Audio Mirror Tubadour III NOS DAC

I have owned this converter for several months and I think I'm ready to share some findings on it. I learned about this DAC while browsing the Audiogon forums where there are several threads discussing it. Audio Mirror is not really a known manufacturer, AFAIK it's a one man show run by a man named Vlad. Their current products are this DAC and SET monoblocks using the Russian 6C33C triode.

The Tubadour III is a non-oversampling converter based on the AD1865N-K chip from Analog Devices. This is a popular R2R IC for non-oversampling DACs, not as ubiquitous as the TDA1541 but according to some just as good. The DAC costs $1500 USD with a 14 day return policy, but my unit has two specific upgrades. First the output capacitors are replaced with Duelund CAST CuSn, and second the signal path resistors are replaced with Vishay Z-Foil. This brings the price up to $2200. It has all major digital inputs but you can also add I2S input and balanced XLR output via transformer conversion as extra options. I was using USB for most of my listening. The USB input on this DAC is very good.

Before we discuss further about the design of the DAC, first a shot of the internals of my unit:

I hope Vlad does not mind me posting the internals of the DAC, but in my opinion no manufacturer should be ashamed or hide what their product looks like inside. It does not paint a complete picture of the quality of sound but it gives us some ideas of what to expect certainly. I try to be as educated as possible about what is going into the design of a product I am buying to avoid being ripped off.

The top board is the digital board, there are two AD1865 stacked on top of each other, paralleled to improve linearity. The USB input is floating on a separate board. Interestingly, while all the PCBs are labelled Audio Mirror, some parts are clearly borrowed from a firm called HQ-Audio who seem to be another DAC manufacturer. I am not sure what the story is here.

The bottom board contains a potted toroidal transformer which makes up the power supply for the digital section. The Chinese R-core in the bottom left for the analog section. The left board is AC input and filtering with MOSFET rectification. The right board is the I/V conversion and analog output. As you can see the I/V conversion is via sub-miniature triodes, two per channel, and then cap coupled on the output. You can swap 6922/6N1P/6DJ8 etc but I don't really see why you would want to, the 5977 included are rugged and long lasting tubes.

The DAC took about 100 hours or so to break in. It is my first experience owning a non-oversampling DAC, which I have before avoided due to the stereotype that they are slow, syrupy or warm. I have now heard the Tubadour III in multiple systems, with speakers and headphones. I am pleased with it and I think it is competitive with the Yggdrasil which I have owned twice previously now. Which is better comes down solely to preference and system matching. My notes below will largely be in comparison to the Gungnir Multibit/Yggdrasil as that is what this community is most familiar with and what my previous reference for affordable R2R goodness was.

Cliff notes version of the good:

• Very linear tonality. Having heard now AD1865 and AD1892 in different applications, these are just not warm sounding converters. Not warm, not warmish, but with a sweetness or richness to the sound that can still be considered natural.
• Very good timbre. Decidedly less gray and bleached than Gungnir Multibit A2.
• Less forward, edgy or in-your-face sounding than the Yggdrasil/Gungnir Multibit A2. This is a very big plus for me especially with speakers. Not what I would call relaxed or polite though, terms which I usually view as negatives.
• Good sense of timing and flow to the music, transients and harmonics seem better preserved with non-oversampling
• Resolution largely on par with the Yggy2. Exceeds Gumby2.
• Great dynamics, however...

Cliff notes version of the not as good:

• Given the triode I/V conversion and the cap coupled output, the bass performance will not match the Schiit. The Yggy2 will have more slam and extension in the lowest octaves, which can give the impression of greater dynamics.
• The high frequency roll-off from the sinus(x)/x loss inherent in all NOS designs is noticeable. In this DAC, it's heard as a slight dimming of the uppermost frequencies, like someone turned down the lights. Cymbal crashes and hi-hats still sound great, and I personally do prefer a bright and vivid sound, so this is something I had to get used to a little bit. It's just a presentation thing that you may or may not dig.
• There is a different presentation to the stage with NOS designs. On headphones this translates to a flatter headstage, you will not get the tunnel-like depth of the Schiit DACs. On speakers, I don't mind it at all. Images seem more fleshed out if less precisely placed.

I like this DAC a lot. I know it in my heart it is not 'the one' but I am happy with it for the time being and I do not think I will ever go back to the Yggdrasil after hearing what good NOS can sound like. The Tubadour III possesses the X-factor that allows me to get goosebumps from certain musical passages, even if the rest of the chain is very modest in stature. It is very easy to listen for hours without fatigue and get sucked into the music.



What is holding this DAC back from being 'da best'? Well at least on paper, I think a capacitor coupled output with such large value caps (1.0uF) is inherently flawed and should be avoided, even with caps as good as the Duelunds. The alternative I would like to see is transistor I/V conversion with proper transformer-coupled SET output buffer but very good transformers would raise the price and chassis size significantly. We could also add tube rectification and choke input filtering. However the Audio Note Kits 5.1 DAC has all of these things and yet one user reported that he could barely distinguish its performance from the stock Tubadour III!

If there are senior members who would like to try this DAC, I would be open to putting it on loaner in the future.

 

Pavane incorporates the ‘good’ and addresses the ‘bad’, in my experience.

 

The usual "don't want to go all Kevin Gilmore on you" disclaimer, but damn... This is not how a finished product should be constructed. Before you use it any further, check whether the enclosure is safety-grounded, I can't make out from the photo if it's connected.

Overall this does look worse than my first headamp build. The primaries going to the output stage trafo are not isolated on the board, live AC is being switched by a metal turn-switch, those tubes better be glued together by silicone sealant (not hot glue), the caps are glued to the enclosure and those undersized (yet copper!) U-fasteners. Generally this is a HQ Audio design with a slightly re-tuned output stage.

I don't think that money should be given to people selling borderline dangerous (depends on the safety ground) designs with little to no added intellectual value.

 

I was under the impression with the Tubadour that you could roll tubes?

Looks like they are soldered on to the sockets?

 

K4star....having owned the stock and "mini maxed out version" i conclude with much that you have stated....I to was sucked into owning the Schitt yggy2 not once but twice. As stated on the Audiogon AM T3 blog....I went thru a lot of Dacs..sum as high as 8k and as low as the 1k MHDT Orchid Dac and concur with most if not all your Assessment's on the AM T3...my only follow up is like you this is not a end game dac...but at the present..I know of no other stock$1500 dac that can touch it...But let me throw sum audio food for thought on upgrading this dac..so let me give you a much cheaper option....instead of the Highly respected Duelund caps... i opted for the Miflex KPUC caps(courtesy of Don Sachs) and the Z foil resistors and jumped out the fuse...well this very good stock Dac just grew in every important Perimeter...Noise level dropped below the floor...Soundstage grew in all directions....width...height and depth....music just flowed to the point of not knowing.... what component i was listening to...(Dac or my 5k anolog rig)....and the best part of this upgrade was $140 for two Miflex Caps vs $460 for two Duelund caps...not saying which one is better....but i have a hard time to justify spending almost $500 on caps on a $1500 Dac and like you cold not go back to the Yggy2...this is a great dac...in the right system...but in my all tubed based system was overbearing ...upfront and just not fun...Take it for what its worth...but I am digging my system( Martin Logan Montis Electrostatic speakers...Latest Vandersteen Dual Subs....Latest Rogue m 180 "Dark Revision mono blocks....New Supratek Chardonnay Preamp.( Latest Gen 3 best audio deal off all time. my humble Opinion ..gorgeous to the ears as it is to look at).....AM T3 Dac(modded as stated above) cambridge CXC transpot(weakest link..looking to upgrade ASAP) all wired with top of the line Acoustic Zen Cables And The Music Is Flowing Like NEVER B 4...TRUTH!

 

I guess I have to chime in after a few customers was referring to this post with concerns.
I'll say this first. I built my first tube amplifier in 1984. My first Tubadour DAC, first version was designed and built in 2005 by me.
Now I will separate and answer one by one to all the conclusions/opinions "Hrodulf" posted about the new Tubadour III NOS DAC.
It is funny how people draw conclusions than post them and influence other people.
I understand not everyone is a technical person, but at least the one who claim to be technical and knowledgable and express his opinion- should be trustworthy and back up his opinion by facts or at least explain. Not just throw words and confusing other readers.
BTW I've never agreed the internal pictures of my DAC to be taken and posted from the original owner, because of that same reason. There are people who spend all day on forums and writing misleading posts.

"Hrodul" claims that his first headamp (normally this means a guitar amp) he built looks better. I would like to see some pictures to back his claim.
1. This is not how a finished product should be constructed. Before you use it any further, check whether the enclosure is safety-grounded, I can't make out from the photo if it's connected.
What he meant by constructed? Overall design? Topology? Chassis is grounded. It has always been grounded.
2. Overall this does look worse than my first headamp build.
What exactly looks worse? Can we see pictures of your headamp?
3. The primaries going to the output stage trafo are not isolated on the board.
The phrasing shows his level of knowledge. The correct phrase should be something like this: The primaries of the output stage trafo are not isolated on the board.
Look at the board he is talking about. These are jumper pads to switch between 120 and 240v mains.
4. live AC is being switched by a metal turn-switch.
Yes I prefer metal switch with better quality than plastic one. The housing of the switch is metal. This doesn’t mean that it is hazardous, but the way post is written sounds like it is.
The manufacturer of the switch is “Clarostat”. Well known American based company. I think they know what they are doing by manufacturing metal housed switch.
5. those tubes better be glued together by silicone sealant (not hot glue).
Well I built my first tube amp in 1984. I have been manufacturing and selling vacuum tube equipment in US since 2001. Before that I was doing that same thing in Bulgaria. I probably know something about tubes, heat and hot glue.
I always use silicon ))
6. the caps are glued to the enclosure and those undersized (yet copper!) U-fasteners.
The caps are glued to the pc board and the chassis. The “yet copper” brackets are just a little bit of overkill.
Caps are totally secured just by being glued. That’s been tested. If you have to remove the caps it will take some force.
I like to overbuild my equipment and that’s why I aded brackets. Being copper is on purpose - not to interfere with magnetic field or inductance.
7. Generally this is a HQ Audio design with a slightly re-tuned output stage.
Yes the pc boards are manufactured by HQ Audio for me.
What exactly is he saying?



I don’t spend much time on forums, because I am really busy with my orders and building audio equipment. You can check what other people say about me and sound quality of my products.
I totally understand your concerns and there is nothing wrong with that. I wouldn’t survive American market as Audio Mirror for 20 yrs if my reputation was bad or if my builds were bad quality or unsafe.

 

These are pictures from CD/DVD players made by Panasonic/Pioneer with a missing ground pin on IEC power inlet.

 

But does an owner of your product really need to get an agreement from you? I don't think so. You are selling a physical device. Once the device is sold it belongs to the owner. It is the owner decision what to do with it. Nobody is posting here a schematics which might be treated as your intellectual property.

 

You are absolutely correct. I probably should say inform me, not get a permission. Sorry for confusion.

 

P.S. There are some things I wouldn't repeat today, but this was my first rodeo with a soldering iron. I ended converting the amp to US voltage and sold it to the Head-Case forum admin.

 

I guess you understand my concern about internal pictures. People just comment what they think they know and as I mentioned before other people not very technical believe the first one. I had a customer who was asking for internal pictures and than he "advised" me to replace my power supply with ultra linear, low noise power supply, not to use this switching power supply. The power supply I use in that particular design is a ultra low noise MOSFET linear power supply.
You can see my point I guess.

 

Really good for a first build! I like it!

 

Hoping for more posts after the new interest spurred on by the Audiogon threads and pending review by Terry London for Stereo Times.

 

So close to pulling trigger here.. I'm waiting for the emotional cliff to jump from, to make the purchase. ;D I know it's somewhere around here.. that "it would be insane not to buy this right now(!)" clarity moment.

 

With one significant exception, I haven't yet invested enough money into any single audio purchase that really required that sort of emotional push. Fountain pens are another matter entirely but yeah I wasn't entirely right in the head with some of those spends.

Also, your post is effectively noise; this runs counter to the sort of discourse the forum encourages. What DAC do you currently run, what improvements are you looking for, what gear will you be pairing it with, and most importantly are you spending money that might constitute significant strain on your finances despite being unsure about whether or not this'll be worth your while?

EDIT:
https://www.superbestaudiofriends.org/index.php?threads/what-is-sbaf-10-articles-for-behavior.5555/

and

http://www.superbestaudiofriends.org/index.php?threads/new-members-introduce-yourself.17/