After some mixed results with pcm1730 I'll try a design with pcm1798. I want to use the Pass D1 IV stage, so the output of pcm1798 should be better suited.
I have finished a draft for the schematics. Comments are very welcome.
I'll make the layout suitable for home etching, but double sided. I already made the other design with cs8416/pcm1730 work, but I think the pcm chip was burned or something, cos it would only play for a couple of hours and then start with a scratching noise. The reset was crab too, so now I'll redo the whole thing with a different chip.
I have left some of the options configurable using jumpers, but marked my choices. I think you'll have a hard time following the nets around those jumpers, but I haven't had time to straighten them out.
What is the best grounding strategy? I'll end up having 2 psu boards, 1 digital and 2 I/V boards. How do I avoid ground loops then?
- Christian
I have finished a draft for the schematics. Comments are very welcome.
I'll make the layout suitable for home etching, but double sided. I already made the other design with cs8416/pcm1730 work, but I think the pcm chip was burned or something, cos it would only play for a couple of hours and then start with a scratching noise. The reset was crab too, so now I'll redo the whole thing with a different chip.
I have left some of the options configurable using jumpers, but marked my choices. I think you'll have a hard time following the nets around those jumpers, but I haven't had time to straighten them out.
What is the best grounding strategy? I'll end up having 2 psu boards, 1 digital and 2 I/V boards. How do I avoid ground loops then?
- Christian
Layout
I have also finished the layout. I have tried to keep the distances between decoupling capacitors and power pins as short as possible.
The image is a bit broken due to the color exportfeatures in my pcb program.
Green, brown and light red are component side
Light and dark blue and dark red layers are on "solder side"
Is it worth etching?
I hope so.
I have also finished the layout. I have tried to keep the distances between decoupling capacitors and power pins as short as possible.
The image is a bit broken due to the color exportfeatures in my pcb program.
Green, brown and light red are component side
Light and dark blue and dark red layers are on "solder side"
Is it worth etching?
I hope so.
Hello, nice design.
I'm actually working on a project with a STA310 from st. This device has one S/PDIF input. Because of that I wanted to use th CS8416 to "route" several S/PDIF signals to the STA310, so that you can choose your source. Input RXP[0:3]=>Output TX. But when I was working on the schematic I took the datasheet of the CS8416 again to look up something and I read that on page 12 of the pdf document:
"Figure 5 and Figure 6 show the power supply and external connections to the CS8416 when configured for software and hardware modes. Please note that all I/O pins, INCLUDING RXN AND RXP[7:0], OPERATE AT THE VL VOLTAGE."
You said that you used the device already. Did you use the normal input for S/PDIF directly connected as you have it in this schematic or did you make a level convertion? 'Cause as far as I know the level of the S/PDIF signal is about +-0,5V.
I'm actually working on a project with a STA310 from st. This device has one S/PDIF input. Because of that I wanted to use th CS8416 to "route" several S/PDIF signals to the STA310, so that you can choose your source. Input RXP[0:3]=>Output TX. But when I was working on the schematic I took the datasheet of the CS8416 again to look up something and I read that on page 12 of the pdf document:
"Figure 5 and Figure 6 show the power supply and external connections to the CS8416 when configured for software and hardware modes. Please note that all I/O pins, INCLUDING RXN AND RXP[7:0], OPERATE AT THE VL VOLTAGE."
You said that you used the device already. Did you use the normal input for S/PDIF directly connected as you have it in this schematic or did you make a level convertion? 'Cause as far as I know the level of the S/PDIF signal is about +-0,5V.
Thank you for your comments!
I chose the 98 because I could get those devices, but I think 94 is pin compatible. 92 is controlled with spi/i2c, so I would need a microcontroller.
I like having the D1's separate boards so that I would be able to test other I/V stages, but it would be quite easy to merge them to one board. Or you could just avoid cutting the boards...
I have used the input circuits shown on page 55. The signal is AC-coupled, so the operating point should not be a problem. On page 7 the input characteristics are stated and as I understand it, the S/PDIF swings should be enough.
I'll order the rest of the components this weekend and maybe etch the board in the beginning of next week.
dw8083 said:
I chose the 98 because I could get those devices, but I think 94 is pin compatible. 92 is controlled with spi/i2c, so I would need a microcontroller.
I like having the D1's separate boards so that I would be able to test other I/V stages, but it would be quite easy to merge them to one board. Or you could just avoid cutting the boards...
flybysun said:
I have used the input circuits shown on page 55. The signal is AC-coupled, so the operating point should not be a problem. On page 7 the input characteristics are stated and as I understand it, the S/PDIF swings should be enough.
I'll order the rest of the components this weekend and maybe etch the board in the beginning of next week.
Ok thanks for the answers,
I don't know maybe I save this chips for some other project and select the input with some mechanical part like a relais or so. The S/PDIF receiver is worth more then signal routing I would say. But I have some basic question: What is a D1 I/V you are using the pcb for?
Cheers
Holger
I don't know maybe I save this chips for some other project and select the input with some mechanical part like a relais or so. The S/PDIF receiver is worth more then signal routing I would say. But I have some basic question: What is a D1 I/V you are using the pcb for?
Cheers
Holger
flybysun said:Ok thanks for the answers,
I don't know maybe I save this chips for some other project and select the input with some mechanical part like a relais or so. The S/PDIF receiver is worth more then signal routing I would say. But I have some basic question: What is a D1 I/V you are using the pcb for?
Cheers
Holger
If you just make proper termination of the S/PDIF signals I'm quite sure you could get away with some sort of mechanical switch between the inputs.
The D1 I/V section is designed by Nelson Pass. You can look through the Pass Labs forum for more information. I found the thread by Promitheus very informative. The stage sounded so unbelievably good that I can't rest before I make this work.
Why?
I have made the pcb's for my design, but it doesn't play.
The problem could be related to the fact that I am reusing a cs8416 from an old board. I might have fried the chip with my hot air gun. My supply voltages are all correct, but the there is only static noise (not much) and no music.
I have attached my schematics - if anyone can find showstopper-errors I'll be happy!
I think I'll try with another old cs8416 in the weekend. I guess the only way to sort this out would be using a scope - I think I have to buy one soon, cos it's really annoying not to have one at home.
I have made the pcb's for my design, but it doesn't play.
The problem could be related to the fact that I am reusing a cs8416 from an old board. I might have fried the chip with my hot air gun. My supply voltages are all correct, but the there is only static noise (not much) and no music.
I have attached my schematics - if anyone can find showstopper-errors I'll be happy!
I think I'll try with another old cs8416 in the weekend. I guess the only way to sort this out would be using a scope - I think I have to buy one soon, cos it's really annoying not to have one at home.
I'd bet on the chip being fried. One question for you. Why does the reset to the DAC have a 100k series resistor and bypass cap? I'm using the same reset chip without anything. By the way, you may want to look at my schematics, if you haven't already. My DAC is similar to yours, and it is working.
still no progress
I got some cs8416 from digikey today, but I still can't get the thing to play. The schematics is still the same (attached).
I have also changed the 1798 i case it had gotten fried too, but nothing helps. I'm not sure how to go on from here - I have tried to measure for opens and shorts everywhere, but with no luck.
I tried a scope a few days ago, but it was too slow and the probes where no good. Any ideas what to try next? Would it make sense to etch a new pcb and try again?
I got some cs8416 from digikey today, but I still can't get the thing to play. The schematics is still the same (attached).
I have also changed the 1798 i case it had gotten fried too, but nothing helps. I'm not sure how to go on from here - I have tried to measure for opens and shorts everywhere, but with no luck.
I tried a scope a few days ago, but it was too slow and the probes where no good. Any ideas what to try next? Would it make sense to etch a new pcb and try again?
I asked a question above about the reset chip, but you didn't give an answer.
Also, although this probably isn't the problem, why do you have VCOML and VCOMR going through the same cap? They should each have their own.
I'm trying to help here, so please answer the questions, otherwise, that's the last advice I'm giving.
Also, although this probably isn't the problem, why do you have VCOML and VCOMR going through the same cap? They should each have their own.
I'm trying to help here, so please answer the questions, otherwise, that's the last advice I'm giving.
Thank you for trying to help!
The resistor and cap was to get the cs8416 clock running before releasing the reset on pcm1798. I have tried to subvert it but nothing changes - I didn't ignore your questions, I was just too frustrated to answer.
On page 18 in the pcm1798 datasheet, the cap is connected to both vcomr and vcoml.
The weird thing is that with the pcm1730 on my last attempt I got some wonderful music through, but with a very similar design, nothing seems to work.
The resistor and cap was to get the cs8416 clock running before releasing the reset on pcm1798. I have tried to subvert it but nothing changes - I didn't ignore your questions, I was just too frustrated to answer.
On page 18 in the pcm1798 datasheet, the cap is connected to both vcomr and vcoml.
The weird thing is that with the pcm1730 on my last attempt I got some wonderful music through, but with a very similar design, nothing seems to work.
cviller said:
You know, I never noticed that. The PCM1794 data sheet shows a separate cap for each, and that's how I did it. Well, at least, now I know that is o.k. for PCM1798, too, because my DAC currently has it set up that way. I'll take a closer look at your schematic tonight, and see if anything comes to me. Honestly, though, it could be shorts. I gave one of my boards to someone over a month ago, and he never got it to work.
Analyze this...
When I turn on the power, the system is quiet, but if I reset the system, (I have removed the 100k and cap), it starts making static noise.
Removing the digital supply voltage does not help, but if I pull out the spdif receiver supply (VA3.3) and reinsert it, the board goes back to the quiet state....
You might be right that it is just some sort of short or bad component - I'm leaning towards that explanation too. Maybe I should just make a new board...
When I turn on the power, the system is quiet, but if I reset the system, (I have removed the 100k and cap), it starts making static noise.
Removing the digital supply voltage does not help, but if I pull out the spdif receiver supply (VA3.3) and reinsert it, the board goes back to the quiet state....
You might be right that it is just some sort of short or bad component - I'm leaning towards that explanation too. Maybe I should just make a new board...
ITS ALIVE!!!
It was simply the filter components. I ripped them all off and soldered on some new ones. I suspect the 22nF which I changed from a 1206 to 0805, but might have received some with the wrong values. Now I'm back with the 1206 and it works perfectly!!!
I don't have time to write about the details cos now I have to listen...
It was simply the filter components. I ripped them all off and soldered on some new ones. I suspect the 22nF which I changed from a 1206 to 0805, but might have received some with the wrong values. Now I'm back with the 1206 and it works perfectly!!!
I don't have time to write about the details cos now I have to listen...
Re: ITS ALIVE!!!
Cool. Get out your camera...
Also, you never showed the schematic for your output stage. What does that consist of?
cviller said:
It was simply the filter components. I ripped them all off and soldered on some new ones. I suspect the 22nF which I changed from a 1206 to 0805, but might have received some with the wrong values. Now I'm back with the 1206 and it works perfectly!!!
I don't have time to write about the details cos now I have to listen...
Cool. Get out your camera...
Also, you never showed the schematic for your output stage. What does that consist of?
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