the OPAMPS
input +/- supply pins, then you are indeed fortunate. This type of driver
section is usually only used in audiophile grade home amplifiers. Ed
performed a miracle and got it to work for a car amplifier. Those amps
also typically us Burr-Brown Audio grade OPAMPS as well.


I've replaced op amps for people who asked me to before (sometimes along
with the discrete components so that I could modify xovers and the like, but
that's another story), and never found a noticeable difference afterwards.
But admittedly, I never a/b'd them. I wouldn't expect a difference though,
since the distortion characteristics of modern op amps tend to be top-notch
(and in fact, superior to discrete components as I found out the hard way in
one design I was doing for another application).

In short, That amp of yours and it's next of kin the P850 are indeed great
amps. Just stay away from Constant Bass. This function was implemented
incorrectly. If it were done right, it would be a blessing. But, it was
implemented wrong and kills your sound stage. Engage this feature and
listen to a "sound staging" test CD. You will indeed hear the loss of

your
soundstage.


I'd like to be able to find a higher power 2-channel relative to the P840
for my rear speakers. I currently have a 240 (?) that looks the same, but I
was hoping to find something closer to 80x2. Did they make one?


  #55   Report Post  
TheBIessedDead
 
Posts: n/a
Default Clean Power?

Yep. Guys like that, and guys like Zarella (think they know EVERYTHING) are
the reasons why I got out of retail also. You can only beat the hell out of
them so often before the cops get sick of coming to get them from your
store.


Funny, I recall you mentioning how your store was running all the other stores
out of business. Kinda hard to do that when you aren't even in retail, don't
ya think?

Nick


  #56   Report Post  
Pug Fugley
 
Posts: n/a
Default Clean Power?


"TheBIessedDead" wrote in message
...
Yep. Guys like that, and guys like Zarella (think they know EVERYTHING)

are
the reasons why I got out of retail also. You can only beat the hell out

of
them so often before the cops get sick of coming to get them from your
store.


Funny, I recall you mentioning how your store was running all the other

stores
out of business. Kinda hard to do that when you aren't even in retail,

don't
ya think?


Go back and read it again, Dick....er..Nick. You misread something
somewhere.


  #57   Report Post  
Captain Howdy
 
Posts: n/a
Default Clean Power?

How does that saying go? An amplifier is only as good as its power supply. I
for one can sure as hell hear a difference between the "cheap" amps and
"costly" amps as I have stated below. If Mark thinks that all amps have the
same exact power supplies in them, then that works out great for him, at least
he can get away with running cheap amps while we have to pay a lot more to
make our ears just as happy. I have owned enough different amps in my time
(cheap and costly ones) to know that all amps don't yield the same sound
quality. Here's a page about power supplies and sound quality, it's written
around home amplifiers, but the same rules apply to car amps as well.
http://www.tnt-audio.com/clinica/ssps1_e.html



In article k.net, "Pug
Fugley" wrote:
That's mainly a product of the power supply. But Zarella seems to think that
ALL amps have the same exact power supplies in them for some reason.



  #59   Report Post  
Mark Zarella
 
Posts: n/a
Default Clean Power?

How does that saying go? An amplifier is only as good as its power supply.
I
for one can sure as hell hear a difference between the "cheap" amps and
"costly" amps as I have stated below. If Mark thinks that all amps have

the
same exact power supplies in them, then that works out great for him, at

least
he can get away with running cheap amps while we have to pay a lot more to
make our ears just as happy.


No Mark doesn't think that, nor did Mark or anyone else in this thread say
that. Pug needs to create an argument that he can win, so he came up with
that one.

I have owned enough different amps in my time
(cheap and costly ones) to know that all amps don't yield the same sound
quality. Here's a page about power supplies and sound quality, it's

written
around home amplifiers, but the same rules apply to car amps as well.
http://www.tnt-audio.com/clinica/ssps1_e.html


If you want references (you know, credible ones - references that have been
published either as books or as articles in reputable journals; not
websites), I'll be more than happy to supply them.


  #60   Report Post  
Pug Fugley
 
Posts: n/a
Default Clean Power?


"Mark Zarella" wrote in message
...
How does that saying go? An amplifier is only as good as its power

supply.
I
for one can sure as hell hear a difference between the "cheap" amps and
"costly" amps as I have stated below. If Mark thinks that all amps have

the
same exact power supplies in them, then that works out great for him, at

least
he can get away with running cheap amps while we have to pay a lot more

to
make our ears just as happy.


No Mark doesn't think that, nor did Mark or anyone else in this thread say
that. Pug needs to create an argument that he can win, so he came up with
that one.


Obviously you can't read.

Now THAT'S an arguement I can win...and I did!







  #61   Report Post  
Soundfreak03
 
Posts: n/a
Default Clean Power?

This NG is called rec.audio.car. Your picture is of a home amplifier. Not
even close to the same environment. Car=harsh environment. Home=not harsh
environment. There is lots of good old home equipment available, I find and
sometimes buy it at the local good will stores.


I have owned Sony and
Pioneer amps way back in the late 70's, but fish paper PCB's do not hold up
all that well in the long term. They all gave out and the cost to diagnose
and repair was prohibitive.


John,

Did you miss the topic? Reliability is one of the reasons to buy a more
expensive amp. Noone is arguing the point you are making. So why are you making
it?

Les
  #62   Report Post  
Soundfreak03
 
Posts: n/a
Default Clean Power?

Funny, I recall you mentioning how your store was running all the other
stores
out of business. Kinda hard to do that when you aren't even in retail,

don't
ya think?


Go back and read it again, Dick....er..Nick. You misread something
somewhere.


So Pug where is your shop?? You said it ran the others out but you still wont
answer where it is at.

Les


  #63   Report Post  
Soundfreak03
 
Posts: n/a
Default Clean Power?

How does that saying go? An amplifier is only as good as its power supply. I
for one can sure as hell hear a difference between the "cheap" amps and
"costly" amps as I have stated below.


Like hell you can. Then take the challenge. Call up Clark and get your 10,000
dollars. Should be easy.

If Mark thinks that all amps have the
same exact power supplies in them, then that works out great for him, at
least
he can get away with running cheap amps while we have to pay a lot more to
make our ears just as happy.


Noone said that. QUOTE WHERE MARK OR I HAVE SAID THAT.

Here's a page about power supplies and sound quality, it's written
around home amplifiers, but the same rules apply to car amps as well.


Ha. Why dont you have a credible source? You can find anything on the internet.
Including idiots and strawmen like Howdy and Puggy.

Les
  #64   Report Post  
Soundfreak03
 
Posts: n/a
Default Clean Power?

Obviously you can't read.

Now THAT'S an arguement I can win...and I did!


How? What in the hell are you talking about? You made up stuff and think you
won.
BTW where is your shop? Still avoiding that one. I think everyone is seeing
through you and your lies.

Les
  #65   Report Post  
Captain Howdy
 
Posts: n/a
Default Clean Power?

What makes you think that something printed on paper is more credible then
something printed in html ? What part of the webpage did you find false other
then the fact that it contradicts what you are saying?

If you want references (you know, credible ones - references that have been
published either as books or as articles in reputable journals; not
websites), I'll be more than happy to supply them.




  #66   Report Post  
John Durbin
 
Posts: n/a
Default Clean Power?

You could say the same about an original Sony XES-M1 or M3... I think
you need to establish an apples to apples comparison, can't compare
premium product with run of the mill stuff and expect them to "age" the
same.

JD

John Andreen wrote:

Mr Zarella

You are correct, there is always a trade-off between a "clean" amplifier and
a "dirty" amplifier. But the "dirty" amplifier will always loose in terms
of reliability, distortion, sound quality etc. All at the expense of good
Engineering practices and a handful of parts.

On a side note, what would you rather be driving, a Yugo or a Mercedes? Ok,
not the same, but how about a Yugo or a Ford Focus? But if your life
depended on its proper operation all the time, which would you choose?

Here is another case in point. Old school PPI amplifiers. Some of these
amplifiers are over 15 years old and they are still operating and making
great sound. In fact, these units are still highly sought after. Can you
say the same for an equally aged Pioneer or Sony? I think you are perhaps
using a shifting baseline as to what is "clean" today.

Could you also be confusing distortion with noise? They are not the same.
You should do some investigation on these subjects. What you say is a
measurement of distortion is actually called "THD +N" a.k.a. Total Harmonic
Distortion + Noise. Then to make matters worse, some audio companies use
filters (read A-weighted) to make there units appear to have low THD+N. To
add even more confusion into the mix, this "THD+N" is almost always
computationally measured using FFT methods. There are more than a dozen
FFT windows ( read measuring envelope ) that can be used to make the
measurement. Each will give a return a different value for "THD+N". There
is one more thing about measuring "THD+N". One must also specify the power
of the signal being measured. One can measure at 1W, 5W, Full rated power,
etc. "THD+N" is not constant at all power levels. It is usually higher at
very low power levels and very high power levels. At very low power
levels, the major component comes from "noise". At very high power levels,
the major component comes from "THD". Really "clean" amplifiers have "TH
+N" values nearly equal at all power levels under clipping.

I can take even the "dirtiest" amplifier and measure extremely low values of
distortion. On the order of 1/1000 of a %. That is, if I can choose my
own method and power level of distortion measurement.

There is also harmonic distortion caused by the sum and difference of two
signals. Let's say a 40 kHz square wave from a power supply and a 1 kHz
sine wave. There will be strong harmonic distortion at 39 kHz and 41 kHz.
There are also artifacts called sub-harmonics of these two signals that
will be present. These are the artifacts that can appear down in the audio
spectrum. I would also like to point out that music isn't just 1 kHz, but
a plethora of frequencies.

I have told this group many times not to be concerned with "THD+N" as a
figure of merit when buying an amplifier. The human ear doesn't mind even
1-3% THD. It is a "Marketing Tool" designed to sway the masses. Go listen
to a high quality pure tube amplifier and a high quality transistorized
amplifier of the same output power specifications. Do this test blindly.
I am absolutely certain that you will always pick the tube amplifier over
the transistorized one as having the better sound. But, that tube
amplifier will have distortion figures SEVERAL HUNDRED TIMES WORSE than the
transistorized amplifier. Instead, try to buy an amplifier that has Low
"TIM" and low S/N. TIM stands for Transient Intermodulation Distortion.
Good audio distortion analyzers can find this kind of distortion using the
"IMD" settings.

Now, onto the subject of noise. Noise is ever present in the audio world.
It comes from the amplifiers SMPS. It comes from the Automobiles charging
system. It comes from solar wind. It comes from the power transmission
lines. In short, it comes from just about everywhere. In my last post, I
stated several things that make for a "clean" amplifier. Those things are
the items or methodologies used to eliminate or diminish the ingress of
noise into an amplifier. I forgot one them. Decoupling capacitors. Once
again, do not do any or all of those items, and more effective noise will
make it into the audio path. Do all of them right and you will diminish
the ingress of noise into the audio path and have a "clean" amplifier.

I have measured and tested amplifiers from many of the "top" car audio
companies. Some had signal to noise ratios of -50dB, some had signal to
noise ratios greater than -100dB. In other words, the best amplifiers S/N
was 64 times better than the worst. The reason, one amplifier was more
"clean" than anothers. Once again, you can fudge these numbers too. S/N
is different depending upon the position of the gain pot. At max gain, S/N
to noise will be different than min gain. The difference, a handful of
parts and good Engineering practices. QED

John Andreen


Mark Zarella wrote:



There is such a thing as "clean" and "dirty" power. A perfect case in


point


would be to run your amplifier with a cheap battery charger as its B+
supply. You will hear a tremendous amount of "hum". In other words, it


is


"dirty" power. At the other extreme, hook up a whole bunch ( maybe 10 )


of


automotive batteries in series. Tap the "GND" from the connection
between
battery 5 and battery 6. Tap the amplifiers output rails (+/-) from the
the top and bottom posts. to do this, you must eliminate the SMPS
section
and some other items. The Rectifying diodes and the bulk rail capacitors
to be exact. You now have "clean" Power for your 400W/ch RMS amplifier.

Many things can affect just how "clean" an amplfier is. Power supply
topology, filter capacitors, Inductors, ferrite beads, transformer type,
board layout, star grounding, trace capacitance, trace inductance, PCB
layers ( e.g. 1, 2, 4 ). Do all these things right, and you have a


"clean"


power amplifier. Do any one or all these things wrong and you now have a
"dirty" power amplifier. There is even an extreme case where when the
output rails do not have enough bulk capacitance, the output feedback
circuit goes "open loop" for just a microsecond or so. In this time, the
output transistors modulate or "burst" at their peaks causing audible
distortion. Lots of cheap amplifiers will do this just before clipping
at full power.

Not all things are created equal. Power is one of them.

If you want a mechanical analog, how about a V-8 piston engine and a jet
turbine


That's all well and good, but the important thing to examine here is
whether
the results are significant during normal operation. Hint: by
significant,
I mean audible. While there are several ways to lower distortion
(sometimes at the expense of noise, or at the expense of reliability, or
at the expense of other forms of distortion, and so forth), there is of
course a threshold at which further reduction is not warranted, nor is it
necessarily recommended since there's almost always a tradeoff in some
manner or another.

So your engine analog holds true, but if your application is to just drive
down a road, then either one will perform as well as the other.






  #67   Report Post  
John Durbin
 
Posts: n/a
Default Clean Power?

You must be referring to the px/a...

JD

John Andreen wrote:

Mark

I can also tell you that A/D/S pretty much made extremely good units except
for a few choice "dogs". I can only currently think of only one. I can't
remember the model, but it had several DSP processors on board. Also had
5, yea 5 separate power supplies. Each one "yanking" the amplifiers ground
all over creation. They also had a rather good Audio Engineer's ( Ed
Meitner ) pre-driver stage that was particularly good at rejecting Power
supply noise or any "common-mode" noise for that matter. It was partly
their saving grace. I think that your P840 shares this pre-driver
technology. If you can get your hands on a schematic of your P840, look
for the pre-driver stage. If you see some OPAMPS whose output pins are
tied to GND and has JFETS between the +/- 15 volt rails and the OPAMPS
input +/- supply pins, then you are indeed fortunate. This type of driver
section is usually only used in audiophile grade home amplifiers. Ed
performed a miracle and got it to work for a car amplifier. Those amps
also typically us Burr-Brown Audio grade OPAMPS as well.

I was working at A/D/S when we made great product, I was there when we
knowingly made crap and I was there when we started to make good product
again. I was there when good Engineers left, I was there when bad
Engineers came in and I was there when these bad Engineers either left or
were fired. Those bad Engineers "talked the talk" but didn't "walk the
walk". FYI, a couple of those bad Engineers were really marketing guys who
were Engineering wannabe's. IMHO, Engineers cogitate and marketing types
scheme. The real downfall of PPI/ADS/ORION was pretty much due to these
guys lack of skill and knowledge when it came to Audio Engineering. On
another side note, these same Engineers had a little something to do with
making bad ORION product as well. Bad PPI products also came about around
this time frame as well due to a person who was in "New Products
Development" ( read Marketing ). It was his scheming and back door dealing
( Engineering was left out of the loop ) that created the first gen of the
PCX amplifier. This line was a year late, poorly thought out and had many
issues. This is what you get when you have Marketing telling offshore
firms how to make an amplifier. This new line of PCX amplifiers was even
approved for production after only visually inspecting the prototype
models. Hell, they "looked" great. The marketing man was pleased. Little
did he know.........

In short, That amp of yours and it's next of kin the P850 are indeed great
amps. Just stay away from Constant Bass. This function was implemented
incorrectly. If it were done right, it would be a blessing. But, it was
implemented wrong and kills your sound stage. Engage this feature and
listen to a "sound staging" test CD. You will indeed hear the loss of your
soundstage.

JA


Mark Zarella wrote:



Mark,

Why the A/D/S amplifiers? It is because they are well made according to
Engineering practices and very high quality parts. I know, some of my
"work" is in that amplifier.


John, I run the a/d/s/ P840 for my front set because it supplies an
adequate power distribution to my a/d/s/ 641is set allowing me to triamp
them and level control the individual drivers, and it has built-in
crossovers that allow me to bandpass the midbass and midrange speakers and
highpass the
tweeters, all with continuously adjustable xover points. Also, its flat
depth means it can be installed up in the rear deck. These features,
along with great support I've had with JD and Directed so far with my
other a/d/s/
equipment, and decent reliability is why I bought this amp. Oh yeah, and
it only cost me $220.






  #68   Report Post  
John Durbin
 
Posts: n/a
Default Clean Power?

The P2110 was good for 110wpc...

JD

Mark Zarella wrote:

I can also tell you that A/D/S pretty much made extremely good units


except


for a few choice "dogs". I can only currently think of only one. I can't
remember the model, but it had several DSP processors on board. Also had
5, yea 5 separate power supplies. Each one "yanking" the amplifiers


ground


all over creation. They also had a rather good Audio Engineer's ( Ed
Meitner ) pre-driver stage that was particularly good at rejecting Power
supply noise or any "common-mode" noise for that matter. It was partly
their saving grace. I think that your P840 shares this pre-driver
technology. If you can get your hands on a schematic of your P840, look
for the pre-driver stage. If you see some OPAMPS whose output pins are
tied to GND and has JFETS between the +/- 15 volt rails and the OPAMPS
input +/- supply pins, then you are indeed fortunate. This type of driver
section is usually only used in audiophile grade home amplifiers. Ed
performed a miracle and got it to work for a car amplifier. Those amps
also typically us Burr-Brown Audio grade OPAMPS as well.



I've replaced op amps for people who asked me to before (sometimes along
with the discrete components so that I could modify xovers and the like, but
that's another story), and never found a noticeable difference afterwards.
But admittedly, I never a/b'd them. I wouldn't expect a difference though,
since the distortion characteristics of modern op amps tend to be top-notch
(and in fact, superior to discrete components as I found out the hard way in
one design I was doing for another application).



In short, That amp of yours and it's next of kin the P850 are indeed great
amps. Just stay away from Constant Bass. This function was implemented
incorrectly. If it were done right, it would be a blessing. But, it was
implemented wrong and kills your sound stage. Engage this feature and
listen to a "sound staging" test CD. You will indeed hear the loss of


your


soundstage.



I'd like to be able to find a higher power 2-channel relative to the P840
for my rear speakers. I currently have a 240 (?) that looks the same, but I
was hoping to find something closer to 80x2. Did they make one?





  #69   Report Post  
Mark Zarella
 
Posts: n/a
Default Clean Power?

The P2110 was good for 110wpc...

Do you know if it has a HP/LP or a bandpass xover?


  #70   Report Post  
Mark Zarella
 
Posts: n/a
Default Clean Power?

What makes you think that something printed on paper is more credible then
something printed in html ?


Because articles printed in reputable journals are peer-reviewed. And
original work printed in reputable journals describes the methodology
involved and the results of implementing this methodology, so that the
reader can determine whether or not the results are as applicable as the
authors' interpretations are. That's why those of us in the science field
don't tend to run to web pages for our information. There are, however, two
pieces of work printed online yet not in a peer-reviewed journal that I do
look at, but those are from two of the leading scientists in my field and
they're only review articles anyway.

What part of the webpage did you find false other
then the fact that it contradicts what you are saying?


Well, aside from not addressing the point I've been making, nothing about
the electronics seems wrong upon a brief initial inspection. The
psychophysical aspect of our discussion is ignored on his website. As such,
he did make some hasty assumptions that would not have been made if he
addressed the human part of the problem.




  #71   Report Post  
BANDIT2941
 
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Default Clean Power?

Exactly. That's what I'm saying, but Zarella says that all amps are created
equal with the same power supplies. I just don't know what to say, I'm
actually at a loss for words here. I can't believe that someone could be
that stupid and still be able to operate a computer and log on to the
usenet. I'm just baffled.


If you're so baffled then why don't you post proof as to your positions? What
competitions have you won?
First you claim to have a store, then you claim to have gotten out of retail.
Which is it?

Mark Zarella is more of a man then you will ever be. He has helped many a
person on here(including myself on multiple occasions, on usenet and through
email) and all of his answers are backed up with facts and proof that are
easily understood and/or checked.

Nobody on here is claiming that there is no physical differences between the
amps. The claims made are that the differences are inaudible. Since you seem to
have no trouble telling them apart, maybe you should talk to your old buddy
about getting his $10,000. Until then, maybe you should stop putting words in
the mouths of people like Mr. Zarella and Les and spend some time posting proof
and facts to back up your assertions.
  #72   Report Post  
Florida_Kid :-\)
 
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Default Clean Power?

Mr. Fugley's "shop" is located in the Orlando, Florida area. Though I doubt
he really has one anyway.


"Soundfreak03" wrote in message
...
Obviously you can't read.

Now THAT'S an arguement I can win...and I did!


How? What in the hell are you talking about? You made up stuff and think

you
won.
BTW where is your shop? Still avoiding that one. I think everyone is

seeing
through you and your lies.

Les



  #73   Report Post  
John Andreen
 
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A/D/S did make some higher powered amplifiers prior to my working there. I
believe that they were 2 x 100, but I can't be certain. During my tenure,
the most powerful amplifiers were the ADS P450, P650 and the P850. They
actually made closer to 75 watts per channel. These amplfiers are really
PPI Powerclass outputs with the crossover sections being true ADS. The
input sections were my design. Not really, because I simply got my
inspiration from another design that I found on the web. I did change it
though to suit our requirements. I can also tell you that there are two
distinct versions of these units. Maybe three now, the third being DEI's
version. Without actually looking at the PCB's there is no real way of
telling if it is the earlier version ( pure A/D/S ) but has issues, mostly
turn on pop and the later versions ( A/D/S / PPI ) which are really
stellar performers. The digital displays of the PH30 and PQ40 are actually
quite worthless as it doesn't really display the frequency, but a frequency
found in a lookup table relative to the position of a potentiometer ganged
with the frequency pot. This is only an approxomation at best, and there
is inherent slop and backlash associated with potentiometers. I also had
to modify the software coding ( Many thanks to Campbell Kelly for his
help ) to stop the display from drifting or blinking.

I seem to recall 5 distinct amplifiers in the A/D/S line during my tenure.
the P450, the P650 and the P850 and the two models with the digital
displays. These other two units were the PQ40 and the PH30. These are the
units that make 4 x 100 (PQ40) and 6 x 75 (PH30). Really great amplifiers,
but never trust the frequency displays. BTW the LED displays were supposed
to be blue, but we had a butt load of RED LED displays leftover from an
older version. All the .2 versions of these 5 amplifiers have the true
balanced differential input section that I had a hand in. Makes for a much
quieter amplifier.

JA

Mark Zarella wrote:

I can also tell you that A/D/S pretty much made extremely good units

except
for a few choice "dogs". I can only currently think of only one. I can't
remember the model, but it had several DSP processors on board. Also had
5, yea 5 separate power supplies. Each one "yanking" the amplifiers

ground
all over creation. They also had a rather good Audio Engineer's ( Ed
Meitner ) pre-driver stage that was particularly good at rejecting Power
supply noise or any "common-mode" noise for that matter. It was partly
their saving grace. I think that your P840 shares this pre-driver
technology. If you can get your hands on a schematic of your P840, look
for the pre-driver stage. If you see some OPAMPS whose output pins are
tied to GND and has JFETS between the +/- 15 volt rails and the OPAMPS
input +/- supply pins, then you are indeed fortunate. This type of
driver
section is usually only used in audiophile grade home amplifiers. Ed
performed a miracle and got it to work for a car amplifier. Those amps
also typically us Burr-Brown Audio grade OPAMPS as well.


I've replaced op amps for people who asked me to before (sometimes along
with the discrete components so that I could modify xovers and the like,
but that's another story), and never found a noticeable difference
afterwards.
But admittedly, I never a/b'd them. I wouldn't expect a difference
though, since the distortion characteristics of modern op amps tend to be
top-notch (and in fact, superior to discrete components as I found out the
hard way in one design I was doing for another application).

In short, That amp of yours and it's next of kin the P850 are indeed
great
amps. Just stay away from Constant Bass. This function was implemented
incorrectly. If it were done right, it would be a blessing. But, it was
implemented wrong and kills your sound stage. Engage this feature and
listen to a "sound staging" test CD. You will indeed hear the loss of

your
soundstage.


I'd like to be able to find a higher power 2-channel relative to the P840
for my rear speakers. I currently have a 240 (?) that looks the same, but
I
was hoping to find something closer to 80x2. Did they make one?


  #74   Report Post  
John Andreen
 
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Default Clean Power?

I was trying to think of that one JD, but I couldn't remember that far back.
I seem to recall it being a lighter shade of gray than the new units. I
also think that it may have had a self oscillating power supply. I even
think I owned one to drive a pair of A/D/S 300i's in a 1977 Datsun King
Cab. It got stolen. Replaced it with a Nakamichi P300. It got stolen. I
replaced it with a "True" David Hafler MA-1 ( I think that was the model)

John Durbin wrote:

The P2110 was good for 110wpc...

JD


  #75   Report Post  
John Andreen
 
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Default Clean Power?

Sorry, I did not mean to offend anyone. But the gentleman posted a link to
an article showing a 20 year old Pioneer home amplifier as proof that
Pioneer does make equipment that can stand the test of time. I only
rebuffed because it was a picture of a home amplifier. My apologies if I
have offended anyone.

John Andreen

Soundfreak03 wrote:

This NG is called rec.audio.car. Your picture is of a home amplifier.
Not
even close to the same environment. Car=harsh environment. Home=not
harsh environment. There is lots of good old home equipment available, I
find and sometimes buy it at the local good will stores.


I have owned Sony and
Pioneer amps way back in the late 70's, but fish paper PCB's do not hold
up
all that well in the long term. They all gave out and the cost to
diagnose and repair was prohibitive.


John,

Did you miss the topic? Reliability is one of the reasons to buy a more
expensive amp. Noone is arguing the point you are making. So why are you
making it?

Les




  #76   Report Post  
John Andreen
 
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Default Clean Power?

I can't argue that fact as your are correct. I was only trying to make a
quick comparison between life spans of products. You and I have been in
this vocation a long time and we've had our share of product. I kind of
think you had at least one single sided fish paper amplifier board crack
somewhere along the way. That was the gist of the point I was trying to
make.

John Andreen

John Durbin wrote:

You could say the same about an original Sony XES-M1 or M3... I think
you need to establish an apples to apples comparison, can't compare
premium product with run of the mill stuff and expect them to "age" the
same.

JD

John Andreen wrote:

Mr

  #77   Report Post  
John Andreen
 
Posts: n/a
Default Clean Power?

Hey John,

Have you noticed that these long threads slowly but surely get distorted as
well? I have. Guess it is just another form of audio noise. The real
message and discussion just seems to get lost in the chaff.

But I for one really appreciate great debates, even if they drift off
center. They are good for all involved and really quite handy for
educating others as well as being educated by those same others. I admit
that I am sometimes amused by another views, but I will never laugh at or
demean another for asking a question. One can only learn if we pose
questions.

I noticed this thread has begun to show signs of attacking and sniping at
others for their opinions. mostly upon Pug Fugly and Mark Zarella. I for
one, find Mr Zarella a really good contributor to this NG. You too Pug
Fugly. Even Captain Howdy is rather good at stating an opinion and sticking
to it. I applaud and admire that. We all should. That scenario was kind
of like two people on either side of a curved wall. One says its a convex
wall. The other says it is concave. Who's right? Depends on your
perspective.

To those others reading this post sniping doesn't do any of us any good.
What it does do is to stifle those who really would like to ask a question
or voice an opinion for fear of retribution. Words can cut deeper than
even the sharpest of knives. And it is real easy to forget civility when
we hide behind a facade called the Internet.

Why am I posting this to JD you ask. It is because he has a lot to offer
this group and when he gets sniped at, his response is always civil. We
can learn much if we do as he does.

John Andreen




  #78   Report Post  
Captain Howdy
 
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I guess that I am missing something as I though this post was about power
supplies and cheap amps performing as good as high end amps.



they're only review articles anyway.

What part of the webpage did you find false other
then the fact that it contradicts what you are saying?


Well, aside from not addressing the point I've been making, nothing about
the electronics seems wrong upon a brief initial inspection. The
psychophysical aspect of our discussion is ignored on his website. As such,
he did make some hasty assumptions that would not have been made if he
addressed the human part of the problem.


  #79   Report Post  
Soundfreak03
 
Posts: n/a
Default Clean Power?

I guess that I am missing something as I though this post was about power
supplies and cheap amps performing as good as high end amps.


Thats where you didnt read everything and listened to Puggy starting that lie.
Here is what it is about.
When you operate an amp within its linear range, ie no clipping, the
differences in Sound Quality between amps are inaudible to the human ear. There
ARE differences, noone is arguing that. But those differences are below the
threshold of hearing.
Now the performance is a different issue altogether. By performance I take you
mean things like performing to its rated specs, it actually working
consistently, not the SQ in other words. The performance issue, along with
other things, is the reason too buy the more expensive amp.
Maybe next time you should read everything before getting involved and then you
would have known what the thread was about and what Puggy threw in to confuse
noobs like you.

Les
  #80   Report Post  
Mark Zarella
 
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Default Clean Power?

I guess that I am missing something as I though this post was about power
supplies and cheap amps performing as good as high end amps.


I didn't answer your question?


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