Wyred 4 Sound DAC-1 Mods

This DAC had an unpleasant, hard sounding sheen to the upper mid to top end. I previously had a DAC-2 with a brash top end, but this one was much worse, as if magnified. I opened it to see if there was anything that I could do to make it perofrm as well as I thought it could. I really wanted to like this DAC.

I immediately noticed that the main filter caps were bulging with one of them ready to rupture. The original filters are 22000uf 25V G-Luxon which is owned by Yaego, makers of cheap and unreliabe capacitors - it's no suprise that they measured less than 1/3rd of their original value. This was not a good part choice for the manufacturer, even to save money.

The power supply seemed very simplistic for a DAC. This supply provides regulated +/- 15VDC. Connected after the regulated +15V half is a +12V regulator followed by a +5V regulator followed by a fanout of 3.3V and 1.2V regulators to supply the chip. This loads the +15V supply more than I would like. My $400 Gustard X9 DAC has a better power supply!

There were a couple of centrally located 1000uf SMD filter caps for the +/-15V rails. This seemed an obvious opportunity for improvement. These were replaced with four 470uf 35V and four 33uf 35V Nichicon Fine Gold radial leaded capacitors. These capacitors were distributed very close to the amalog circuits using unused header connector holes.

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Immediately after repair/upgrades, the sound became smoother and more flowing - palateable. The sound continued to smooth out and become more refined in the weeks following. I could stay in the room much longer than before. Upper midrange and top end were much improved but still had the same somewhat brash mid to upper end my DAC-2 had. Yes, brash is exactly the word to describe the sound.

The next modifications were aimed at the digital power supply. I removed the USB card immediately - it performs poorly (synchronus USB), and has a limited sampling rate. The card also draws power, so removing it takes the load off the 5V supply and the noise that it creates as well.

The next step was to serperate the +5V supply from the +15V supply. This was accomplished by severing the PCB trace between the regulated +15V supply and the input of the +12V regulator, and installing a new DC supply. A rectifier (full wave) and filter capacitors were connected to the transformer secondaries on the mainboard. The rectified and filtered DC then feeds the 12V regulator directly.

At first, the difference did not seem that great. I played this on a new and unfamiliar system and thought I noticed was slightly deeper and more dynamic bass and maybe a more defined soundstage. Listening on my main system, however, showed the sonics to be significantly cleaned up! I could (and do) listen all day and not experience any harshness unless it was in the music. The DAC also sounded rather warm, which was a bit of a surprise. Any trace of upper midrange and lower treble harshness/brashness was now entirely gone.

I like ESS 90x8 DAC chips. I cannot hear any distortion during peaks or when things get loud and complex. Not even the Wolfson chips in my X9 can play that clean.

At this point, I was pleased enough with the sound to put down the iron and just enjoy the music, but since I got the same Crystek oscillator as used in the W4S Femto Clock mod, I had to install that too. I definitely noticed a difference. The sound became cleaner still, and became focused as well. I used a 100MHz oscillator (the original clock was an 80MHz crystal) which caused the display to read half the sample rate, i.e.; 192kHz reads 96kHz, 96kHz reads 48kHz, and so on. This can be changed by accessing a register on the 9018 that reports the bitrate.

This is as far as I needed to go with modifications on this DAC. I got it to perform like it should, and then I got it to perform better by isolating the 5V supply.

There is still more that can be done for the +5V supply - give it its own transformer, remove the +12V regulator, and replace the +5V regulator with a faster/quieter/higher current discrete regulator. From there, even more love can be showered upon the regulators immediately around the DAC chip. If this was my only DAC, then I would have gone this far with modifications.

I think the analog section is pretty good, so I have no desire mess with it. But there are still many analog mods that can be done to bring this to another level. Wyred 4 Sound upgrades/modifies their analog sections at the factory for a price. One guy online put a pair of chokes on the +/- rails - I bet that would sound really nice along with the seperate +5V supply mod!