Analog Ipod out to SPDIF

mitchjs · 2nd November 2006, 02:14 AM

I want to take the analog line out from the dock connector and turn it into spdif

i will use a DIT4096 to take i2s to spdif

now i need some help on the analog to I2s

can someone point me to the right direction

i want some quality here

should i go into a opamp then to a ADC to get me to i2s

there there is all the clks needed...

help

i wish there was 1 IC that took in analog and out came spdif..

thanks
Mitch

Clutz · 2nd November 2006, 07:24 AM

Your post is a little bit confusing. You first say you want to convert the analog out to SPDIF, but then you say you will use a DIT4096 to convert I2S to SPDIF, but analog out isn't I2S.

Where are you going to get the I2S from? I believe the PCM2902 has an ADC in it, and it conviniently has an SPDIF output. So, without thinking about it very much, that's what I'd use. I don't know why you'd put an opamp in before the PCM2902. The analog out on the dock connector is a line out, so I can't see why you'd have any reason to give that signal any voltage gain.

I think that the PCM2902 is the one IC solution that you want.

That said, why do you want to go from analog out to SPDIF? Going to then take the SPDIF and put it into a DAC? You won't end up improving the audio going that route, versus just taking the line out of the iPod and connecting it up to a preamp before your power amp. If anything, it'll be worse.

mitchjs · 2nd November 2006, 01:22 PM

I think I was clear

Analog to Spdif!

before i can get to spdif you have to get to I2S

as for pcm2902, that is some USB Codec IC ...

unless it can work without ever being connected to USB
and convert analog audio to SPDIF....

as for opamp, i didnt say with any gain.... maybe as a buffer
thats why i need help

mitch

dangus · 2nd November 2006, 10:44 PM

About the cheapest off-the-shelf S/PDIF ADC is the ADV-2000, but the specs on the ADC chip it uses aren't the greatest. The Behringer SRC-2496 gives much better performance.

Building your own using TI or AKM chips should get you something more compact for less money.

Archwn · 3rd November 2006, 07:48 AM

Why do you have to go that way digital > analogue > digital ?

Why don't you come this way digital > digital out?

I'm not so sure if we can get digital out right from our ipod thing. anyone?

DoomPixie · 3rd November 2006, 11:49 AM

ditch it and get one of the old school (read original) creative jukebox zen mp3 players, its pretty easy to get digital out from one of them, my mate did it to his, it has seperate dac chip inside and you can pull out the (think its i2s) from its pins... not sure if they made any revisions of it but he had the original one before it was even out in this country.. only problem was after a year or so the ide controller stopped working.
Owen

mitchjs · 4th November 2006, 07:21 PM

I didnt want to bring up any Philosophical questions about
digital -> analog -> digitial

the device i want to connect the IPOD to, ONLY has Optical SPDIF in...

and NO modifications to the IPOD can be made...

so... i need a A-to-D (i2s) then to SPDIF

anyone have some simple solutions?

maybe a sample circuit with a CS5340 and clock circuits

mitch

dangus · 5th November 2006, 12:33 AM

Well, the ADV-2000 is an off-the-shelf solution; 92 dB S/N A-weighted (according to the ADC chip specs). TC9287 datasheet:
http://www.datasheetarchive.com/semi...asheet=2070690

To DIY, there's the PCM1801U which comes in a 14 pin SOIC (relatively big), and does 16 bits, 93 dB S/N, or the PCM1800E, 20 bit, 24pin SSOP (small) 95 dB S/N.
http://www-s.ti.com/sc/ds/pcm1801.pdf
http://focus.ti.com/docs/prod/folder...t/pcm1801.html

mitchjs · 5th November 2006, 12:59 AM

thanks

im eyeing a PCM1802 but i cant find a simple use of it

the EVal board from TI is bloated and confusing...

id think someone would have posted a schematic somewhere for

2 channel in to i2s or spdif

mitch

gmarsh · 5th November 2006, 02:52 AM

Quote:

Originally posted by DoomPixie
ditch it and get one of the old school (read original) creative jukebox zen mp3 players, its pretty easy to get digital out from one of them, my mate did it to his, it has seperate dac chip inside and you can pull out the (think its i2s) from its pins... not sure if they made any revisions of it but he had the original one before it was even out in this country.. only problem was after a year or so the ide controller stopped working.
Owen

iRiver IHP-120 has native optical SPDIF output. It's not made anymore, but you can still find it lots of places for sale.

2nd November 2006, 02:14 AM	#1
mitchjs diyAudio Member Join Date: Oct 2004	Analog Ipod out to SPDIF I want to take the analog line out from the dock connector and turn it into spdif i will use a DIT4096 to take i2s to spdif now i need some help on the analog to I2s can someone point me to the right direction i want some quality here should i go into a opamp then to a ADC to get me to i2s there there is all the clks needed... help i wish there was 1 IC that took in analog and out came spdif.. thanks Mitch

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2nd November 2006, 07:24 AM	#2
Clutz diyAudio Member Join Date: Dec 2005 Location: Vancouver, BC, Canada	Your post is a little bit confusing. You first say you want to convert the analog out to SPDIF, but then you say you will use a DIT4096 to convert I2S to SPDIF, but analog out isn't I2S. Where are you going to get the I2S from? I believe the PCM2902 has an ADC in it, and it conviniently has an SPDIF output. So, without thinking about it very much, that's what I'd use. I don't know why you'd put an opamp in before the PCM2902. The analog out on the dock connector is a line out, so I can't see why you'd have any reason to give that signal any voltage gain. I think that the PCM2902 is the one IC solution that you want. That said, why do you want to go from analog out to SPDIF? Going to then take the SPDIF and put it into a DAC? You won't end up improving the audio going that route, versus just taking the line out of the iPod and connecting it up to a preamp before your power amp. If anything, it'll be worse.

2nd November 2006, 01:22 PM	#3
mitchjs diyAudio Member Join Date: Oct 2004	I think I was clear Analog to Spdif! before i can get to spdif you have to get to I2S as for pcm2902, that is some USB Codec IC ... unless it can work without ever being connected to USB and convert analog audio to SPDIF.... as for opamp, i didnt say with any gain.... maybe as a buffer thats why i need help mitch

2nd November 2006, 10:44 PM	#4
dangus diyAudio Member Join Date: May 2004 Location: Vancouver Island	About the cheapest off-the-shelf S/PDIF ADC is the ADV-2000, but the specs on the ADC chip it uses aren't the greatest. The Behringer SRC-2496 gives much better performance. Building your own using TI or AKM chips should get you something more compact for less money.

3rd November 2006, 07:48 AM	#5
Archwn diyAudio Member Join Date: Oct 2006	Why do you have to go that way digital > analogue > digital ? Why don't you come this way digital > digital out? I'm not so sure if we can get digital out right from our ipod thing. anyone?

3rd November 2006, 11:49 AM	#6
DoomPixie diyAudio Member Join Date: Jun 2005 Location: Aberystwyth / Llanelli (wales)	ditch it and get one of the old school (read original) creative jukebox zen mp3 players, its pretty easy to get digital out from one of them, my mate did it to his, it has seperate dac chip inside and you can pull out the (think its i2s) from its pins... not sure if they made any revisions of it but he had the original one before it was even out in this country.. only problem was after a year or so the ide controller stopped working. Owen

4th November 2006, 07:21 PM	#7
mitchjs diyAudio Member Join Date: Oct 2004	I didnt want to bring up any Philosophical questions about digital -> analog -> digitial the device i want to connect the IPOD to, ONLY has Optical SPDIF in... and NO modifications to the IPOD can be made... so... i need a A-to-D (i2s) then to SPDIF anyone have some simple solutions? maybe a sample circuit with a CS5340 and clock circuits mitch

5th November 2006, 12:33 AM	#8
dangus diyAudio Member Join Date: May 2004 Location: Vancouver Island	Well, the ADV-2000 is an off-the-shelf solution; 92 dB S/N A-weighted (according to the ADC chip specs). TC9287 datasheet: http://www.datasheetarchive.com/semi...asheet=2070690 To DIY, there's the PCM1801U which comes in a 14 pin SOIC (relatively big), and does 16 bits, 93 dB S/N, or the PCM1800E, 20 bit, 24pin SSOP (small) 95 dB S/N. http://www-s.ti.com/sc/ds/pcm1801.pdf http://focus.ti.com/docs/prod/folder...t/pcm1801.html

5th November 2006, 12:59 AM	#9
mitchjs diyAudio Member Join Date: Oct 2004	thanks im eyeing a PCM1802 but i cant find a simple use of it the EVal board from TI is bloated and confusing... id think someone would have posted a schematic somewhere for 2 channel in to i2s or spdif mitch

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