Channel D Pure Vinyl 5 & Seta L phono preamplifier

Ever since I stopped using my Audio Research SP10 preamplifier in the early 1990s—its eight phono-stage tubes used to get too noisy too quickly—I tried a variety of standalone phono preamplifiers. Seeing the most service through the 1990s and 2000s were, first, a Mod Squad Phono Drive EPS, then a Linn Linto, both of which I purchased. But when I measured Channel D's Seta Model L, which Michael Fremer reviewed in the August 2010 issue, the Linto was pushed to one side. The battery-powered Seta L (footnote 1) had the lowest noise and distortion I had encountered in a phono preamplifier, and I eventually bought the sample I had been sent for a follow-up review in 2013.

The beautifully built Seta Model L ($3799) is intended for use with low-output moving-coil cartridges. It has balanced and single-ended inputs (the RCA jacks are connected in parallel with pins 2 and 3 of the XLR jacks); Flat (unequalized) balanced outputs; optional RIAA-equalized balanced and single-ended outputs ($1199); adjustable loading; a switchable, 10Hz high-pass filter (Channel D recommends leaving this filter enabled); and four gain settings (43, 46, 49, and 53dB). A balance trim control allows the gain for one channel to be set up to 2dB higher than the gain for the other to cope with cartridges that don't have well-matched channel outputs. The high–output-current internal AGM batteries are rechargeable and should last five years or more if kept charged. The Seta automatically disconnects the 15V battery-charging wall wart when a signal is detected.

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For my 2013 review, I made 24/192 LP needle-drop recordings with the inexpensive VinylStudio app, using the Seta L's RIAA-equalized outputs to feed my USB-connected Ayre QA-9 A/D converter. (The LP player was my Linn Sondek LP12 fitted with a Linn Ekos tonearm and Linn Arkiv B phono cartridge.) "Clean, clear, detailed, open," I wrote about the sound of those needle-drops, adding that the Seta L wasn't emphasizing high-frequency detail. "Instead, the detail was there when I listened for it, just as occurs with live sound, but without the rolled-off highs produced by some phono preamps that also excel in this area," I decided.

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As well as the distortion from the Flat outputs being vanishingly low at typical recorded levels (fig.1), the Seta L's optional RIAA equalization was both superbly accurate and well-matched between channels (fig.2). But as Channel D's Rob Robinson had written persuasively in a paper presented at the 123rd Audio Engineering Society convention in 2007 (footnote 2), about the advantages of applying the RIAA de-emphasis in software (with 24-bit data capture), I decided to experiment with Channel D's Pure Vinyl app and rip some LPs using the preamplifier's Flat outputs.

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Fig.1 Channel D Seta Model L, Flat balanced output, spectrum of 1kHz sinewave, DC–10kHz, at 5mV input (linear frequency scale, 10dB/vertical div.).

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Fig.2 Channel D Seta Model L, response at RIAA-corrected outputs with infrasonic high-pass filter active (left channel blue, right red) (0.5dB/vertical div.).

Pure Vinyl 5
First introduced in 2006, Pure Vinyl, in version 3.0, was reviewed by Michael Fremer in August 2010. The current version is Pure Vinyl v5.b31 ($379), which is compatible with Mac OS 10.6.8 or later, including OS 10.14/Mojave. Mac OS 10.11.6/ El Capitan and onward is required for internet lookup features, but the app was not yet compatible with macOS 15/Catalina at the time of writing. Pure Vinyl has a 64-bit internal signal-processing path.

Michael described Pure Vinyl's user interface at length in his review, so I will concentrate on the new features. Now, when you are ready to rip an LP, when you click on the image of the spindle, a dialog window opens in which you enter the album's catalog number or the artist name and album title. This done, the app takes you to the appropriate page on the Discogs website. If the album has been correctly identified, Pure Vinyl fills in the title, track name (and time information when available), then allows you to enter other metadata, such as the hardware being used to make the needle drop.

The app waits for you to lower the stylus before starting to record and pauses recording when you lift the stylus at the end of each side. Then, starting with the Discogs track time information, then adjusting those times if necessary by detecting the relative silence between tracks, Pure Vinyl automatically splits the recorded file into individual tracks, trimming the silence as appropriate with its "Tidy Tail" function. (If any music is detected between tracks or there is a question about timing, the trimming will be skipped.) It then creates the cue-guide image of the LP that will be shown in playback mode.

The silence at the end of an LP side can be trimmed manually, as can the silences at the ends of tracks. Pure Vinyl 5 can surgically remove pops and clicks before suggesting a normalized peak level. Rumble filters for playback or track rendering can be set to a turnover frequency between 8Hz and 64Hz—the default is 20Hz—with slopes up to 24dB/octave for playback (the default is 18dB/octave) and up to 96dB/octave for digital rendering. The rendering filter, called Zephrr, is claimed to have zero phase shift. I asked Robinson about this. He explained that the file is filtered twice, once reading the data conventionally from beginning to end, the second reading it in reverse. The phase shifts for each operation therefore cancel.

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Also new is multichannel output capability, and versatile high- and low-pass filter options allow playback to be configured with up to a four-way crossover and a subwoofer feed.

After I installed Pure Vinyl 5 on my 2014 Core i7 Mac mini (fitted with 16GB RAM and running OS 10.14.6/ Mojave), the next question involved the hardware I was going to use. Front end would be my Linn Sondek LP12/ Ekos/Arkiv B connected to the Seta L's single-ended inputs, the preamp's Flat outputs then connected to the Ayre QA-9 with short lengths of balanced Canare cable. Robinson strongly advises recording at 192kHz—"Pure Vinyl was designed and optimized with that sample rate in mind (back in 2003!)" he wrote to me in an email—but for monitoring the recording in real time, the playback D/A converter needs to be sample-synchronous with the A/D converter. Otherwise, there would be occasional clicks from the DAC as the unsynchronized clocks drifted. (This doesn't affect the recorded file or playing back that file when a recording is not being made.)

I own a Metric Halo MIO 2882, which has the A/D and D/A converters in the same box, but it is limited to a maximum sample rate of 96kHz. (The Lynx Hilo ADC/DAC that Michael Fremer uses to rip LPs is perfect in this regard and is recommended by Channel D.)

I wanted to stick with the USB-connected Ayre ADC for ADC conversion because it sounds superb at 192kHz with its antialiasing filter set to "Listen." So instead I set up our review sample of the original Mytek Brooklyn DAC for monitoring. As the Ayre has a Word Clock output, I connected it to the Word Clock input on the Mytek, connected to the Mac mini via USB. That seemed to do the trick—until I started recording, at which point the Mytek lost sync. (Channel D warns that with USB or FireWire audio devices, it's best to have only one active connected audio device at a time, footnote 3). I disconnected the clock link and lived with the clicks while monitoring.

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When I started Pure Vinyl, the Audio Hardware screen in the Preferences menu allowed me to set both ADC and DAC to the 192kHz sample rate. (A warning message appears if you don't match sample rates.) As I was going to use the Seta L's Flat outputs, I made sure I clicked on "Apply vinyl correction curve—Standard RIAA EQ Correction" before I clicked on the image of a blank LP's spindle to record. That way, although the file would not have RIAA correction applied, it would be applied to the monitor signal sent to the DAC. I was ready to rip some vinyl, but first I used the pink noise track on the Hi-Fi News & Record Review Test Record (HFN001) to set the Ayre's recording level and to equalize the Linn player's two channel levels with the Seta L's balance trim control.

Robinson had advised that I should aim for "Dry" signal level peaks in Pure Vinyl between –20 and –4dBFS. "Provided that peaks usually reach these levels, it's not necessary to have to adjust the gain setting frequently, or at all," he said, adding that it was prudent to allow at least 4–6dB of headroom below full scale to accommodate unexpectedly loud modulation levels. He also recommended allowing the stylus to move fully through the lead-out groove at the end of each side (and bump against the label once or twice) to allow the track locator to have all the information it needs to automatically trim the extraneous dead space at the end of each side.

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What to record? An album I had ripped in 2013 using the Seta L's RIAA-equalized output was the classic Fairy Tales by the late Norwegian singer Radka Toneff, accompanied by Steve Dobrogosz on piano (Odin LP03). I clicked the LP spindle and Pure Vinyl found Fairy Tales on Discogs. I clicked on "hide album credits" and selected the album, then lowered the stylus onto the lead-in groove, and I was out of the starting gate. (I was monitoring on headphones so that the LP player wouldn't be affected by sound from loudspeakers.) Side 1 ended. I lifted the stylus and Pure Vinyl paused recording. I turned the record over, clicked "ready to record," lowered the stylus, and Pure Vinyl started recording side 2.

After the stylus had followed the lead-out groove to the label and I stopped recording, Pure Vinyl displayed the message "cutting vinyl image" for both sides, then, the "Audio Cue Locator is Active," and finally "Edit this album or record another LP?" I selected "Edit."

The album had been recorded as a single lossless-compressed file: "Fairytales (Raw).caf." I clicked on the Editor icon and checked that the track starting times were correct—they were, other than some extra "dead wax" time at the ends of the sides that I trimmed manually. Then, after I selected "Peak Detection," "Normalize," "Pop/Click," and "Render Tracks," Pure Vinyl created an Apple Lossless file for each track, with RIAA equalization applied pops and clicks mostly eliminated—this record has seen some hard times—and rumble removed. I kept the 192kHz sample rate for these files, but Pure Vinyl offers a high-quality sample rate converter function if required.

How did the files sound when equalized in software rather than with electronic circuitry? I copied the new files to the hard drive where my Roon library lives and, opening the Roon app, cued up first the original transfer of Jimmy Webb's "The Moon Is a Harsh Mistress," then the new version. Everything was the same other than the RIAA equalization method and the fact that my Arkiv B is now seven years older than when I originally made a needle drop of this track. For the comparisons, I used the Roon-Ready version of MBL's N31 DAC with an MBL N11 preamplifier, Parasound Halo JC 1+ monoblocks, and the Marten Oscar Duo loudspeakers that Michael Fremer reviews elsewhere in this issue.

Ah. A complication. The original transfer sounded considerably quieter than the new one. Its perceived loudness (ITU-R BS.1770-3 units) was –29.50 LUFS compared with the 2020 version's –24.47 LUFS. Fortunately, its peak level was sufficiently low that I could use Adobe Audition to create a new file with the perceived loudness raised by 5dB. I copied that file into my Roon library and started the comparison afresh: first one file, then the other. And again. And again. I resorted to Audeze LCD-X headphones driven by the Mytek.

An hour later, other than not wanting to hear "Moon" for a long time, all I can say was that I couldn't hear any difference between the two renditions, other than differences in how the clicks and pops had been handled.

To say that I was impressed with the quality afforded needle drops by Pure Vinyl would be an understatement. While the user interface is not as intuitive as I would like, the versatility on offer is extraordinary, and the comprehensive user guide can be called up from within the app. The next task on my to-do list (after getting hold of a Lynx Hilo) is to use Pure Vinyl to transfer essential albums to digital. First up: Earl Wild's The Art of the Transcription (Audiofon Stereo 2008-2), recorded live at Carnegie Hall in 1981 by Peter McGrath. After that classic, 2000 LPs are waiting in line on my shelves.


Footnote 1: The Seta L costs $3799; the internal RIAA Correction Module adds $1199. The similar Seta Model H is optimized for use with moving-magnet cartridges. Channel D Corp., 1570 Harbourton Rocktown Rd., Lambertville, NJ 08530-3001. Tel: (609) 818-0700. Web: http://channld.com.

Footnote 2: "Filter Reconstruction and Program Material Characteristics Mitigating Word Length Loss in Digital Signal Processing-Based Compensation Curves used for Playback of Analog Recordings," downloadable here. A series of short videos showing how to get the best from Pure Vinyl can also be found at this link.

Footnote 3: See channld.com/digitalsyncmultipleinterfaces.html.

COMMENTS
CG's picture

I'd think the QA-9 would provide somewhat better audio quality than the Lynx, but perhaps not.

The interesting thing is that it's likely that many, if not most, recording companies probably use a converter equal to the Lynx.

So, aside from the lucky few who have great home reel-to-reel machines and tapes to match, I guess that you now can do as well at home as the recording companies.

I'm not sure how I feel about that.

JRT's picture

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Ortofan's picture

... JA1 has his priorities straight in regard to the order in which the LPs in his collection should be transferred to digital.

That two-disc set of the Earl Wild concert recording is, indeed, an essential album. Kudos to Julian Kreeger and Peter McGrath for capturing and preserving the moment.

A review by Mrs. JGH: https://www.stereophile.com/content/recording-january-1983-ithe-art-transcriptioni

tonykaz's picture

From a time management perspective, how long does it take to complete a One Album transfer?

Can we presume a few minutes for a 'proper' record cleaning?
then,
a stylus cleaning followed by a spot playback test to assure a properly working system?

So, one and half hours for each LP Stereo Album?

Transferring 2,000 Albums would realistically take approx. 3,000 hours or 1 1/2 years if it were a full-time employment job.

I'd also predict it would burn out 3 phono cartridges's suspension, I'm not anxious to use the pricy Koetsu on a project like this.

Those lads with 10,000 Album Museums are facing a mental crisis if they contemplate a 'Transfer' project like this. No audiophile has enough time to transfer a vast collection.

I've been 'transferring' music since the arrival of the 'compact- cassette', it's not something I like or enjoy doing. In fact, I'm willing to do without some cherised piece of music.

I live a pleasant life with what I already have and the exciting new releases I learn about from eclectic Gear Reviewers.

Thank You,

Tony in Venice

ps. please let us know how the project is advancing and how you systematised the work.

PeterPani's picture

I am happy, if I can listen to some vinyl from time to time, and to my r2r-collection. I recorded some vinyl to digital years ago. I listened to those files for checking only once. I bought already so many DAC's and was never happy with one. Cheap or expensive DAC's - even a Nagra. After several weeks of listening they imprint their stamp on the music and everything sounds the same. In my experience state-of-the-art DAC are in the mastering studios when producing vinyl. At least different records are mastered through different DAC'S and different results.I will never be able to improve on their equipment for going from digital back to analog anyway. What I still do is recording one record to musiccassette every appr. 2 months. That's nice to use my Walkmans with new music from time to time (parallel with my Ipod touch and sometimes even the original Ipod of 2002).

Ortofan's picture

... how much digital storage space will be occupied by 2,000 LPs when converted to 24/192?
Would about 10TB suffice?

Glotz's picture
Glotz's picture

the value in transferring everything to digital files is a mixed-bag.

It requires an equally-great digital equipment investment, in addition to the large outlay for high-performance analog. If one wants to replace their current phono pre with this, great- bonuses all around.

Qobuz and Tidal provide access to most of the previously-released albums in a format with less outlay and hassles.

On the other hand, there are a lot LPs that will sound closer to the master tapes of recordings 50+ years old that simply have seen too many pressings over the years, and one way or another the sources have been compromised.

MF's reports on Analog Planet (and here) have shown that many of his original pressings have out-performed re-releases and remasterings many years later. For certain LP's and needs, Channel D's products do solve a dilemma.

CG's picture

From what I can tell, an awful lot of the LPs produced in the 70's and before were remastered in some way when they were transferred to CD and saved for later digital distribution. Some changes might have been for the better, some not so much.

Some times this was proclaimed as a feature. ("This classic was recently redone by an engineer who never knew anybody who performed on the album or anybody who helped originally produce it. In fact, the engineer had never even heard of the artists until this job. So, it's fresh new take! Buy it now!") While other times, nothing was even hinted at.

Whether you think vinyl reproduction is the greatest thing ever or whether you think it's the worst, it's hard to disagree with the idea that the original album likely comes closest to what the original artist and producer had in mind at the time. If that matters to you, the original album may be the closest you ever can get. Digitizing the album can be a real chore, but not much in this life worth anything comes for free.

Scintilla's picture

Which is actually pretty common with most of the regular wags here, bloviating endlessly about nothing. Here it is; read it slowly and then discuss amongst yourselves: you don't have to rip your albums to use Purevinyl.

Quelle horreur!!

I have been happily using Purevinyl for 7 years for real-time playback with never any intent to rip files. For one thing, it takes away a lot of the fun of playing records to rip them. I also apply a convolution filter in real-time for room correction. Try that with a conventional RIAA phono preamp kids.

Now, back to your normal puerile squabbles and unsolicited opinions about everything all knowing ones...

herman's picture

Scintilla has the right idea. It is an excellent way to put together a phono stage for the cost of a good pro audio interface with microphone inputs and the software. The Lynx mentioned in the article and others like it that don't have microphone inputs need further amplification like the stage under review or similar.

I've also used it for years to play records real time as I find recording them to be a real PITA.

Scintilla, what plug-in and convolution filter are you using? The only AU plug-in I found is LAconvolver and use filters created with AudioLense

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