Audiophile Digital to Analog Conversion; Something To Consider?

The process of Audiophile Digital to Analog Conversion is tossed around by Douglas Moore.

Since digital music was introduced on compact discs to the commercial market in 1982 Digital to Analog conversion has been a formative issue. The first CD players had very rudimentary converters that did their basic job but had problems to face. Separate digital to analog conversion was not heard of back then so what your CD player came with was it. A lot of early “audiophile” adopters jumped on the new disks because of the promise of “perfect” sound quality and a disk that would not wear out over time.

On the flip side to this were the die-hard analog purists that thought that the CD was a flawed technology. In a sense, they were both right at the time. CDs were a digital medium which meant that there was no physical interaction between the laser and the disc so wear and tear was not an issue in that regard. (Even though later some CDs had other wear issues). The analog purists had a point as well. Even though the dynamic range and distortion of compact discs were much better, some audiophiles did not like the sound.

Studios at the time were so used to producing analog recordings that this new format was hard to adapt to. A lot of engineers simply tried to go on with life as usual in their workflows recording music like they always have and not taking advantage of digital music’s technical benefits. Between this and the limited knowledge, engineers had of D/A conversion at that time, the resulting sound quality of the first CDs was limited at best.

As time went on many engineers and audiophiles alike started figuring out what digital music was actually about and how to make it better. Starting at the studio level a new crop of audio engineers learned more about how to get the most out of digital and take advantage of the lower distortion and higher dynamic range it offered. Most of us that were audiophiles in the 90s in fact should remember that compact disc was, for the most part, the only way to get new music at the time.

Then in the early 2000s, a new format appeared, the MP3. Overnight music became more portable than ever and much more convenient to store and play. This seemed to be the case and although internet bandwidth meant the MP3 file was the main format being used, in its basic design, it can at sometimes destroy the integrity of the music in many people’s opinions. Nevertheless, the introduction of the MP3 was a pioneering event that brings us up to today where we can walk down the road proudly listening to better than CD quality 24-bit 192KHz music!

Over the years as digital music matured into the most popular format the foremost audio engineers also have worked hard to improve its configuration. Outboard Digital to Analog converters started coming out from brands like Theta Digital and PS Audio in the 80s through today that promised to improve the sound of audiophiles’ CD players. It is much more common today to see an outboard DAC in a high-end system that a CD player. These DACs can handle inputs from CD Transports, computers, and streamers that serve digital music to them for conversion.

This brings us to the main topic I am going to talk about today which comprises a few different types of outboard DACs and their design profiles plus why I feel they are superior in many ways to the now standard, Delta/Sigma “chip” DACs you see many reputable high-end companies producing.

A Technical overview and comparison of the Audio Note CD 3.1x/II CD player, Border Patrol SE-I DAC, and Denafrips Venus II DAC:

I will preface this discussion by saying that all 3 of these digital components are designed with engineering that steers clear of delta/sigma conversion. The designers feel that delta/sigma digital to analog conversion sounds inferior to the more traditional R2R design. They argue that Delta/Sigma designs use too much modulation and oversampling; thus causing ringing which demands that they must be heavily filtered. This can cause in many cases, enough changes to the music to prohibit it to sound as natural as it should.

These three units are not the only high-end DACs that utilize proprietary circuits and design but are units that we are quite familiar with, have reviewed as of of late, and can surely attest to their sound and build qualities.

The Audio Note CD 3.1x/II uses an Analogue Devices AD1865 digital to analog converter chip. This chip has been around since the ’80s and is out of production today. Audio note chose that chip because it is known to be a very musical and non-digital sounding chip.

Designer Peter Qvortrup chose no filtering on its output and keeps the digital stream in its native format while converting. Audio Note believes this to be the best way to keep the conversation close to analog and as pure as it can. They also use two ECC88 tubes and house-made copper foil capacitors in their output stage.

While some can argue that the measurements from this unit will not compete with the best delta/sigma converters the actual listening will give the user a warm and welcome sound that is closer to analog than many DACs can muster.

Audio Note believes in concentrating on the format that most people’s music is in. While their standalone DACs can accept 24/48KHz and 24/96KHz files their CD players are set to 16/44.1KHz. No DSD, No MQA. The CD 3.1x/II is a CD-only player but they do offer the DAC 3.1x/II which is essentially the DAC-only version of the player that accepts coax RCA or balanced digital signals.

The Border Patrol SE-I DAC is very similar in some ways to the Audio Note. This DAC uses a Philips TDA1543 R2R digital to analog converter chip. This chip is also from the ’80s and is sought after for its musical presentation. Both the Audio Note and Border Patrol units use chips that are quite similar in their design, the main difference being Border Patrol uses an EZ80 tube circuit in their power supply and choke filter but does not use an output buffer as Audio Note does. The tube circuit can be turned off as well.

The SE-I version of their DAC adds Jupiter beeswax film and foil signal capacitors, a custom R-core power transformer, and an ELNA Cerafine power supply reservoir capacitor. The Border Patrol DAC can handle up to 24/96KHz files. No DSD, No MQA. The SE-I can be optioned with both coax and asynchronous USB inputs.

To the people that do more measuring than listening and enjoying music in their systems, these DACs are probably not for you. They are a listening-first type of design that has some similarities to a lot of high-end tube products. They sound great but you aren’t going to win any measurement awards.

The Denafrips takes a different approach to the R2R design. They make their R2R boards and components themselves instead of getting a manufactured chip. They first source the best resistors they can, then test them, and only choose resistors that meet their very high standards to build their boards. The high-speed FPGA circuits to control the 4 sets of R2R networks in the unit are hand selected for DSD and use 32-step FIR filters to decode DSD.

The Venus II can handle up to 24/1536KHz and DSD1024 on USB and I2S, and 24/192 DSD64 on all other inputs, with No MQA. The Venus also has a separate chamber for its dual O-type transformers (separating analog and digital sections). They use TCXO (Temperature-Compensated Crystal Oscillator) in their signal for improved clarity while also incorporatig WIMA German film capacitors and EVOX MMK power supply capacitors as well.

In seeing the technologies used in these three units. One could say the Denafrips is the most capable technically with what file formats it can handle. And that it is the most up-to-date as far as the components used. The fact that it is the only DAC on this comparison that can handle all the high-resolution formats and DSD will automatically call out to some people that want to be able to play their highest resolution files. But think of it this way. High-resolution digital has been out for quite a while now and most of today’s music still comes in the form of CD Quality 16/44.1KHz files or disks .(see Mojo Audio “mystique”X below).

Furthermore, there is a lot of discussion going on as to how much of a difference high resolution makes in overall sound quality. As a person that studies digital music and digital component design, I know that the way the music is recorded and the way the studio mixes and masters it, is way more important to the resulting sound than any format difference.

There are many different opinions on DAC design. Some people would say the Audio Note and Border Patrol are machined using out-of-date hardware that was relevant in the ’80s. While the chips they use are from a bygone era the way they implement them is nowhere near how it was done then. So, to put that argument to bed would be to say that using these chips is not the whole story.

From the power supply to the output stages these DACs simply bring out way better results than was possible years ago. All three of these products are designed and built by engineers that have spent a lot of time researching and testing different designs and technologies as well as having unrelenting, musically enthroned ears and full time listening experiences.

Hopefully, you can get the chance to go and listen to one of these DACs or one of the many other designs that stay away from Delta/Sigma processing. I know a lot of audiophiles that have gone in this direction and have not turned back!!!