Channel D at SFAS
By David Hicks, SFAS Director of Analog Development
I love the sound of vinyl records, but I’m not a snob about needing to listen to music only on vinyl. Formats are formats- just a means of delivering the music, and each format whether analog or digital, has undeniable advantages. But whatever the format, I think the music should come first. I can hear a song I love on a cheap transistor radio and it can get me up and grooving to the music. And I must admit that I’ve been seduced by the ease of digital files. Hundreds more albums than I could carry on vinyl can now be carried around in a flash drive, and portable hard drives can contain thousands of albums. And not just MP3’s rips of those albums. Today’s inexpensive memory devices can hold a lot of data. 1,000 CD’s worth of uncompressed data will fit in about 700 Gigabytes, and high resolution files take up about 3 times as much space, so with a little over 2 Terabytes of storage space you could easily fit 1,000 albums ripped in 24/192. And while driving? As far as I know, no one is making and selling those little turntables anymore like in your mother’s car, or George Harrison’s Jaguar.
So for driving, my choices are all digital: SeriusXM, or the CD player, or files from my phone or iPod.
But not everything I like on vinyl exists in a high resolution format that I can buy, and why should I re-buy what I already have anyway? And if I do re-buy those “high resolution files,” it turns out that not all of them are truly high resolution. An AP newspaper article by Ryan Nakashima from July, 19th of this year recounts that “more than 90 percent of the PonoMusic store’s inventory of high resolution files are essentially digital copies of CD’s. The difference is that you’ll pay $17.99 for that high resolution file of Bob Dylan’s “Shadows in The Night” when you could get the same digital data from the CD it was ripped from for $9.70 on Amazon.” The article later states that 70 to 75% of the titles PonoMusic sells have more info than the CD’s do, so there’s quite a discrepancy in what was reported in that one article, but it’s likely that PonoMusic isn’t alone. HD tracks is probably the most famous high resolution file download site, but they don’t list the provenance of their “HD” files, stating in reply to inquiries that they rely upon what the music labels supply them. That’s not exactly reassuring to me as I know that high resolution repackaging shenanigans have been going on for some time, most infamously with Nora Jones album, “Come Away With Me.” After selling millions of CD’s of Jones first album the label released a version on SACD that was much more costly to buy but contained the exact same digital information as on the CD; unless you count all of the extra digital space filled up with zeros.
What’s an audiophile to do?
Well, everything that I have on vinyl can by digitized into a high resolution file that will, to a large degree, maintain the characteristics that my system will supply with vinyl playback. This works well enough that Michael Fremer of Analog Planet fame, who has done more than anyone else to popularize vinyl records, frequently posts high resolution rips from his vinyl collection, and those rips are good enough to let the listener discern the differences between one $10,000 cartridge and another, or one $28,000 tonearm and another.
How can you and I do that- minus the $28k arm? This is where Rob Robinson of Channel D comes in.
Rob is at heart an audiophile, and specifically a vinyl loving audiophile. His heart’s passion for the sound of vinyl playback combined with his head’s ability to design and engineer- (he has an advanced degree in electrochemistry and worked at Bell Communication Research -originally part of AT&T Bell Labs) led him to endeavor to be able to record the magic he heard in the grooves of his vinyl records into a digital format that let everyone hear those magical vinyl characteristics.
So in 2006 Rob released Pure Vinyl, a product he designed from scratch for the express purpose of recording and integrating vinyl with digital audio. (http://www.channld.com/).
If you’ve been to any of the big audio shows you may have met Rob before. He gets out a lot and in fact this is his second visit with The SFAS. (Like many audiophile product manufacturers, I think he likes visiting the wine country when he’s here, or maybe it’s just us?)
Pure Vinyl is a component that can be added to Rob’s Pure Music software that allows a user to rip files from vinyl records into a high resolution format that captures and divides up the tracks on an album into their individual components as well as letting you do the usual adding of meta data, and pop and click removal. There may be other software products out there that do individual parts of what Rob’s software does, or that patch together individual programs to accomplish much of Pure Vinyl’s features, but when watching Rob demonstrate his software it was easy to see that Pure Vinyl is a product designed to include everything you’d want in one relatively easy to use package. One caveat- PC’s need not apply, the software works on Macs only.
I’ve been using Rob’s Pure Music software for a few years now with great success on a Mac mini with a solid state drive connected to a Synology server. Rob is incredibly accessible and helpful on a personal level as far as the use of his products is concerned. I actually contacted him before purchasing his Pure Music software (upgradeable to Pure Vinyl) because I had some questions about getting the best components for my music server that I’d be running his software on and I wanted to make sure the integration was going to be seamless. He recommended specific hard drives to go with my Synology server which I chose because the server lets me store my files and access them from a PC in one room and the Mac in another. Pure Music software integrates with iTunes, but uses iTunes only for the file handling, iTunes is not involved in any of the decoding and playback. Pure Music also overcomes iTunes limitations for file formats in that it lets you to play DSD and FLAC files after you manually mark them for notation through the Pure Music software so that iTunes can find the files and load them when you want them. Pure Music improves the sound quality of files it plays back vs. the sound quality of those same files played back through iTunes and the software has won multiple awards from multiple audiophile magazines and computer audio sites for its ability to do so. See the Channel D web site for all the accolades. You also need Pure Music in order to run Pure Vinyl, and you can buy Pure Vinyl directly with Pure Music included, or buy Pure Music first and add Pure Vinyl when you are ready to rip your LP’s. Both products are available for download with a 15 day free trial.
The SFAS Event!
So on Sunday May 28th, Rob Robinson came to Casa Lundin in Orinda (aka The Audiophile garage) to talk to a group of SFAS members about his Mac-based Channel D software product, Pure Vinyl. He also came armed with three different Channel D phono stages, one of which, the Seta Model L, Stereophile reviewer John Atkinson gushed over, saying among other things, “It’s an understatement to say that I was impressed by the Seta Model L used as a conventional RIAA preamplifier. It measured more like a piece of laboratory equipment than a typical high-end component, and sounded superb to boot.” To be clear, that “to boot” is in addition to, you do not need to boot up this phono stage even when you connect it to your computer.
The SETA+ phono preamplifier is available in natural anodized aluminum, or gorgeous red powder coat finish, as shown in the photo of Rob pointing at the component . Seta means “silk” in Italian.
One of the tasks of a phono stage is to untweak the signal that was originally tweaked to get all of the analog information in the grooves in the first place. When a musical track is recorded on a vinyl record the bass portion needs to be attenuated so the grooves aren’t overly wide, and the treble needs to be amplified so the clarity of the highs is retrievable and distinct from surface noise in the groove. To make all of this sound like what was originally played by the musicians, you need to reverse the process when you’ve retrieved the information from the groove via your phono cartridge. Therefore, a phono pre amplifier doesn’t just amplify the cartridge signal, it emphasizes the amplification of the bass signal and decreases the amplification of the high frequencies you’ve retrieved. Got that?
Your phono stage accomplishes this task with electronic components that are designed to follow the Standardized RIAA curve (you can look this up). Electronic components are naturally subject to the variances of their designers and manufacturers. Components values will also change over time as the components age and eventually wear out. These are some of the reasons phono stages can sound so remarkably different. It’s also why Rob Robinson’s phono stages comes with the ability to let you bypass the RIAA equalization and pass the unequalized signal to your computer when recording, instead they allow you to do the equalization much more precisely in the digital world, which is where your files will end up when you are recording them anyway.
Rob went over this information and some of the specific features that make his phono stages stand out from the competition. Most noteworthy to me was the bandwidth, which doesn’t stop at 20K Hz but goes out to 2,000,000 Hz on the Model H phono stage (for moving magnet cartridges), and up to an amazing 5,000,000 Hz on the SETA Model L (for low output moving coil cartridges).
This design feature greatly reduces intermodulation and harmonic distortion in the critical audio range, particularly in the treble region, resulting in unsurpassed ease of presentation, dynamics, clarity, imaging and neutrality. Ultra wide bandwidth also minimizes any disruption to the listening experience resulting from fast-risetime impulse noise (LP pops and clicks) because of Seta’s excellent transient tracking and immunity to signal overload. Seta also includes a low impedance rechargeable AGM battery power supply, sited in the same chassis as the circuitry for maximum performance. All Channel D phono stages feature balanced and unbalanced inputs and outputs, ultra low noise and distortion and ultra wide signal
bandwidth; modern surface-mount-component multilayer construction and board-mounted connectors for the shortest possible signal path; ultra-low ESR polymer dielectric bypass capacitors; and hand-selected components including ultra precision 0.1 percent tolerance low noise metal film resistors and sputtered-metal-contact polypropylene capacitors for tight adherence to the standard phono RIAA curve: better than plus or minus 0.1 dB and better than plus or minus 0.02 dB channel match. All preamplifiers are individually tested and calibrated and include their own individual RIAA accuracy measurement graphs. Wow!
Before we started recording we listened to the SETA+ and got to hear the effects of some of that amazing bandwidth on a couple of LP’s Rob had brought along- Elvis is Back (Acoustic Sounds 45 RPM reissue) & a recording by Gary Louris – (Vagabonds LP.)
The SETA was inserted into Leslie’s front room system which this day consisted of the Davone Model Ray-S speakers ($8,600). Rogue Pharaoh integrated amp ($3,500). Anti-cable Level 3 reference speaker cables (approx. $300). High Fidelity Ultimate Reference Helix, Platinum Power cord ($12,900) plugged into the Rogue.
As good as Leslie’s system usually sounds; vinyl playback was morphed to an entirely higher level with the SETA+ in the system. Detail, micro and macro dynamics, soundstage and instrumentation placement all were vastly improved beyond what had been heard from vinyl playback with just the Rogues built in phono stage. This is not too surprising when you consider the cost of the SETA+ is nearly double the cost of the Rogue pre amp by itself and that the phono stage on the Rogue comes built in at that price. Still, the proof was in the listening, and with the SETA+ in the system, Leslie, who knows her system best, stated that she thought she needed to put the SETA+ into her system on a permanent basis.
All of the pre-event listening sounded spectacular, but it soon came time to get to the day’s main event: making a high resolution digital recording from a vinyl record.
For the source on the actual recording Rob chose Cat Stevens – Tea for the Tillerman (45 RPM Acoustic Sounds reissue).
After demonstrating the proper setting of the record levels it was time to begin. Rob was using Pure Vinyl 4 Recording, Editing and LP RIAA EQ software for Mac OS: $299 with along with a Lynx Hilo 192 kHz USB ADC/DAC that he’d provided ($2499 & also available with Thunderbolt instead of USB) and a Turntable Audio Interface Adapter: ($75 / pair from Channel D (for connecting the TT to the Lynx Hilo.)
The video output from the MacBook was patched through to a monitor that was easily viewable for all attending members with adequate eyesight. One of the cool parts about Rob’s Pure Vinyl software appeared on the monitor as the software processed the vinyl information, automatically sensing the space between grooves and displaying the information with Rob’s unique and patented “virtual vinyl” cue guide image feature: which displays a replica of a vinyl disc generated from the audio in the recording as if you were recording onto an actual vinyl record in your computer.
There’s a host of features built into the software, too numerous to list in this brief event write up, that you can read about on the Channel D website. Essential features are things like being able to select the areas where the tracks begin and end manually and perhaps the most frequently requested feature for recording vinyl records into a digital file is the automated pop and click removal tool. More selectively than just plucking out the offending noise spikes, you can actually remove (Rob calls this “surgical removal”) the offending digital information and paste in a sample of information more representative of what should have existed beneath the pop/click. Rob says that removing pops and clicks is much easier to do when one has the pre-RIAA equalized signal available. With a fast moving coil cartridge and a flat, wide bandwidth phono amplifier like the SETA+, some pops are only a couple of samples long, even at a 192 kHz sample rate. These are easily excised without audible impact. That’s not true after passing such pops through an RIAA filter. RIAA filters will stretch the pops considerably, leaving you anywhere from 10 to 20 polluted samples to clean up instead of only 1 or 2, making for a much more difficult repair.
You can listen to the sound from a recording made with Pure Vinyl software and the SETA pre amplifier on your own system if you go to the Channel D website and download a “snippet” of a track that Rob’s posted there. (http://www.channld.com/purevinyl/) If you are interested in getting started using the Pure Vinyl software you don’t need to have one of the Channel D pre amplifiers in order to do so. If you like the way your vinyl playback system sounds now, and you have an analog to digital converter, and some means to play back high resolution files- requiring a digital to analog conversion-(and a Mac-based computer) you’re good to go and can do so risk free by taking advantage of that 15 day free trial for Pure Vinyl Software.
As for the playback of the sound quality of the digital recording we made from the vinyl record compared to the actual vinyl record playback? Those I spoke with almost all said the sound we heard played backed was essentially indistinguishable compared to what we heard come off of the vinyl record when it was played directly. Of course, if you played back a record that was other than new and was flawed by pops and clicks, or plagued with a bit of rumble from your turntable, or had some other offending noise pollution, and you had Pure Vinyl clean that up, you could end up with a recording that you preferred to the direct vinyl playback experience. You would also be able to listen to the recording without further wear and tear on your stylus, whenever and wherever you wanted, and you’d also save further wear on the vinyl record. Those digital bits really don’t wear out!
An added bonus to Rob’s presentation was that he actually brought a new member to The SFAS. Leo Hoarty, Founder of Sweet Vinyl in Mountain View, has been using Channel D software and pre amplification for some time in the furtherance of obtaining source material for archival and re-issue purposes. It turns out that some of the best examples of old recordings are not always contained on the original magnetic tapes, and other times those tapes are no longer even available. Sometimes the best source is actually in the grooves of the vinyl records from long ago.
Sweet Vinyl is also working on an LP meta data service for vinyl records. This is something that would be available for use with Pure Vinyl software, letting the user automatically have the meta data entered into the files one records. As it is now, most all of the meta data out there is for CD versions of albums that the artists created. CD’s with their 80 minute capacity tend to have additional material not contained on the vinyl LP’s, and sometimes even have the tracks arranged in alternate order, making that data not directly insertable in your recordings.
So, the mix tape can live once again, but this time you can carry it around on a flash drive with you, or load it on your Pono Player. And no more tangled and mangled tapes with low resolution and warbley playback.
And just as importantly, after your purchase Pure Vinyl and the associated equipment, making recordings will cost you nothing as you’ll be recording from the vinyl records you already own, and because you know the source of the recordings you’ll be making is of the highest quality, you’ll never have to worry about making a high resolution digital purchase that contains mostly zeros.