Slow construction of ESS9018 dac

[Gregje]

Some time ago a colleague from my work gave me a fried populated ESS9018 DIYINHK pcb. Well, he has already removed the dac itself.
I was quite intimidated by the prospect of soldering an expensive chip with so tiny legs. I considered buying another board with ESS9018K2M.

I mentioned the project to my father, who suggested he could ask the people from his former lab whether they would solder the chip for me.
I ordered the chip and it got soldered in. The quartz has been replaced as well.

Unfortunately, the dac would not work. I pretty quickly purchased the Bus Pirate and was pretty relieved that the chip was not totally dead. It actually talked to the bus pirate. I asked at diyaudio. People suggested I should check the contacts between the pins and vias. Again easier said than done.
After more session with the bus pirate I concluded that the sampling frequency was 0. People at diyaudio suggested that there was no incoming signal. At that stage I started poking the legs of the chip with my meter. I actually attached some sewing pins to my meter's probes. Using the magnifying glass I could check for contacts between the pins and via. Indeed two of I2S pins showed no contact. With hammering heart I resoldered them (I cannot really say I have much smd soldering experience).

The blessed thing started playing music!

[Gregje]

I also got (on a loan) the usb->i2s board and psu's from the guy who gave me the fried dac board.

The PSU boards were from DIYINHK. The most important voltage for the this dac is 3.3V AVCC (analog part of the chip). The DIYINHK claims 0.8uV noise in their PSUs. I was not convinced that such a low noise figure is soooo important here. I had to figure it out myself. I was aware that LM317 will not do. So my first attempt was ADP151 preregulated with LM317. ADP151 seems pretty decent (on paper) and certainly better than AMS117 widely used as a 3.3v reulator. I cobled a PSU with two LM317. One provides 5V. This will be used from the Arduino controller. The other provides some voltage which is further egulated down to 3.3v.

I compared this PSU with the DIYINHK. The sound of my PSU was pretty flat and uninvolving.
So I started looking around.

[sq225917]

Nice work on saving the board. I'd be looking at splitting the rails for the clock, avcc and the opamps. The opamp look like they have good local decoupling already.

[Gregje]

Hi sq! I will continue, hopefully tonight. As for the PSUs your contribution will be mentioned ;-)

[Gregje]

Nice work on saving the board. I'd be looking at splitting the rails for the clock, avcc and the opamps. The opamp look like they have good local decoupling already.

Any of the setups I have tested used separate +/-12V for the opamps and a separate 3.3V for the digital part of the chip and another 3.3V for the analogue part. The pcb provides a possibility to split the later (AVCC) into the left and right channel supplies. This apparently improves the sound even more.

Coming back to my experiments. As mentioned above I was not happy with the sound of adp151 regulated 3.3v AVCC. I attacked the problem in two ways. I decided to daisy chain opamp regulator (with LM49710) after the 3.3v regulator (APD151 provide V ref for the LM49710). Opamp regulation seems to be recommended by ESS themselves. Even if it does not provide LT3045-like 0.8uV noise benchmark. The other line of attack was to make sure that I have my own LT3045 supply. Sq225917 kindly offered me on diyaudio some left over pcbs from stammheim. These are dual boards which can take up to 3 regulator chips per channel be making them good up to 2x1.5A. I populated them for now with one LT per channel, but I figured out I will better off with these PCBs because I will be able to add more regulators if they prove to be good sounding. In the attached pics you can see stammheim's boards revealing my humble smd soldering skills. As for the opamp regulator, I piggy backed it on the board with two adp151. ADPs are soldered on the adapters (underneath, what you see on top are in and out caps). 3.3V DVCC is meant to be taken from one ADP, 3.3V AVCC after the opamp. I know I am open to critique about my grounding here...

[Gregje]

A better shot of my humble opamp regulator.

[Gregje]

The is really a slow thread. I got distracted by puting RPi with Allo Boss into a (reasonably) nice box. I am also pretty happy with the sound and functionality of the Pi so Es9018 has been put aside.
Still, I guess it would be nice to finish it, especially that I get tempted by some DACs in the Private Exhibitions here! So finishing this project might save me some money as well!

I have two possible donors for a chassis. A Sony Cd player (with TDA1543) and a Samsung TV box. Samsung is a bit smaller which suits me very well. The only issue is my 20x4 LCD display does not fit there.
I will have to look for something smaller maybe an OLED display.

Anyway, it will be nice to put the DAC to service. Even without extra functionality provided by the Arduino with the LCD display. This is what I managed to do today.

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[Gregje]

Even more. The white PCB with tall capacitors is the dual 3.3V PS (one for digital circuits; one for analogue) the for the 9018. The PCB in the last photo is the +-15V opamps PS.

[Gregje]

I got the dac operational today. The pictures will follow.

At the moment it works in the hardware mode, ie it jumps into some default state. I cannot set up filters etc. It is configured to accept usb.
When arduino comes, or rather I have a display that fits in my enclosure I should be able to have volume control, set up filters. I will try to add an spdif input. But I am running ahead of myself. Maybe I will stop here as there is so much music available through usb...
The nice thing would be to feed i2s signal from the RPi, but this apparently does not work with different sampling rates and bit depths.

Btw I had a wonderful evening (still more to come, but now with headphones using Pelerano's Zen head amp) listening to NPR Tiny desk concerts with Hillary Hahn and Yo Yo Ma and many others...

[Gregje]

The promised pictures.

As you can see I installed my humble home mage PS for the DAC chip. It provides 2x5v using LM317 preregulators, one 5V is unused for now. The other one is regulated to 2x3.3V using adp151 and one 3.3V is regulated with LM49710 as recommended by ESS.
I still can't decide whether I prefer this 3.3V supply or a dual LT3045.

The chassis is predrilled to accept both now.