Whoosh!
I have actually spent years working with A/D and D/A converters and low noise amplification.
The claims of audiophiles are such extravagant bullshit that one imagines some of them are making it up and laughing at the gullible idiots. Obviously, if I am transferring audio as a string of bits, I am not going to affect the bass or stereo separation in the slightest, because the bit strings are not affected by the source (so long as the file is accurate). The only things that affect the sound quality are the encoding (from the microphone to the A/D and the signal processing) and the decoding (converting the bit string to DAC inputs, DAC accuracy, and the accuracy of the audio output.) Unless there are gross errors in the bit storage and transmission, that itself is lossless.
But what Sony is talking about here is different. It is a phenomenon familiar to every EE who has worked with high resolution digitisation. Both in recording and reproduction there is a point where a small, analog signal is passing through the system, either from the microphone or from the digit-to-current stage of the DAC through the audio preamplifier. This small analog signal is susceptible to electrical noise, whether it is crosstalk from other signal lines or from the power planes.
Modern ICs run at very low currents and voltages and so, on a circuit board, they produce little electrical noise compared with the old 5V TTL we had to work with in the 70s. But an external SD card is a bit different because there is an electrical connector between it and the motherboard, and relatively high level signals pass across it. If the layout is less than perfect, an SD card can introduce digital interference which can possibly reach the very sensitive analog stage of the preamps or even the DAC, and create low level analog noise.
An SD card could presumably be designed with circuitry to minimise signal overshoot and jitter, and this could reduce the noise floor. It would only be noticed in pp or ppp passages, and probably only by a young person with classical musical training. But I canāt rule it out as a real effect. Noticeably, iPhones have very low noise floors, no SD slots and nano SIMs. The iPhone 4s had a noise floor of -91dB, while an HTC One V was about -82dB, a noise floor of nearly 10 times louder. The HTC One S achieved about the same as the iPhone 4s, so noise floor in phones is definitely a measurable phenomenon. The 6+ improved to -94dB, but the Note 3 achieves an amazing -96. I would be unsurprised if plugging an SD card into a Note 3 raised the noise floor, though nowadays I donāt have access to the equipment to perform that kind of test.
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It would look nice, but junction FETs could give almost identical performance, did not need heaters and donāt wear out quickly. Nuvistors donāt even look very exotic - they just look like early RF ICs that went in metal can transistor cases.
Are you just trying to make an EMP-proof amp so you can listen to your vinyl records after the nuclear apocalypse?
You had a Faraday-caged office? I had to work in a Faraday-caged trailer and wear a mechanical watch if I wanted to know the time. But I was working on ultra-low-noise circuits, not trying to keep Brezhnev from reading my memos.
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thanks
āThis oneās in elevenaryā
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Math is a commonly used binding agent in snake oil.
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Iāll confess, I never was able to decode WifnProof: but allegedly, mathematics is an utterly ambiguous, if terse way of expressing certain truths. however, many people canāt get past the symbols.
the innumerate may be awed by mathematics used as woo glue, but the flaws should be obvious to anyone trained in the art.
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Reminds me of someone I used to work with. One of his previous jobs was the white van speaker scam. One potential mark took offense with their assertions about quality, and made them bring a pair of speakers to the house so he could A-B them. His speakers were audibly superior but my friend said they kept up with the pitch, anyway.
(Apparently the speakers werenāt bad, as my friend kept a pair for himself.)
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Best tumblr ever. I could spend hours there.
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@LDoBe @dobby @OtherMichael
Sure you could use one of those āartisinalā sources of electricity ā if you want to ruin your audio experience!
Personally, I use a herd of angora bunnies in a perspex room that collects the electrons with an oxygen-free proprietary copper alloy electron harvestorā¦ This results in the softest purest electrons known to science.
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The tumblr links to http://www.musicdirect.com - is that site for real?
The product descriptions are like text-generators wet dream:
http://www.musicdirect.com/p-258466-shunyata-dfss-dark-field-suspension-system.aspx
Shunyata DFSS - DarkField Suspension System
The Brand-New 2015 Shunyata DF-SS - DarkField Suspension System is Sold in A Set-of-Three
Utilized in studios and audio systems all over the world, Shunyata has just engineered a new cable-isolation device called DarkField Suspension System (DFSS).
The most significant advance is the dual-band cable suspension bridge,
which supports any cable while dissipating energy through tensioned
polymer bands. The base is filled with an energy-absorbing granular
compound that absorbs energy which would otherwise enter the cable,
causing signal degradation. This yields improved clarity, depth, and
spatial information within any system.
http://www.musicdirect.com/p-9686-hifi-tuning-disc-demagnetizer.aspx
HiFi Tuning Disc Demagnetizer
Improves Digital Playback, Both Audio and Video
After months of hands-on testing by dedicated audiophiles, HiFi-Tuning has created this latest version of the Disc Demagnetizer, adding a second demagnetization cycle at a different frequency. This makes the HFT Disc Demagnetizer much more effective than other demagnetizers, yet it costs less, too!
Very Fast, Very Effective
Each demagnetizing cycle on the Disc Demagnetizer takes
about 8 seconds. For best results, after the first cycle, flip the disc
over and run a second cycle. You will hear greater clarity, focus and a
substantially lower noise floor. On video discs, the improvement can be
profound, offering stunning improvements to video playback.
Demagnetize a Disc?
We are frequently asked how itās possible for an aluminum disc to
magnetize. The important thing to remember is that just because a disc
is nominally made from polycarbonate and aluminum, this does not mean
these are the only ingredients. Inks used on the disc label and even the
aluminum substrate itself may contain materials that can pick up and
store a magnetic charge. This can happen as the disc is moved in and out
of the case or even in the CD transport itself as the disc is spun at
high speeds. The benefits of demagnetization can be heard on all discs
from brand new CDās to CD-Rs, even DVDs, Blu-Ray and other formats will
benefit.
http://www.musicdirect.com/p-7419-ps-audio-noise-harvester-black.aspx
PS Audio Noise Harvester
The First Power Conditioner to Actually Eliminate Power Line Noise
For a Limited Time Save Up to 50% When You Buy Two or More
Eliminate noise right at the source. The PS Audio Noise Harvester is the worldās only device that actually eliminates line noise
from your homeās power lines. Most power conditioners attempt to
isolate your equipment from all the power line noise, but they cannot
eliminate or remove power line noise. Only the Noise Harvester removes AC noise and converts it to another form of energy, light. Give your power conditioner a nice head start by lowering your noise floor in the first place.
You will actually see the Noise Harvester working as it converts all this noise into light. You will easily be able to hear the improvements, and the effect is cumulative: the more Noise Harvesters the better. Place one on any outlet where you have a computer plugged in, a refrigerator,
a lamp or light with a dimmer switch and place a few in the room with
all of your audio and video gear. This best-selling budget tweak from
design team at PS Audio really makes a dramatic audible improvement. Any system will reap the benefits of the Noise Harvester.
http://www.musicdirect.com/p-9352-nordost-sort-kones-ea.aspx
This stuff is so bizarrely hyperbolic, do people really part with money for this crap?
Iām in the wrong line of businessā¦
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Did you see these? http://www.synthtopia.com/content/2015/01/29/korg-noritake-introduce-futuristic-nutube-vacuum-tubes/
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Do it do it do it! 
And show it off as an ultimate portable player for audiophiles. With the glowy tubes behind a window.
Who knows, maybe people would even buy it!
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Only not in that particular order.
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Sadly, the nuvistors used in aircraft have metal cans and donāt glow.
There are other micro tubes (used for instance in hearing aids) that do have heated cathodes and glass envelopes but they emit very little light. Nor does the EF91 [edit- should be EF86, but I have a box of EF91s] used in so many audio preamps.
The best tubes for glow are the big output beam tetrodes like the 807. Not only do they have kick-ass heaters, the vacuum was very slightly soft on some of them giving a wonderful blue glow. More modern tubes like the KT88 are a little disappointing in this regard.
[edit - a tube amplifier with the case off and 4 big 807s actually produces a very sexy lighting effect in a dark room, such that nobody may be listening too hard to the audio.]
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Thatās why I make Nixie tube wristwatches. Lotsa orange glow and purple haze from the neon and mercury, and a pair of nipples on top of the tubes!
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