Ripping LPs with Pure Vinyl 4

"Our goal is not just to create a portable digital copy of an analog LP; it is to honor the high-fidelity aspects of vinyl by making a digital copy that sounds indistinguishable from the original." So spoke Rob Robinson, PhD (above), creator of Channel D's Pure Vinyl and Pure Music Mac apps, at the start of a recent presentation members of the Bay Area Audiophile Society.

Speaking to a capacity group of 22 BAAS members, who gathered in the living room of a hillside-perched Marin County home, Robinson spent close to two hours reviewing all aspects of using Pure Vinyl to rip LPs. His visit, which came less than three months after the release of Pure Vinyl 4, and a little over a month after the release of Pure Music 2 file playback app, was arranged by Peter Truce (below left), the newly appointed treasurer of what may soon become the non-profit San Francisco Audiophile Society, "serving music and audio enthusiasts throughout the greater Bay Area."

After the session, Robinson explained by phone that Pure Vinyl 4 has over 50 new features compared with the original version. Most important are a simplified user interface that hides more specialized options so as not to confuse users, and a simplified rendering/mastering window. Greatly improved features for editing tracks include an automatic track locator, a snap-to function that enables the program's virtual stylus to snap to the start of a track, and a new Tidy Tail feature that trims silence at the end of a track.

It goes without saying that to use Pure Vinyl, you need, first of all, an LP player. Robinson does not recommend the USB turntables currently on the market because of their quality limitations. Of equal importance is an Apple computer and, if you frequently rip vinyl to CD-R, a durable, external, tray-style burner such as those supplied by OWC.

Pure Vinyl 4's user interface is based on the LP cutting and playback paradigm

While a phono preamp is not necessary—see later—you do need a device that contains both an ADC (analog-to-digital converter) and DAC slaved to the same clock. In practice, that usually means that both are in the same box. This enables you to monitor audio and hear what you're recording. Although Robinson recommends the reasonably priced TC Impact Twin, which is manufactured for the pro-audio market, or the far more expensive Lynx HiLo for those who desire the highest-quality conversion, he brought along a diminutive Baby Face ADC/DAC because of its portability. If needed, Channel D markets adapters for these units that work with different cartridge loads.

"Assuming your ADC is good, once you get above a certain price point, it doesn't matter that much," Robinson claims. "The prime factor for creating excellent quality copies is applying RIAA in the digital domain. Most of the sound quality improvement you get is from our application of the RIAA curve in the digital domain, not from the ADC."

"There are probably more reasons to apply RIAA in the digital domain than I can count on my 10 fingers," Robinson clarified after the event. Many of these have to do with the conversion chain's absence of a phono preamp, which would normally apply the RIAA de-emphasis. "We eliminate the phono stage because I don't want its sonic signature on the signal," he added. "Performing the RIAA equalization in the digital domain also significantly increases resolution from 24 to about 26-bits. Since each bit is approximately equivalent to 6dB, applying RIAA in the digital domain gives you an extra 12dB headroom that you lose with a conventional phono stage." It also allows Pure Vinyl to incorporate an adjustable rumble filter.

Take a deep breath, DSD diehards. Pure Vinyl operates in the PCM domain, rather than DSD, because you can't perform mathematical operations on DSD data. In Robinson's opinion, "As PCM converters have improved, the advantages of DSD over PCM have diminished. If the recording engineer has done a good job, I really think PCM is better at this point."

All calculations in Pure Vinyl are done with 64-bit precision (Double Precision, Floating-Point). Robinson's preference is to use a 24-bit word length and a 192kHz sample rate for digital conversion because he wants his customers to use the highest amplitude and sample rate commonly available. "Vinyl has an extended frequency response up to at least 96kHz," he said, "and its amplitude resolution is much closer to 24-bits than 16 bits. Yes, some converters, not all, do introduce more noise when you go from 96 to 192, but it's so far below the noise floor of vinyl that you don't need to worry about it. In addition, RIAA compensation in the digital domain works much better at 192 than at either 44.1 or 96. You can find more about this in the "Getting Started with Computer Audio" section of the A HREF=>Channel D website.

"When I was first working on Pure Vinyl 12 years ago, I used 176.4kHz with the notion that it would be easier to create CD copies and more faithful to the signal," Robinson explains. "But in practice, while conversion of 192 to 44.1 is mathematically a little more involved, there's no difference in quality whatsoever. And there aren't enough really great ADC/DAC units out there that will do 384kHz sampling. If there were, I would be using 384."

A spectrum analysis of LP playback was shown as part of the Pure Vinyl 4 presentation.

Pure Vinyl is compatible with Apple's new Mavericks OS (10.9) As for RAM, Robinson recommends either 8 or 16GB. The performance of my own 3.4 GHz Intel Core i7 iMac running OSX 10.9.4 increased markedly when I recently upgraded the RAM from 8GB to 12GB.

When Robinson told BAAS members that he uses lossless compression for file storage to save disc space, I noted that some computer audio experts claim that on-the-fly conversion of lossless files (including FLAC and Apple Lossless) to PCM uses up vital computer power and denigrates sound quality. Robinson countered that because his software converts lossless compressed files to flat PCM before they are played, this is not a consideration.

The session concluded with lunch on the host's pricey-view deck (below), and listening to a most impressive system. Robinson's presentation was a hard act to follow, but Coincident Pure Reference Extreme (93dB-sensitivity) loudspeakers, Shindo Giscours preamp, and WAVAC 805M amps equipped with "super rare NOS tubes including. 1943 RCA 805s," High Fidelity Enhanced loom, Shindo 301 System turntable, Auditorium 23 Hommage T1 SUT, MSB UMT Plus transport and MSB Analog DAC, AudioQuest Diamond USB cable, and a Mac mini proved a pleasure to listen to.

georgehifi's picture

These digital copies will only sound the same as the vinyl if they copy the lousy channel separation separation characteristics of a cartridge.

35db at 1kz
10-15db at 30hz and 10khz.

Only then will it sound like vinyl.

Here is the sound of vinyl scaned by taking a high rez photo of the groove, then converting the peaks and troughs into digital with software, but the problem is, no lousy channel separation that the cartridge would give.

And here is the original vinyl sound.

Cheers George

Et Quelle's picture

You just turned a nice ribeye to a greasy burger. But I know old vets have got to save their collections.

dalethorn's picture

Capturing and preserving the actual sound of an LP is an incredible benefit of advanced digital technology, but as others have alluded to, getting a true reference LP playback system to start with is a major challenge in itself. Unless there are relatively inexpensive ways to eliminate the sonic variables.

Edit: To think that someday soon I could buy 96k or better copies of many of my current digital tracks, but transcribed faithfully from top-quality vinyl by one of the download services - that would worth sampling for a whole lot of reasons.

Azteca X's picture

but as they point out, no need for a phono pre! "While a phono preamp is not necessary—see later—you do need a device that contains both an ADC (analog-to-digital converter) and DAC slaved to the same clock." I've also heard of people using the PS Audio Nuwave phono converter to digitize apply the RIAA in real time, then they play back the digital. I believe the Nuwave can do so without a computer present.
The law prevents me from saying too much but there are amazing vinyl rippers out there with excellent setups and excellent files. I don't think an above-ground service exists for vinyl rips but you can check out

Osgood Crinkly III's picture

Azteca X: Just compared your online sample of Basie's "Blues in Hoss' Flat" to my version, a wav ripped into iTunes from the 2003 EMI CD reissue of the Roulette original, "Chairman of the Board" (1411 kbps, 44.1 kHz). Can't even here the cymbals on your version. Upper frequencies, e.g., the trumpets, gone, totally gone, in your sample. Your sample sounds like mud, without dynamic range.

Azteca X's picture

the hell are you talking about? I didn't post a sample.

Osgood Crinkly III's picture

Am referring to the link you provided to, which has a sample of the tune in question.

Osgood Crinkly III's picture


Bluejimbop's picture

Old white guys that worship dead black guys.

Osgood Crinkly III's picture

Bach wasn't black.

It should be "WHO worship."

Osgood Crinkly III's picture

Too complicated. Need a black box with simple controls, one wire in, one wire out, & a simple display. And an ethernet/wi-fi connection to update software. How many people have an Apple laptop hooked up to their hi-end stereo? Psss, iPhones & iPads now rule. These guys are 10 years behind the times. The train has left the station.

Sure, sure, no preamp required. Sure, sure, the DAC/ADC gear listed above can handle low output MC cartridges, preserving their tonal balance and keeping the noise floor low.

Don't know about you, but don't recognize any of the components listed in the text. Shindo? Looks pretty cheesy in the picture, too. Does this guy have a wife or ever entertain guests?

Marin: hot tubs, diets and boredom (c.f., song "Boredom" by Procol Harum).

Bluejimbop's picture

At least I wasn't accused of being a racist with a capital 'R'.

Mycophile's picture

Too complicated. Need a black box with simple controls, one wire in, one wire out, & a simple display. And an ethernet/wi-fi connection to update software. How many people have an Apple laptop hooked up to their hi-end stereo? Psss, iPhones & iPads now rule. These guys are 10 years behind the times. The train has left the station.

I’ve seen uninformed things posted in Internet forums, but this just about takes the cake. You might have thought to at least do your homework first.

- The iPhone was introduced 7 years ago, not 10. So by your reckoning, the train isn’t going to leave the station for another 3 years. Including the iPad (introduced 4 years ago) would mean 6 years from now.

- USB transmits bidirectional data (as well as power), so there is only one wire. As in the above article. That’s even better than what you are suggesting.

- The iOS devices you mention (iPhone, iPad) cannot play (let alone store reasonable amounts of) 192 kHz 24 bit audio (as depicted in the article). They never have and may not be able to do so for some time, because playing high resolution audio goes hand in hand with higher power consumption. As evidenced in the (still) yet-to-be-released Pono portable player’s (claimed) meager 8 hour battery life, despite having a relatively large battery. And the iPhone has a much smaller battery than that.

Osgood Crinkly III's picture

1) The black box would contain memory, hard drive, software, computer processing, DAC & ADC. No external computer or processing, thus no USB needed. Black box must be self-contained. Simplicity and ease of use is the idea here, duh.

2) Smartphone or, preferably, tablet type device COULD be used for display and interaction (e.g., keyboard, menus, etc.), and as ultimate playback device. These portable devices should be able to dock to the black box (no USB, no wire). Memory and processing power of these devices is increasing by leaps and bounds. USB input/ouput optional, not required for function.

3) Analog output needed to monitor the device during use. Analog input required, as well. Thus "two wires" needed, one in, one out.

4) Taking "10 years" so literally reflects a seriously defective imagination. If one is going to spend hundreds or thousands of dollars on a black box, one would hope that it will interface with devices of the future, not the past.

5) What exactly are you going to use as a playback device? A computer hooked up to your hi-end system? A laptop with earphones? Isn't portability and transmitability the whole idea of converting analog vinyl to digital? If you're stuck sitting in front of your hi-end speakers to listen to the digital conversion, why not just play records on a record player? Earphones attached to a cumbersome, delicate laptop is NOT a viable playback medium. It isn't sexy. It won't sell.

6) Wi-fi and/or ethernet connection (a 3rd wire) required to sync black box with home network and other devices.

cundare's picture

All very interesting, but ultimately useless for the majority of us who do not currently own, will likely never own, and have never had any interest in owning, an Apple computer. Although I'm a hardcore Stereophile fan dating back to when Holt distributed it as a low-distribution two-color card-stock covered labor of love, I continue to be annoyed by this inexplicable Apple bias. Yes, the magazine does occasionally review Windows software (Linux not so much), but the majority of software articles are worthless to most readers because they describe only software that is limited to the Apple platform. Come on.

Jason Victor Serinus's picture

When J River or another manufacturer of PC-based audio music players presents a seminar in a territory that Stereophile can cover, I expect we'll cover it. To my knowledge, however, no such seminar has taken place in the Bay Area, where I remain based until July 30.

Mycophile's picture

Come on, back at you: instead of blaming Stereophile for a lack of coverage, perhaps you should blame the companies making the other (non-Apple-platform) products you are promoting? Pure Vinyl has been exhibiting (and setting up their own audio demo room systems) at major audiophile expos for the last 8 years amounting to well over 20 trade shows according to their website. That represents a pretty sizable commitment in terms of time and money, and demonstrates that they are truly interested in meeting the needs of audiophiles. Have one of the companies with products you are thinking of ever exhibited at an audiophile trade show, even once?