I would suggest you trying my new designed ES9028Q2M DAC HAT. It a very flexible pure 9028Q2M core board with RAW balanced output. Power supplies, clock, I/V stage, controller, configuration, Sync/Async everything can be upgrade. There will be a lot of ways for effort to improve sound quality.
Actually I designed both ES9028Q2M and ES9038Q2M DAC HAT at same time. But ES9038Q2M is only capable output current as half as ES9028Q2M does. So, ES9028Q2M would be better option for a transformer I/V at this point.
Update of ES9038Q2M DAC HAT will be posted later.
ES9028Q2MDACHAT1 by Ian, on Flickr
Regards,
Ian
Pretty! more info about the board? Probably unreleased, nothing on the github readme yet. Thank you
Beautiful layout work Ian! Good to see all those ground stitching vias keeping stray RF fields as contained as possible. I assume you can break out the onboard regulators and wire in power of your choice?
If it sounds as good as it looks....
If it sounds as good as it looks....
Last edited:
Hi Nikola Krivorov,
A lot of things need to be test for integration, different I/V stages, power supply solutions, clock solutions, hardware/software controllers, isolator, FIFO ...
But I'll try to make them available soon.
Regards,
Ian
Ian, you know I’m just waiting for a sign from you. I need that dac hat and output board. And I can cannibalize a couple of Lundahl trannies from my old rig if necessary. 🙂
Just say the word...
(My project is dead in the water without the dac hat. )
Just say the word...
(My project is dead in the water without the dac hat. )
@simon
Yes, you can break those onboard regulators. They can be replaced with other regulator board, shunt, local decoupling network or battery/super/ultra capacitors for each power rail.
It is a very fixable design for our audiophile DIYers achieve better sound quality by using most optimized power supply solution.
I'll do more test to see what I can get.
Regards,
Ian
ES9028Q2M DAC HAT is working with RaspberryPi3 and LL1674 passive I/V stage.
ES9028Q2M DAC HAT has a standard I2C port connected to GPIO, Linux driver will be needed in this configuration to perform volume control and format switching. Otherwise, a hardware based controller is required to provide more powerful control directly.
ES9028Q2MLL1674 by Ian, on Flickr
Ian
ES9028Q2M DAC HAT has a standard I2C port connected to GPIO, Linux driver will be needed in this configuration to perform volume control and format switching. Otherwise, a hardware based controller is required to provide more powerful control directly.
ES9028Q2MLL1674 by Ian, on Flickr
Ian
Last edited:
Ian,
I'd give this a try in a second!
This along with your output stage experimenter board looks like a VERY nice step up from your Gen1 board, which itself was very good and in the top 3 of the RPi DAC HATS I've tried. I especially like the new flexibility in output stages & regulation. Those are both critical to the SQ of any DAC... my best results with your Gen1 board was using it on an RPi -> IsolatorPi -> Allo Kali -> Ian ESS9018K2M HAT stack with a separate Uptone Audio LPS-1 each powering the isolator, reclocker, and DAC HAT and a good linear supply on the RPi. And I made plans to try an alternative output stage (OPA1632 balanced I/V), but never got around to it.
I am also curious how these newer ESS chips will compare in ASRC mode versus Sync mode. As I mentioned to you when testing your Gen1 board, I preferred it on an Allo.com Kali reclocker and configured to work in Sync mode. This has been true of all of that generation ESS DACs that I've tried. Some have suggested that the current generation works better in ASRC mode and the differences are smaller. I'll be very curious on how that plays out with your new DAC HAT.
I'm also curious on how it will play with an Isolator board like yours and Allo's... I've now used both and both are very good.
This should be a very nice boardset for the RPi DIY'er and offer a LOT of room for customization. I wonder who'll be the first to plop a tube buffer stage on top?
Looking forward to playing with it!!!!
Greg in Mississippi
Last edited:
Looks very very nice!
Do you have a hint on the final price of the dac board with 9028q2m and the output stage?
Do you have a hint on the final price of the dac board with 9028q2m and the output stage?
Hi Greg,
That's great. I'll assemble a ES9028Q2M DAC HAT for you. Hopefully by the end of this weekend. You can try your I/V stage and your configuration on it. You will have full control on optimizing the sound quality.
Regards,
Ian
Ian,
Many thanks!
I'm also working to modify a Pi with low-noise power rails using this board:
Mezzanine Power board<br>for Raspberry Pi
Hopefully will have it running by the time I get the board to test, I'm hoping it will take the SQ of a Raspberry-Pi sourced setup up a couple of notches, just as implementing a fully linear ATX supply did when I was running a motherboard-based computer music playback setup.
Greg in Mississippi
Many thanks!
I'm also working to modify a Pi with low-noise power rails using this board:
Mezzanine Power board<br>for Raspberry Pi
Hopefully will have it running by the time I get the board to test, I'm hoping it will take the SQ of a Raspberry-Pi sourced setup up a couple of notches, just as implementing a fully linear ATX supply did when I was running a motherboard-based computer music playback setup.
Greg in Mississippi
Got it, and already replied. 🙂
Now, I have a couple of questions. Open to anyone...
1. Have you tried the circuit floating?
2. Is there any smart way to adjust the transformer ratio so that you could get the standard 2V output? (Avoid blowing up the amps/speakers by mistake...)
I've tried many different configurations. This is the one I like the most. Here is the schematic. Please let me know if there is any other better option.
LL1674BalancedIV by Ian, on Flickr
Ian
Just wondering if the cap to ground really necessary?
I have a LL1636 , tried 2 x 10ohm to ground on primary. But output is too low. I will try a higher resistor value later.