THE ORRONOCO AUDIO DIY

This might be my last post in this year. Personally I felt that this year is the most exciting for me, not because of the pandemic, but the working from home condition that makes me more productive. I can use my time which previously spent communiting on the road, from home to office, vice versa, now with more flexible time, I can make some great audio project. This year my blog is full of DAC's project. I think I had enough great time for that. Then the rest of the day in this year, I just need to enjoy what I've made. Before I closing this year, I want to upgrade my integrated amplifier. As you probably already know that I am loyal to LM3886 Gainclone amplifier. I love the simplicity audio system that consist of one box integrated amplifier + DAC, a pairs of speaker and a simple WAV player. Then I remember that I have one thing to do with this amplifier, which has planned long time ago, is to replace the speakers binding post. Recently I got this original CMC binding post in ...

My best effort when building DAC is when I'm using the TDA1541A in non oversampling, fully independent voltage regulator on every voltage pins, and separate transformer for analog and digital circuit. I called this ultimate DAC built on  here  and  here . I amazed on how great the result from optimized power supply to the sound quality compares to the minimalist approach So I named this built is the first ultimate DAC . Lately I am in love with the sound of the another ultimate DAC + headphone amplifier using the oversampling AD1865 DAC. It is theoretically better in specification and also great sound quality result as well. It is a smooth sounding DAC, great details, great depth and great stereo separation. You can also check this another ultimate DAC built on my previous post in November 2021. Since I still have the parts that I need to make another one, so I think I will replacing the DAC board on the first ultimate DAC to this new build oversampling AD1865 DAC. Of...

At the very beginning of this year, I committed to explore the best multi-bit R2R DAC. This is simply because I have plenty of the resources (from broken old unit CD player of course) and ability to build them up. If you think this kind a recycle from old un-used unit to become something useful, than I should stated myself giving contribute for greener world:) After all DAC that I built in this year, I think it is better for me to list them up again in one single page like this. Then I will rank them up in a simple tier list. The reason for this, so you all know what my opinion about of those vintage multibit R2R DAC especially in the sound quality.

Yes, it is been awhile since I finished my another ultimate DAC using AD1865 with CXD1144 Sony over-sampling IC. I made this DAC including a simple headphone amplifier in one box, just for make this unit more functional. I will consider to add another line output and the selector switch just to give an option if this DAC want to connect to other audio system or just like this, using the headphone out. But for now, I am quite often listen through my headphone with this DAC, so I will let this unit just like this for a while. This AD1865 DAC has been reviewed by my friend. I leave it for a week at his house so he can evaluate the sound quality deeply. He is using Arcam TDA1541 S1 CD player modify to a DAC. He is also using Rotel CD player as transport, Camelot External Digital Filter and I am not sure about the power amplifier and the speakers he use. Please continue reading.

With the schematic provided from my previous post  part 1   part 2   part 3  and of course I already have the main components on my hands, then I can start to design and build this another ultimate DAC. The starting point for building a DAC is determined what box will be using. This would become the appearance of the finished project. I always using high quality aluminum box enclosure and it is not cheap. Preferable black color anodized for a great looking finish. Then, because the box comes in many shapes and size, this is also the reason why I don't like using commercial PCB available. The reason for this, because the PCB design which in most cases will not suitable to the box I preferred. Other than that, it is others people design and schematic, not authentic personal build. But that just my personal opinion. Let's continue.

I have explained before on how to connecting the SPDIF input to the digital receiver and then goes to the digital filter. The IC that I use are YM3623 and CXD1144  here  and  here . You might wondering what would be my candidate DAC IC for this another ultimate DAC build, and here it is, the AD1865 DAC from Analog Device. The reason for this is because I still have several AD1865 in my bin. Other than that, especially for the sound quality, in my opinion AD1865 is sound great. It is R2R DAC and very simple to build compares to more complicated and rare PCM63 or AD1862.

In this part 2, I will focusing on how to connect from the digital receiver IC to the digital filter IC. This part 2 is continuing from the  Part 1  which explained how to convert from SPDIF CMOS to TTL digital format required by the YM3623. At the glance, you might wondering why I prefer the over-sampling instead just a simple non-oversampling glue-logic? And this where the fun begin. The fun why I am refuse the dogma that always told you for the non-oversampling is the best sound quality compares to the oversampling. Theoretically the oversampling is required to smoothing the ladder steps on the frequency band created by the digital domain. Ok, I a not going to much technical, but this oversampling is required for the smoother overall audio frequency response. The oversampling also reducing the complexity in the low-pass filter at the analog section. The result for this oversampling is better audio performance in all audio frequency band.