Asynchronous I2S FIFO project, an ultimate weapon to fight the jitter - Page 111 - diyAudio
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Old 4th October 2012, 02:10 AM   #1101
qusp is offline qusp  Australia
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yep, so about 50-60ma total, plus a tiny bit for whatever the second clock uses in standby. powering the clock board, or even entire fifo board on battery is totally viable, still not sure why you would use USB to charge but hey its not a huge deal, but if you add having to
A. power the fifo in its entirety plus a dac on battery and fit it all inside something you can call transportable...
B. power the fifo clock board and clock side isolator only, plus IV with 2 different battery voltages and charge both with USB, stepping up the voltage for the IV batteries...
it becomes a bit more complicated.

for the second case, you could of course wire the batteries differently for charging and disconnect this connection via knife relays; so that they are charged in parallel 5v sections, but used in series for 24v.

all seems a bit of a pita. just buy a reasonable dedicated charger, newer ones can be connected to, monitored by and controlled by the computer. so would be not so difficult to know when the dac isnt in use and automatically enable the charger.
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Old 4th October 2012, 03:22 AM   #1102
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Quote:
Originally Posted by qusp View Post
yep, so about 50-60ma total, plus a tiny bit for whatever the second clock uses in standby. powering the clock board, or even entire fifo board on battery is totally viable, still not sure why you would use USB to charge but hey its not a huge deal, but if you add having to
A. power the fifo in its entirety plus a dac on battery and fit it all inside something you can call transportable...
B. power the fifo clock board and clock side isolator only, plus IV with 2 different battery voltages and charge both with USB, stepping up the voltage for the IV batteries...
it becomes a bit more complicated.

for the second case, you could of course wire the batteries differently for charging and disconnect this connection via knife relays; so that they are charged in parallel 5v sections, but used in series for 24v.

all seems a bit of a pita. just buy a reasonable dedicated charger, newer ones can be connected to, monitored by and controlled by the computer. so would be not so difficult to know when the dac isnt in use and automatically enable the charger.
Passive battery management PCB samples arrive as well. A lot of "backdoor" left. Anything is possible . Will play with it after I finish testing the isolation board.

Ian
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Old 4th October 2012, 07:27 AM   #1103
ggking7 is offline ggking7  United States
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Quote:
Only the clock board needs really low noise power supply like battery.
Does this mean the battery board can not power the FIFO? If I use a noisy PSU on the FIFO, will the isolator board prevent conduction of the noise to the DAC?

May I ask what are the input voltages of the FIFO and clock board?
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Old 4th October 2012, 01:23 PM   #1104
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Originally Posted by ggking7 View Post
Does this mean the battery board can not power the FIFO? If I use a noisy PSU on the FIFO, will the isolator board prevent conduction of the noise to the DAC?

May I ask what are the input voltages of the FIFO and clock board?
Battery can power whole FIFO KIT, that's no any problem. But only clock board cares much about the PSU noise. Isolator board can prevent noise introducing from front end to clock board via PSU, GND or signals and makes the clock board as a local part of DAC.

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Old 5th October 2012, 01:01 AM   #1105
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Default FIFO isolator board is working

I assembled two isolator boards today. One uses IL260E, and the other uses Si8650BC. IL260 mounted on top of the PCB. Si8650 at the bottom.

I stack the isolator board on top of the FIFO board just as I posted. One 6”FFC/FPC cable and three 4” u.fl cables connected to the isolator board from FIFO side. Clock board side was as same as the old connections between FIFO and clock board.

Two independent battery packs were employed powering the dual xo clock board and the FIFO board from both side. There was no any galvanic connection in between. Clock board belongs to the DAC 100% now.

They started running right away on my BIII ESS9018 DAC with SYNC configuration. 32 bit Loop test passed without any problem. Bit perfect confirmed. It sounds wonderful. All results are positive. But I don’t want talking too much about that. I’ll leave this part to the testing group.

I did some comparing between IL260E and Si8650BC. No significant in difference. But it feels like Si8650BC a little little bit better, very tiny. I know it was most probably my psychological factors. However I noticed that 8650 comes with higher speed (150 MHz) and less propagation delay.

This small isolator board makes it possible that powering the clock board with independent low noise battery based power supply, while the FIFO board just from a normal regulated power. It would be much easier having a supper low noise PUS just for a small section of circuit. Longer battery life and less EMI noise from other section.

Next step, I’ll test the passive battery management board together with this isolator board to see if there is any possible achieving higher audio performance.

Please refer the pictures and picture names below for more details.

Since the isolation board is confirmed functional, I’ll send them to the testing group for evaluation on this weekend. 6" FCC cable and resistor packs will be included.

Ian
Attached Images
File Type: jpg WithESS9018Sync.JPG (461.4 KB, 532 views)
File Type: jpg IL260_1.JPG (539.0 KB, 518 views)
File Type: jpg IL260_2.JPG (493.4 KB, 499 views)
File Type: jpg Si8650TOP.JPG (573.8 KB, 481 views)
File Type: jpg SI8650BOTTOM.JPG (361.2 KB, 457 views)
File Type: jpg IsolatorRunning.JPG (414.2 KB, 258 views)
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Last edited by iancanada; 5th October 2012 at 01:29 AM.
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Old 5th October 2012, 02:44 AM   #1106
qusp is offline qusp  Australia
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just powering the clock board i'm looking at about 60hrs on my battery pack =) sweet

looking good mate!

you know that board being on top like that and necessarily cracked down the middle, it gives me a cool casework idea, to extend that crack down the middle of the section of roof
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Old 5th October 2012, 02:55 AM   #1107
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Indeed, excellent work Ian!

I guess now with the isol in the system as shown, if there is source components fed from the same transformer as the DAC there may be coupling between the secondaries of this transformer that allows some noise propagation?

In my case I'll have usb->i2s device powered from same transformer as my DAC, so there is some coupling between the transformer secondaries. Now I could go and add batteries to the DAC, but then I have linestage/IV connected back to the same transformer also (custom toroid with 6 secondaries, for compactness).

I need to work out a way of quantifying that coupling I guess, just something else to ponder on those sleepless nights I suppose.
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Old 5th October 2012, 03:00 AM   #1108
qusp is offline qusp  Australia
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R1 and R2 resistor networks are going to be fun, could almost tack them down and draw a bead of solder down them at the same time theyre that close together

hochopeper, almost a good reason to power the usb board over usb =) given the USB psu is going to have pretty much no significance once this is in place

Last edited by qusp; 5th October 2012 at 03:02 AM.
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Old 5th October 2012, 03:05 AM   #1109
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Originally Posted by qusp View Post
R1 and R2 resistor networks are going to be fun, could almost tack them down and draw a bead of solder down them at the same time theyre that close together

hochopeper, almost a good reason to power the usb board over usb =) given the USB psu is going to have pretty much no significance once this is in place
That answer is so obvious, how did I miss thinking of that?


Anyways, why are you being so logical!?
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Old 5th October 2012, 03:41 AM   #1110
qusp is offline qusp  Australia
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Originally Posted by hochopeper View Post
That answer is so obvious, how did I miss thinking of that?


Anyways, why are you being so logical!?
exhaustion? at this point in the project I just want to get it in a box, it sounds incredible as it is, anything that cuts clutter and more power supplies without penalty is on my radar
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