November 2003

MSB Technology PAD-1 Analog-to-Digital Converter

Review Summary Sound "The similarities in background noise…and consistency of timbre made the two versions [LP and CD] initially sound like identical twins," although "depth is subtly reduced, [along] with a homogenizing of images and a reduction of high-frequency air -- a general lessening of resolution." Features "Takes in an analog signal and outputs 24-bit data at either 44.1, 48, 88.2 or 96kHz via an S/PDIF interface"; "balanced and single-ended analog inputs and RCA, AES/EBU and TosLink digital outputs." Use "Setup of the PAD-1 and associated equipment was a fairly complex process" -- see sidebar for details. Value "The MSB PAD-1 is an example of an audio component that can actually save you money, and there aren’t too many of those around."

If you have hundreds or even thousands of records that you cherish, and if you resent laying out $20 for a CD just so that you can listen to your music in the car, you’ve no doubt thought about recording your LPs onto CDs. Perhaps you’ve considered one of those standalone CD recorders, or even looked askance at the burner in your computer. Either way, converting analog waves to digital bits is a daunting concept that’s fraught with difficult decisions.

The standalone recorders necessitate, here in Canada at least, the purchase of expensive consumer-grade discs, where the additional cost over and above that of data discs goes to pay for the Kaaza crowd’s copyright-infringement shenanigans. Since you already own your LPs legally, why should you have to pay this? Add in the questionable quality of the built-in analog-to-digital converters, plus the lack of an upgrade path, and this route starts to look rather unattractive.

Since you’re reading this on a computer, it’s probably occurred to you to record your LPs right onto your hard drive, using the computer's built-in soundcard. However this isn’t cut and dried either. Your computer is a noisy environment in which to make the sensitive analog-to-digital conversion. Plus, we’re back to that question about the quality of the ADCs that are in the soundcard. There are, however, some real advantages to using a computer, such as GUI editing and data manipulation, but the disadvantages in this instance weigh heavier.

These issues have been on my mind for a while now, and while at the CES 2003, I spied a potential solution in MSB Technology’s room. MSB is the company that made its name with external digital-to-analog converters, with their most popular and well-known product being the overachieving LINK DAC. Quietly tucked away amongst their digital-to-analog converters, which use the same chassis, was MSB’s Professional Analog to Digital converter, PAD-1 for short, which takes in an analog signal and outputs 24-bit data at either 44.1, 48, 88.2 or 96kHz via an S/PDIF interface. This device can be used to feed either a computer or a standalone CD recorder, via each unit’s digital inputs. The $799 USD PAD-1 has balanced and single-ended analog inputs and RCA, AES/EBU and TosLink digital outputs. Although there are both line- and phono-level inputs, Scott Rust of MSB warned me that the phono facilities are vestigial and shouldn’t be used.

The PAD-1 measures 17"W x 14"D x 1 3/4"H and weighs 18 pounds. The PAD’s power supply is a chunky unit that’s incorporated into the power cord, and is sort of a super-wall-wart job. The PAD-1 is compatible with MSB’s P1000 power base, which retails for $399 and is contained within the same chassis as the PAD-1. For this review, I used the stock power supply.

MSB is keen to point out that the PAD-1 is upgradable for future digital formats. The stock PAD-1 as I reviewed it can output a 24-bit 96kHz signal, but I didn’t have any equipment available that could take advantage of this resolution. Scott explained to me that I’d still get excellent sound quality by setting the unit to use a 44.1kHz sampling frequency and then amputating the extra 8 bits by recording a 16-bit word. However, the MSB’s ability to output 24/96 data shouldn’t be overlooked. With the advent of DVD burners and the low price of hard-drive storage, the PAD-1 undoubtedly has more potential than I’m able to realize at the present time.

Setup of the PAD-1 and associated equipment was a fairly complex process, which I feel is a charitable description of the aggravation I encountered while dealing with a combination of computers and audio equipment. See my sidebar for details. However once I was past the steep part of the learning curve, the PAD-1 itself was a pleasure to use, as it consistently and without drama took in the analog signal and passed out a digital stream.

Equipment conglomeration

I used the PAD-1 in my reference system, where the source was my Roksan Xerxes/Artemiz/Shiraz analog combo, which in turn fed my Sonic Frontiers SFP-1 Signature phono stage. I routed that signal into my Sonic Frontiers SFL-2 preamp or a Musical Fidelity A308 integrated, depending on which was in the system at that time. The signal went from there via the tape out to either a Musical Fidelity A3cr or Eastern Audio MiniMax preamp, which I used to bring up the gain. The signal then made way to the MSB PAD-1. Cables were my usual Acoustic Zen Matrix Reference and Satori, and homemade Canare Starquad interconnects.

For comparison of the original signal to the digital copy, I used a Musical Fidelity A3 CD player in my reference system. My middle-floor rig was as follows: Musical Fidelity A3cr power amp fed by a Museatex Bidat DAC with a Rotel 975 CD player used as a transport. Cables here were Analysis Plus Solo Crystal Oval.

I also played back the discs in my car system (having fresh music for the road was the primary reason that I embarked on this endeavor). The system here consisted of a Nakamichi CD45z receiver, KEF Uni-Q coaxial door speakers, a JL Audio 10W6 subwoofer, and a Soundstream 604 amplifier.

Sound in the round

The resultant CDs that I re-mastered (yes, I'm proud to say it!) sounded consistently good and were eminently listenable. A/Bing back and forth from the burned CD to the original LP isn’t a totally fair way to evaluate the prowess of the MSB PAD-1. This method of comparison involves a further digital-to-analog step, and the quality of that conversion is really outside the scope of this evaluation. However, it’s basically impossible to tell how these discs sound without listening to them, so here goes.

Flipping back and forth from the burned CD to the LP source could be confusing, due in part to the high quality of the transfer. The similarities in background noise (ticks and pops as well as surface noise) and consistency of timbre made the two versions initially sound like identical twins. A deeper, closer listen does reveal differences, and they’re of the sort that you might expect. Depth is subtly reduced, with a homogenizing of images and a reduction of high-frequency air -- a general lessening of resolution.

While this loss of resolution is definitely noticeable, it’s not overly intrusive. I took Son Volt’s Wide Swing Tremolo [Warner 9 47059-1] out of the burner and put it straight into my Toshiba DVD player, and even with this low-end unit the crisp and relaxed nature of the music shone through. The guitars had the same bite as portrayed on the LP, Jay Farrar’s voice retained its gritty salt-o'-the-earth texture, and the high-frequency sheen came through pretty much intact. I can’t seem to figure out why, but some LPs made the conversion to CD with better results than others, and this was one of the stars. To tell the truth, I was almost as happy listening to Wide Swing Tremolo on the burned CD as I was listening to the LP.

Tom Waits’ Heartattack and Vine [Asylum X6E-295] was another LP that made a swell-sounding CD. There’s plenty of low-level information on this album, with lots of air around Waits’ voice, especially on the title track, where you can almost see the spit flying from the corners of his mouth. The copy I made retained almost all of that air, with just the small amount of the foreshortening mentioned earlier. The bass and midbass retained a large portion of the analog warmth that’s present on the LP, which raises some interesting questions about the claimed superiority of vinyl’s sound quality. If its virtues can survive the transfer to CD, then how can one support the concept of LPs having an essence that CDs lack or are unable to capture? Hell, I still like LPs better, but this analog-to-digital conversion experiment has raised some interesting issues.

Although the copy of Heartattack and Vine retained almost all of the low-frequency extension of the source, there was a very small difference in the bass between the LP and the CD copy. I know that this sounds strange, but the bass guitar on "In Shades" was missing some high-frequency definition. The sensation of an actual string in the action of being plucked was somewhat reduced on the copy. This is the leading edge of the bass note, and the slight subtraction of the midrange and treble portion of the instrument served to make some bass instruments sound a little bit like they were submerged in gelatin.

The neatest part about recording music and editing the resultant files on a computer is the ability to see what the music looks like. The Analog Ripper software that I used on my Mac laptop shows the music on a moving graph, which maps amplitude over time, with the output looking somewhat like an electrocardiogram. Most of the music I recorded -- the jazz and pop stuff anyway -- has a rather limited dynamic range. Other than the occasional crescendo, everything sort of hovers around the middle of the graph, and when you crank up the gain in order to bring the levels up, the noise floor rises proportionately. As you might expect, good audiophile recordings have the greatest dynamic range and lowest noise floor, but I have to mention one startling example. Muddy Waters’ Folk Singer [Mobile Fidelity MFSL 1-201] had a vanishingly low noise floor -- almost below the resolution of The Analog Ripper software's display -- and startlingly high dynamic range. On "My Home is in the Delta," when Muddy’s voice peaks, the display showed a spike that rode from the bottom right to the top of the screen.

The recording of Folk Singer that I made with the MSB PAD-1 captured pretty much all of that dynamic range, and even managed to retain some of the aforementioned analog magic that makes LPs so pleasurable to listen to. The loping guitar line on "Good Morning Little Schoolgirl" retained the rhythmic drive that my Roksan combo portrays so well, and the rich, easy-to-listen-to midrange and treble kept their user-friendly nature. While it’s true that a bit of the depth that’s present on the LP didn’t survive the conversion to digital, you’ve got to remember that this is a copy. And since the LP is itself a copy that’s sourced (hopefully) from the master tape, then the CDs made via the MSB PAD-1 are in fact copies of copies. That these CDs sound as good as they do is a startling achievement, and as such is a testament to both the high sound quality of LPs and the technological prowess of the MSB PAD-1.

I was somewhat worried that low-level resolution would suffer due to the truncation of the 24-bit words to 16 bits as they were captured on my hard drive. I’m happy to say that this was not the case. Prog-rock group Brand X’s best album by far was Moroccan Roll [Charisma 9211-1126]. It featured Phil Collins on drums -- back when he had both hair and musical integrity -- and Percy Jones on bass. Moroccan Roll has many passages that are extremely low in level and which at the same time contain tons of musical information. On "Malaga Virgen," the guitar and bass carry on a conversation that’s so low in volume that the instruments are fighting with the noise floor of the LP. The PAD-1 captured the subtle details of this interplay without difficulty, which resulted in a presentation that was commendably similar to the source material in its rendering of subtle details.

Conclusion

The MSB PAD-1 has a definite place in the system of any music lover with a significant collection of LPs. During my time with this unit, I recorded over 50 LPs for use in my secondary system and in my car, and if I had to buy those CDs at retail prices, they would end up costing more than the price of the PAD-1. While I would still choose to spin the original discs while listening to my reference rig, the ability to record my LPs for use in other systems proved invaluable. The MSB PAD-1 is an example of an audio component that can actually save you money, and there aren’t too many of those around.

...Jason Thorpe
jason@soundstage.com

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