Hello everyone,
I am a music and audio equipment enthusiast, I enjoy building tube equipment and modifying, repairing, improving audio equipment. I own a modified Teac P700, which transport, using various DACs I built, as well as a Conrad Jhonson Premier Nine, (magnificent devices the Premiers). The transport employs a Sony CXD1125Q DSP, which also has three connections for Sony's “2's complement signal 16bit” format. I would like to be able to take advantage of this output to connect it to one or two AD1865 DACs in NOS configuration. Unfortunately, I cannot find an interface, perhaps even a simple one, to bring the Sony format, 16bit to 18bit, compliant with what is needed for the DACs.
Is anyone aware of or has experienced such logic? Perhaps for 20bit or 24bit DACs to be derived........
I welcome advice and guidance of any kind.
Thanks in advance
ICHINO
I am a music and audio equipment enthusiast, I enjoy building tube equipment and modifying, repairing, improving audio equipment. I own a modified Teac P700, which transport, using various DACs I built, as well as a Conrad Jhonson Premier Nine, (magnificent devices the Premiers). The transport employs a Sony CXD1125Q DSP, which also has three connections for Sony's “2's complement signal 16bit” format. I would like to be able to take advantage of this output to connect it to one or two AD1865 DACs in NOS configuration. Unfortunately, I cannot find an interface, perhaps even a simple one, to bring the Sony format, 16bit to 18bit, compliant with what is needed for the DACs.
Is anyone aware of or has experienced such logic? Perhaps for 20bit or 24bit DACs to be derived........
I welcome advice and guidance of any kind.
Thanks in advance
ICHINO
Do you have more of a spec on what Sony's 2's complement format looks like? Is there a timing diagram? Signal levels? 5v logic, 3.3v logic, etc.?
If the Sony format specifics are known, then I2S format is described at: https://en.wikipedia.org/wiki/I²S
After that its just a matter of figuring what bits need to be diddled around to go from one format to the other. Then you decide if you want to do it with discrete logic, or maybe in a CPLD, etc.
If the Sony format specifics are known, then I2S format is described at: https://en.wikipedia.org/wiki/I²S
After that its just a matter of figuring what bits need to be diddled around to go from one format to the other. Then you decide if you want to do it with discrete logic, or maybe in a CPLD, etc.
hi, markw4
I attach CXD chip data from a service manual. I2S is a different format. I think the problem is going from 16bit words to 18bit words.
I attach CXD chip data from a service manual. I2S is a different format. I think the problem is going from 16bit words to 18bit words.
It shouldn't be a problem. What you do is set the two least significant bits of the 18-bit word to zero.
Yeah, but what can I achieve this effect with? what chip to mount for a simple circuit. Do you have a schematic?
CXD1125Q outputs EIAJ format which is right justified. To convert it to I2S LRCK needs to be delayed by 7 BCK cycles and inverted.
Here is an example of EIAJ to I2S converter using logic gates and shift register.
https://www.diyaudio.com/community/...rs-pay-to-maintain-diyaudio.25177/post-297035
Here is an example of EIAJ to I2S converter using logic gates and shift register.
https://www.diyaudio.com/community/...rs-pay-to-maintain-diyaudio.25177/post-297035
I had seen that circuit, but someone said it didn't work, and the person who presented it said he hadn't tested it.
I was thinking maybe something simple with 74HC164....e 04, but I am not good enough to calculate the uses and therefore make a schematic.
I was thinking maybe something simple with 74HC164....e 04, but I am not good enough to calculate the uses and therefore make a schematic.
Forgive me, but I do not need to transform the signal to I2S: the EIAJ signal must remain as such, only increase by 2 bits (in the case of AD1865), 4 bits (in the case of PCM63) or 8 bits (in the case of PCM1704).
Also the project that was pointed out to me converts EIAJ to I2S, it does not seem applicable to my needs.
The CXD comes out with EIAJ in 16 bits, and it needs to be upgraded to 18 bits.
Also the project that was pointed out to me converts EIAJ to I2S, it does not seem applicable to my needs.
The CXD comes out with EIAJ in 16 bits, and it needs to be upgraded to 18 bits.
Neither EIAJ nor I2S works with AD1865 or PCM63/PCM1704 so you need some glue logic for format conversion. There are examples of converting I2S for these DAC chips but AFAIK not for EIAJ. So one possibility is to first convert to I2S and then to AD1865 or PCM63/PCM1704 format.
http://pavouk.org/hw/audiosystem20/en_ad1865dac.html
https://www.diyaudio.com/community/threads/dac-ad1862-almost-tht-i2s-input-nos-r-2r.354078/
http://pavouk.org/hw/audiosystem20/en_ad1865dac.html
https://www.diyaudio.com/community/threads/dac-ad1862-almost-tht-i2s-input-nos-r-2r.354078/
There is no need to convert to I2S. Just delay LRCK by 2 BCK cycles and invert it and delay the left channel by 24 putting it in the same timeframe as the right.
Thank you rfbrw, and other guys too
yes I don't want to switch from I2S, I would like something simple and it seems to me that what rfbrw says makes sense: could you sketch out a scheme, or point me to one, a thread, or who already used it?
yes I don't want to switch from I2S, I would like something simple and it seems to me that what rfbrw says makes sense: could you sketch out a scheme, or point me to one, a thread, or who already used it?