6.5 x 3.5 mm is the 1.27 mm version normally. I wil wait for mine.
Do you want such a tiny board? Then send me a PM.
Do you want such a tiny board? Then send me a PM.
OK, I gambled a bit and ordered boards. I ended up with 10 x 12.5 mm which is about as large as a DIL8 opamp. Boards are made in black just like the SU-1 mainboard. In cooperation with @Anatolii_A it was clear only 1 pin of the header is usable and that is pin 1 being GND.
This info is appliable to owners of SU in external housing with a few independed power supplies, like an example of jean-paul device in start post.
After some experiments with my DIY board on AK4493S I've found that disabling the internal LDO for digital rail dac supply also brings good improvements in sound.
In case of SU we will get an additional benefit in deviding AVDD and DVDD power supplies (analog and digital parts of DAC). Also in this way we came closer to manufacturer datasheet recommended circuit.
1. We have unnecessary 5.5V DC-DC step-up converter
2. We have unnecessary 5.0V LDO
3. To devide AVDD and DVDD we need to cut some places shown at photo between old 5V LDO and 3.3V LDO and also on the bottom side of board (always use multimeter and verify all what you see and all what you do).
4. To disable internal LDO we need to put 2pcs 1.8V LDO's instead 3.3V and 5V and to cut 16 pin (LDOE) of DAC chip from DVDD and put it to GND, also connect together 1 and 48 pins (TVDD and DVDD). Both of 1.8V LDOs we need to connect 1 and 3 pins together with 5V main input.
Big capacitance not necessary on VREF only when using 2 individual very good LDOS for each side of vref. When we share one supply with both sides capacitance matters in some way.
Dont forget about individual supply for XMOS AVDD PLL
After some experiments with my DIY board on AK4493S I've found that disabling the internal LDO for digital rail dac supply also brings good improvements in sound.
In case of SU we will get an additional benefit in deviding AVDD and DVDD power supplies (analog and digital parts of DAC). Also in this way we came closer to manufacturer datasheet recommended circuit.
1. We have unnecessary 5.5V DC-DC step-up converter
2. We have unnecessary 5.0V LDO
3. To devide AVDD and DVDD we need to cut some places shown at photo between old 5V LDO and 3.3V LDO and also on the bottom side of board (always use multimeter and verify all what you see and all what you do).
4. To disable internal LDO we need to put 2pcs 1.8V LDO's instead 3.3V and 5V and to cut 16 pin (LDOE) of DAC chip from DVDD and put it to GND, also connect together 1 and 48 pins (TVDD and DVDD). Both of 1.8V LDOs we need to connect 1 and 3 pins together with 5V main input.
Big capacitance not necessary on VREF only when using 2 individual very good LDOS for each side of vref. When we share one supply with both sides capacitance matters in some way.
Dont forget about individual supply for XMOS AVDD PLL
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Mmm, I could have included such on the board. A bit late now as the PLL PSU boards will arrive monday.
bad advice, just give another users to try some new. I have an a similar board with xmos with this 4.7Ohm resistor + cap as a filter but it is a full crap instead of independed power supply on PLL rail. If you don't hear this that's another point
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This was advice from someone who has successfully developed and made more than a dozen different USB-I2S interfaces on XMOS, hardware and firmware.
No problem, maybe the bad layout on this board requires something very special....
I was talking in general and not about this board.
Alex.
I wasn't the only one who listened to them.
P.S. You forgot to say "your equipment has insufficient resolution"(c)сссссундук. 😀
Alex.
P.S. You forgot to say "your equipment has insufficient resolution"(c)сссссундук. 😀
Alex.
I believe you listened to this at PC multimedia speakers, because I can't understand how to not to hear that AVDD PLL power supply?
So don't flood the topic, let people to make their own DIY changes and then we'll hear a feedback
You didn't understand what I wrote.
Even if I listened to it on multimedia speakers (although I don't have any), what did hundreds of others listen to it on?
If you device sounds bad, it is not a problem of PLL power.
You lost "somewhere", but you are looking "where it is light"...
Alex.
Even if I listened to it on multimedia speakers (although I don't have any), what did hundreds of others listen to it on?
If you device sounds bad, it is not a problem of PLL power.
You lost "somewhere", but you are looking "where it is light"...
Alex.
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Perhaps you just haven't compared dc-dc step down switcher with linear regulator at PLL AVDD supply ? You wrote that you are using linear regs on this rail
Most of my devices does not contains switchers at all, just linear regulators at all rails.
But I have few devices with step-down for XMOS, not at PLL power directly - see above.
Again:
1) PLL power supply, as well as VDD (1v) of XMOS affect the operation of the CPU Core and USB.
2) If USB works stably, it means that the CPU Core is OK.
3) In case of the previous item - there is no influence of PLL and Core power on I2S operation.
4) If there are any problems with USB connection stability or I2S signal integrity - it does not just "reduce sound quality", it leads to clicks and distortions, and not just "lack of crystal-clear sound of frosty winter morning".
4) About AK4493 and jitter - it is (like many modern ICs) sensitive only to MCLK signal jitter.
All other I2S signals (WCLK, BCLK, SDATA) are not important in terms of jitter.
Alex.
But I have few devices with step-down for XMOS, not at PLL power directly - see above.
Again:
1) PLL power supply, as well as VDD (1v) of XMOS affect the operation of the CPU Core and USB.
2) If USB works stably, it means that the CPU Core is OK.
3) In case of the previous item - there is no influence of PLL and Core power on I2S operation.
4) If there are any problems with USB connection stability or I2S signal integrity - it does not just "reduce sound quality", it leads to clicks and distortions, and not just "lack of crystal-clear sound of frosty winter morning".
4) About AK4493 and jitter - it is (like many modern ICs) sensitive only to MCLK signal jitter.
All other I2S signals (WCLK, BCLK, SDATA) are not important in terms of jitter.
Alex.
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OK we know how it works, soon, as people implement the little board I hope reports will come in. Maybe someone has a good ADC and can record a snippet with and without the mod?
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All my three devices with different XMOS chips are with switchers at core and PLL, and I get a good result with additional LDO for PLL supply on all of them. Lets wait for jean-paul mod and review. Unfortunately I don't have good ADC.
BTW I didn't invent the wheel, here at forum we can find information about it, but I hadn't read this before and came to this simply through experimentation
https://www.diyaudio.com/community/threads/xmos-dsd-384-khz-32bit-usb.236028/page-30#post-4578668
https://www.diyaudio.com/community/threads/modding-topping-dx3-pro.333258/page-3#post-5685765
BTW I didn't invent the wheel, here at forum we can find information about it, but I hadn't read this before and came to this simply through experimentation
https://www.diyaudio.com/community/threads/xmos-dsd-384-khz-32bit-usb.236028/page-30#post-4578668
https://www.diyaudio.com/community/threads/modding-topping-dx3-pro.333258/page-3#post-5685765