"I sure have been listening to a lot more music since I started using my MacBook with a USB DAC as a source," said Stephaen. Stephaen is a long time friend and neighbor with consummate taste in audio, music, wine, food, humor (and lots of other important life-things), which make him a lot of fun to be around. The neighborhood audio quartet of Stephaen, Pete, Bill, and I have managed to squander away quite a few perfectly grand days playing with Hi-Fi gear, listening to good music, eating good food, drinking a little good wine, and talking about all those things friends do. So at an afternoon get together when Stephaen told me how the combination of a MacBook and USB DAC was supercharging his musical life, I paid close attention. He said he was listening to more music and a greater variety of music as a result. Thanks to iTunes and a well-stocked hard drive, Stephaen could create music play lists along certain themes, or just listen to random selections as iTunes selected the next song for him. The result was more music in his life—and that's a really good thing.

Intrigued, I bought a MacBook, loaded up a good portion of my CD collection onto the hard drive, and began thinking about USB DACs. As is my custom, I bent my ear towards the audio underground to see what whisperings might come my way. I heard positive vibes about the Mhdt Labs Paradisea+ (pronounced Paradisea 'Plus') USB DAC pulse through the ether of the underground. "Musical," they said. "Good sonic performance," they said. "Nice build quality," they said. "Very fair price," they said. "Hmm," I said, "I'd better check out the Paradisea+." I emailed Mhdt Labs about the possibility of writing about the Paradisea+ USB DAC for my pals here at Positive Feedback Online and received a speedy and friendly response of "yes" from Mhdt Labs' Lin-Li.

The audio underground was right on target about the Paradisea+ USB DAC -and I was impressed with it from the moment I laid eyes and ears on it—but before I go into a more detailed description of its attributes, let me introduce you to the music lovers who are Mhdt Labs.

The Fab Four of Mhdt Labs: Mouse, Horse, Dog, and Tiger

Four friends with a shared love for music and Hi-Fi founded Mhdt Labs in 2002: Jiun-Hsien, Lin-Li, Ting-Ann, and Gia-Ann. Mhdt is an acronym created by using the first letter of the Zodiac name of each of the four friends: "M" is for mouse (Jiun-Hsien), "h" is for horse (Lin-Li), "d" is for dog (Ting-Ann), and "t" is for tiger (Gia-Ann). They later decided that Mhdt also stands for "Music Heaven Development Team" because they were getting so much musical pleasure in their lives from their pursuits at Mhdt Labs.

Lin-Li told me, "We were music lovers and very hard working people with decent jobs and good incomes here in Taiwan. We liked to enjoy a Hi-Fi music massage after working long hours every day. We went through the age of vinyl and then were attacked by the digital revolution. The first generation of the digital revolution was ok and it was very convenient, but we were not satisfied with the performance. During this time we stopped listening to and enjoying music for a number of years due to the very long hours we were working every day. When we came back to music we found the digital age had "upgraded" to Delta-Sigma DACs and a digital signal processing (DSP) approach, but we found the music didn't have the same level of feeling that we remembered from before. We decided the modern DACs did not sound musical to us and that we needed to drag ourselves back to the experience of music with feeling, so Mouse designed our first DAC which we called the "Digital Password", because it was our password back into music with feeling. Later we offered the Digital Password for sale to those like us who wanted the feeling restored to the music."

Mhdt Labs operates on a person-to-person basis and you can order the Paradisea+ USB DAC directly from the four friends Mouse, Horse, Dog, and Tiger through their web site. Mouse and Horse told me, "Our reputation is the most important issue to us, so we design and build our products with very durable materials and components, and we do all warranty service ourselves to make sure it is done right. We offer a one-year warranty and if a product is faulty during that period, we send out a new unit to replace it. However, the relationship with our customers is important to us, and we will still help our customers even after this period is expired."

The Mhdt Labs Paradisea+ USB DAC

Jiun-Hsien, or Mouse as his friends like to call him, is the designer for Mhdt Labs. Mouse has done some really nice design work with the Mhdt Labs Paradisea+ USB DAC which is housed in a low-noise acrylic chassis. The DAC uses the legendary 16 bit/44.1KHz NOS Phillips TDA1545A non-oversampling DAC chip, has no digital filters, uses the award winning National Semiconductor LM4562 operational amplifier for active I/V conversion, and features a vacuum tube buffered output stage (a single NOS GE5670).

The Paradisea+'s acrylic chassis reminds me of the cutting edge Tom Evans Audio Design (TEAD) Vibe Lithos 7 preamplifier that I wrote about for 6moons back in December of 2005. Tom's early career working with ultra-low level electrical signals in defense industry applications led him to choose acrylic for the chassis of his statement products; which he felt was superior to everything else in terms of maintaining maximum signal performance by keeping field effects to a minimum. Tom told me then that, "Most of my products are wrapped in acrylic for sonic reasons. One problem with metal boxes is that the fields produced by the mains power transformers end up on the 'box' and act like a winding to set up a field that affects the flow of electrons through the signal circuits."

The attention to signal performance that an acrylic chassis implied, impressed me in a statement product like the TEAD Vibe Lithos 7 preamplifier, and I find it even more impressive to find that same level of attention to detail in an affordable $599 product like the Mhdt Labs Paradisea+ USB DAC. A nice little side benefit of using an acrylic chassis is that it has a degree of transparency—like a dark-tinted pair of sunglasses—that allows you to see its shaded internals from outside the chassis. I happen to think the dark-tinted acrylic chassis with contrasting gold casework screws is very attractive. There is an on/off switch and some tasteful silk-screening of the Mhdt logo and Paradisea+ moniker on the front panel.

On the back panel of the Paradisea+ there are RCA outputs for connection to a preamplifier and a standard three-prong power cord connector awaiting the power cord of your choice (the Paradisea+ ships without a power cord). There is also a switch on the back panel that allows you to select between a USB input for connection to a computer or a coaxial RCA input and a Toslink optical input for connection to a transport. On the bottom of the Paradisea+ are four nice gold-colored footers containing a polymer pad to address potential vibrations. Kudos to Mouse at Mhdt Labs for the Paradisea+'s impressive and thoughtful chassis design.

The Fab Four of Mhdt Labs don't think the modern Delta-Sigma approach to DACs provides a musical or natural presentation and that the older R-2R DACs are much better at keeping the 'feeling' of the music intact. Delta-Sigma DACs use oversampling and interpolation as a pulse density conversion technique which allows them to user a lower resolution (and less expensive) 1-bit DAC internally. Delta-Sigma DACs use a low pass filter, step nonlinearity, and a negative feedback loop to achieve Delta-Sigma modulation of the signal. An R-2R DAC utilizes a simpler form of conversion using matched resistors in a ladder configuration that results in greater precision and less signal manipulation during the conversion process. Mhdt Labs feels this simpler and purer conversion process does less damage to the signal and provides a more musically natural presentation, and from what I'm hearing from their Paradisea+, I'm inclined to agree with them.

Mouse and Horse told me, "We use the R-2R DACs because this structure and philosophy seems much more correct to us for preserving the music. Sadly R-2R DAC chips are not manufactured anymore due to the very high cost of the laser trimming process when manufacturing them. But our goal is to produce the most musical DAC possible, the most real and natural sounding DAC that we can, so we use new old stock (NOS) R-2R DAC chips in the Paradisea+ DAC."

The Paradisea+ uses a vintage NOS Phillips TDA1545A non-oversampling DAC chip. The 16-bit continuous calibration stereo Phillips TDA1545A DAC chip has become something of a legend with custom DAC builders for its relaxed, dark, smooth, and musical performance—the antitheses of the timbrally bleached and brittle sound that is normally associated with the phrase 'digital sound'. The TDA1545A has a reputation for being among the best of the Phillips TDA154X series with its superb sonics, glorious mid-range, and easy to like musicality. For example, the spendy ($15,470 USD) Zanden Model 5000 Signature DAC uses the Philips TDA1541A 'Double Crown' chip, as does the $8500 USD Abbingdon Music Research (AMR) CD-77 CD player. I heard Srajan's (6moons) Zanden digital front end with the TDA1541A DAC chips while visiting him in Taos, New Mexico, prior to his move to Cyprus. I was impressed with the way the Zanden played music. It had a nice relaxed, smooth, and organic musical presentation that was true to the music. I liked the Zanden a lot, but at over $15K it was way out of my middle class price range.

Jiun-Hsien told me, "The TDA1541A and TDA1545A are both R-2R multi-bit DAC chips developed in the Golden Age of digital. The TDA1541A is the premium version of the chip family with one channel per chip, where the TDA1545A is the economical version of the TDA1541A with two channels on one chip. The TDA1541A one-channel chip is definitely better than the TDA1545A two-channel chip, however, you need a lot more components to finish a TDA1541A based DAC than you do a TDA1545A based DAC. If you compare the sound quality of these two famous DAC chips you get very interesting results. Let's say we use an imaginary scale of 1 to 100 to measure the sound quality and musical performance of the DAC. The TDA1541A based DAC will result in a score of somewhere between 60 and 95 depending on a lot of factors in the overall design. The TDA1545A based DAC scores between 80 and 90 quite easily. Therefore, we chose the TDA1545A for the Paradisea+ because it is possible to get very near the ultimate performance of the best TDA1541A DAC designs while using far less components, which fits very well with our philosophy that 'less is more'".

Some designers even think that the TDA1545A chip used in the Paradisea+ has even better performance than the TDA1541A used in the high-priced Zanden and AMR players. The fact that Mhdt Labs chose to use such a vaunted R-2R NOS Phillips TDA1545A DAC chip in the Paradisea+ really impresses me, and the good news is that I have found the Mhdt Labs Paradisea+ USB DAC to have a smooth, natural, and musical Zanden-like presentation for a small fraction of the cost of that high-dollar rig …but I'm getting ahead of myself.

The Paradisea+ DAC uses active I/V conversion that is carried out via an LM4562 operational amplifier designed by National Semiconductor specifically for high performance audio applications. The LM4562 is from National's Power-Wise® family of op-amps and has "…ultra-low distortion, low noise, high slew rate …optimized and fully specified for high performance, high fidelity applications". National Semiconductor won the Electronic Products Magazine Product of the Year Award for the design of the LM4562 op-amp, and the LM4562 has developed an almost cult-like following with audio modders and the DIY community due to its high-performance design specifications.

As many of you reading this article are aware, a number of DACs – like those from 47 Labs and Audio Note – have eliminated digital filters in their designs to achieve better sound quality. Ryohei Kusunoki wrote an insightful three-part article published in the highly regarded Japanese MJ magazine from November of 1996 through December of 1997 that explains the deleterious effects of digital filters from a technical perspective. Yoshi Segoshi, the importer of 47 Labs products to the USA, has written a nice English summary translation of those articles you can read here http://www.sakurasystems.com. After reading Yoshi's summary of Kusunoki San's articles in MJ, my take on the digital filter situation is this: Digital filters in a DAC generally do more damage to the signal than they do good as they filter out noise that is already above the threshold of human hearing and then introduce unpleasant noise artifacts of their own that are audible in the range of human hearing; the result degrades the music listening experience.

Jiun-Hsien chose to go the filterless route with the Paradisea+ USB DAC; he felt that elimination the digital filters improved the sound quality resulting in an increase in musicality. He told me, "There are no digital filters in the Paradisea+ DAC. Digital noise effects can be minimized in a simpler fashion by using a ferrite bead, capacitor, or even a PCB trace with a thoughtful components layout. The use of a digital filter or filtering chips is not necessary in an audio DAC design because the digital noise is beyond human hearing, and using a digital filter will actually give worse results because it will degrade the sound and kill the music."

The Paradisea+ uses a NOS GE 5670 vacuum tube stage that acts only as a buffer, and which Jiun-Hsien says, provides additional digital noise isolation from the analog signal. The Paradisea+ also has a nice complement of internal parts in addition to those already mentioned above: special order flameproof low noise resistors made by vacuum sputtering metal film on high thermal conductivity ceramic rods, a heavy duty 2 ounce copper trace fiberglass printed circuit board, special order polypropylene film and aluminum foil (film and foil) capacitors, gold plated switches, and Nichicon MUSE series top KZ grade and Fine Gold grade capacitors.

The design of the Paradisea+ USB DAC shows impeccable attention to detail coupled with a high build quality—I'm impressed. Jiun-Hsien told me that the major principle that guided his design of the Paradisea+ was less is more: by using zero oversampling, no passive or active digital filters, direct coupling, no chassis wires, a careful selection of components and circuit layout, he achieved less signal degradation so we would get more music. Yeah!

Impressions

My current Hi-Fi love affair—and the system I used for this article—consists of the hand-made Leben HiFi Stereo Company RS28CX vacuum tube preamplifier and the matching Leben CS660P stereophonic vacuum tube power amplifier. Both use Acoustic Revive Power Max II power cables that are plugged into a Acoustic Revive RPT-4 Ultimate Power Supply Box. The loudspeakers are Harbeth Super HL5 loudspeakers which sit atop Skylan stands. Auditorium 23 loudspeaker cables and Audio Tekne interconnects round the system out.

The Paradisea+ USB DAC is extremely easy to use. All you have to do is plug in the RCA interconnects from the preamplifier, plug in a USB connector between the DAC and computer (the USB connector is provided if you order from the Mhdt Labs website), and attach a power cord. I found Audio Tekne interconnects and the Furutech G-320Ag-18 IEC power cord ($300 and $99 USD respectively) to be an excellent—and not too spendy—match for the Paradisea+ DAC. The Paradisea+ was literally a plug and play device with my MacBook computer—I plugged it in and began to play music through iTunes immediately without a hitch. If you use a Microsoft Vista operating system, Mhdt Labs recommends downloading and installing the 'asio4all' USB driver at their website so your computer will output a SPIDF digital stream for better sound quality.

Mhdt Labs recommends a 30-day break-in period, although I found that the Paradisea+ continued to improve sonically and musically for at least twice that length of time. I gave the Paradisea+ plenty of break-in time before making any judgments about it, and it changed musically and sonically in pretty dramatic fashion during the first six weeks of the break-in process. Before the Paradisea+ breaks in fully it can sound a little discombobulated, almost like the motional elements of melody, rhythm, and harmony aren't tracking together in the music quite right. The bass response was tipped up a little bit which may or may not bother you depending on your personal preferences. During the break-in period this is what you can expect: the resolution of detail improves, the imaging improves, the sense of space improves, tone colors become more saturated, the overall presentation becomes smoother and richer, instrumental timbres become more accurate, and the motional elements of melody, rhythm, dynamics, and harmony become perfectly integrated, and musicality goes completely off the scale. The bass response remained a bit 'big', but that is easy enough to fix with a quick adjustment of the iTunes equalizer.

Once broken in the Paradisea+ USB DAC was a revelation in musicality, and in that regard, obliterates any digital device I've had in my system to date. The Paradisea+ has an almost magical ability to transform all the music going through it into an emotionally transfixing experience that never ceased to amaze me during the review period. Music that I had written off as hopelessly pedestrian, or that I thought was recorded so poorly as to be nearly unlistenable, bloomed into full musical life through the Paradisea+ USB DAC. There's a lot more music encoded into those Redbook CDs than I would have ever imagined possible based on past experiences listening through other digital devices.

Like Isaac Newton with an apple bouncing off his noggin', I realized that something important was happening here and that the Paradisea+ USB DAC was no ordinary DAC. It doesn't really seem to matter if you're listening to Vivaldi's Oboe Concerto in A minor, Tony Rice blue-grass picking his flat-top guitar, Miles blowing his jazzy horn, Crosby crooning, or the Rat Pack gooning, the music comes across as completely engaging regardless of the musical genre or the recording quality.

You might be tempted to think that the Paradisea+ accomplishes its high level of musicality (and tolerance for poor recording quality) by compromising on the sonics—by going for a smooth, warm, but low resolution approach—but that's not the case at all. Rather, the non-musical sonic elements on recordings—like imaging, soundstaging, soundspace, detail recovery, immediacy, and the like—are actually very, very, good. Take for example, Charles Mingus' Flamingo from the Tijuana Moods album, which presents a very wide and deep soundstage with absolutely pinpoint imaging through the Paradisea+. The sonic images on Flamingo are rendered with a solid 'flesh and blood' feel to them and a good sense of immediacy that really lends a sense of life-likeness to the performance. The level of detail the Paradisea+ recovers from the music is totally commensurate with what makes sense for the recorded perspective (i.e. how far away the performers in the recording seem to be), adding to the illusion that real live musicians are playing just for you.

Where the Paradisea+ DAC is particularly remarkable is in how it portrays the musical elements of a recording. Things like instrumental timbres and dynamics, the melody line, the rhythm, the harmonies, the beat, the emotional and tactile sense of real musicians interacting and creating music together—those elements that trick your brain into thinking that there's real music going on in your listening room—are remarkably persuasive through the Paradisea+ USB DAC. Take Jorma Kaukonen's Blue Country Heart album as an example. I like to use Blue Country Heart as a reference for timbral accuracy, as Jorma plays the exact same Gibson Advanced Jumbo guitar made out of Brazilian Rosewood and Adirondack Spruce on it that I do (only he plays it lots better!). The Paradisea+ DAC portrays the Gibson's timbre within a believable range of reality, albeit a bit darker and richer, and perhaps even more beautiful than the real thing—but not in a way that I find objectionable by any measure. If anything it might be a bit more beautiful than the real thing. I forget who made the rather whimsical Don Quixote'ish like comment in an audio review: "If real music doesn't sound like this, then maybe it should." It certainly applies to the Paradisea+ in spades. Instrumental timbres are so achingly beautiful through the Paradisea+ it can come as quite a shock if you're used to the more typical bleached, brittle, and sterile sounding digital playback.

The way the Paradisea+ blends and portrays the combination of the sonic and musical elements of recordings is sheer artwork. Poorer recordings are completely musical and convincing and great recordings are simply stunning. The Paradisea+ recovers a lot of musically natural detail, and that coupled with the natural and extended way the notes decay, provides a level of nuance and articulation that is something to behold. Take for example Ernest Ansermet's performance of the Nutcracker from The Royal Ballet Gala Performances album; the Arabian Dance was so amazing it almost knocked me out of my listening chair. The sweep of beautifully rosinous strings, the bell-like perfect pitches of the percussion, work together to yield an amazingly nuanced and emotive portrayal of the music.

A couple of years ago I had a very nice digital front end consisting of a Meridian 508.20 used as a transport and an exquisite Audio Logic 2400 vacuum tube DAC to process the digits. That digital front end struck a very nice balance between sonics and musicality, as it should for the combined price of $8000. Then something peculiar happened: two friends—Pete Riggle and Michael Lavorgna (6moons)—told me how much they were enjoying the musical chops of that underground digital favorite, the Sony PlayStation 1 SCPH-1001. Michael had even sold his high-priced Audio Aero DAC and begun to use the PS1 as a reference for musical digital. I decided I too should investigate the PS1 and bought one for my own use. Sure enough, Pete and Michael were right on, for the PS1 was truly a remarkable musical device. Like Michael, I too sold off my expensive digital front end and never looked back. I've been using the PS1 for a couple of years as my reference for a musically engaging digital device, and for the paltry price I paid for it—about $30—it makes for an absurdly fun counterpoint to the usual audiophile ultra-expensive Hi-Fi gear.

But why bring up the giant killer PS1? Well, simply because there is a new King in town, as the Paradisea+ USB DAC betters it by an order of magnitude in every way. If we use an imaginary scale of 1 to 10, where 1 is a very detailed and bright Hi-Fi'ish presentation, 5 is the natural sound of acoustic instruments, and 10 is a Grateful Dead concert back in the days when they handed out Kool-Aid laced with LSD to concert attendees, then the PS1 scores somewhere between 4 and 6 on the musical engagement Richter Scale. The Paradisea+ comes in at a solid 9, and that's without the LSD. In short, it's a revelation musically speaking. The Paradisea+ is darker, warmer, and richer than the PS1. It is also more nuanced, more detailed, more liquid, and more beautifully expressive than the PS1. The Paradisea+ also has more rhythmic prowess, more artful melodic flow, and a more luxurious harmonic development than the PS1. It might sound like I'm dissing the PS1, but I'm not, as I still have the highest regard for its overall musical prowess. The PS1 shall maintain its place as my reference for a musical digital device on an ultra-tight budget. But my, oh my, is the Paradisea+ a musical wonder.

Oh, and lest I forget, I predict rockers will be particularly enamored with the Paradisea+ for its ability to play loud without any strain whatsoever on the part of the listener—you can just let her rip! The Paradisea+'s way of presenting the music keeps my ears from shutting down at higher volumes, almost like the way Shindo gear does, and it's likely to be a trait many of its owners will find particularly endearing.

Ok, you've no doubt come to the conclusion that I really like the Paradisea+ USB DAC a lot. I do. It is one of most enjoyable Hi-Fi products I've come across, and it's staying put in my system for sure.

Summary and Conclusions

The Paradisea+ USB DAC at $599 is a highly recommended bargain. I think it will find particular favor with those listeners who want a relaxed, natural, warm, smooth, liquid, and emotive musical performance from their digital. Remember the first time you had sex? The Paradisea+ is better than that. Ok, well maybe not, but it's really good, and perhaps the musical equivalent of a special evening with that special someone.

For my tastes the Paradisea+ has only one weakness—the bass is a bit overdone. That's not really a deal-breaker though because it's easy enough to dial the bass right in to where you want it using the iTunes equalizer. And speaking of iTunes and Macs, using a computer as a digital source opens up a whole new vista of musical fun. Like my friend Stephaen, I too found the combination of a USB DAC and my MacBook had me listening to a lot more music, and as I said earlier, that's a really good thing.

One of the Paradisea+ DAC's most endearing traits is that it portrays poorly recorded music as a completely natural and enjoyable musical experience. The crispies, edgies, and nasties of poor recordings are somehow shuffled away from your attention, and replaced with just plain good ol' foot tappin' music. Music lovers who like to listen to a lot of historically important music of widely varied recording quality (read poor) will particularly find the Paradisea+ to be a joy in day-to-day listening sessions. With good recordings I was very impressed with the Paradisea+'s sonic prowess, and it is one of the few digital products at any price that is able to combine excellent sonics and superb musicality in one package.

Music flows out of the Paradisea+ with unparalleled ease, better than anything in my experience at this price level for sure, and better than most things at any price level. As far as I'm concerned, the Fab Four of Mhdt Labs have a platinum hit on their hands with the Paradisea+ USB DAC, and Jiun-Hsien may very well be one of the most talented DAC designers on Planet Earth for the music lovers among us. Very, very, highly recommended to music lovers everywhere. Jeff Day

Mhdt Labs
web address: http://dhost.info/mhdtlab/

Paradisea+ Vacuum Tube USB DAC
Retail: $599 USD plus $40 shipping from Taiwan to the USA. See the Mhdt Labs web site for shipping costs to other countries.

Distribution: Mhdt Labs products are sold direct via their web site. See the Mhdt website for more information.

Quality of Packing: The Paradisea+ DAC was wrapped in bubble pack for protection and ships in a standard weight cardboard shipping box. Nothing fancy for packing, but it worked just fine and did its job, getting the Paradisea+ to me in perfect condition.

Condition of component received: Perfect.

Completeness of delivery: The Paradisea+ USB DAC ships without a power cord so the new owner will need to provide one. I found the $99 USD Furutech G-320Ag-18 IEC power cord to be an excellent match.

Owner's Manual: A paper owner's manual is not provided, but one is not needed as the Mhdt Labs web site covers topics of interest to new owners such as the break-in time, recommendations for alternate tube choices, changing voltage settings for different countries, and a user guide that describes the meaning of the various front panel LED lights and the rear panel connections.

Warranty: One year.

Human interactions: Friendly, professional, and with very quick responses to inquiries and questions.

Pricing: At $599 USD the Paradisea+ USB DAC is a bargain considering the quality of materials and construction, and its musical and sonic prowess.