4 ms·

> “This is noise on the power grid. Power integrity will cause more degradation of chip performance. That is not only for the advanced nodes, but we have seen t

> “This is noise on the power grid. Power integrity will cause more degradation of chip performance. That is not only for the advanced nodes, but we have seen that more and more on the legacy nodes — 28nm and 40nm are having the same problem.” Reminds me of audiophiles getting their own utility poles installed to prevent this [1]. [1] https://news.ycombinator.com/item?id=18779434 https://news.ycombinator.com/item?id=18779434

segfaultbuserr 7y ago
No. You are misreading it (and it's not your fault, the article assumes the reader already has a background in semiconductor engineering). The "power grid" here refers to the internal power distribution network on the chip, not utility electrical power grid. Signal and power integrity in electronics is a serious area of research supported by applied electromagnetism, measurements, modeling, simulation, and industrial experience. Never confuse signal integrity with "audiophile" voodoo practices, which is supported by none of them. For example, all audiophiles seemed to care about noises from the power lines, but it seems not all of them understand that the power is rectified, filtered, and DC-DC converted, filtering again, routed to the chip, bypassed and filtering again, before the power in finally delivered to the system. The noises on the power rail can have effects on sound quality, but it's the actual power supply and PCB design that dictates power integrity. While it's likely that transients from the utility power can have an effect on the circuit operation (and ground loop is a major problem), but the majority of noise is likely coming from the switching noises on the Hi-Fi amplifier itself. Even the physical location of the traces on the PCB can have much more influence than the utility grid, A wire that should be routed to the left of the board but routed to the right can be problematic. If the voltage of your DAC is unstable because the current loop area is excessive, adding your utility poles or using a gold-plated cable does absolutely zero to the performance of the amplifier.
- sandworm101 7y ago
  >> The "power grid" here refers to the internal power distribution network on the chip, not utility electrical power grid. It's the same problem, just at a different scale.
  - mdszy 7y ago
    It absolutely isn't. The issues caused by mains 60Hz AC are vastly different from the issues caused by switched mode power supplies. Saying they're the same thing is straight up ignorant.
    - fuzzfactor 7y ago
      >You cannot design the power grid independent of the rest of the design Never could, even the equivalent during vacuum tube efforts. Even without an electronic power supply you can use a battery. Sounds so easy, still need to watch it. Consider how they do it with competition car stereos. There are extra storage capacitors to augment the batteries since they can discharge faster than the battery to provide less distortion on large transients. Basically a car stereo amplifier is designed to neutralize your battery in time with the music. If your battery is not capable of providing the dynamics your amplifier needs, it then will not be able to reproduce them. Audio amplifiers running on AC line voltage are actually just power supplies. Power supplies which convert and filter the low AC line frequency to DC, then draw from the DC a waveform according to your incoming music preamp signal which is AC of varying amplitude & frequency, often in the distinct pattern of pop music. While your speakers' AC pattern tries to represent the preamp signal fluctuations coming in, your power supply tries to provide the continuous power fluctuations, or represent "music noise", called for during that reproduction. Anywhere along the power supply lines, an image of some small kind resembling the output can be found, mostly at the higher power extremes. This is the part of the circuitry most thoroughly isolated from the audio input & output path but there it is. The purpose of the isolation by design is to keep the line noise away from the audio reproduction components, but it must let the power through in the pattern requested by the incoming audio signal. Largely, frequencies will also broadcast over greater distances the higher the frequency is and the higher the amplitude. And wiring, especially unterminated leads, acts as antennae according to their length and direction, for both broadcast and reception. This is whether between chasses miles apart such as amateur broadcasters and recievers, within the same chassis as unwanted electronic "feedback" from one part of the circuit or power supply to another part which would ideally be perfectly isolated instead, or within the same chip, especially when the frequency is high enough, the distance small enough, and the lead length unfavorable enough to serve as the broadcast & reception antennae needed to overcome either the air gap or the electronic filtration. With linear power supplies the 50/100 or 60/120 Hz noise requires an optimized approach different than the much higher frequencies of switchers. Modern swichers can broadcast their noise further and also more easily defy the type of wiring acceptable for linear alternatives. And they can sound worse than hum too once you hear that trash, especially bad when ultrasonics are throwing audio-range harmonics down at you from other supposedly inaudible modulations.
- yellow_lead 7y ago
  Thanks for the insight. I actually started reading the comments on that old discussion after digging it up and it does seem like "voodoo" as you call it :)
  - segfaultbuserr 7y ago
    I believe many claims made by audiophiles do have a point, and some are true. But in order to distinguish them, one needs to actually read from better sources to learn how electronics work in general, for example, an introductory book, primary sources like industiral standards from Audio Engineering Society, or the CD Red Book. The audiophile community and the industry is plagued by many cargo cult and voodoo practices, and it is supported by many vendors.
    - LinuxBender 7y ago
      I am not an audiophile, but I have had to clean up the sloppy power in my neighborhood. The transformer near me is very old and about to blow, but power company won't fix it. I've had to use a combination of isolation transformers, double-conversion Liebert UPS, step-start power distribution switches just to keep from losing internet every time the neighbors spetic pump kicks in. I also had to filter the RF cable as well, as it suffers from the same power spikes from cheap cable modems power supplies. Even my old Sony reference line receiver could not filter out that garbage. I'm in the middle of nowhere though, so this is probably not common for people in the city, just guessing.
      - yellow_lead 7y ago
        This sounds pretty interesting. Did you ever do a write-up of it?
        LinuxBender 7y ago
        No, I just complain to the power company a couple times per year. One of the neighbors also complains to them, as they smoked 2 of his UPS units. They burnt up a few of my cheaper UPS units prior to having the liebert double-conversion UPS. The 1200W APC caught fire. The other ones just smoked. The smaller APC units (power strip form factor) never smoked, they just tripped a lot.
taneq 7y ago
The problem is real with chips, though. Audiophiles are notorious for doing silly things “to improve the sound quality” in ways undetectable in a double-blind test (but clearly audible to “real audiophiles” otherwise.) At macro scale a UPS with good filtering is more than sufficient to power audio equipment.

segfaultbuserr 7y ago

No. You are misreading it (and it's not your fault, the article assumes the reader already has a background in semiconductor engineering). The "power grid" here refers to the internal power distribution network on the chip, not utility electrical power grid. Signal and power integrity in electronics is a serious area of research supported by applied electromagnetism, measurements, modeling, simulation, and industrial experience. Never confuse signal integrity with "audiophile" voodoo practices, which is supported by none of them. For example, all audiophiles seemed to care about noises from the power lines, but it seems not all of them understand that the power is rectified, filtered, and DC-DC converted, filtering again, routed to the chip, bypassed and filtering again, before the power in finally delivered to the system. The noises on the power rail can have effects on sound quality, but it's the actual power supply and PCB design that dictates power integrity. While it's likely that transients from the utility power can have an effect on the circuit operation (and ground loop is a major problem), but the majority of noise is likely coming from the switching noises on the Hi-Fi amplifier itself. Even the physical location of the traces on the PCB can have much more influence than the utility grid, A wire that should be routed to the left of the board but routed to the right can be problematic. If the voltage of your DAC is unstable because the current loop area is excessive, adding your utility poles or using a gold-plated cable does absolutely zero to the performance of the amplifier.

sandworm101 7y ago
>> The "power grid" here refers to the internal power distribution network on the chip, not utility electrical power grid. It's the same problem, just at a different scale.
- mdszy 7y ago
  It absolutely isn't. The issues caused by mains 60Hz AC are vastly different from the issues caused by switched mode power supplies. Saying they're the same thing is straight up ignorant.
  - fuzzfactor 7y ago
    >You cannot design the power grid independent of the rest of the design Never could, even the equivalent during vacuum tube efforts. Even without an electronic power supply you can use a battery. Sounds so easy, still need to watch it. Consider how they do it with competition car stereos. There are extra storage capacitors to augment the batteries since they can discharge faster than the battery to provide less distortion on large transients. Basically a car stereo amplifier is designed to neutralize your battery in time with the music. If your battery is not capable of providing the dynamics your amplifier needs, it then will not be able to reproduce them. Audio amplifiers running on AC line voltage are actually just power supplies. Power supplies which convert and filter the low AC line frequency to DC, then draw from the DC a waveform according to your incoming music preamp signal which is AC of varying amplitude & frequency, often in the distinct pattern of pop music. While your speakers' AC pattern tries to represent the preamp signal fluctuations coming in, your power supply tries to provide the continuous power fluctuations, or represent "music noise", called for during that reproduction. Anywhere along the power supply lines, an image of some small kind resembling the output can be found, mostly at the higher power extremes. This is the part of the circuitry most thoroughly isolated from the audio input & output path but there it is. The purpose of the isolation by design is to keep the line noise away from the audio reproduction components, but it must let the power through in the pattern requested by the incoming audio signal. Largely, frequencies will also broadcast over greater distances the higher the frequency is and the higher the amplitude. And wiring, especially unterminated leads, acts as antennae according to their length and direction, for both broadcast and reception. This is whether between chasses miles apart such as amateur broadcasters and recievers, within the same chassis as unwanted electronic "feedback" from one part of the circuit or power supply to another part which would ideally be perfectly isolated instead, or within the same chip, especially when the frequency is high enough, the distance small enough, and the lead length unfavorable enough to serve as the broadcast & reception antennae needed to overcome either the air gap or the electronic filtration. With linear power supplies the 50/100 or 60/120 Hz noise requires an optimized approach different than the much higher frequencies of switchers. Modern swichers can broadcast their noise further and also more easily defy the type of wiring acceptable for linear alternatives. And they can sound worse than hum too once you hear that trash, especially bad when ultrasonics are throwing audio-range harmonics down at you from other supposedly inaudible modulations.
yellow_lead 7y ago
Thanks for the insight. I actually started reading the comments on that old discussion after digging it up and it does seem like "voodoo" as you call it :)
- segfaultbuserr 7y ago
  I believe many claims made by audiophiles do have a point, and some are true. But in order to distinguish them, one needs to actually read from better sources to learn how electronics work in general, for example, an introductory book, primary sources like industiral standards from Audio Engineering Society, or the CD Red Book. The audiophile community and the industry is plagued by many cargo cult and voodoo practices, and it is supported by many vendors.
  - LinuxBender 7y ago
    I am not an audiophile, but I have had to clean up the sloppy power in my neighborhood. The transformer near me is very old and about to blow, but power company won't fix it. I've had to use a combination of isolation transformers, double-conversion Liebert UPS, step-start power distribution switches just to keep from losing internet every time the neighbors spetic pump kicks in. I also had to filter the RF cable as well, as it suffers from the same power spikes from cheap cable modems power supplies. Even my old Sony reference line receiver could not filter out that garbage. I'm in the middle of nowhere though, so this is probably not common for people in the city, just guessing.
    - yellow_lead 7y ago
      This sounds pretty interesting. Did you ever do a write-up of it?
      - LinuxBender 7y ago
        No, I just complain to the power company a couple times per year. One of the neighbors also complains to them, as they smoked 2 of his UPS units. They burnt up a few of my cheaper UPS units prior to having the liebert double-conversion UPS. The 1200W APC caught fire. The other ones just smoked. The smaller APC units (power strip form factor) never smoked, they just tripped a lot.

taneq 7y ago

The problem is real with chips, though. Audiophiles are notorious for doing silly things “to improve the sound quality” in ways undetectable in a double-blind test (but clearly audible to “real audiophiles” otherwise.) At macro scale a UPS with good filtering is more than sufficient to power audio equipment.