Vacuum Tube Non-oversampling PCM1704 DAC Components Upgrade

From my previous DAC project, I was working on my non-oversampling PCM1704 DAC using the Zen IV. It is a pair of 2SK170 and 2SJ74 JFET transistor per channel as a DAC IV converter. It is a good sounding DAC but still, in my opinion, DAC using vacuum tube at the output give more life to the music.

In contrast, if compare to the super accuracy of the op-amps or the neutral sound of the Zen IV, I prefer this PCM1704 DAC using vacuum tube at the output. It make the sound beautiful.

This PCM1704 DAC built here is using resistors as the IV converter. Then the vacuum tube multiple the gain output up to 10 times, so the voltage output are around 2 volt.

It is sound great and lots of potential to upgrade the components inside especially for the IV resistor and the capacitors output.

First things first, the components use for this DAC upgrade are all the boutique parts. Or in short, they are expensive. I am a components quality believer that may improve the sound. But for more realistic reason, they are expensive because the materials using in those components are mostly from precious metal such as silver and gold.

Many people consider for the expensive components are not necessary in audio. They think the more important is the design and the right components values. Not wrong at all, but if I think if the design and components are all well calculated, then I shall going forward to this components upgrade anyway.

The most expensive components in this DAC upgrade is the Mundorf Supreme silver oil capacitors. This is the most important components because the analog signal pass through this components at the output of the vacuum tube.

The others expensive components are the IV resistor using Vishay Z foil. This is the only components that do the conversion from current to voltage at the DAC IC output. So the quality matters.

The next components is the Jensen capacitors for high voltage vacuum tube power supply. This components also important to make sure the voltage coming into the analog circuitry are clean enough. 

The last components is the wires for the connection between the components. I using pure silver wire covered with Teflon jacket.

Previously I use this wires in my TDA1541 DAC components upgrade for the connection between the PCB to the RCA terminals and in my opinion this wire gives magic to the music.

The others components upgrade are the electrolytic capacitors at the PCM1704 DAC section. They will replace with the Audio Note capacitors.

Few resistors are also replaced, mostly at the vacuum tube analog section with also the Audio Note tantalum resistors.

The rest of this progress are replacing the old components and install the new one.

It takes some time to replace the components since the size of the new components are way bigger than before.

I also switch the DAC board and the analog board, so the length of the wire use in this new layout are less and more efficient.

This DAC components upgrade is all done.

Since all components use in this DAC are mostly brand new, so they need some time to breaking in before gets the full potential of the components itself.

In my experience, it doesn't takes weeks for the new components breaking in. It is just need a day playing some music, then on the next day, I already notice the sound are actually changes. Mostly the sound become more relax, more revealing and less noise.

So how does this upgrade result?

This boutique components reveal the music to the next level. The most noticeable improvement is in the mid-range that become so lively.

One album that catch me so much when listen this DAC with the new components upgrade is when I played the music from Kaoru from her album Ghibli The Classics and I confess that the violin sound in my system are very engaging, live and presence that I can experience the artist are playing it in front of me.

The musicality and the imaging are superior, so much different if compare before the components upgrade.

The music presentation are glorious, far from ear fatigue, so much musical but with the fast dynamic.

I compare this vacuum tube PCM1704 DAC to my others solid-state DAC and with the same music, I can conclude that this PCM1704 DAC after this components upgrade is the DAC that I can live forever with it.

Actually the upgrade not stopping yet. It is continue by replacing the vacuum tubes from OTK 6N1P as my initial vacuum tube in this DAC to Mullard CV2493.

Then the big Mundorf capacitors also bypass with smaller capacitors using Miflex 0.01uF.

With this additional components upgrade, the sound are improve again and I think this might be my full stop of finding the best multibit DAC.

The sound are mind blowing and unbelievable for such this DAC can brings the music to live.

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