December 2008

MHDT Labs Havana Non-Oversampling Tubed DAC
With USB Input
CD players are absolutely dead!
Review By Scott Faller
Click here to e-mail reviewer

  I'm not sure if you read it or not but a couple of years ago completely by accident, I stumbled across MHDT Labs on eBay selling an extremely nice sounding tube DAC called the Paradisea. I wrote about both the Paradisea and their Constantine DACs in this article. I'd recommend going back to read that article. There's some information in that article that will help fill in a few blanks you might find in this article. Since that time, tons of people have discovered the same Paradisea goodness that I found. In fact over at AudioCircle.com, there is a thread still chugging along with over 38 pages and 750 posts. There, many have shared their own experience with the MHDT product line. Some of the guys have made quite a few hardcore tweaks to the Paradisea like replacing the OpAmps, output caps and a myriad of other circuit mods that has changed the sound to one level or another.

In the last couple of years Jiun-Hsien Wu, designer of MHDT Labs DACs, began offering what he called the MHDT Paradisea Plus. This was essentially the Paradisea with a USB input. When I saw this offering, I thought about contacting him and getting a copy so I could give it a listen. Unfortunately, for the past twelve or eighteen months I have been absolutely buried at my real job... hence the reason you haven't read many new articles from me.

A couple of interesting things happened during that timeframe. Here in St Louis, the highway department decided to completely shut down a stretch of highway that runs directly next to my office for about two years. Those that office right next to this highway (like me) and who also drive a considerable distance to work (30 miles in my case) were facing a two-hour commute in each direction. Well, rather than spending half my waking hours stuck in my car listening to NPR (which has been directly linked to going postal) I did what any 21^st century employee would do, I assembled a home office in one of my spare bedrooms. I converted the smallest of my listening rooms, the Grape Room into a highly functional home office. It was completely outfitted with everything I needed to get my ‘real' job done without missing a heartbeat. Little did I know, my boss was going to back a shit wagon up to my front door and dump it on me. My reasonably demanding eight to ten hour, five day a weaker suddenly transformed into ten to twelve hours a day and at least one solid eight hour day on the weekend. The only saving grace to all this work was the fact that I assembled a kick ass little office system that I listened to day in and day out. Granted, there was no sitting in the sweet spot and drifting off, getting lost in the music but I was able to have killer sound playing in the background full time.

Since my main computer was in the office with me (a Dell Optiplex 755), I decided to start exploring USB converters and USB DACs. I tried the Trends UD-10.1 (USB to S/PDIF converter), the Pop Pulse PC Digital Link II (USB to S/PDIF converter) and the Super Pro DAC707SE (USB DAC). I also had the very nice sounding Consonance Cyber 10 which had a USB input and a KT-88, single ended tubed output that I used for quite a while. Each of them had their strengths and weaknesses in a given system configuration. On the whole though, I was able to tweak the system with each of the USB interface devices installed where I could get me most out of them. The overall sound I was able to achieve from each of these units was eye opening.

One day late last spring I happened to return to the house after a meeting to find a note on the door from my mail lady. It said that I had a package to pick up at the Post Office. I thought it might be the replacement Trends I had been expecting for a while. When I picked up the box the following day at lunch, I noticed it was from Taiwan and heavy. Well, at least heavier than the little Trends UD-10. So when I got outside of the post office I sat the box on the trunk lid of my car and opened the package. I was pleasantly surprised to find the brand new offering from MHDT Labs, their Havana. I had been reading about this for a week or so on the boards and was completely taken with the design. Since I was so busy with work, I didn't dare commit to taking on a new piece of gear to write about. On the other hand, seeing the Havana in that box sure was a very pleasant surprise.

Pieces Parts
First things first, Jiun-Hsien has chosen to stay with the non-oversampling scheme for this design. Second and another big one as far as I'm concerned, is that MHDT Labs has eliminated the opamp that was used downstream of the DAC. Jiun-Hsien has also chosen to stay with the same Western Electric 396A (or any of its variants) as the output gain stage for this DAC. Woo Hoo!, a real live, tube output DAC with no opamp in sight….anywhere! I'm here to tell you, Jiun-Hsien is a designer after my heart.

Throughout the rest of the DAC there are other fairly significant changes. The one that leaps right out of the picture is that they now use a beefy torrid transformer rather than a split bobbin. Also the new design utilizes a pair of well-regarded, 16 bit, Burr Brown PCM56PK monolithic DAC chips. The BBs are mounted in sockets rather than being soldered directly to the board. Also as you look closer at the parts used in this, the flagship offering from MHDT, are a chassis full of Nichicon Fine Gold (FG) Muse capacitors. And back for a return engagement are the rather nice sounding MHDT labeled film and foil small value caps. Again MHDT Labs has chosen to go ‘filterless' on the DAC, opting not to use a brick wall filter. As a side note, after reading a post on one of the audio forums, I clarified a point that was stated regarding the future of the Havana. Jiun-Hsien told me that the BB PCM56PK DAC chip would cease production on February 2009. In turn, MHDT has stocked up on this chip to insure a long production run of these units.

The Havana comes with your choice of USB, coax S/PDIF or Toslink optical inputs. You also have a standard IEC female so you can use your favorite flavor power cord with this DAC.

When it comes to the USB digital conversion, MHDT has chosen to use the C-Media CM102+ to convert the USB signal to S/PDIF. Then the signal is passed to the Cirrus Logic CM8414 96kHz digital receiver and then travels along to the Burr Brown PCM56P DAC then to the dual triode vacuum tube analog output. If you choose to use the coax input located on the back panel in lieu of the USB input, the signal is directly input into Cirrus Logic CM8414 digital receiver then to the BB PCM56P DAC and so on. I'm not a digital designer, nor do I know enough about the USB design or conversion philosophy utilized to comment one way or the other on the strengths or weakness of this USB conversion so I guess you're stuck with my very subjective listening impressions.

Finally, the Havana is about an inch wider and a couple of pounds heavier than the Paradisea. Most of this is due to the added space required for the new torrid transformer. Also, on this version, Jiun-Hsien has chosen to go with a steel case in lieu of the previous acrylic wrapper. The front panel is still acrylic and you can still see the LEDs to make sure you have communication with your source. Overall, the build quality of the Havana is top shelf.

The Setup
For the past couple of years I've been using the Paradisea as the main DAC in my system. It has been connected downstream of my Bolder modified Squeezebox 3. That combination makes some of the best digital I'd heard in my system to date.

Just as a quick refresher on my system for those who may have forgotten, starting at the source I have the Bolder modified SB3 with the Bolder MkIV power supply. It feeds the MHDT Paradisea DAC via an Audio Note AN-Vx cable. From the MHDT is another AN-Vx interconnect feeding my heavily modified Korato KVP-20 tubed pre. The Korato feeds a heavily modified Pioneer SF 850 active crossover which in turn feeds (for this test) my Handmade Audio 2A3 Deluxe driving a pair of Lowther PM2As in an open baffle (cut off at 125 Hz). Filling in the bottom are a vintage pair of 15-inch Goodmans in 5 cu ft vented cabinets being driven by an AKSA 55 with the Nirvana mods. The rest of the cabling in the system is my DIY MilSpecCuAg wire with Teflon dielectric. All of the power is transformed and cleaned by a BPT 2.0 Signature. Needless to say, this system is clean, crisp and clear yet harmonically rich and brutally revealing.

I'm going to start with a direct comparison between the Paradisea and the Havana and then I'll follow up with some comments about the Havana as a stand alone DAC. How I'm going to do the side-by-side comparisons between the Paradisea and the Havana is like this. Since my Korato doesn't have a remote, I've inserted an NEC AVX-910 that will take care of the remote source switching duties. From there all I have to do is install matching interconnect cables from the two DACs, then do some quick SPL level matching (via my Sencore SP-295) and I'm ready to start listening to the differences.

On the Havana, I have chosen to feed the digital signal via USB with Foobar using the latest ASIO plug in (the equalizer feature in Foobar is disabled). A simple read across my network pulls up my nearly 300 gigs of FLAC files. The USB cable I'm using is a simple, off the shelf Belkin 5 meter cable. In my listening room I've got an older desktop that sits under the side table next to my listening chair. I've installed a fair amount of damping material inside it to quiet it down along with some acoustic treatments downstream of the power supply fan to suppress some of its noise. All in all, it's reasonably quiet.

Unfortunately I haven't had a chance to build my MilSpecAgCu with Teflon USB cables yet. When I do, I'll publish a DIY article with my impressions and all the details you need to build a set for yourself. I thought using a standard USB cable would be similar to what most people would do so I went that route rather than getting a hold of a Kimber or CryoParts for an audiophile USB cable.

The Big Comparo
So, here we have both DACs sitting side by side, both fed with matching power cords, both with matching interconnects and finally, both with matching Western Electric 396A output tubes with matching build dates and near perfect match according to my calibrated Tripplett 3423 tube tester. Oh, one thing I forgot to mention, the Havana probably has 500 to 600 hours on it. It spent a lot of time in my office system running in. I level matched the two DAC's and started flipping through my usual array of reference tracks. After settling my mind down and getting into the tunes, when you begin switching back and forth between the two, the differences in some areas are immediately obvious and in other areas, they are quite subtle.

As I Listen and switch back and forth, the first thing that simply jumps out at me is the upper bass to lower mid-bass. The Paradisea has a fairly prominent hump right in this band when you compare it to the Havana. This is something I hadn't paid much attention to in all this time I've spent with the Paradisea but sure enough, song after song I heard the same thing. Where it was the most apparent was on the plucked notes of an upright bass.

The next noticeable item is the Havana's lack of grain when compared to the Paradisea. This became especially noticeable when you listened to things like female vocals. Cases in point are those margin recordings we all have in our collections. Allison Moorer's release Miss Fortune fits this profile. I've always considered this recording as good but not quite ‘reference' material because of that little bit of grain I've always heard on the edges of her voice and the instruments. Songs like Tumbling Down have always sounded just fine until you turned up the volume. Then the grain began to rear its ugly, audible head. I had always written this off to being a slightly poor recording. Well, come to find out it isn't the recording.

Another audible difference between the two DACs is that the Paradisea can lean towards the aggressive side. When you do a direct comparison, this aggressiveness manifests itself in the leading edges of notes. Others hide in the grain that I mentioned previously. When you compare the two DACs side by side, you soon realize that those aggressive leading edges are actually artifice. Cool though they may be, they don't tend to exist in real music. Listening to everything from the Kodo drummers to Gary Burton on vibes, the leading edges of music reproduced on the Havana sound far more natural and ‘real' sounding than on the Paradisea. I've no doubt in my mind that this is primarily because of the opamp in the Paradisea's output signal path. That aggressiveness on the Paradisea isn't obtrusive by any means but it is there. Its only when you flip back and forth that it becomes apparent.

This next item is relatively subtle but it most definitely exists when you do a direct comparison. Both are 16 bit, non-oversampling DACs and voiced similarly but in close comparison, the Havana definitely has better low-level resolution. That resolution is fairly easily hear in the sustain and decay of notes. Simple songs like Ella Fitzgerald singing Good Morning Heartache with its opening notes struck on a triangle show the Havana's ability to better resolve sustain and simply dig deeper into your music collection. Along with better low-level resolution, this gives us a more open and airy presentation to the music. This also lends itself to much better focus of the performers on our virtual soundstage. Every song I listened to, it was much easier to follow small movements from performers like drummers who were minimally mic'ed. Again, I suspect that with the removal of the OpAmps and its accompanying circuitry is the reason for the increased detail.  One less piece of electronics in the signal path can do nothing but help, especially an OpAmps.

Regarding depth of stage, the nod once again goes to the Havana. The soundstage increases in depth by a solid two to three feet. Considering my Lowthers are a fairly forward sounding pair of speakers, the stage depth is approaching eight to ten feet. That is quite an accomplishment in my books. On stage width, the Havana again exceeds the Paradisea once again. Using my usual track to gage this, the opening bits from Pink Floyd's Signs of Life have the water lapping on the shore every bit of six feet outside the speaker boundaries. Both of these are the best performance I've heard from a NOS DAC in my system to date.

When it comes to the quality of the bass produced by the Havana, it is nearly identical to that of the Paradisea. The depth, tonality and solidity are nearly indistinguishable. The sole exception being the upper bass hump I mentioned earlier. The lowest three octaves of bass are very tight and impactful.

Just a quick note on the Havana's operation, when the USB cable is plugged in to the back of the Havana, it dominates the input. That is to say, if you use both the USB and the S/PDIF inputs, you will need to unplug the USB cable to get the S/PDIF or coax to work, even when using the switch on the back. Not a big deal in the grand scheme of things but it is definitely worth mentioning.

Speaking of the USB and S/PDIF, I was curious if I could tell a difference between the two means of input on the Havana. I used the S/PDIF from my Bolder modified Squeezebox as the transport and plugged it into the coax input of the Havana to use it as a true DAC. As I switched back and forth between the USB and S/PDIF inputs, I couldn't hear an appreciable difference in the way the music was presented. Tone, timbre, depth, width or any other measure we audiophiles use to gage a piece of equipment. I'm not quite sure how to interpret what I heard, or didn't hear as the case was. Those of us that have been into computer based audio for a while have likely read many of the posts on numerous forums where a person extols the virtues of a given USB or digital to analog design over another ‘inferior way' of accomplishing the same task. In the past, those statements have made me hesitant, almost afraid to invest any money on the ‘wrong' technology. Well I'm here to tell you, the USB conversion that MHDT has chosen sounds damned fine. If it can hang with something like the Bolder, it's a pretty safe bet when you decide to plunk down your hard earned audiophile bucks.

So...
If you couldn't tell from my write up, I personally I love the sound of the Havana. It reminds me of a slightly more refined version of the Audio Note 2.1 Signature DAC that I lived with for some time a while back. The sound of the Havana is big, open, airy and fluid. In the realm of NOS DACs, the Havana is one of the best, if not the best NOS DAC I've heard to date. It does a phenomenal job of low level resolution for a non-oversampling DAC and doesn't ‘color' or get in the way of the music. Music simply flows without any hints of sounding forced or artificial at all.

In my system, the Havana has been able to take that last remaining digital edge out of digital. In turn, MHDT has taken another fair sized step towards the analog domain. I have to honestly say that in my system, this very reasonably priced DAC comes close to competing with my big vinyl rig. That says truckloads about how this DAC sounds.

Now for the caveats. First and foremost you have to remember, this is a non-oversampling DAC. A NOS DAC may not sound great in everybody's system. When it comes to selecting a DAC for your system, care must be taken. Within every system out there lies a delicate balance of synergy. If you have a forward sounding system, a NOS DAC may likely sound quite good. It helps bring your system into ‘balance'. If your system is reasonably laid back, you may be better off with an upsampling DAC. Again, it's all about balance. One last item before I get sidetracked, if you are a detail freak (read=ICE amps, upsampling and bright speakers), don't even think about a NOS DAC.

Not to get sidetracked but this is worth repeating. I can't tell you how many audiophiles I've talked to (or read) over the years that that have commented about a given piece of gear that doesn't sound near as good as others have stated when they hear it in their system. When I drill down a little further on their comments and systems, I find that they tried inserting a given piece of gear into a system that likely won't compliment the rest of the system (read=system synergy). In turn, they are dismissive about that same piece of gear regarding it as an ‘inferior' piece. What they fail to realize is that much of the audio gear we play with is NOT plug and play. Taking this to extremes let me use the venerable large Advent speakers an example. Those of us that grew up listening to these speakers know and love the way they sound. In turn to get the best out of these speakers, you really need a fairly forward sounding cast of characters supporting these speakers (read=upsampling, detailed solid state, or tube gear with bright sounding tubes). I (personally) would never try to mate an NOS DAC or some other ‘laid back' sounding piece of gear to these speakers. If you do, you won't be able hear the Advents sound their best. On the opposite end of the scale sits something like the Avantguarde line of speakers. The last thing I'd consider doing is installing an upsampling DAC and Bryston amps to drive these speakers. It's all about proper balance. Keep that in mind when you read comments about any piece of gear.

Sorry for getting sidetracked. For those of you that are wondering about upgrading your Paradisea+ to the Havana, well I am going to give a little different advise. The two designs sound similar but quite different at the same time. The major difference is the Havana's lack of mid-bass forwardness. If this is something that you've noticed as being ‘off' in your system, definitely consider upgrading to the Havana, it will eliminate that. For those that simply can't live with that last bit of digital edge like myself, the Havana all but neutralizes it. If you have the Paradisea and are looking to get a bit more detail and openness while staying with a NOS DAC, the Havana will definitely deliver the goods.

For those who have been contemplating trying a non-oversampling tube DAC for some time and have yet to make the move, now is the time. The Havana does a tremendous job either as a stand alone DAC or as a straight up USB DAC. Programs like Foobar with ASIO4All work well and are utterly simple to use. Granted when you do the computer thing you have limitations like 5 meters on a USB cable and you need a reasonably quiet PC because it sits in your listening room but after that, it's all good. I've heard from a couple of people that a Mac sounds better than a PC when it comes to reproducing music but I haven't taken that step….yet. So the jury is still out on that one.

Personally, I've gone off the deep end with PC based audio. I'll say it again, CD players are absolutely dead. There is absolutely no reason to own one, yet alone buy a new one. When you can get a USB DAC like the Havana that simply blows away any CD player costing three-four-five times its meager $900 price tag, why would you even consider it? Especially when you can rip all your CDs to a hard drive and have literally every piece of music you own right at your fingertips. Those that contend PC audio is inferior are simply wrong. This couldn't be further from the truth. Now, is the Havana as good as my Opera LP-5 with the Dynavector 507MkII arm loaded with the Cartridge Man's Music Maker? No, not hardly. Is the Havana the best digital I've heard in my system to date? Yes, without a doubt.

In the end, the Havana comes with my highest recommendation. If your system mates well to an NOS DAC and you have sufficient system resolution to be able distinguish minute differences between gear, the Havana may well be your last stop on the NOS DAC train. If you read my ratings, I was extremely torn. I really wanted to assign quite a few 5's up and down the scale because of how good the Havana is. Trouble is, there are a couple of high quality USB, NOS DAC's that I've yet to experience. I've been trying to secure the models that most interest me but I can't seem to garner any interest from the manufacturers. Hmmm, I wonder why?

My Ratings
Please keep in mind this rating system is used to compare the MHDT Labs Havana DAC against absolute perfection, or a money no object Non-Oversampling DAC design. If you see what you think may be a low(ish) score, it's because there are DAC designs that are even more refined but consequently cost considerably more. To top that off, if I assign 5's across the board, I've just painted myself into a corner leaving no room for that ‘ultimate' NOS DAC. You won't see me handing out many 5's. In turn, I feel I need to leave room in the ratings system to accommodate those speakers.

Specifications
Type: Digital to analog converter
Tube compliment 5670 or one of its variants
Inputs: USB, Coaxial S/PDIF and Toslink
Output: 2.6V, < 800 ohms
Dimensions: 28 x 15 x 7.5 (LxWxH in cm)
Weight: 3.5 lbs.
Voltage: 115/ 230 volts, selectable
Price: $872 plus shipping from Taiwan

Company Information
Mhdt Labs, Taiwan
Proprietor: Lin-Li Chuang
Designer: Jiun-Hsien Wu
E-mail: mhdtgang@yahoo.com
Website: www.geocities.com/mhdtlab/