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Quote:
Originally Posted by keyboardcat  /t/1468509/how-would-you-describe-sim-audio-moon-amps#post_23209749


Are they bright sounding? Do they have a lot of bass like a Nad? What other amp brands would you compare the sound to?

So, you are saying that Sim-Audio-Moon-Amps and NAD amps are substandard and sold new broken?


These plots from http://www.stereophile.com/content/simaudio-moon-i33-integrated-amplifier-measurements say:








"Not so broken - at last as good as the power amps in a good AVR".


OTOH, this set of graphs:

http://www.stereophile.com/content/nad-m2-direct-digital-integrated-amplifier-measurements








Describe an amp that I might not want. Maybe NAD does better with more traditional designs.
 

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Arny, I think the amp makers need to throw the rulebook out the window and create solid state amps with their own signature sound. Make the frequency response all wonky with huge dips and peaks. Then we can have discussions about the "sound" of solid-state gear.
 

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Good old Arny.


He may not have an answer for you, but he can throw 20 graphs at you to give the illusion that he MIGHT know something....


The fact is that the "sound" of amplifiers is due mainly to two things; how much current can they deliver to a load and how much distortion is caused by their coupling capacitors.


Companies like Audio Research have discovered that coupling capacitors cause audible distortion in preamps and amplifiers, and spend a LOT of money on the best-sounding ones available to get the distortion down to vanishingly low levels in their amplifiers.


I personally took an old Audire amplifier (a very good one) and put in some Dynamicaps to replace the original input coupling capacitors, and even Arny would hear the difference in 10 seconds. It improved the sound quality considerably. But they are so expensive that they won't be found in less-expensive amplifiers. It cost me $100 to upgrade that one amp (four capacitors); but it was well worth it.


The reason having a very large power supply is important is because of the wild impedance variations the average speaker has over the audio range. Only an amplifier with a MASSIVE power supply can supply a speaker with more and less current as demanded and maintain anything resembling a linear dynamic frequency response.


Arny's graphs are showing what happens with a fixed resistance connected across the amplifier and a fixed signal level applied, and a speaker and amplifier in actual operation is NOTHING like that!! Graphs can't show you what REALLY happens in real life amplifying music, with frequencies, load impedances, and voltage levels constantly changing. The interaction is so complex that even computer simulations are only crude approximations, and those simple graphs are ludicrously simplistic.


That is like checking the towing capacity of a truck by testing it only on level ground at a fixed speed. It doesn't tell you what will happen when you have to tow that 5-ton trailer up or down a 4% or 7% grade at varying speeds!!!


The bottom line is that time has proved to the most knowledgeable audio engineers that even the best most expensive audio analyzers still can't give as much information as YOUR EARS.



P.S.- The reviews I have read on Simaudio amplifiers indicate to me that they are probably better-sounding in a general sense, with many speakers, than the NAD amps that are under $1000. NAD also makes some much better amplifiers that cost a lot more money (like the 375BEE).


As i have indicated above, the actual SOUND of an amplifier is going to be inseparable from the speakers it is driving. There is a synergy between amplifier and speaker that makes it foolish to assign a "sound' to an amplifier alone. One can only speak, In my opinion, of the "sound' of a particular amplifier in combination with a particular speaker.
 

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Quote:
Originally Posted by keyboardcat  /t/1468509/how-would-you-describe-sim-audio-moon-amps#post_23209749


Are they bright sounding? Do they have a lot of bass like a Nad? What other amp brands would you compare the sound to?

If Simaudio amps were audibly "bright," then that would be obvious from test measurements. VERY obvious. I'll think you'll find their response to be flat.


Meanwhile, NAD amps produce no more bass than any other modern solid-state amp, although they generally deliver lots of power relative to their ratings, which might matter some of the time (high levels, large rooms, low-sensitivity speakers).


I seriously doubt, under honest, objective conditions, that you'd be able to tell a Simaudio amp from any other solid-state amp kept within its operating limits. Why would you be able to?
 

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Some amplifiers will sound "bright" with some speakers, because of the interaction between the amplifier and speaker. You don't seem to get the basic engineering principles involved.


The simplest reason for this would be because the speaker has relatively high impedances at the upper-midrange frequencies (which is not uncommon) and the amplifier does not have a low-enough output impedance to avoid "going along for the ride' and putting out more voltage at those frequencies in response to the higher impedance load it is seeing; hence the "bright sound"; more output at those frequencies.


A much larger amplifier (bigger power supply hence lower output impedance) will be affected a lot less than a smaller one, and so the "brightness' of the speaker response will be minimized. The combination of the same speaker with the bigger amplifier "sounds better" because the amplifier exerts more "control" and maintains a more constant output in response to the impedance variations of the speaker.


Starting to get the idea yet??


The speakers with the best sound at a modest price point tend to be those with a very constant impedance over the audio frequency range, but very few speakers do. It is certainly instructive to look at the impedance versus frequency graph before thinking about buying a speaker.


It also follows that a relatively smaller amplifier will do a better job with speakers that don't have huge impedance variations, and do a poorer job when the speaker's impedance varies a lot over the audio range.


If your speakers have a lot of variation in their impedance, they may not sound very good unless you have a very powerful high-current amplifier with a very low output impedance that can keep their imperfections under control.


Once again; to speak of a "bright" amplifier or "bright" speaker displays a lack of fundamental understanding of what is taking place.


The COMBINATION of a given amplifier and speaker is what produces a given sound characteristic; the SYNERGY between them is what produces a certain sound quality.


The cheap amplifiers and small power supplies in most HT receivers will only sound good with a very limited number of speakers that have relatively high impedances at ALL frequencies. When people try to use other kinds of speakers the result is poor sound quality. This is a common issue that hardly anyone seems to understand.




Quote:
Originally Posted by Brownstone322  /t/1468509/how-would-you-describe-sim-audio-moon-amps#post_23225582


If Simaudio amps were audibly "bright," then that would be obvious from test measurements. VERY obvious. I'll think you'll find their response to be flat.


Meanwhile, NAD amps produce no more bass than any other modern solid-state amp, although they generally deliver lots of power relative to their ratings, which might matter some of the time (high levels, large rooms, low-sensitivity speakers).


I seriously doubt, under honest, objective conditions, that you'd be able to tell a Simaudio amp from any other solid-state amp kept within its operating limits. Why would you be able to?
 

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Quote:
Originally Posted by commsysman  /t/1468509/how-would-you-describe-sim-audio-moon-amps#post_23225668


Some amplifiers will sound "bright" with some speakers, because of the interaction between the amplifier and speaker.

It is quite true that there are a few power amps that provide relatively high source impedances particularly at high frequencies and can do exactly what you say. These amps are typically vacuum tube or switchmode devices. It is equally true that the vast majority of power amps provide a sufficiently low source impedance for this to not cause an audible effect.


This is not new knowledge, and I have been posting about this situation on AVS for many months and illustrating it with frequency response curves from reliable sources such as Stereophile magazine. Consider my post http://www.avsforum.com/t/1468509/how-would-you-describe-sim-audio-moon-amps#post_23211287 of 3 days ago to this very thread. I can't believe that you are unaware of it!


There is an interesting situation where it might be possible for the automated system optimization facilities (Audyssey, MCACC, YPAO, etc) now standard features in many AVRs to adjust these kinds of variations out of the system as part of their normal operation.
 

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Quote:
Originally Posted by commsysman  /t/1468509/how-would-you-describe-sim-audio-moon-amps#post_23225470



The fact is that the "sound" of amplifiers is due mainly to two things; how much current can they deliver to a load and how much distortion is caused by their coupling capacitors.

Please provide evidence that amplifiers are frequently limited by how much current they can deliver, except of course while they are clipping and thus creating non-subtle amounts of distortion.


As far as distortion due to coupling caps goes, virtually every modern power amp lacks the output coupling caps that were common in the 1960s SS power amps, and this has been the rule for over 30 years. Coupling caps only cause distortion when they are electrolytic s and the signal being actually dropped across them exceeds the steady-state DC voltage that they are blocking. Thus coupling caps large enough to avoid frequency response losses don't have this problem.


Bottom line is that both of the situations you have described will produce readily measurable artifacts when they exist, so all you have to do is provide easily measured evidence of it (if it exists) in order to convince reasonable people that it is a problem.


I might add that this kind of distortion was not uncommon in some portable digital players, but the better players have eliminated it by using clever virtual earthing circuits to eliminate blocking capacitors from their single-supply headphone amplfiiers: This kind of refinement has become very common and is present in very inexpensive players such a the Sansa Clip and Fuze as well as higher-priced players from Apple.

http://www.maximintegrated.com/products/audio/headphone_amp.cfm
 

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Quote:
Originally Posted by commsysman  /t/1468509/how-would-you-describe-sim-audio-moon-amps#post_23225470


Good old Arny.


He may not have an answer for you, but he can throw 20 graphs at you to give the illusion that he MIGHT know something....


The fact is that the "sound" of amplifiers is due mainly to two things; how much current can they deliver to a load and how much distortion is caused by their coupling capacitors.


Companies like Audio Research have discovered that coupling capacitors cause audible distortion in preamps and amplifiers, and spend a LOT of money on the best-sounding ones available to get the distortion down to vanishingly low levels in their amplifiers.


I personally took an old Audire amplifier (a very good one) and put in some Dynamicaps to replace the original input coupling capacitors, and even Arny would hear the difference in 10 seconds. It improved the sound quality considerably. But they are so expensive that they won't be found in less-expensive amplifiers. It cost me $100 to upgrade that one amp (four capacitors); but it was well worth it.


The reason having a very large power supply is important is because of the wild impedance variations the average speaker has over the audio range. Only an amplifier with a MASSIVE power supply can supply a speaker with more and less current as demanded and maintain anything resembling a linear dynamic frequency response.


Arny's graphs are showing what happens with a fixed resistance connected across the amplifier and a fixed signal level applied, and a speaker and amplifier in actual operation is NOTHING like that!! Graphs can't show you what REALLY happens in real life amplifying music, with frequencies, load impedances, and voltage levels constantly changing. The interaction is so complex that even computer simulations are only crude approximations, and those simple graphs are ludicrously simplistic.


That is like checking the towing capacity of a truck by testing it only on level ground at a fixed speed. It doesn't tell you what will happen when you have to tow that 5-ton trailer up or down a 4% or 7% grade at varying speeds!!!


The bottom line is that time has proved to the most knowledgeable audio engineers that even the best most expensive audio analyzers still can't give as much information as YOUR EARS.



P.S.- The reviews I have read on Simaudio amplifiers indicate to me that they are probably better-sounding in a general sense, with many speakers, than the NAD amps that are under $1000. NAD also makes some much better amplifiers that cost a lot more money (like the 375BEE).


As i have indicated above, the actual SOUND of an amplifier is going to be inseparable from the speakers it is driving. There is a synergy between amplifier and speaker that makes it foolish to assign a "sound' to an amplifier alone. One can only speak, In my opinion, of the "sound' of a particular amplifier in combination with a particular speaker.

Oh dear. I don't even know where to start.
 

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Quote:
Originally Posted by commsysman  /t/1468509/how-would-you-describe-sim-audio-moon-amps#post_23225668


Some amplifiers will sound "bright" with some speakers, because of the interaction between the amplifier and speaker. You don't seem to get the basic engineering principles involved.


The simplest reason for this would be because the speaker has relatively high impedances at the upper-midrange frequencies (which is not uncommon) and the amplifier does not have a low-enough output impedance to avoid "going along for the ride' and putting out more voltage at those frequencies in response to the higher impedance load it is seeing; hence the "bright sound"; more output at those frequencies.


A much larger amplifier (bigger power supply hence lower output impedance) will be affected a lot less than a smaller one, and so the "brightness' of the speaker response will be minimized. The combination of the same speaker with the bigger amplifier "sounds better" because the amplifier exerts more "control" and maintains a more constant output in response to the impedance variations of the speaker.


Starting to get the idea yet??


The speakers with the best sound at a modest price point tend to be those with a very constant impedance over the audio frequency range, but very few speakers do. It is certainly instructive to look at the impedance versus frequency graph before thinking about buying a speaker.


It also follows that a relatively smaller amplifier will do a better job with speakers that don't have huge impedance variations, and do a poorer job when the speaker's impedance varies a lot over the audio range.


If your speakers have a lot of variation in their impedance, they may not sound very good unless you have a very powerful high-current amplifier with a very low output impedance that can keep their imperfections under control.


Once again; to speak of a "bright" amplifier or "bright" speaker displays a lack of fundamental understanding of what is taking place.


The COMBINATION of a given amplifier and speaker is what produces a given sound characteristic; the SYNERGY between them is what produces a certain sound quality.


The cheap amplifiers and small power supplies in most HT receivers will only sound good with a very limited number of speakers that have relatively high impedances at ALL frequencies. When people try to use other kinds of speakers the result is poor sound quality. This is a common issue that hardly anyone seems to understand.

Show me some measurements, please, where the output impedance of a modern solid-state amp has an effect of more than, say, 0.5dB frequency response variation depending on the load impedance. Or are you talking strictly about tube amps?
 

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Quote:
Originally Posted by commsysman  /t/1468509/how-would-you-describe-sim-audio-moon-amps#post_23225470


Good old Arny.


He may not have an answer for you, but he can throw 20 graphs at you to give the illusion that he MIGHT know something....


The fact is that the "sound" of amplifiers is due mainly to two things; how much current can they deliver to a load and how much distortion is caused by their coupling capacitors.


Companies like Audio Research have discovered that coupling capacitors cause audible distortion in preamps and amplifiers, and spend a LOT of money on the best-sounding ones available to get the distortion down to vanishingly low levels in their amplifiers.


I personally took an old Audire amplifier (a very good one) and put in some Dynamicaps to replace the original input coupling capacitors, and even Arny would hear the difference in 10 seconds. It improved the sound quality considerably. But they are so expensive that they won't be found in less-expensive amplifiers. It cost me $100 to upgrade that one amp (four capacitors); but it was well worth it.


The reason having a very large power supply is important is because of the wild impedance variations the average speaker has over the audio range. Only an amplifier with a MASSIVE power supply can supply a speaker with more and less current as demanded and maintain anything resembling a linear dynamic frequency response.


Arny's graphs are showing what happens with a fixed resistance connected across the amplifier and a fixed signal level applied, and a speaker and amplifier in actual operation is NOTHING like that!! Graphs can't show you what REALLY happens in real life amplifying music, with frequencies, load impedances, and voltage levels constantly changing. The interaction is so complex that even computer simulations are only crude approximations, and those simple graphs are ludicrously simplistic.


That is like checking the towing capacity of a truck by testing it only on level ground at a fixed speed. It doesn't tell you what will happen when you have to tow that 5-ton trailer up or down a 4% or 7% grade at varying speeds!!!


The bottom line is that time has proved to the most knowledgeable audio engineers that even the best most expensive audio analyzers still can't give as much information as YOUR EARS.



P.S.- The reviews I have read on Simaudio amplifiers indicate to me that they are probably better-sounding in a general sense, with many speakers, than the NAD amps that are under $1000. NAD also makes some much better amplifiers that cost a lot more money (like the 375BEE).


As i have indicated above, the actual SOUND of an amplifier is going to be inseparable from the speakers it is driving. There is a synergy between amplifier and speaker that makes it foolish to assign a "sound' to an amplifier alone. One can only speak, In my opinion, of the "sound' of a particular amplifier in combination with a particular speaker.

This distortion you speak of that is supposedly due to the coupling caps .... can it be measured?


As for your claim that you replaced caps and improved the sound quality in such an obvious manner, well....just how fast can you solder? I'm assuming you're so fast that you somehow swapped the caps in under, say, a second or so, right? And your entire before/after comparison within just a couple of seconds? Because your auditory memory is pretty short. Otherwise, I'm pretty confident saying your imagination had as much to do with the improvement as the cap swap.


As for the claim that the best audio equipment isn't as good as your ears, well, you need some new equipment! I'm assuming your community college had more than DC voltmeters, no?
 

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Quote:
Originally Posted by commsysman  /t/1468509/how-would-you-describe-sim-audio-moon-amps#post_23225470


Good old Arny.


He may not have an answer for you, but he can throw 20 graphs at you to give the illusion that he MIGHT know something....


The fact is that the "sound" of amplifiers is due mainly to two things; how much current can they deliver to a load and how much distortion is caused by their coupling capacitors.


Companies like Audio Research have discovered that coupling capacitors cause audible distortion in preamps and amplifiers, and spend a LOT of money on the best-sounding ones available to get the distortion down to vanishingly low levels in their amplifiers.


I personally took an old Audire amplifier (a very good one) and put in some Dynamicaps to replace the original input coupling capacitors, and even Arny would hear the difference in 10 seconds. It improved the sound quality considerably. But they are so expensive that they won't be found in less-expensive amplifiers. It cost me $100 to upgrade that one amp (four capacitors); but it was well worth it.


The reason having a very large power supply is important is because of the wild impedance variations the average speaker has over the audio range. Only an amplifier with a MASSIVE power supply can supply a speaker with more and less current as demanded and maintain anything resembling a linear dynamic frequency response.


Arny's graphs are showing what happens with a fixed resistance connected across the amplifier and a fixed signal level applied, and a speaker and amplifier in actual operation is NOTHING like that!! Graphs can't show you what REALLY happens in real life amplifying music, with frequencies, load impedances, and voltage levels constantly changing. The interaction is so complex that even computer simulations are only crude approximations, and those simple graphs are ludicrously simplistic.


That is like checking the towing capacity of a truck by testing it only on level ground at a fixed speed. It doesn't tell you what will happen when you have to tow that 5-ton trailer up or down a 4% or 7% grade at varying speeds!!!


The bottom line is that time has proved to the most knowledgeable audio engineers that even the best most expensive audio analyzers still can't give as much information as YOUR EARS.



P.S.- The reviews I have read on Simaudio amplifiers indicate to me that they are probably better-sounding in a general sense, with many speakers, than the NAD amps that are under $1000. NAD also makes some much better amplifiers that cost a lot more money (like the 375BEE).


As i have indicated above, the actual SOUND of an amplifier is going to be inseparable from the speakers it is driving. There is a synergy between amplifier and speaker that makes it foolish to assign a "sound' to an amplifier alone. One can only speak, In my opinion, of the "sound' of a particular amplifier in combination with a particular speaker.
 

Which is more informative: 20 graphs or 11 non-responsive paragraphs with buzz-phrases like 'synergy'?

 

The bottom lines:

 
  • If it isn't measurable, it can't be audible.
  • If it is measurable, it may or may not affect the listener.

 

Except for listener perception, there are no hidden variables about this kind of electronic design.
 

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Quote:
Originally Posted by commsysman  /t/1468509/how-would-you-describe-sim-audio-moon-amps#post_23225668


Some amplifiers will sound "bright" with some speakers, because of the interaction between the amplifier and speaker. You don't seem to get the basic engineering principles involved.


The simplest reason for this would be because the speaker has relatively high impedances at the upper-midrange frequencies (which is not uncommon) and the amplifier does not have a low-enough output impedance to avoid "going along for the ride' and putting out more voltage at those frequencies in response to the higher impedance load it is seeing; hence the "bright sound"; more output at those frequencies.


A much larger amplifier (bigger power supply hence lower output impedance) will be affected a lot less than a smaller one, and so the "brightness' of the speaker response will be minimized. The combination of the same speaker with the bigger amplifier "sounds better" because the amplifier exerts more "control" and maintains a more constant output in response to the impedance variations of the speaker.

Assuming we had a pair of speakers that presented such a load, these variations in response could easily be measured and demonstrated. We'd need a change of several decibels in the mid range to invoke a perception of variation in "brightness" or "warmth." That's very unlikely among modern solid-state amplifiers, which are mature technologies.

Quote:
Originally Posted by commsysman 

Starting to get the idea yet??

Your smug, condescending tone speaks poorly of your character; the internet has a way of eliciting boldness from cowards. If you make a habit of speaking to complete strangers this way in person, you're likely to be shunned or get your ass kicked. Maybe you've already experienced that, I dunno.

To the original poster: If you're concerned with tonal balance, concentrate on speakers, speaker placement, corrective EQ, furnishings and room treatments. Swapping out electronics will require effort and expense and accomplish essentially nothing.
 

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Quote:
Originally Posted by commsysman  /t/1468509/how-would-you-describe-sim-audio-moon-amps#post_23225470


There is a synergy between amplifier and speaker that makes it foolish to assign a "sound' to an amplifier alone.

The period in the above sentence seems to have been placed one word too late.


Poor commie. I almost feel sorry for the guy, but then I was always one to defend those who rode the short bus to school.
 

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