Audio Note Kits
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ANK Audiokits DAC 3.1
Transformer Coupled Non Oversampling Digital-to-Analog Converter


" I'm writing only to tell you that the DAC 3.1 is amazingly fine and my equipment has improved so noticeably that I can't find words to express myself! "

Audio Note DAC 3.1

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The latest version of the DAC3.1 for 2014 is using our new upgraded EI core transformers – we have put them on a slightly larger core for improved overall response – the sonics are stunning in the lows and highs for no extra charge!

Building upon the highly regarded and popular DAC 2.1, the DAC 3.1 has even more advanced features and comes with an upgraded driver board plus the addition of two 33:1 step-down output transformers.

Using such a transformer coupled output stage has many advantages both sonically and for matching purposes. And it's low impedance output means that it will match with virtually any pre-amplifier or integrated amplifier - valve or transistor - making it highly versatile.

To complete the pure digital to analogue design of the DAC 3.1 the digital board uses the Audio Note Non Oversampling architecture for sonic purity and has No Analog Filtering (analog filtering has been totally removed). We have found Oversampling and having Analog Filtering in the signal path has a marked detrimental effect on sound quailty. .

Here are some of the things that make this DAC kit a clear cut above the rest:

We have recently written a report titled Understanding How DACs Work. The article explaines the architecture of Ladder type Dac chips
(which we use in our DACs) and the more common Delta-Sigma type DAC chips and how these can have a negative impact on sound quality.

If you are unsure about what a DAC is or its role in your hi-fi system see our explanation here.

* The Signature Digital Board includes an Audio Note Digital Interface Transformer (with toroidal core made from very thin laminate spun 80% nickel strip).

A USB interface is available for all configurations of the DAC 2.1 and 3.1 as a buyer selectable option in our Shop pages.

The M2 Power Supply is an enhanced PCB version of the original M2 Power Supply taken from Audio Note UKs finished products line. It uses a Mains Transformer/Choke combination with 6X5 for Tube rectification and the ECL82 for regulation. This powers a high quality 5687 Analog Output stage which, in turn, drives two high quality 33:1 step-down Output Transformers.

Also, as with all the very latest Audio Note DAC's, the DAC 3.1 comes without an analog filter.

Signature Digital Board

The Signature Digital Board includes an Audio Note Digital Interface Transformer (with toroidal core made from very thin laminate spun 80% nickel strip). Digital Interface Transformers are used in all Audio Note UK's finished product DAC's from their Level 1 range upward.

The Signature Digital Board comes as standard with the DAC 3.1.

USB Input Options


The USB Interface Option allows you to connect a P.C. to your DAC - a highly requested option that gives you the ability to experiment in that direction (software is not included but the interface is Plug-and-Play compatible).

General Specification

Available Inputs Switchable between any two inputs from the following three choices:
  • Standard 75-ohm RCA (S/PDIF)
  • 110-ohm AES/EBU balanced (XLR)
  • USB (requires additional USB add-on board option)
Available Outputs Single-ended stereo outputs via Left/Right RCA sockets
Output Impedance 13 Ohms
Output Level 2.5V RMS both channels
Chassis Dimensions 15" wide, 16" back to front, 5.75" height including height from floor

Pricing and Configuration

DAC 3.1 $2,175(USD)
The Standard version of the new DAC Kit L3.1 from AudioNote Kits includes the following:
Signature Digital Board inc. torrodial input transformer and Tantalum resistors on its output
I/V Transformers between the digital and analog sections
Upgraded Digital Power Supply
PTFE wire (silver plated copper)
M2 Power Supply Circuitry - Beyschalg resistors and Audio Note Tin capacitors
Hard-wired or PCB version of 5687 Line Board with Beyschlag resistors, Audio Note Tin capacitors, and Panasonic FC Electrolytics
IE core output transformers: new design from Mid 2013 - see below)
USB Input Option $129(USD)
The USB Interface board allows you to use your computer as a transport and is simple to install.
New Transformers for 2013 & Balanced Option

The DAC 3.1 comes with I/E core output transformers for RCA (single-ended output) only.

Mid 2013 we redesigned the output transformers used in the DAC3.1. The design has resulted In outstanding high frequency reproduction and even more detailed bass.
The transformers are slightly larger with more laminations – the sonic results are even more outstanding. This is our standard transformer now for the DAC 3.1.

The following alternative transformer is also available - these can be used in BALANCED or RCA (single-ended) configurations: Select the option you require in our Shop pages.

I/E Core for Balanced output Add $125(USD)

If you would like to purchase the DAC 3.1, please follow the SHOP link.


Inputs and Outputs

There is one RCA input, one XLR input, and one USB input (if USB Option is fitted). Any two of these can be made active and switched between using the switch located on the rear panel.

Two RCA, line level outputs are available as standard. The optional balanced output transformers allow balanced output via XLR connectors.

I/V Transformers

The I/V transformers were specially designed by Audio Note Engineering to provide an affordable yet highly effective transformer for the DAC Kit range. I/V Transformers are used to maximize the energy transfer during the Current-to-Voltage phase of the conversion; resulting in increased dynamics.

An extract from the article 'Why is Audio Note's 1x oversampling unique?' by Andy Grove describes the use and advantages of the I/V transformer:

The output of most resistor ladder DAC chips is in the form of a current rather than a voltage. There are many ways to convert the current into a voltage but the most commonly used system is that of an op-amp connected as an I to V converter. This system requires the use of a high degree of feedback, and as a result there are problems associated with it. One of those is internal slew rate limiting of the op-amp itself. The rate of change of current at the output of even an audio DAC is very fast indeed. Even modern fast op-amps will slew limit internally and that affects sound quality. Some engineers have found that using extremely fast op-amps improves the sound quality, but we have completely sidestepped the issue by using a transformer I/V system. The transformer not only provides an I to V function but the way it is used in our latest DACs transfers maximum energy from the DAC chip itself. This in itself reduces overshoot and ringing and because the system is slightly overdamped the rise time is reduced to an acceptable rate as well.

The full article can be seen in the Related Links section below.

General Support

We have included a 1KHz test tone WAV file here that may be useful when you are building your DAC Kit. It allows you to feed the signal into your DAC so that test voltages can be measured.

Click here to play the file. To download the file to your computer, right-click on the link and select 'Save Target As...' (Internet Explorer) or 'Save Link As...' (Firefox) from the pop-up menu.

We provide easy to follow, step-by-step wiring instructions with the manual.

Check out the detailed wiring Guide for the DAC Kit L3.1 by clicking on the wiring image on the right.

More Pictures

Click on an image below to zoom-in or cycle through the images using the arrow buttons below.

What customers are saying about the DAC 3.1

What I'm able to hear now from a CD overwhelms my expectations: music is plenty in harmonics, new information and details; vocals and strings are now REAL (quite real); basses are deep, well controlled and powerful; and the high range is full of sweet details, with very high frequencies that I thought my ears weren't able to hear any more.


This thing sounds fantastic! Vinyl is no longer a necessity.

Thanks for continuing Audionote Kits,

Jim Mainqui

...The Audio Note Kits DAC L3.1 has an uncanny ability to go right to the soul of the music...

Joachim Wabnig

The DAC has a great capacity to resolve individual sound sources, to place them in three dimensions, and to sound compelling. It's such a pleasure to listen to CD's without fatigue. I guess that's the main thing, because my previous 24 bit uploading DAC while having outstanding capacity for resolution and detail, always created a sense of unease in my ears. Fatigue is the term commonly used, and gets the point across, but for me it's more of an interference, as if an unseen presence were there, overlaying the music. If this were a taste it would be acrid, leaving an edge upon the teeth. Now that has completely gone. The music is itself, as good as is the recording on the CD. That's what I call hi-fi. Viva valve technology, nice circuits, PCBís and good quality components, and above all viva zero upsampling!

Misha Norland

The kit is done and it sounds great: very dynamic, much more detail, much richer sound, very analogue. It was worth waiting. Building the kit was easy for me as I had built a M3 Phono 3 years ago.

K Mueller

"The DAC getting better sound every day, very detailled, very good soundstage, deeper bass than my goldmund (that i will sell quickly) It sound also very natural, So it does everything very well and i love the way it sound. "

Franck Lafage

"All I can say for now is after turning it on and listening to the first song, the tonality of this DAC is outstanding! It sure does sound natural."

Ken Sim

Hi Brian,

Just got back from a short holiday to find that the DAC had arrived. All the components look absolute first class and due to the excellent packaging, no damage! This kit looks better in real life than it does on the website, it just oozes quality!! Anyway I'll send you my impressions once it's running.Thanks again, talk to you soon.

Best Regards,
Peter (Australia)

"I've been listening to the L3.1 for a week now and it exceeds any dac I've ever heard. The sound is extremely musical and detailed with incredible bass. Some of my cd's rival my best lp's now. The Kit was very well laid out and was a breeze to assemble thanks to the very straight forward instruction manual."

John Uyeyama

"The Dac Kit L3.1 is really becoming something special. It sounded good from the start but the difference from last Saturday is amazing. The amount of detail and the quality of the sound are very impressive to say the least."

Ron Underwood

Comments on upgrade from L2.1 Level B to L3.1...

...The upgrade exceeds my expectations and I didn't expect to say that. One of the reasons I sought the upgrade is, after many, many hours of listening I came to feel that certain elements of a performance, especially vocals, were not foward enough in presentation. I was hoping the upgrade would improve that. It turns out that it does improve it quite noticibly.

Besides a more satisfying presentation of vocals though, I see a noticible improvement in the separation/resolution of all sounds. The sound stage is appearing expanded and more detailed. Front to back resolution can be more clearly discerned. Performances seem more like they're actually occuring in the room with me. Music sounds more exciting.

The low frequency response has been expanded lower. This is very noticible on things like base drum sounds. The strike can almost be felt as much as heard, as in a live performance...

Christopher Miller

Well, I just finished my DAC Kit L3.1 Sig and I have to say it's just fabulous. It pulls off the truly amazing trick of being ultra-highly-resolving, extended, and dynamic whilst still being about as subliming musical as possible - perhaps what Audio Note's all about? Anyway, it's far & away the best digital source I've had here and I've had many all the way up to $7500 cost-wise.

Some time later...

The DAC C is so damn good it has made vinyl less necessary.

Paul also wrote a review at Audio Asylum - see the following link...

Paul Folbrecht

...The DAC Kit L3.1 is smooth, natural and, generally speaking, neutral. The L3.1 has lots of drive and packs a terrific bass wallop without sounding tubby. I really enjoyed listening to acoustic bass through the Level C. Ray Brownís "Bass Face," from Bassface: Live At Kuumbwa (Telarc CD-83340), was an especially enthralling listen, as the L3.1 captured the subtlety and power of the masterís playing in fine detail. Quieter details like offstage crowd noises were much more clear than through my old DAC Kit L2.1...

...In the middle range, the L3.1 is warm, as would be expected of a tube-based product, but it doesnít push the midrange way out in front of the rest of the music. Instead, the Level C makes vocalists sound a little more human and acoustic instruments a little more natural, with neither being given any more prominence than the recording engineer intended. Jethro Tullís Irish-folksy "The Whistler" from Songs from the Wood (Chrysalis 81570), for example, offers a well-recorded interplay between Ian Anderson on acoustic guitar and Ian Anderson on the flute. The L3.1 faithfully captured the essence of these instruments, those resonances and tones that tell your ears that youíre hearing natural materials in all their glory...

...In the end, is the DAC Kit L3.1 worth the effort and expense? In a word, yes! For such a high-grade kit, the Level C is very easy to build and is well within the reach of the novice builder. Iím pretty confident in saying that you wonít find another DAC in the Level Cís price range that comes close to matching it in parts quality, or one that was engineered by someone who designs five and six-figure components in his day job. Twenty-five hundred dollars may seem a lot for a kit, but just imagine what the DAC Kit L3.1 would cost as a finished product.

Colin Smith -

"Hi Brian,

My AN DAC is up and running now. It sounds a lot better than my Denon 2910 SACD player. AN Dac is very transparent and detailed. I love this DAC.

I can't wait to start working on my L2 pre amp."

Sai Pong Siu

I have finally completed installing the L3.1 upgrade (with C-Core Hi-B transformer) to my DAC L2.1 Signature and I am writing to share my initial impressions.

The upgrade not only met my expectations but exceeded it quite significantly. Granted I only have it running for few days and it is still breaking-in, almost every attributes of the sound seemed to have improved quite significantly. More detail (but not being a distractively hyper detailed) and sense of space/ĒairĒ (but not sounding harsh or bright), better sound stage and imaging, significantly improved musical coherence and sense of pace, perceptively flatter frequency response etc. etc. My writing skills are not good enough to articulate why or how but it seems to highlight the essence of the musical performance much more prominently than any digital front-end equipment that I have ever owned. The well recorded/mastered CD sounds significantly better but it now also highlights the imperfections of the poorly recorded/mastered CD bit more prominently than before but still in an understated way typical to AN products that I have heard in the past (i.e. never makes them un-listenable.)

I feel like wanting to listen to all of my favorite CD again and playing them louder than ever before. As you can tell, I am very happy that I installed this upgrade.


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