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Old 14th May 2013, 11:24 PM   #2771
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Default Real captured Si570 control protocol data

Hi hochopeper, Hi bigpandahk,

Here are real captured Si570 communication protocol data from a logic analyzer (with serial protocol analyzer plug-in) and a PC com port. Hope they help for your software R&D.

This communication happened when Fs switched from 88.2KHz to 96KHz. Just listen from Si570, external controller didnít take any control.

The first on is the full communication timing captured by a logic analyzer. Please note the time interval between sending events, by comparing with the protocol source code from the userís manual, you can figure out where is the control window and how to display and control it.

The following ones are data readings of each events translated from Txd waveform by the protocol analyzing plug-in of the logic analyzer.

The finial one is what a PC com port listened form Si570. They are exactly as same as what you can see from the logic analyzer. The setting was 9600,N,8,1

Let me know if you have any question.

Good luck to your software.

Ian
Attached Images
File Type: png FullTiming88to96.png (9.7 KB, 556 views)
File Type: png FirstEventM1.png (10.5 KB, 554 views)
File Type: png SecondEventM2.png (9.6 KB, 550 views)
File Type: png ThirdAndFourthEventsM3.png (9.9 KB, 550 views)
File Type: png ListenFromComPort9600N81.png (6.5 KB, 337 views)
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Old 15th May 2013, 12:44 AM   #2772
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Ian

Thanks, You always give us the best support. For the connection to PC com port, what software you are using to monitor the comm port? I got nothing from hyperterminal and the LEDs on i570 keep on flashing when I connected the comm port.
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Old 15th May 2013, 03:20 AM   #2773
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After several weeks listening both with and without isolator. I setup with options:
1 - Amanero - Acko Isolator U1 - FIFO - Ian Isolator - Double Dual Clock - Buffalo IIISE.
2 - Amanero - FIFO - Ian Isolator - Double Dual Clock - Buffalo IIISE.
3 - Amanero - Acko Isolator U1 - FIFO - Double Dual Clock - Buffalo IIISE.
4 - Amanero - FIFO - Double Dual Clock - Buffalo IIISE.

Listen on my system, the sound has big difference between with and without isolator but I like the sound no isolator ( option 4), the sound is more natural.
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Old 15th May 2013, 07:28 PM   #2774
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Quote:
Originally Posted by bigpandahk View Post
Ian

Thanks, You always give us the best support. For the connection to PC com port, what software you are using to monitor the comm port? I got nothing from hyperterminal and the LEDs on i570 keep on flashing when I connected the comm port.
Hi bigpandahk,

1. The first thing you have to make sure is that your PC serial port is working at 3.3V LVTTL logic level. If it was from RS232 level, it will not work with it. You have to convert it into LVTTL, otherwise, you may get your board damaged. I use a USB to serial port adaptor which comes with LVTTL logic level originally.

2. The connections have to be: Txd(Si570) to Rxd(PC), Rxd(Si570) to Txd(PC), GND(Si570)to GND(PC). If you just want to listen to Si570 for now, I suggest you leave Rxd of Si570 board unconnected first. An isolator is highly recommended.

3. Hyper Terminal was not design for this application. The software I use was from our TFT drive supplier to debug their KIT. You can find a lot of this kind of serial port debugging tools from internet. But you have to meke sure they are safe enough. You can try this free tool from its offical website first: Comm Echo - Serial Port Debug software

Good luck

Ian
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Old 15th May 2013, 08:55 PM   #2775
zapio is offline zapio  Poland
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Hello,
At first I'm sorry for not very good English, but I would like to share the results of my tests with Si570 board. My current setup is : Spdif board-> FIFO -> Isolator board -> Si570board -> Buffallo III SE with Legato and Tridents. Iam using Salas SSLV's for Buffalo, Legato, and spdif board. And using my own version of Salas reg bith as pre-reg and as local reg for clock board.

After many tests, I was able to achieve IMHO a significant improvement in sound, due to changes in the configuration of power Si570 board. After changes , sound became more dynamic, natural, with more sounstage, and details.

1. I replaced the TPS LDO board with shunt reg. based on Salas SSLV with low Vth nmos ( IRF 3708) and some other changes. It's stable with 0.5uF
decopling cap, so that I could try using only decoupling film caps here without any ele or MLCC.

-After change the sound od Si570 board is still very dependent on the type of decoupling film cap on shunt reg, but is a lot better than with any MLCC (X7R,X5R,NPO) or electrolytic (alu and polymer )- tested em with both TPS and shunt reg configuration.
- PET and PEN decoupling caps give sound significantly worse than polypropylenne or PPS
- PPS ( 5x100nF AVX ), give very very huge sounstage after 2-3 days break, very dynamics and clear sound but is a bit "plastic" - needs more break in ?
- most musical so far is WIMA FKP3 ( 5x 100nF ), didnt try Vishay MKP1837 yet

2. Removed sequentally all MLCC 1206 decoupling caps from Si570 board. The more MLCC caps removed - the better sound with shunt reg and film decopling caps. I didn't replace removed MLCC caps with pps so far , will try it later. I have two pieces of Ian Si570. After several days of listening to the modified version, I replaced it with an original Si board for a direct comparison. The sound has become so ugly, so quickly returned to my setup.

I found that polymer SMD caps ( using Panasonic 56uF / 9mohm ESR ) in Salas regs give better results than Nichicon Muse in my setup.

I am a bit surprised at the results, it seems that even in digital domain , more important for reclocking is the accuracy of the decoupling caps in local reg, than the its inductance. I dont why that is ( feedback quality in error amp in local reg due to low DA and no piezo efect or so ? ) I'm curious if anyone else tried a similar way and what were his impressions.

There is my setup and Si570 local reg schematic. It works with BC550/BC560 too.
Attached Images
File Type: jpg setup.jpg (467.3 KB, 179 views)
File Type: jpg Si570shuntreg.jpg (344.4 KB, 200 views)
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Old 16th May 2013, 12:55 AM   #2776
qusp is offline qusp  Australia
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do you have any actual evidence of improvement aside from subjective sighted tests and handwaving? shunts instead of tps is cool for the supplies, shunts can be excellent for low noise and low impedance. Using pretty and highly inductive film caps instead of the local SMD decoupling caps will result in more HF ripple, RFI and EMI making it into the circuit and those surrounding it, with higher phase noise; thats a fact. this arrangement simply cannot physically effectively deal with frequencies up into the high MHz range, they will become an aerial. so maybe you like higher phase noise?

Last edited by qusp; 16th May 2013 at 01:03 AM.
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Old 16th May 2013, 12:59 AM   #2777
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Thanks Ian, will try this weekend.

Great info, Zapio.
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Old 16th May 2013, 03:13 AM   #2778
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Quote:
Originally Posted by zapio View Post
Hello,
At first I'm sorry for not very good English, but I would like to share the results of my tests with Si570 board. My current setup is : Spdif board-> FIFO -> Isolator board -> Si570board -> Buffallo III SE with Legato and Tridents. Iam using Salas SSLV's for Buffalo, Legato, and spdif board. And using my own version of Salas reg bith as pre-reg and as local reg for clock board.

After many tests, I was able to achieve IMHO a significant improvement in sound, due to changes in the configuration of power Si570 board. After changes , sound became more dynamic, natural, with more sounstage, and details.

1. I replaced the TPS LDO board with shunt reg. based on Salas SSLV with low Vth nmos ( IRF 3708) and some other changes. It's stable with 0.5uF
decopling cap, so that I could try using only decoupling film caps here without any ele or MLCC.

-After change the sound od Si570 board is still very dependent on the type of decoupling film cap on shunt reg, but is a lot better than with any MLCC (X7R,X5R,NPO) or electrolytic (alu and polymer )- tested em with both TPS and shunt reg configuration.
- PET and PEN decoupling caps give sound significantly worse than polypropylenne or PPS
- PPS ( 5x100nF AVX ), give very very huge sounstage after 2-3 days break, very dynamics and clear sound but is a bit "plastic" - needs more break in ?
- most musical so far is WIMA FKP3 ( 5x 100nF ), didnt try Vishay MKP1837 yet

2. Removed sequentally all MLCC 1206 decoupling caps from Si570 board. The more MLCC caps removed - the better sound with shunt reg and film decopling caps. I didn't replace removed MLCC caps with pps so far , will try it later. I have two pieces of Ian Si570. After several days of listening to the modified version, I replaced it with an original Si board for a direct comparison. The sound has become so ugly, so quickly returned to my setup.

I found that polymer SMD caps ( using Panasonic 56uF / 9mohm ESR ) in Salas regs give better results than Nichicon Muse in my setup.

I am a bit surprised at the results, it seems that even in digital domain , more important for reclocking is the accuracy of the decoupling caps in local reg, than the its inductance. I dont why that is ( feedback quality in error amp in local reg due to low DA and no piezo efect or so ? ) I'm curious if anyone else tried a similar way and what were his impressions.

There is my setup and Si570 local reg schematic. It works with BC550/BC560 too.
Thanks zapio for sharing your experiences with us, and thank your for your effort. I'm very interested in a closing picture of your mod Si570 board, is there any possible you post some?

Have you every try to replace the 1uF CNR (C10) on the TPS7A4700 LDO board with a film capacitor? I did some test last week and the result was quite amazing.

I'm looking forward to your good news.

Regards,

Ian
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Old 16th May 2013, 07:11 AM   #2779
zapio is offline zapio  Poland
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Hello Ian,
I've never tried to change the CNR cap. Only I tried various combinations of decoupling caps on both the regulators and the Si board. I have not found significant differences in sound between TPS board and shunt regulator when I used the same type of decoupling capacitors. The first significant improvement was achieved by using high-quality film capacitors only, the second after the removal of some of the MLCC's from clock board.
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Old 16th May 2013, 08:17 AM   #2780
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The most important phase noise in digital to analog conversion is that close to the carrier, 10 Hz offset and below. As you move away from the carrier the phase noise has less impact on the sound. Phase noise at 1 MHz offset does not affect the sound, and whatever oscillator is quiet at such offset.
With a clock really good, below 1 Hz, the sound change totally: 3-D aspect increases dramatically, the sound stage becomes more real, bass is controlled and not mushy, highs becomes natural, harsh, and strident sensations disappear.
Below 1 Hz offset from the carrier, the phase noise is dominated (crystal quality aside) by the flicker noise, so quiet active devices and ultra low noise (1/f noise)/low impedance power supply are essential.
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