If we align our perception in term of vintage resistor-to-resistor (R2R) ladder DAC, it is specific to the over the shelf DAC like Burr-brown and Analog Device DAC. In their golden years of vintage multibit DAC around 80's to 90's, only those two manufacture built DAC IC in this R2R configuration. Philips with TDA1540, TDA1541 and TDA1543 is Dynamic Element Matching DAC, which is also multibit, but different in the internal configuration compare to the R2R DAC.
I am pretty sure in those golden era, lot's of money spent in their R&D to achieve the best R2R multibit DAC, starting from PCM53, 54, 56, 58, 61, 63, 1702, 1704 and AD1856, 1861, 1862, 1865. Those DAC exists before this audio industry force them to shift to more economic and easy to build DAC, it is Delta Sigma DAC.
Fast forward today, audiophile still believe that vintage multibit DAC sound superior to Delta Sigma DAC (hey, it's me:). The Delta Sigma DAC is not become a true single bit anymore. Few manufacture like AKM and ESS that focus to improve their Delta Sigma DAC start to use multibit Delta Sigma to improve the sound quality. I always believe that rely on one high-speed faucet will never give the same result with lower-speed multi faucet, which is same like Delta Sigma and R2R DAC.
So, what actually I want to share with you guys?!
In this post, I will share the latest modern R2R DAC that build by (practically) the new comer in audio Industry, if compare with Burr-brown and Analog Device, it is Fiio BR15 R2R DAC. How far for modern R2R DAC can go and how well the vintage R2R DAC can withstand with the current technology?
Let's find out.
This post is not a review.
I was called by my friend who just acquired used Fiio K11 and BR15 DAC with modest price tag. Both are modern R2R DAC and they are affordable when buy new. Special notes come with Fiio BR15 DAC, which the first impression when my friend listen the music, it sounds natural. The sound just like the best vintage multibit DAC.
Long story short, Fiio BR15 was lend to me to test.
First, I may explain what is the different between modern R2R compare with vintage R2R DAC. You may check the online photos for the Fiio BR15 internal components as reference.
The modern R2R DAC in general use many high precision resistors which controlled by serial/parallel data converter ICs to sum out the current as the signal output. The value of each resistor should be precise, probably 'handpicked' (not sure for Fiio manufacture procedure) to maintain each individual resistor tolerance. With this resistors array design, the PCB inside the DAC mostly filled with the converter ICs and resistors around that. Probably takes space as small as 5 cm x 3 cm for single channel 24-bit R2R resistors array.
In vintage R2R DAC, those components are the same but far smaller. They are packed inside a die of single IC that size less than 2 cm x 0.5 cm for DIP-16 package IC, or 3.5 cm x 1 cm for DIP-24 package IC. The precision of resistors are not 'handpicked', meaning the tolerance will be measure after the DAC come out of the production table. Later on, they marked the highest to lowest tolerance with grades, such as K, J, or non-grade since the resistors tolerance will direct impact to the precision bit output.
Looking to this Fiio BR15 R2R DAC, it has many features that hard to compete with my own DAC build. The Fiio DAC is industrial approach that put many features as possible to meet wide target market. While I am struggling to put more than one function in my DAC built because it will add complexity, especially when the feature added will use in the future, or maybe it downgrades the overall sound performance.
Fiio BR15 R2R DAC has 1 coaxial input, 1 optical input, 1 optical output, Bluetooth receiver and 2 USB input at front and back panel. The audio output are 2 pair single-ended RCA output and 1 pair balanced. It also features a bright multi color LCD screen that display input selection and sampling frequency.
The Fiio BR15 R2R DAC is aluminum top case with solid build and feel, including the two knobs at the front panel for control the menu and volume control. Those menu also can be navigate through included remote control.
I listen my music collection, that mostly in 16-bit WAV format from my iBasso DX-90 through SPDIF coaxial output, or Astell & Kern AK100 through Toslink optical output to this Fiio BR15 R2R DAC or to my other R2R DAC build.
First impression listening the music with this Fiio BR15 R2R DAC is dryness in the vocal.
But everything was perfect!
What this mean?
My current benchmark vintage R2R DAC is my own built PCM63 DAC here which the vocal sound is king. The sound is rounded and focus with highly precision music instruments pin-point. Fiio BR15 R2R DAC is similar to the sound of my PCM63 DAC, plus-minus in general, but the overall sound is dry. It is acceptable after few hours of listening and I can say it is not bad at all.
I am pretty sure the engineer at Fiio is benchmarking PCM63 DAC for this BR15 R2R DAC. Both Fiio BR15 and PCM63 DAC have the same sound signature. They are not overly details and sharp music presentation, I could say warm and musical just like vintage multibit DAC sounds like.
The most surprising result from Fiio BR15 is the sound-stage that presenting like in a bubble over your head. This creating immersive soundstage that I think my PCM63 DAC cannot compete. The PCM63 DAC soundstage presenting the music in front of the listener as the stages where the performer perform, which also makes it different in music presentation.
The more you listen the music through Fiio BR15, the more you will like the sound from this affordable modern R2R DAC.
I aware the status for Fiio BR15 R2R DAC will not presenting all modern R2R DAC in general and I also aware that my PCM63 DAC built also not presenting the same way as others vintage multibit DAC. But I hope you get my point here. When you ask me to build another vintage multibit DAC using PCM63 IC, the cost will outperform more than double of the brand new Fiio BR15 DAC alone. It takes time to build and find the good components today also a burden. I am not mention for the risk to the sound quality potentially will not perform as planned and need more time to evaluate it and probably modify the design.
In summarized, it is not easy to build a vintage multibit DAC for beginner and I suggest just buy available modern R2R DAC in the market like this Fiio BR15 to get the similar sound to the high quality vintage R2R DAC.
Additional review!
Fiio BR15 R2R DAC has its own digital volume control that I think useful if you want connect this DAC directly to the power amplifier. I didn't notice any sound degradation from maximum volume to half of it.
The optional menu is EQ setting which I never use it at all and NOS or OS setup. While mostly I listen to NOS (non-oversampling) that sound raw and more forward sound presentation, the OS (oversampling) is not bad at all. OS sound more like Delta Sigma DAC, which more crisp high details and lay-back vocal.
The plastic material for bottom of the case is look and feel cheap.
Bluetooth module inside this Fiio BR15 is from Qualcomm QCC5181 which is support LDAC high resolution audio receiver, but it never becomes my choice for high-quality music playback, period.
I saw few op-amp ICs, pair of OPA1642A which I believe for LPF or buffer and pair of OPA2521U which I believe for balanced output.
I posted my first modern Vs. vintage multibit DAC comparison here.
Disclaimer: Any statement and photos in this article are not allowed to copy or publish without written permission from the writer. Any injury or loss from following tips in this article is not under writer responsibility.
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