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#41
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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
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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
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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
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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
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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
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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
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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
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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
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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
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Clean Power?
That's mainly a product of the power supply.
Please elaborate. You keep dodging this question. |
#51
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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Clean Power?
The P2110 was good for 110wpc...
Do you know if it has a HP/LP or a bandpass xover? |
#70
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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
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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
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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
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Clean Power?
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
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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
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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 |
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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
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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 |
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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. 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
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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
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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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