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Alpha audio just presented new measurements.
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Geert
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Seen what? The streamer powersupply test https://alpha-audio.net/videocast/alpha-labs-the-influence-of-power-supplies-on-streamers/?
He doesn't even bother to show the levels of noise he's measuring, nevertheless his audience is already convinced of a big discovery. At the end he mentions something along the lines of -150dB to -160dB. Probably a waste of time trying to explain what that means.
He doesn't even bother to show the levels of noise he's measuring, nevertheless his audience is already convinced of a big discovery. At the end he mentions something along the lines of -150dB to -160dB. Probably a waste of time trying to explain what that means.
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Geert
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Power conditioner test same story, we can hardly see what he's measuring. Also not clear what his measurement rig looks like, so unclear if his lab equipment might impact the measurements. The reason I bring this up is that his base measurement of the Bryston power amp already starts with a 20dB higher 50Hz noise tone than other measurements found online. So I would love to see more details.
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Geert
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When it comes to measurements and electronics in general, he's an amateur at best. Note that he's a journalist, he has no formal education in electronics.
Geert
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Probably the fact that this guy purchased some lab equipment to make it look likes he can fight ASR on their own territory. It's good enough for his audience.
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A fool with a tool.....
KSTR
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This guy's measurements look completely OK to me as I see the same things all the time in my tests when the hookup is not 100% error-free.
The point is, he's *not* actually measuring the noise at the outputs of the devices, rather he dominantly**) measures the noise at the end of the unbalanced cables at the analyzer's inputs. While he uses a separate ground lead in an attempt to divert the main leakage ("ground loop") currents away from the interconnects this is not sufficient, obviously. So what he is mainly seeing is the voltage drop from the balancing currents that develops along the shield of the interconnects. Simple 2-prong SMPS wall-warts are notoriously bad wrt these mains leakage currents.
**) However, some devices have such a bad internal grounding layout that any leakage current through the device already creates these voltage drop errors.
But hey, in some sense this is a very valid real-life scenario, of course, as that is what will happen quite often with unbalanced interconnects depending on the total system's grounding and supply schemes. The good specs of any piece of equipment then usually fly right out of the window as the mains leakage current "ground loop" noise will dominate SINAD etc. We (@pma, myself and some others) have pointed that out already, over and over.
If one were to measure the true noise as actually present right at the device outputs one must use balanced interconnects to the analyzer even when hooked to unbalanced outputs. By this, the cable influence is eliminated but any mentioned bad layout-induced errors will be seen. To double check, on needs a completely floating analyzer... then even the bad layout type of error is removed (this is important for example for headphone amps where the load is truly floating, not connected to anything else), and in the complementary test, defined leakage current through the device can be injected to get reproducible data.
The point is, he's *not* actually measuring the noise at the outputs of the devices, rather he dominantly**) measures the noise at the end of the unbalanced cables at the analyzer's inputs. While he uses a separate ground lead in an attempt to divert the main leakage ("ground loop") currents away from the interconnects this is not sufficient, obviously. So what he is mainly seeing is the voltage drop from the balancing currents that develops along the shield of the interconnects. Simple 2-prong SMPS wall-warts are notoriously bad wrt these mains leakage currents.
**) However, some devices have such a bad internal grounding layout that any leakage current through the device already creates these voltage drop errors.
But hey, in some sense this is a very valid real-life scenario, of course, as that is what will happen quite often with unbalanced interconnects depending on the total system's grounding and supply schemes. The good specs of any piece of equipment then usually fly right out of the window as the mains leakage current "ground loop" noise will dominate SINAD etc. We (@pma, myself and some others) have pointed that out already, over and over.
If one were to measure the true noise as actually present right at the device outputs one must use balanced interconnects to the analyzer even when hooked to unbalanced outputs. By this, the cable influence is eliminated but any mentioned bad layout-induced errors will be seen. To double check, on needs a completely floating analyzer... then even the bad layout type of error is removed (this is important for example for headphone amps where the load is truly floating, not connected to anything else), and in the complementary test, defined leakage current through the device can be injected to get reproducible data.
Geert
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The point is he doesn't realise any of this, doesn't clarify it to his audience, it's not how measurements are usually done, and if people would run into this issue in a real life application where it matters, meaning noise becomes audible, they could still troubleshoot the grounding issue.
Instead he suggests ASR doesn't know how to measure these things, and in the YouTube comments he argues even the -150dB noise from a switched power supply matters as it gets amplified and 'it adds up'. He's playing the 'lowers the noise floor' audiophile myth. Refering to inaudible noise that nevertheless audibly improves, typically when connecting audiophile cables or mains filters.
Rather a man with a plan. He is using measurements to confirm his bias. Not the first time, probably not the last.
I used to read the reviews on Alpha Audio because especially Jaap liked neutral sounding speakers like Revell and Grimm Audio and I liked his honest reviews, but lately there is more and more BS on Alpha audio, better sounding cables, better sounding switches etc. Most irritating is that they pretend to do good testing but the test are so flawed that it is just a joke. Guess they found out that there is more money in the snake oil department 
Geert
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You should also read his opinion piece about our hearing system https://alpha-audio.net/background/our-best-measuring-tool-our-own-ears/. Picking some quotes from scientific research to build his own reality and to convince people our hearing is much more precise than we think and there is a lot science doesn't understand yet.
To give you an idea: "in terms of detail and dynamic range, 16 bit and 48 kHz is sufficient on its own. Especially with dithering. However, in terms of timing, that resolution is not accurate enough. 96 kHz is basically needed to ensure the “flow” and richness in the music. And frankly, that is indeed audible in good recordings".
To give you an idea: "in terms of detail and dynamic range, 16 bit and 48 kHz is sufficient on its own. Especially with dithering. However, in terms of timing, that resolution is not accurate enough. 96 kHz is basically needed to ensure the “flow” and richness in the music. And frankly, that is indeed audible in good recordings".
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I read the test of digital cables. I'm impressed. Impressed enough I don't need to read or hear anything more from the fellow or his website.
He clearly doesn't understand the sampling theorem
It's the bits that give you time accuracy, not the sample rate.- Thread Starter
- #18
Agree.
Here we go again lol
