Powering electronic equipment is an area of great research in virtually all electronic systems. Designs that waste less power, run cooler and manage fluctuations of voltage and current to provide “clean” power to our devices are very important.
We hear a lot about the LPS (Linear Power Supply) and the SMPS (Switch Mode Power Supply). In GENERAL it has been shown that high quality Linear Power Supplies improve the performance of audio equipment. An LPS design can be rather simple. Improving the quality of the DC power to our devices can get expensive.
The SMPS has gotten a bad “rap” in the industry and is shunned do to issues around leakage and RF noise. In many applications the SMPS is the only way we can supply power to our devices efficiently. Small SMPS power supplies give us the portability we need for devices like phones and laptop computers.
Here is a little more info from WikiPedia: https://en.m.wikipedia.org/wiki/Power_supply
The High Definition Multimedia Interface (HDMI) standard has overshadowed almost any other means of providing a digital video signal from a source to a display. It combines video, audio, control and more in a single cable and connector. The standard has been evolving since it's inception. The electrical properties of the cabling have changed and a whole lot more. The standard is controlled by a single entity, and they are almost rabid about enforcing licensing.
While the idea is a good one, simplify hooking video devices to one and other is great there are some dark sides. There are DRM control methods in the system, and some of the control methods are less than perfect in operation. HDMI boards in A/V receivers are prone to issues such as mechanical and electrical damage due to users no powering devices off when changing cables. HDMI is is a very complex system.
You can read a lot more here: https://www.hdmi.org
I am sure that many of you have been told to be careful with your car or your new lawnmower to break-in the engine properly. You manage speed, vary the load, etc. until there are a certain number of miles or hours. The oil is changed early, etc.. Many mechanical devices need this period to run properly over the long term.
Electronic and electromechanical equipment has some of the same needs. The mechanism is different but the need is there. Capacitors have to form up, and more. Some equipment has this done at the factory. The equipment is put in a chamber that is hot and the gear is operated. This burn-in period can vary a lot depending upon the gear. One example I have heard more than once is a new phono cartridge. After it has been installed and you play the first couple of records the sound can be thin. You can hear it open up over 20 to 30 minutes. It is wonderful.
Here are a couple of links about burn-in that may be helpful to you:
Servers, Servers everywhere but not a bit to drink!
As I outlined when talking about the DAC, music data is sent serially to the DAC. I like the record player analogy. The stylus on the turntable is transferring what is in the grove at this very second.
So what does the server or streamer do? In the most basic form, it provides the user interface to operate the software. That software then reads the data from the local hard drive, or it connects to an online service and reads the music file data from there. Finally, it sends that data to the DAC for decoding and playback.
Streamer or server software can be designed to run on all kinds of hardware: your PC or Mac, or NAS, an iPhone or iPad. In more advanced systems the server/streamer is run on dedicated equipment purchased for the purpose. One example is the Chord Poly. It is a dedicated streamer that only works hooked up to a Chord Mojo DAC/AMP. There is streaming software built into some network bridges like the Sonore Rendu series. Another example is the Roon Labs nucleus products that are purpose-built for this work.
The Roon Labs How Roon Works webpage is a cleanly done pictorial overview of their software. They break their system into multiple parts and explain them succinctly.
I have a lot more to say about servers and software. There will be more posts on this subject.
I love acronyms, but these are a mouthful.
S/PDIF (Sony/Phillips Digital Interface)
TOSLINK Toshiba Link
AES3 or AES/EBU Audio Engineering Society/European Broadcasting Union
The standards were co-developed for the consumer / professional markets. They define both the data transmission formats as well as the connectors and cabling used to connect devices to transfer digital audio. These standards include stereo and multi-channel audio formats.
There is some complexity in cable designs.
In AES3 the first is a balanced connection using the XLR connector. The second is an unbalanced connection using 75-ohn BNC connectors and cable. The third is TOSLINK.
S/PIDF uses an unbalanced connection with RCA connectors and TOSLINK.
The TOSLINK standard defines fiber-optic connectors and cabling for both the professional and consumer designs. There is a second connector standard called Mini-TOSLINK fits into a 1/8in audio jack where the emitter and sensor are at the tip of the connector.
NOTE: TOSLINK is not the same standard as computer networking optical cabling. It just happens to use a similar fiber-optic cable.
These connections are subject to some of the same issues that USB has. There are both clocking and jitter issues and like USB cabling matters.
Here are some Wikipedia articles to take you further.
Digital to Digital conversion is a "process" that translates one type of digital into another. D to D conversions have multiple use cases such as converting USB to SPIDF or I2S.
One example of this kind of device is the Sonore UltraDigial. Another is the Aurender UC-100. You can visit their product pages for more information.
In modern networking, there are multiple media types including various types of Ethernet, Fiber Optic and Coax cabling. The Small Form Factor (SFP) transceiver is a standards-based device that is used to allow different physical network media connections to network devices such as switches. SFP has a standard mechanical and electrical interface for interchangeably.
Many applications of the SFP are for fiber-optic network connections that provide electrical separation or long distance transmission needs. In most home networking situations, we do not see any use of SFP devices. There is a growing use case for fiber-optic networking cabling to provide electrical noise isolation. I will expand on this in a later blog post.
For reference here is the Wikipedia entry for SFP:
Welcome to my first Analog Wednesday! "Stuck in the Middle With You" With apologies to "Stealers Wheel."
DAC's to the left of me, Speakers to the right, here I am, Stuck in the middle with you
I do not want to leave out the parts of the system that make the sound! In a file-based or digital music system something has to make the air move, and that is the speakers. (OR Headphones). Working upstream from the speakers we need amplification to power the speakers. In a system of separate components, there are usually two devices.
The Pre-amplifier takes signals from a DAC or a CD player or in a particular case a Turntable. Many times the preamplifier has an input selection switch system to pick the source input. Most preamplifiers have the volume control for the system. The inputs and outputs of the preamplifier are at what we call line level. Line level cannot drive speakers! So the pre-amp is an input switcher and volume control!
The next device in line is the power amplifier. This is where line-level or low voltage signals are transformed to drive speakers.
Where this gets interesting is in devices like the Mytek Brooklyn DAC that is a DAC, Phono-stage, digital or analog volume control, input switch, and pre-amp. WHEW, a stereo swiss army knife! Another device that is "all-in-one" is the Naim Unity Atom that does even more by including a power amplifier. And do not forget the Chord Mojo and others that are a DAC with integrated headphone amplifier built-in.
There are also systems like the KII Three or the KEF LS50W that have it all neatly tucked into the speakers! These are not your 1970 JBL's!
I will discuss the analog portions of the system over time and will try for Wednesdays!
USB stands for Universal Serial Bus which is used to connect peripherals to computers. USB is used for data transfer, audio, power delivery and more. The USB standards group has released three major versions of the standard.
In our daily lives, we use USB to charge all kinds of devices. The mouse and keyboard on your computer probably use USB interfaces in one way or another. We synchronize or transfer data between devices such as printing or file transfer to disk drives. The USB "stick" is another regular use case.
The universal aspect of USB does mean complexity. One example in the head picture of this post is the Chord Mojo DAC/Headphone amp. There are two Micro-USB connections on the Mojo. One is for power/charging, and the other is for data transfer to the DAC.
What I am here to talk about is USB audio. I am going to "gloss over" this subject as it is just too extensive. There are links below for further study. The USB standards group has released three variants of USB Audio. Almost all of our USB DACs use USB Audio Version 2.0. On macOS and Linux you usually do not need drivers; on Windows, drivers are almost always required.
The technology used to transfer audio between the computer and the DAC is NOT the same as transferring data files to a disk drive. Errors in this process that can and do influence/corrupt the audio data. It is an imperfect transfer mode.
Some of the factors that can cause issues in USB audio are listed here:
Electrical noise from the computer
Interference in the cable
Imperfect clocking or jitter
Even with these issues, USB audio is one of the most used methods of getting digital or file-based audio to the DAC for audio playback. You can spend a lot of money in a system to up the odds of delivering better data to the DAC.
As I said above, there is a LOT more to talk about USB, and this is not exactly the right place for extended discussion it is an introduction!
The DAC is the heart of a file-based or streaming digital audio system.
Storing music or video for that matter in a digital format has some significant advantages. The physical space needed is trivial to non-existent as a problem. There are a lot fewer issues with long term storage such as moisture problems, print-through on magnetic tape and many more. Digital also makes the effort of copying and transferring content almost zero. File-based storage of music brings up issues of copyrights and much more. I will not dwell on that here.
Computers can store music in files using many different methods. For the sake of brevity, I am going to ignore format here. Getting the digital data from the computer to the DAC is done using several methods. In the end, the DAC receives the digital music file serially from start to end. The music file is not transferred to the DAC as it would be to a disk drive.
***Now all you DAC designers out there give me this one. I am overly simplifying on purpose. ***
A DAC can use one or multiple methods of conversion. The process is rather simple. In PCM (Pulse Coded Modulation) audio formats, a group of digital bits is formed up into a numeric value depending on the specified encoding size such as 16 or 24 bits which sets an instantaneous analog audio output level. The process happens at that prescribed bit rate of the audio file such as 44..1 Kbps. (44 thousand times per second in this example).
While PCM is pervasive, there is another format called DSD (Direct Stream Digital). This format is encoded and decoded differently than PCM. While the process is different, the intended results are the same.
Finally, there is another encoding format called MQA that is used to envelop the PCM data to provide information to the DAC subsystem. The stated purpose of MQA is to inform the decoding process about the original recording and encoding of the data to improve playback. MQA has a HOTLY contested premise, and I am only re-stating the purpose here not endorsing or otherwise commenting.
In this extremely brief overview of the DAC, I am not discussing filtering, clocking or other processing methods used in production equipment.
I want to discuss one other about the DAC. The influence of other things around the DAC. One example is the power supply for the DAC. We have many instances where a "good" power supply improves the sound quality of the DAC. The influence of upstream components on the DAC is wild. Welcome to the center of your digital universe.
Here are three articles on Wikipedia for reference. Please note that Wikipedia has these marked for some edits.
The NAS (Network Attached Storage) is a type of computer that, in general, has a single function. It contains some form of data storage devices such as disk drives or SSD devices. The primary purpose of a NAS is to make the information stored on the drives available to other computers on the network through file sharing. Ordinarily, the user interface is via a web browser.
Over time the operating system and applications on NAS computers have gotten more powerful. Companies such as Synology and Qnap have developed many tools in their NAS devices to allow them to function on many more roles that the file server. In audio applications, the NAS is principally used to store large quantities of music files. Also, the NAS can have software applications installed to act as a music server and more.
There is more information on Wikipedia:
I just made an account here. First post. I'm a 26 year old musician/producer/mixer. I started taking interest in audiophile questions about two years ago, stemming from a quest for dead-accurate monitoring. I've been all over the audio internet, and I've heard a good deal of systems in person. Audiophile and pro, analog and digital, cheap and expensive. It's funny how the audiophile world and the pro world don't really like to mix, even when they're taking interest in the same questions.
One of my favorite audiophile writers is Herb Reichert, because he's obsessed with sound that is -direct- and -naked-. Corporeal and palpable. "In the room" explicit. He is allergic to sheen or gloss. His writing asserts that there must still be technological aspects essential to convincing playback that we haven't yet learned to measure, since systems with textbook A+ measurements can still lack this elusive naked quality. Herb prizes this directness over perfect frequency response, dynamic response, or resolution. For him, it is its own parameter with its own merit, and its origin and relation to the others remains mysterious, though he is constantly investigating. Systems that check other boxes, but lack this essential quality, are for Herb false and deceptive, since they offer everything but the soul of the music.
Now of course, there are many in the audio world who feel this way, or who perhaps feel similarly about some other quality they've discerned. Most people call them "subjectivists". To me...it seems like they're misunderstood. Their general claim is simply: we haven't learned to measure everything that's important, so one has to keep an open mind and seek undiscovered correlations. We hear differences outside of what is reflected in the measurements.
Philosophically speaking, any measurement that reliably correlates to reality, ever made, in any science, was initially correlated to the human subjective senses, or rests on proofs, which ultimately rest on correlations to our naked senses. The most basic proof for 1+1=2 is that you can pick up one twig, pick up another, and there, you have two twigs in your hand. The subjective layer is the FIRST data layer. You always view numbers on pages THROUGH this layer, and interpret them through mental proofs BASED on it. All accepted science is based on subjective impressions our ancestors agreed on.
Even the number one is based on subjective experience. The experience of a whole. The experience that an object can be separate from it's environment in the first place. The experience that a pebble is a separate thing from the air or water around it, and that it has a high enough degree of self-consistency to be given a name at all.
It seems wildly arrogant to assert "we're at the end of audio science" the way "objectivists" do. What if we aren't? In the past, whenever we thought we were, in any field, were we? No. It's not an intelligent position to take, as far as I'm concerned. Staunch objectivists make a wager: "I bet our theories are perfect." Does that seem like a good bet?
The measurements obsession, in my view, and the philosophy it begets, becomes a kind of fascism that grows in the mind. One ends up losing trust for one's sensory impressions, and dogmatizing the impressions of others. OBVIOUSLY blind tests are better. Obviously people's minds can trick them. Obviously measurements are useful. But the fact is, with self-awareness and curious self-skepticism, one can improve one's recognition of sound, in incredibly various ways. We aren't aware of the limits. There are hearing masters who slay blind tests. Charles Hansen posted about a man he knew who could reliably make insane calls blind, including about gear riser materials, etc.
In science, data has to be critically interpreted, and fit into hypotheses and theories. Data is also reinterpreted. Endlessly. It always should be. Hypotheses are recrafted and retested. Ultimately, the human is the master of science, not the tool. People seem to be forgetting this...and it honestly creeps me out.
One of the most magic parts of life is that you can actually improve ALL of your senses. And you can have a critical, evolving relationship with how you interpret them. It's amazing. You don't need to be a measurement machine's bitch, or a slave to whatever theories are in hegemony. You get to develop your own experience and your own ideas. You can actually plumb the depths of human sense down paths no one has gone before. And you can craft interpretations which are entirely new. Forever.
We ought to hammer this out more so we don't lose more folks to the personless, non-critical void.
Nicky Hopkins (1944-1994) was one of the best keyboard artists of the classic rock era. He passed at only 50 years of age, much too early. He worked with the Kinks, The Rolling Stones, The Who and many other groups.
Listen to Sympathy for the Devil on the Beggars Banquet album and you will know what I mean. Maybe the best rock piano track ever.
The Songs Remain the Same Only Better (previously published at blog.talkofthemountain.com)
Over the last couple of years I converted my compact disc collection to digital files. This allows me to enjoy the music in whatever venue I happen to occupy: car, living room, basement lair (aka the "country bunker"), MARC commuter train, interplanetary shuttle or molecular transport. No need to lug the discs and player with me and through the magic of miniaturization I simply plug a AudioQuest Dragonfly Red DAC (digital-analog converter) into the lightning connector on an iPad. Said iPad reads the files from a terabyte-sized storage device and to the headphones via the DAC which happens to include a headphone amp.
Apple has presented a bit of a hurdle in connecting high capacity storage to their portable devices. You cannot just plug something in. In this case a tiny RAVPower FileHub connected to a 1TB external storage device is wirelessly sending files via a built-in wi-fi. Does one terabyte seem like overkill? Au contraire, so far my music collection consumes over 250GB. To date this does not include video but someday ...
Once down the path of hosting a file-based music collection, purely digital distribution attracted my oft fleeting attention. These days my favorite purveyor is HDTracks who has become one of if not the largest seller of digital music files. My travel system is optimized for 24 bit/96kHz and the remastered version of the Beatles "Sgt. Pepper's Lonely Hearts Club" album presents an incredibly clear sound at this bit depth and resolution. At this point let me say that not all recordings will present in an improved fashion in uncompressed format(s). Something that was heavily manipulated, compressed during recording, mixing or mastering, or otherwise adulterated may not offer a perceptible sonic improvement at 24 bit/96kHz (or for that matter anything over the lowly CD's 16 bit/44.1kHz) and occasionally one may even prefer the MP3 rip. YMMV but modern recordings and remasters from quality source material including HDTracks cofounder David Chesky's Binaural+ Series do quite well in the upper stratosphere of lossless file containment.
Of course after I had "ripped" all the discs to digital files using MP3 encoding, the benefits of a lossless format became obvious as my audio playback chain improved. Nothing wrong with MP3 when listening in a noisy environment but with KEF headphones running through the Dragonfly, baby wants, even needs lossless compression. So a second pass was made of digitizing the CDs using the dBPoweramp CD Ripper and saving to the Apple ALAC file format. In the no-good-deed-goes-unpunished department, I now wish I had used the open-source FLAC format but hey, who's to say I won't re-re-rip all those discs?
Relf was 33 when he died from electrocution, in the basement of his home, while playing his improperly earthed (electrically grounded) guitar. Relf had dealt with several health issues throughout his life, including emphysema and asthma, which may have contributed to his inability to survive the electric shock.
If you have ever heard the Yardbirds version of (H. Wolf's) "Smokestack Lightning" Kieth did the harmonica solo. Maybe the best harmonic solo ever.
Thanks Mr. Rief
People have asked how I go about sorting out systems - and find my answers very unsatisfactory. Well, I have come across a book which very nicely addresses some of the key areas where I find a lot of the issues arise - and gives a lot of suggestions of very, Gasp!!, technical gear that can be used to chase these things down. It's a very practical book, minimum high falutin', equations for equations sake guff - what I find especially endearing is that there are a lot of cheap and cheerful tricks and tips offered; these are what I would instinctively go for ...
The book? https://www.amazon.com/Troubleshooting-Cookbook-Product-Designers-Electromagnetics/dp/1613530196
Links to listen and purchase:
Album Title: Special Event 45 - Yeah You Right
Artist: Eamonn Flynn
Label: Blue Coast Records
Provenance: Recorded in DSD256 and mixed on analog console to DSD256
This post: “okay... the big question... who out there is ready to record live and in the studio direct to DSD? No fixes, no overdubs, no headphones... JUST LIVE” popped up in my Facebook feed. It was posted by Cookie Marenco an audio engineer who owns a studio and record label in Belmont, California just south of San Francisco. I’d recorded with Cookie before, producing and playing keyboards on two albums at her studio and I remembered her working some deep, warm sounding audio magic behind the desk. I knew she was fanatical about capturing great sound and great performances. I knew it was always a great and hilarious hang with her and Patrick her main engineer. I remembered the view from the hills of Belmont looking over Silicon Valley from behind her studio and one time seeing a family of deers come up to check out the music or more likely eat some of her plants. Within two minutes I had responded: ”I nominate ... ME”.
Two days later I was situated behind her Steinway grand piano getting ready to lay down eight of my new songs, one after the other, recording direct to DSD. I have always been a session and touring piano and keyboard player, supporting other people’s music. But a year ago I finally stepped out in front and recorded an album of my own songs and put a band together to play them live. The album was called ‘The Irish Channel’ and it was an amalgamation of my years playing both American and Irish music. People seemed to respond to it very well and I was having a ball in my new role as a ‘frontman’ so I’d written a new bunch of songs for a follow up album. I sat up the night before the session furiously finishing those last few elusive lyrics.