PCM63 DAC Build - My End Game DAC

To closing this year, I think I wanna fill it with the new project.

I will build another PCM63 DAC.

As you might ready my post here, I put this PCM63 DAC at my top tier list and this might be my last DAC built, my end game DAC.

Looking back since 2 years ago, I am more focus to build the vintage multibit DAC. This building process are become an addiction for me. The project are start from finding those rare vintage IC components, designing the whole circuit, point-to-point connection to the layout and decide the final appearance of the DAC unit itself. Those steps are very entertaining for me, not to count the sound quality result from all my DAC built are fantastic.

Same like this build, as you all know that none of my DAC are built the same. In this build is also should be different from what I previously built here

So let's continue.

The photo above is really interesting, at least for me.

I will talk about the casing first.

The casing is one of the expensive components when building a DAC. So I starting my project using a cheap, un-used steel box here and here. Not only for economical approach if compare when I bought the fancy aluminum casing, but I can put my budget more on the better components. Other than that, the size for this casing is perfect. It is compact, not as big as my previously built DAC.

There are some compromise which I have to redesign the whole circuit to become simple without sacrifice the sound quality. This idea will resulting less components to put in this small casing.

Anyway, the thickness of this steel casing is not bad at all. The chassis is 1 mm thick and the top cover is around 0.75 mm thick.

Starting with the casing, it was ugly when it arrived.

No one will look to this ugly casing condition as a part of DAC project like this.

But I saw it differently.

The first things to do is clean up the casing using fine sand paper. Once it is cleaned, the look is now so much better.

Then I measure the casing to make few holes as the main PCB will sit inside.

Then the next step is the painting process.

It become a different story if the casing finished can look as beautiful like this.

Then I continue to the PCM63 DAC build.

The first things that makes this DAC build is different from my previous built is the power transformer.

As you might know that I always put the power supply as the priority components when building a DAC.

In my opinion, the best power transformer for audio is the double C-core type transformer. It will never win in term of power efficiency compares to toroidal transformer, but not for the sound quality. This transformer is famous because the Audio Note using it on their product.

I have the double C-core transformer with the secondary output 2x 18 volt, with the power rating is quite small, only 12 VA.

Unfortunately with this small power rating, I cannot do many alternative at the DAC analog section. The only option I have is using the op-amps. Because op-amps doesn't require so much amount of power, typically bellow 20 mA each.

The power supply layout is a typical full bridge rectifier with C-R-C filter before going to the voltage regulator using LM317 and LM337.

Finished with the power supply section, now I start with the DAC board.

I using the same schematic as my previous PCM63 DAC built before.

The schematic can be found on the PCM63 datasheet, except on the digital receiver, I use the CS8412.

The connection between CS8412 to SM5813APT is the same as my previous AD1862 20 bit DAC built in this post here.

Anyway, the DF1700 is direct substitute to the NPC SM5813APT which I am using here.

The layout of the board is my typical point-to-point connection. It is more fun for me to design the board on the fly, meaning I could easily using many variable size components I like while connecting each components on the board.

Some say for digital circuit like this, using well designed PCB layout is better. But I don't know for sure this claim is valid or not since all my built are working fine without any audible noise, or sound degradation from this kind of method.

The reliability is also not an issue either. My DAC built can be always turn ON and never fail.

The key when building point-to-point DAC like this is you should know how to implement the layout of the grounding between digital, analog and power supply. If they are properly implemented, it will have the same result with the well designed PCB layout no matter what.

So I keep continue this method.

Finished with the main DAC layout, then I start to put another voltage regulators in this DAC board. This additional voltage regulators only to supply the op-amps as IV and LPF in the analog section.

I am using fixed regulator, the 7815 and 7915 which I already have on hand. The reason why I am not using LM317 and LM337 for better power supply is simply when supply to the op-amps, the internal op-amps circuit has more better power-supply noise rejection compares to the others digital IC on the DAC section.

I put the main DAC board in line with the power supply board, they are look so aligned together. Pretty neat design in my opinion.

The last steps is connecting the cables between those boards.

Then once it is done, I can install the RCA plugs for SPDIF input and analog line out.

As you can see, it is completely done.

I check the voltage output for each correspondence IC pins and make sure that all connection are correct.

Once this process is done, I can plug-in the IC's on the sockets.

The last IC to install is of course the PCM63 DAC IC.

As I said earlier, none of my built are built the same, so does this DAC.

In this build, I am using the PCM63P-K. This is the highest grade PCM63 family which are hand picked by the Burr-brown engineering because have better linearity and dynamic range compares to others.

The vintage multibit DAC like this is using ladder resistors. They are sensitive to the resistor tolerance. The closer the tolerance, the better for the linearity measurement.

This is my end-game DAC.

It is using PCM63 P-K and double C-core transformer in a compact casing.

The sound quality is superior.

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