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AAK 4th August 2013 06:03 PM

My ES9018 DAC/Amp/Controller..
 
5 Attachment(s)
Hello Everybody,

After about a year of working nights and weekends (not everyone of course) on my ES9018 DAC, output amplifier (includes the I/V and SE section), the microcontroller code and numerous series/shunt regulated power supplies the design is Finally close to completion. What remains is the input board that accepts two 8-channel inputs of either I2S or DSD or one of each. The input board will stack on top of the 8-channel S/PDIF input board. A tactile switch selects from one of the 8 S/PDIF inputs, or either one of the I2S or DSD inputs.

The goal from the start was to make the design flexible so that I could take full advantage of just about everything the ES9018 has to offer. That meant providing access to nearly all the registers, all the inputs, and the flexibility of stacking DAC boards providing all sorts of parallel combinations with up to 16 DACs per channel, ideal for digital crossovers which was my initial motivation. To add to what I already wrote above, here's more details about the design.

Up to 4 DACs and 4 amplifiers can be stacked. The amplifier I/V section uses an LME49990 with a LME49600 in the feedback loop to handle up to 8 DACS in parallel safely. With a full stack all 8 channels can operate with 4 DACs in parallel per channel. A clock distribution chip fans out the master clock (100Mhz) output to the other DACs with minimal added jitter. The amplifier board provides both balanced and SE outputs. The SE section uses an LME49990 per channel with a 100Khz -3dB cutoff.

The controller section uses a PIC16F886, I2C signals and ground are isolated from the DAC section. The MCU footprint supports PICs with more resources if more processing power is needed. The controller provides access to 31 functions and each of their settings in the ES9018 and displays them on line two of the OLED. All 31 functions and settings can be stored in four different memory banks in EEPROM allowing switching between different banks to make sound comparisons or configure a memory bank for different DAC applications. Volume is controlled using a rotary encoder, and remote. The volume can be adjusted from 0db to -99.5db. The volume setting is stored in EEPROM after 10 seconds of inactivity or by pressing the EEPROM store button. Six tactile switches are used for power, input settings (8xS/PDIF/I2S/DSD), up/down function control (2 switches) and selecting settings (one switch), and the last switch for storing the settings in EEPROM. The remote provides the same controls as the switches with some added selections. The power switch turns on and off the main power supplies but also enables four DPDT relays on the amplifier board to prevent turn on/off thumb by shorting the output resistors to ground for few a seconds for both balanced and SE outputs. The controller also reads the input sample rate nearly instantaneously (checks every 100us) and displays the sample rate on the OLED. In full stack mode a single controller, typically on the top PCB, controls all four DACs.

The DAC has 10 ADP151 regulators on board, and uses two separate series or shunt regulator boards (1x0.5) soldered directly to the DAC board for the critical 3.3 AVCC. For the main power supplies Im using two LT1085 for the DAC and controller section, and one LT1085(+) and LT1033(-) for the amplifier section. An optional series regulator for each rail can be used to power the output amplifier.

The PCBs for the DAC and Amp are 4 layer and measure 2.6 x 2.6.

This project was a lot of fun, and a great learning experience considering I had never programmed an MCU before. The sound is out this world, so quiet and clean with incredible imaging like no other DAC I've ever heard. I'm very pleased with overall design, it's far exceeded my my initial expectations. I look forward to completing the 8-channel I2S/DSD board and testing it sometime in the next week or two, and then putting it all in an enclosure. Ill update the thread as I move along.

If anybody has any questions please feel free to ask. I still have to do another PCB iteration on the DAC and Amp board so Im open to any suggestions that may improve the design. For those wondering, I have thought of making this design available as a kit, but Im not sure I can find the time. My experiences with two fairly large group buys of my PCB version of SymAsym has humbled me, and this project would be far more involved. But maybe just the controller if anybody is interested. Ive attached a few pics. Their not the best pics, I need a better camera. Thanks for your time.

Best Regards,

Al

AAK 4th August 2013 06:11 PM

Amp board
 
1 Attachment(s)
Here's a pic of everything pulled apart showing the top of the Amp board.

Lil Knight 5th August 2013 05:34 AM

The most impressive ES9018 build I've seen so far. Truly all DIY. :) Can't believe you could pull these together within a year.
Any more details regarding the I2S/DSD board?

If you ever change your mind regarding offer kits, I'm fully committed to one set.

Nisbeth 5th August 2013 05:18 PM

Very impressive indeed :)

/U.

KBK 5th August 2013 05:37 PM

It will very likely sound better on that board than it will ever sound inside of any chassis.

:)

And that is almost a 100% indisputable fact. (note I said almost)

'pretty looking' to the shiny crow that lives inside the monkey part of the human mind... has so little to do with electromagnetic and electrical functionality that the two are almost opposites to one another. we can put the device in a box that cost hundreds to build and if not well thought out, end up leaving a very good amount of the sonics not only lost on the editorial floor.... but obscured by crap.

ChrisPa 5th August 2013 06:08 PM

Agreed - very impressive

I'm very interested, for the same reason as you designed it - high quality dacs for a digital crossover, with digital volume

kuribo 5th August 2013 06:26 PM

me too!

enantra 5th August 2013 06:49 PM

hi
interested too!
thanks you

prot73 5th August 2013 09:10 PM

Been looking for a ES9018 DAC so color me interested. "The sound is out this world, so quiet and clean with incredible imaging like no other DAC I've ever heard" That sounds good but how about some hard test numbers?

AAK 6th August 2013 02:22 AM

Thanks everybody, really happy you like my work.

Hi prot73, I'm stickler for detail so don't worry I'll provide measurements. BTW, do you know of any high end equipment or software that I could use that's not too expensive.

Hi Lil Knight, the I2S/DSD PCB design is pretty much complete. To eliminate additive jitter the design will use high speed relays to switch between the different data inputs and isolate ground to only the selected input. I'm hoping I'll have it tested and ready to go in about two weeks. I'll post pics when it's done.

Best Regards,

Al


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