7 ms·

Be aware that these things have serious linearity (signal quality) issues, to the point where us "mere mortals" who design analog circuitry for T&M equipment tr

Be aware that these things have serious linearity (signal quality) issues, to the point where us "mere mortals" who design analog circuitry for T&M equipment try to stay away from them wherever possible. Audiophiles, of course, can hear the difference between copper, silver, gold, or platinum plating on the cable shield's drain wire in their neighbor's washing machine when he's on vacation in Hong Kong, so, you know, use with caution, you don't want to give them a heart attack or anything. (Unless you like the particular flavor of distortion these guys give. Then, by all means, help yourself!)

dylan604 4y ago
connect it to a foot pedal so a guitarist can use it to create a unique sound. it'll sell 10s of dollars!
- xani_ 4y ago
  Unironically diode-to-photoresistor optocouplers are used in some compressors and filters to get that soft analoguey sound (as they are plain slow to react to signal). Which is kinda a supply problem as material they were made with was banned for toxicity
  - squarefoot 4y ago
    True. LDRs (photoresistors) are however still very easy to find on the usual online suppliers (Ebay, Aliexpress etc.) although they're banned in some areas for containing cadmium. I've used them successfully in LED+LDR arrangements to emulate Vactrols in vintage-style audio compressor circuits. To replicate the vintage compressor slow attack, in theory one should use a filament lamp+LDR pair so that the lamp slower attack and very slow decay, compared to a LED, would give that particular curve. However this is something that can be easily replicated using a RC network within the circuit that drives the LED.
    - fuzzfactor 4y ago
      >diode-to-photoresistor optocouplers The crude (but wonderful sounding) type like they have in vintage Fender tube amps are used to effect the signal, not pass the entire signal. Can't read the article but I assume these Audio Optocouplers are intended to pass the entire signal in an acceptable way. I don't think they would be very good for T & M use either unless you were desperate for isolation. I found great use for the regular 4-legged kind of precision non-audio optos, to isolate the physical relay logic from the audio power supply for much lower noise floor under high-gain channel-switching applications.
      - squarefoot 4y ago
        > The crude (but wonderful sounding) type like they have in vintage Fender tube amps are used to effect the signal, not pass the entire signal. Yes, I was referring to the use as variable resistors in compressor circuits; the sound wasn't affected at all but the slow attack-release induced to the dynamics contributed to that particular character in vintage guitar amplifiers.
melony 4y ago
Does the non-linearity come from the diode or does it come from the resistor?
- deleted 4y ago
  [deleted]
- klodolph 4y ago
  Resistors are generally very linear. They're put in the same category as transformers, capacitors, and inductors, where we just ignore the non-linearities--they're usually too small to measure, although reverse-biased electrolytic capacitors are definitely nonlinear and I've heard you can be affected by nonlinearity on carbon-composition resistors if you put enough voltage across them--like, 100V--don't know if it's true, just "heard it somewhere". Diodes are incredibly nonlinear, that's the whole point of having diodes.
  - melony 4y ago
    Isn't the diode linear only within a certain part of the VI graph?
    - jupp0r 4y ago
      No, it's exponential all around. For any infinitesimal small delta V you can assume it to be almost linear. This works for amplifying really small signals.
    - klodolph 4y ago
      It's not really linear anywhere, except in the sense that it's got a smooth VI graph, so you can pick a point on the curve and draw a tangent line if you want. That's not really linear, unless you have small enough signals or bad enough oscilloscopes. It's much closer to exponential, which is Shockley diode equation / "diode law" which is the simplest model you would use besides the "diode is a one-way switch with a voltage threshold" model. The diode law is I = Is[ exp(VD/nVT) - 1 ]. There are more sophisticated models of the diode that use multiple exponentials. Remember that these are all just approximations of reality based on some simplifying assumptions, the only real question is "how much do you want to simplify", and linear models are very rarely useful for modeling diodes.
GeneT45 4y ago
Your comment can only be truly appreciated by plumbing the bizarre depths of "high-end audio" where nitwits (errr... customers) will pay $700 for a 6' Kapton-insulated power cord for their stereo. You know, to plug into the wall where it connects to 100 ft of Romex that cost $0.20/ft... Looks like my favorite example has disappeared, but there are always these: http://www.audio-consulting.ch/?Parts:Woodlenses http://www.audio-consulting.ch/?Parts:Woodlenses
- the_third_wave 4y ago
  $700, where do you buy your cables, at McDonalds? No, if you want to have really clear audio you'd better get one of those Synergistic Research cables [1]. For a mere $10.000,- starting price (6 ft, add $1000/ft if you want a longer cable) it will be as if the musicians are sitting on your table, eating your cookies and petting your dog. It's the Quantum tunneling which does the trick, see? They kick the atoms into the right shape using a Tesla coil and, being obedient little atoms, they stay where they're told. Or something. [1] https://www.synergisticresearch.com/cables/srx-cables/srx-ac/ https://www.synergisticresearch.com/cables/srx-cables/srx-ac...
  - buescher 4y ago
    Before you bag on these guys, even though they deserve it, imagine the customer support issues...
  - elteto 4y ago
    > ...being obedient little atoms, they stay where they're told 50 shades of quantum tunneling
  - unfocused 4y ago
    C'mon! Everybody knows that the Nordost Valhalla 2 Power Cord is far superior than the SRX. It's also only $10,079.99 CAD for 6ft, so it will be less than yours since yours is in USD, saving you money to to buy fridge magnets which will help dampen the magnetic field from any orphan atoms that may leak through. Also, from the manufacturer's brochure: Unlike conventional power cables, which have propagation speeds that are less than 50% the speed of light, the Valhalla 2 Reference Power Cord has a speed of 91% the speed of light. [1] https://audiofi.ca/products/valhalla-2-power-cord?variant=34236938780811 https://audiofi.ca/products/valhalla-2-power-cord?variant=34... EDIT: On a more serious note, check out https://www.audiosciencereview.com/forum/index.php https://www.audiosciencereview.com/forum/index.php for real testing, where the dollar store speaker cable performed (surprise!) as well as the fancy cables. The fancy cable company was not happy.
jeffbee 4y ago
Why would anyone choose these over galvanic isolation?
- klodolph 4y ago
  It's way cheaper. Like, it's not even close. (Note that this IS galvanic isolation--I assume you are talking about transformers, which is the other common way to galvanically isolating circuits.)
  - jeffbee 4y ago
    You’re right that was lazy of me. But you got what I meant: transformers.
    - fuzzfactor 4y ago
      Magnetic isolation more specifically, when you think about it. So at the same time, magnetically coupled. Naturally subject to forces including back-EMF which are not shared by optics.
      - klodolph 4y ago
        just drive your optics hard enough, you'll see back-EMF /s
        fuzzfactor 4y ago
        I've driven non-photo resistors to the point you could see the glowing in time to the music ;-) And smell the smoke. Now with a 1500W space heater as a dummy load on a 1000W amp, you hear a little music come out of the heating elements without any speakers.
fuckstick 4y ago
I bet many of those audiophiles would either not tell the difference or love it if it was marketed accordingly.
xani_ 4y ago
https://www.vishay.com/docs/83708/appnote50.pdf https://www.vishay.com/docs/83708/appnote50.pdf Page 9 if anyone is interested. TL;DR to get good specs out of it is complex, just use ausio isolation transformer
voldacar 4y ago
Just like everywhere else, silliness in the audio world is Pareto distributed. As someone who loves good sound reproduction, it's tiresome to have people endlessly start talking about magic rocks or whatever whenever the topic of audio quality or audio electronics is brought up online. What's sad to me is that a lot of this cynicism seems to come from people who haven't even heard a really good pair of speakers or headphones, and it drives people away from having potentially beautiful experiences. Go visit your local high end audio shop and ask for a demo. They will probably be glad to have you. Listnening to well-recorded music through great transducers and electronics in a well-treated room is a mind blowing experience if you haven't tried it.
- daniel-cussen 4y ago
  Yeah I don't actually value happiness but insofar as I do it simply means headphones. Good headphones. Audio quality yeah, but also unique way it plays songs, listen to everything all over again. And convenience, so for instance Airpods are the best headphone right now because it works well with masks, you don't have to put one over the other, meaning removing one requires removing the other. The convenience, the battery life, all that. Audio isn't just what you hear when everything's set up, it's also hearing sound when other systems would play nothing.
  - brokenmachine 4y ago
    >Airpods are the best headphone right now No.
    - daniel-cussen 4y ago
      Why not?
      - voldacar 4y ago
        The best headphone right now is probably the utopia or x9000 in terms of raw resolution
kazinator 4y ago
If it's nonlinear, the audiophile is guaranteed to relish the warm tone. The definition of an audiophile is: someone who listens to the speakers (or the equipment, in general) rather than the music. Without distortion, there is nothing for the audiophile to listen to.
- pclmulqdq 4y ago
  This hasn't been my experience with many audiophiles. There are many who are obsessed with the "transparency" of their setup, and I have met more of those than people obsessed with "tube sound" or other distortions.
- voldacar 4y ago
  This is just ignorant. Plenty of audiophiles (including myself) go after gear that's as neutral and transparent as possible. Also warmth and distortion aren't the same thing.

dylan604 4y ago

connect it to a foot pedal so a guitarist can use it to create a unique sound. it'll sell 10s of dollars!

xani_ 4y ago
Unironically diode-to-photoresistor optocouplers are used in some compressors and filters to get that soft analoguey sound (as they are plain slow to react to signal). Which is kinda a supply problem as material they were made with was banned for toxicity
- squarefoot 4y ago
  True. LDRs (photoresistors) are however still very easy to find on the usual online suppliers (Ebay, Aliexpress etc.) although they're banned in some areas for containing cadmium. I've used them successfully in LED+LDR arrangements to emulate Vactrols in vintage-style audio compressor circuits. To replicate the vintage compressor slow attack, in theory one should use a filament lamp+LDR pair so that the lamp slower attack and very slow decay, compared to a LED, would give that particular curve. However this is something that can be easily replicated using a RC network within the circuit that drives the LED.
  - fuzzfactor 4y ago
    >diode-to-photoresistor optocouplers The crude (but wonderful sounding) type like they have in vintage Fender tube amps are used to effect the signal, not pass the entire signal. Can't read the article but I assume these Audio Optocouplers are intended to pass the entire signal in an acceptable way. I don't think they would be very good for T & M use either unless you were desperate for isolation. I found great use for the regular 4-legged kind of precision non-audio optos, to isolate the physical relay logic from the audio power supply for much lower noise floor under high-gain channel-switching applications.
    - squarefoot 4y ago
      > The crude (but wonderful sounding) type like they have in vintage Fender tube amps are used to effect the signal, not pass the entire signal. Yes, I was referring to the use as variable resistors in compressor circuits; the sound wasn't affected at all but the slow attack-release induced to the dynamics contributed to that particular character in vintage guitar amplifiers.

melony 4y ago

Does the non-linearity come from the diode or does it come from the resistor?

deleted 4y ago
[deleted]
klodolph 4y ago
Resistors are generally very linear. They're put in the same category as transformers, capacitors, and inductors, where we just ignore the non-linearities--they're usually too small to measure, although reverse-biased electrolytic capacitors are definitely nonlinear and I've heard you can be affected by nonlinearity on carbon-composition resistors if you put enough voltage across them--like, 100V--don't know if it's true, just "heard it somewhere". Diodes are incredibly nonlinear, that's the whole point of having diodes.
- melony 4y ago
  Isn't the diode linear only within a certain part of the VI graph?
  - jupp0r 4y ago
    No, it's exponential all around. For any infinitesimal small delta V you can assume it to be almost linear. This works for amplifying really small signals.
  - klodolph 4y ago
    It's not really linear anywhere, except in the sense that it's got a smooth VI graph, so you can pick a point on the curve and draw a tangent line if you want. That's not really linear, unless you have small enough signals or bad enough oscilloscopes. It's much closer to exponential, which is Shockley diode equation / "diode law" which is the simplest model you would use besides the "diode is a one-way switch with a voltage threshold" model. The diode law is I = Is[ exp(VD/nVT) - 1 ]. There are more sophisticated models of the diode that use multiple exponentials. Remember that these are all just approximations of reality based on some simplifying assumptions, the only real question is "how much do you want to simplify", and linear models are very rarely useful for modeling diodes.

GeneT45 4y ago

Your comment can only be truly appreciated by plumbing the bizarre depths of "high-end audio" where nitwits (errr... customers) will pay $700 for a 6' Kapton-insulated power cord for their stereo. You know, to plug into the wall where it connects to 100 ft of Romex that cost $0.20/ft... Looks like my favorite example has disappeared, but there are always these: http://www.audio-consulting.ch/?Parts:Woodlenses http://www.audio-consulting.ch/?Parts:Woodlenses

the_third_wave 4y ago
$700, where do you buy your cables, at McDonalds? No, if you want to have really clear audio you'd better get one of those Synergistic Research cables [1]. For a mere $10.000,- starting price (6 ft, add $1000/ft if you want a longer cable) it will be as if the musicians are sitting on your table, eating your cookies and petting your dog. It's the Quantum tunneling which does the trick, see? They kick the atoms into the right shape using a Tesla coil and, being obedient little atoms, they stay where they're told. Or something. [1] https://www.synergisticresearch.com/cables/srx-cables/srx-ac/ https://www.synergisticresearch.com/cables/srx-cables/srx-ac...
- buescher 4y ago
  Before you bag on these guys, even though they deserve it, imagine the customer support issues...
- elteto 4y ago
  > ...being obedient little atoms, they stay where they're told 50 shades of quantum tunneling
- unfocused 4y ago
  C'mon! Everybody knows that the Nordost Valhalla 2 Power Cord is far superior than the SRX. It's also only $10,079.99 CAD for 6ft, so it will be less than yours since yours is in USD, saving you money to to buy fridge magnets which will help dampen the magnetic field from any orphan atoms that may leak through. Also, from the manufacturer's brochure: Unlike conventional power cables, which have propagation speeds that are less than 50% the speed of light, the Valhalla 2 Reference Power Cord has a speed of 91% the speed of light. [1] https://audiofi.ca/products/valhalla-2-power-cord?variant=34236938780811 https://audiofi.ca/products/valhalla-2-power-cord?variant=34... EDIT: On a more serious note, check out https://www.audiosciencereview.com/forum/index.php https://www.audiosciencereview.com/forum/index.php for real testing, where the dollar store speaker cable performed (surprise!) as well as the fancy cables. The fancy cable company was not happy.

jeffbee 4y ago

Why would anyone choose these over galvanic isolation?

klodolph 4y ago
It's way cheaper. Like, it's not even close. (Note that this IS galvanic isolation--I assume you are talking about transformers, which is the other common way to galvanically isolating circuits.)
- jeffbee 4y ago
  You’re right that was lazy of me. But you got what I meant: transformers.
  - fuzzfactor 4y ago
    Magnetic isolation more specifically, when you think about it. So at the same time, magnetically coupled. Naturally subject to forces including back-EMF which are not shared by optics.
    - klodolph 4y ago
      just drive your optics hard enough, you'll see back-EMF /s
      - fuzzfactor 4y ago
        I've driven non-photo resistors to the point you could see the glowing in time to the music ;-) And smell the smoke. Now with a 1500W space heater as a dummy load on a 1000W amp, you hear a little music come out of the heating elements without any speakers.

fuckstick 4y ago

I bet many of those audiophiles would either not tell the difference or love it if it was marketed accordingly.

xani_ 4y ago

https://www.vishay.com/docs/83708/appnote50.pdf https://www.vishay.com/docs/83708/appnote50.pdf Page 9 if anyone is interested. TL;DR to get good specs out of it is complex, just use ausio isolation transformer

voldacar 4y ago

Just like everywhere else, silliness in the audio world is Pareto distributed. As someone who loves good sound reproduction, it's tiresome to have people endlessly start talking about magic rocks or whatever whenever the topic of audio quality or audio electronics is brought up online. What's sad to me is that a lot of this cynicism seems to come from people who haven't even heard a really good pair of speakers or headphones, and it drives people away from having potentially beautiful experiences. Go visit your local high end audio shop and ask for a demo. They will probably be glad to have you. Listnening to well-recorded music through great transducers and electronics in a well-treated room is a mind blowing experience if you haven't tried it.

daniel-cussen 4y ago
Yeah I don't actually value happiness but insofar as I do it simply means headphones. Good headphones. Audio quality yeah, but also unique way it plays songs, listen to everything all over again. And convenience, so for instance Airpods are the best headphone right now because it works well with masks, you don't have to put one over the other, meaning removing one requires removing the other. The convenience, the battery life, all that. Audio isn't just what you hear when everything's set up, it's also hearing sound when other systems would play nothing.
- brokenmachine 4y ago
  >Airpods are the best headphone right now No.
  - daniel-cussen 4y ago
    Why not?
    - voldacar 4y ago
      The best headphone right now is probably the utopia or x9000 in terms of raw resolution

kazinator 4y ago

If it's nonlinear, the audiophile is guaranteed to relish the warm tone. The definition of an audiophile is: someone who listens to the speakers (or the equipment, in general) rather than the music. Without distortion, there is nothing for the audiophile to listen to.

pclmulqdq 4y ago
This hasn't been my experience with many audiophiles. There are many who are obsessed with the "transparency" of their setup, and I have met more of those than people obsessed with "tube sound" or other distortions.
voldacar 4y ago
This is just ignorant. Plenty of audiophiles (including myself) go after gear that's as neutral and transparent as possible. Also warmth and distortion aren't the same thing.