I fixed the wording in my post (removed the three erroneous words), thanks for the correction. Glad someone with better electrical knowledge than I can explain it.
Review of Audio-GD DAC-19MK3
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Helmore
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Quote:
A current source and a voltage source are each others dual, just like resistance and conductance each other's dual. The ideal voltage source and ideal current source are just models used to...eh...model the real world. In the real world, we can only produce devices which can approach these models.
An ideal current source will do everything it can to maintain a certain current. When a current source is short circuited, in other words both it's 'input and output' are connected with a zero resistance wire, it will output its set current without any voltage (ideally). When the current source is not connected (open circuit) it will do everything it can to maintain its set current and in this case voltage would rise to infinity.
An ideal voltage source would do everything it can to maintain a certain voltage. When short circuited it will just maintain it's voltage but the amount of current would rise to infinity. If connected to an open circuit it will maintain its set voltage but current would be zero.
In certain ways thus, a current source and voltage source are each others opposite, but both can be used to model the same part of a circuit (Norton equivalent and Thévenin equivalent circuits. I'm not talking about how each is physically implemented though, that's a little more complicated.
Physically a voltage source is a bit easier than a current source. A battery for example is voltage source. Not an ideal voltage source though, but there are no ideal voltage and current sources in the real world, only sources that approach the ideal situation within certain limits. A current source on the other hand can actually be seen as a voltage source which is constantly regulating its voltage to exactly get the set amount of current. Mathematically you can just do your calculations with a current source as if it was a current source, even though it physically appears to be a source that's regulating its voltage to get that current.
In the case of Operational Amplifiers (OPAMPs), in other words pretty much all headphone amplifiers, you are talking about a either a regulated voltage source of a regulated current source. The parameter that's used to regulate them is simply the input of the OPAMP. The input signal can either be the amount current (CAST) or voltage and output is usually talked about as the voltage signal. (Electronic amplifier - Wikipedia, the free encyclopedia)
As for sources, DACs in this case, the output signal is either the amount of voltage or current. With a CAST connection you are using the amount of current as the parameter containing the actual audio signal. That makes it less prone to the quality of the interconnect between the DAC and the OPAMP as the DAC will just try to do everything it can to maintain the amount of current. This results in that the amp connected to the DAC will also see that same amount of current. The actual voltage that the amp sees depends on the quality of the interconnect between the DAC and amp though, but an amp operating in ACSS/CAST mode won't look at the voltage and just amplify the amount of current. A DAC that sends its signal with the use of voltage as its control parameter will be able to set that voltage on its side, but the amp connected to that DAC will see something slightly different because of the voltage drop you have across the interconnect between the two. In the worst case scenario the interconnect itself might introduce a channel imbalance, but that's in such an extreme case and then you can consider the interconnect to simply be broken
. This will not be a problem if the input of the amplifier has an infinity resistance, in which case there will be no current between the DAC and amplifier and no drop in voltage across the interconnect.
That said, an amp and DAC working along the same line as Audioo-GD's ACSS principle isn't inherently better than how most other OPAMPs work, it does have some advantages though. The same can be said for other amps, they also have some advantages over how Audio-GD's amplifiers work.
In the end, it simply comes down to the end result and not how you get there. You should not really judge an amp and DAC by their how their system works (CAST or not, tube or SS), but by their resulting performance. Just listen to what you get for your money and decide on that, don't decide on how that black box you're listing to works.
[size=xx-small]I simplified some things/concepts and may (probably will) be wrong about some of the things I said above. Just say it if you see something I'm wrong about or something you don't agree on. Keep in mind I'm also a just a novice in the world of DACs, amps and headphone.[/size]
| Originally Posted by SoupRKnowva /img/forum/go_quote.gif i still dont understand, everything ive ever learned about electronics has told me you cant "push" current. Current flows when you apply a voltage. A current source, as much as i can get out of that wiki article is just a high output impedance battery, with a zener diode in parallel somewhere to control the voltage drop? but in all reality the battery is still providing a voltage in order to make the current flow at all in the first place. Though i guess you can "push" current, as in a transformer but thats caused by electromagnetic induction, which obviously isnt whats going on here. so after all that lol would you care to explain some more? i really am interested. |
A current source and a voltage source are each others dual, just like resistance and conductance each other's dual. The ideal voltage source and ideal current source are just models used to...eh...model the real world. In the real world, we can only produce devices which can approach these models.
An ideal current source will do everything it can to maintain a certain current. When a current source is short circuited, in other words both it's 'input and output' are connected with a zero resistance wire, it will output its set current without any voltage (ideally). When the current source is not connected (open circuit) it will do everything it can to maintain its set current and in this case voltage would rise to infinity.
An ideal voltage source would do everything it can to maintain a certain voltage. When short circuited it will just maintain it's voltage but the amount of current would rise to infinity. If connected to an open circuit it will maintain its set voltage but current would be zero.
In certain ways thus, a current source and voltage source are each others opposite, but both can be used to model the same part of a circuit (Norton equivalent and Thévenin equivalent circuits. I'm not talking about how each is physically implemented though, that's a little more complicated.
Physically a voltage source is a bit easier than a current source. A battery for example is voltage source. Not an ideal voltage source though, but there are no ideal voltage and current sources in the real world, only sources that approach the ideal situation within certain limits. A current source on the other hand can actually be seen as a voltage source which is constantly regulating its voltage to exactly get the set amount of current. Mathematically you can just do your calculations with a current source as if it was a current source, even though it physically appears to be a source that's regulating its voltage to get that current.
In the case of Operational Amplifiers (OPAMPs), in other words pretty much all headphone amplifiers, you are talking about a either a regulated voltage source of a regulated current source. The parameter that's used to regulate them is simply the input of the OPAMP. The input signal can either be the amount current (CAST) or voltage and output is usually talked about as the voltage signal. (Electronic amplifier - Wikipedia, the free encyclopedia)
As for sources, DACs in this case, the output signal is either the amount of voltage or current. With a CAST connection you are using the amount of current as the parameter containing the actual audio signal. That makes it less prone to the quality of the interconnect between the DAC and the OPAMP as the DAC will just try to do everything it can to maintain the amount of current. This results in that the amp connected to the DAC will also see that same amount of current. The actual voltage that the amp sees depends on the quality of the interconnect between the DAC and amp though, but an amp operating in ACSS/CAST mode won't look at the voltage and just amplify the amount of current. A DAC that sends its signal with the use of voltage as its control parameter will be able to set that voltage on its side, but the amp connected to that DAC will see something slightly different because of the voltage drop you have across the interconnect between the two. In the worst case scenario the interconnect itself might introduce a channel imbalance, but that's in such an extreme case and then you can consider the interconnect to simply be broken
That said, an amp and DAC working along the same line as Audioo-GD's ACSS principle isn't inherently better than how most other OPAMPs work, it does have some advantages though. The same can be said for other amps, they also have some advantages over how Audio-GD's amplifiers work.
In the end, it simply comes down to the end result and not how you get there. You should not really judge an amp and DAC by their how their system works (CAST or not, tube or SS), but by their resulting performance. Just listen to what you get for your money and decide on that, don't decide on how that black box you're listing to works.
[size=xx-small]I simplified some things/concepts and may (probably will) be wrong about some of the things I said above. Just say it if you see something I'm wrong about or something you don't agree on. Keep in mind I'm also a just a novice in the world of DACs, amps and headphone.[/size]
PrTv
100+ Head-Fier
I admit that I haven't read all 35+ pages, but has anyone compared this one with more expensive/mainstream DAC(s) like Benchmark Dac1, Grace M902, or Lavry DA10.
Actually I've just got it today and one thing for sure is it's a lot better than my Rotel RCD-06 (which is now used as a transport), but I'd like to know how it fares against the more expensive ones above.
Actually I've just got it today and one thing for sure is it's a lot better than my Rotel RCD-06 (which is now used as a transport), but I'd like to know how it fares against the more expensive ones above.
slim.a
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Quote:
If you look at part III of my review here : http://www.head-fi.org/forums/f7/rev...-19mk3-435669/, I have already linked to some comparisons with other DACs mentioned in this thread.
| Originally Posted by PrTv /img/forum/go_quote.gif I admit that I haven't read all 35+ pages, but has anyone compared this one with more expensive/mainstream DAC(s) like Benchmark Dac1, Grace M902, or Lavry DA10. Actually I've just got it today and one thing for sure is it's a lot better than my Rotel RCD-06 (which is now used as a transport), but I'd like to know how it fares against the more expensive ones above. |
If you look at part III of my review here : http://www.head-fi.org/forums/f7/rev...-19mk3-435669/, I have already linked to some comparisons with other DACs mentioned in this thread.
Quote:
Do in essence a current source is just a voltage source with constantly variable voltage? man i really need to start my EE degree, then hopefully all this will make sense.
my main block is still that you cant provide current, you can only provide a difference in electrical potential(voltage) that causes electrons to flow(current).
Thanks for the long winded explanation though
| Originally Posted by Helmore /img/forum/go_quote.gif A current source and a voltage source are each others dual, just like resistance and conductance each other's dual. The ideal voltage source and ideal current source are just models used to...eh...model the real world. In the real world, we can only produce devices which can approach these models. An ideal current source will do everything it can to maintain a certain current. When a current source is short circuited, in other words both it's 'input and output' are connected with a zero resistance wire, it will output its set current without any voltage (ideally). When the current source is not connected (open circuit) it will do everything it can to maintain its set current and in this case voltage would rise to infinity. An ideal voltage source would do everything it can to maintain a certain voltage. When short circuited it will just maintain it's voltage but the amount of current would rise to infinity. If connected to an open circuit it will maintain its set voltage but current would be zero. In certain ways thus, a current source and voltage source are each others opposite, but both can be used to model the same part of a circuit (Norton equivalent and Thévenin equivalent circuits. I'm not talking about how each is physically implemented though, that's a little more complicated. Physically a voltage source is a bit easier than a current source. A battery for example is voltage source. Not an ideal voltage source though, but there are no ideal voltage and current sources in the real world, only sources that approach the ideal situation within certain limits. A current source on the other hand can actually be seen as a voltage source which is constantly regulating its voltage to exactly get the set amount of current. Mathematically you can just do your calculations with a current source as if it was a current source, even though it physically appears to be a source that's regulating its voltage to get that current. In the case of Operational Amplifiers (OPAMPs), in other words pretty much all headphone amplifiers, you are talking about a either a regulated voltage source of a regulated current source. The parameter that's used to regulate them is simply the input of the OPAMP. The input signal can either be the amount current (CAST) or voltage and output is usually talked about as the voltage signal. (Electronic amplifier - Wikipedia, the free encyclopedia) As for sources, DACs in this case, the output signal is either the amount of voltage or current. With a CAST connection you are using the amount of current as the parameter containing the actual audio signal. That makes it less prone to the quality of the interconnect between the DAC and the OPAMP as the DAC will just try to do everything it can to maintain the amount of current. This results in that the amp connected to the DAC will also see that same amount of current. The actual voltage that the amp sees depends on the quality of the interconnect between the DAC and amp though, but an amp operating in ACSS/CAST mode won't look at the voltage and just amplify the amount of current. A DAC that sends its signal with the use of voltage as its control parameter will be able to set that voltage on its side, but the amp connected to that DAC will see something slightly different because of the voltage drop you have across the interconnect between the two. In the worst case scenario the interconnect itself might introduce a channel imbalance, but that's in such an extreme case and then you can consider the interconnect to simply be broken
That said, an amp and DAC working along the same line as Audioo-GD's ACSS principle isn't inherently better than how most other OPAMPs work, it does have some advantages though. The same can be said for other amps, they also have some advantages over how Audio-GD's amplifiers work. In the end, it simply comes down to the end result and not how you get there. You should not really judge an amp and DAC by their how their system works (CAST or not, tube or SS), but by their resulting performance. Just listen to what you get for your money and decide on that, don't decide on how that black box you're listing to works. [size=xx-small]I simplified some things/concepts and may (probably will) be wrong about some of the things I said above. Just say it if you see something I'm wrong about or something you don't agree on. Keep in mind I'm also a just a novice in the world of DACs, amps and headphone.[/size] |
Do in essence a current source is just a voltage source with constantly variable voltage? man i really need to start my EE degree, then hopefully all this will make sense.
my main block is still that you cant provide current, you can only provide a difference in electrical potential(voltage) that causes electrons to flow(current).
Thanks for the long winded explanation though
regal
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Quote:
Well an audio signal is a little more complex, think of it this way the frequency and amplitude (changes) are in current instead of the usual voltage.
| Originally Posted by SoupRKnowva /img/forum/go_quote.gif Do in essence a current source is just a voltage source with constantly variable voltage? man i really need to start my EE degree, then hopefully all this will make sense. my main block is still that you cant provide current, you can only provide a difference in electrical potential(voltage) that causes electrons to flow(current). Thanks for the long winded explanation though
|
Well an audio signal is a little more complex, think of it this way the frequency and amplitude (changes) are in current instead of the usual voltage.
Quote:
oh man, thats only gonna make it worse, frequency and amplitude are two diferent attributes. how could both of those be defined by the current? current is just one quantity.
| Originally Posted by regal /img/forum/go_quote.gif Well an audio signal is a little more complex, think of it this way the frequency and amplitude (changes) are in current instead of the usual voltage. |
oh man, thats only gonna make it worse, frequency and amplitude are two diferent attributes. how could both of those be defined by the current? current is just one quantity.
regal
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Current can have two: time domain and amplitude (amount).
| Originally Posted by SoupRKnowva /img/forum/go_quote.gif oh man, thats only gonna make it worse, frequency and amplitude are two diferent attributes. how could both of those be defined by the current? current is just one quantity. |
Current can have two: time domain and amplitude (amount).
Quote:
man this whole thing is throwing me through a loop, cause technically its still in voltage. Or does the system somehow use varying levels of resistance to produce the changes in current so it can keep constant voltage?
| Originally Posted by regal /img/forum/go_quote.gif Current can have two: time domain and amplitude (amount). |
man this whole thing is throwing me through a loop, cause technically its still in voltage. Or does the system somehow use varying levels of resistance to produce the changes in current so it can keep constant voltage?
regal
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A voltage regulator provides a constant voltage with varying current. Don't know how Audio-gn does this but probably a type of discrete voltage regulator with a low output impedance.
Quote:
ok so it does vary resistance to accomplish this, like in a zener diode. Cool, thanks for all the info regal, just trying to understand how it all works, the nuts and bolts really interest me
| Originally Posted by regal /img/forum/go_quote.gif A voltage regulator provides a constant voltage with varying current. Don't know how Audio-gn does this but probably a type of discrete voltage regulator with a low output impedance. |
ok so it does vary resistance to accomplish this, like in a zener diode. Cool, thanks for all the info regal, just trying to understand how it all works, the nuts and bolts really interest me
regal
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Its not so much varying resistance as it is controlling current flow. Wiki :transistor.
| Originally Posted by SoupRKnowva /img/forum/go_quote.gif ok so it does vary resistance to accomplish this, like in a zener diode. Cool, thanks for all the info regal, just trying to understand how it all works, the nuts and bolts really interest me
|
Its not so much varying resistance as it is controlling current flow. Wiki :transistor.
Quote:
But arent transistors just a method of changing resistance? the bias changes the effective resistance of the throughput does it not? allowing more of less through depending on the bias? though im probably wrong, its been quite some time since ive taken electronics
| Originally Posted by regal /img/forum/go_quote.gif Its not so much varying resistance as it is controlling current flow. Wiki :transistor. |
But arent transistors just a method of changing resistance? the bias changes the effective resistance of the throughput does it not? allowing more of less through depending on the bias? though im probably wrong, its been quite some time since ive taken electronics
PrTv
100+ Head-Fier
How can I tell which version of module I have?
I know that there are 2 modules available, Mode A and Mode B, and from the review it seems that mode B may suit me better. The problem is I don't know what version I'm currently using.
Here is an internal picture. Frankly, I don't even know where is that "replaceable module", but if I must guess, I think it's the upper piece with the HDCD chip.
I also found this in a small box that came with this DAC. Is this one of the modules mentioned above?
If it's the module, will the dac lose HDCD decoding capability if I swap the module currently equipped with this one?
I know that there are 2 modules available, Mode A and Mode B, and from the review it seems that mode B may suit me better. The problem is I don't know what version I'm currently using.
Here is an internal picture. Frankly, I don't even know where is that "replaceable module", but if I must guess, I think it's the upper piece with the HDCD chip.
I also found this in a small box that came with this DAC. Is this one of the modules mentioned above?
If it's the module, will the dac lose HDCD decoding capability if I swap the module currently equipped with this one?
regal
Headphoneus Supremus
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The module pictured is the non-HDCD decoding DF1704 module. The HDCD module has a chip labelled HDCD PMD100, thats the one you want.
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