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Reference DAC Module - Discrete R-2R Sign Magnitude 24 bit 384 KHz

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#5,703
Sony CXD1125Q i2s compatibility with dam1021

I have connected my cd transport signal processor (Sony CXD1125QZ) i2s output (was very thin soldering job yesterday as I managed to solder wires to the CXD1125QZ pins) directly to the i2s input of dam1021. But so far I did not manage to get dam1021 locking on.

I have the following connections (CXD1125QZ output -> dam1021):

1. Data ->I2S DAT IN (pin J3/22)
2. LRCK (88.2kHz or 44.1kHz) -> I2S LRCK IN (pin J3/20)
3. BCLK (4.2336MHz or 2.1168MHz) -> I2S BCLK IN (pin J3/18)
4. GND -> ISO GND (pin J3/25)

Sony CXD1125QZ chip generates i2s signal in Sony format, not Philips one (I think the main difference is in LRCK timing diagram, e.g. 7 bits delay).

Does anybody know what the issue could be and if Sony i2s signal format (or Philips one) is compatible with dam1021 i2s input?

NB I checked dam1021 is properly powered and when using SPDIF connection it locks on.
 
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#5,704
#901: I2S Input just need the BCLK, LRCK and DAT signals, plus power to the ISO +3.3V to power the isolator chips.

#295: I2S has fixed format, see https://sparkfun.com/datasheets/Brea...rds/I2SBUS.pdf
#299: So if i understand the card is not compatible with the Right or Left justified 16/24/32 bits formats .
#300: The inputs goes into a FPGA, so I could in principle add any format. But why ? Everything seems to be I2S nowadays....

hth
Ulli
 
#5,705
modmix said:
#901: I2S Input just need the BCLK, LRCK and DAT signals, plus power to the ISO +3.3V to power the isolator chips.

#295: I2S has fixed format, see https://sparkfun.com/datasheets/Brea...rds/I2SBUS.pdf
#299: So if i understand the card is not compatible with the Right or Left justified 16/24/32 bits formats .
#300: The inputs goes into a FPGA, so I could in principle add any format. But why ? Everything seems to be I2S nowadays....

hth
Ulli
Click to expand...

I wish it was that simple indeed, but it is not.

The i2s 'standard' is not well defined and different companies have done it differently. And yes, we are still talking about four wires but signal format and/or timing are not necessarily the same.

As you mentioned under note #299 I suspect that dam1021 would not accept 16/18/20 bits format what is the output format of the Sony CXD1125QZ. And you are right that most likely modern devices communicate using 32 bits, but I do not think this is supported by my signal processor CXD1125QZ.

The first question I am looking answer for is what are the standard dam1021 i2s interface specifications. Timing diagram would really help here (Soren, do you have it?).
 
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#5,706
formatcd3 said:
I wish it was that simple indeed, but it is not.

The i2s 'standard' is not well defined and different companies have done it differently. And yes, we are still talking about four wires but signal format and/or timing are not necessarily the same.

As you mentioned under note #299 I suspect that dam1021 would not accept 16/18/20 bits format what is the output format of the Sony CXD1125QZ. And you are right that most likely modern devices communicate using 32 bits, but I do not think this is supported by my signal processor CXD1125QZ.

The first question I am looking answer for is what are the standard dam1021 i2s interface specifications. Timing diagram would really help here (Soren, do you have it?).
Click to expand...

There is a "Philips I2S bus specification", don't remember where I got it but google is your friend. The dam1021 require 32 bit per word, 2 words per sample, up to 24.576 Mhz clock.

Why don't you just take the spdif output from you cd player ?? The dam1021 reclocks anyway.
 
#5,708
soekris said:
There is a "Philips I2S bus specification", don't remember where I got it but google is your friend. The dam1021 require 32 bit per word, 2 words per sample, up to 24.576 Mhz clock.

Why don't you just take the spdif output from you cd player ?? The dam1021 reclocks anyway.
Click to expand...

Thanks, Soren, this is a very useful info and narrows down the search options. I guess I need to play with a shift register to convert Sony i2s into Philips i2s format. I am going to order some this weekend. The converter circuit is rather simple.

The remaining question is if there is a way to make dam1021 understand word lenght of 16, 18, 20 or 24 bits. Hope there is a solution (other than diving into FPGA programming).

Regarding SPDIF vs. i2s, the expectation is (supported by implementations of other people) that i2s interface produces (much) better QS compared to SPDIF. I am very happy with my current SPDIF performance (after modifying my source SPDIF output circuit as I wrote earlier here), sound is great and dam1021 looks happy and is very stable (so, you do not necessarily need an output transformer after all). But you know, there is always this thought ... 'what else'?
 
#5,709
Take Twistedpearaudio Metronome

Hi,

you can solve your I2S-problem with the Metronome from Twistedpearaudio.

The metronome converts the I2S to 32 Bit. Than the dam1021 can use your signal.

I use the metronome for my Philips CD PRO LF2. I think, that I2S sounds better than SPDIF.

Best regards

Christian
 
#5,711
#5,712
mc002 said:
Hi,

you can solve your I2S-problem with the Metronome from Twistedpearaudio.

The metronome converts the I2S to 32 Bit. Than the dam1021 can use your signal.

I use the metronome for my Philips CD PRO LF2. I think, that I2S sounds better than SPDIF.

Best regards

Christian
Click to expand...

Thank you, looks very nice indeed. I looked at the Metronome data sheet ( www.twistedpearaudio.com/docs/digital/metronome_1.1_manual.pdf ) on their website and it says that the unit is designed for i2s reckloking and 24 bit output. I did not find any mention of 32 bits.

I also looked up the TI SRC4192 chip data sheet wihich says that it 'Supports 24-, 20-, 18-, or 16-Bit Input and Output Data: All Output Data is Dithered from the Internal 28-Bit Data Path'. No mention of 32 bits.

However, this might not be the main issue. I believe the issue I need to solve is converting the Sony i2s signal into Philips i2s signal. It does not look like Metronome does it (which would be introducing controlled/switchable bit delay for different word lenghts).
 
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#5,713
My CD-Pro2 project with the dam1021 and SRC4192

The SRC4192 produces 32 Bit I2S. Input could be 16 Bit, 20 Bit, 24 Bit.

The CD-Pro2 is a 24 Bit device, so I had to convert the signal. It functions perfect! On the base of the SRC4192 Metronome I´ve built my own project.

I control the whole player with a Teensy 3.2. It is similar to an Arduino.

https://www.dropbox.com/s/vkdlbp9quwqtj1l/IMG_0188.jpg?dl=0

https://www.dropbox.com/s/qf1yk2r4hol7s4m/IMG_0181.jpg?dl=0

https://www.dropbox.com/s/0888kdx4c1lbxcl/IMG_0180 Kopie.jpg?dl=0
 
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#5,714
Hi Soeren!

Wouldn't it be a good idea to make the buffered outputs switchable? A jumper-construction in future DAM 1021 board incarnations for example would offer the possibility to completely separate them if not needed.

With my rev1 board I get annoying noise pollution caused by wlan and computer switching activity- with both, single ended or balanced outputs. The raw output is absolutely silent in the same configuration.

Greetingz, Robert
 
#5,715
mc002 said:
The SRC4192 produces 32 Bit I2S. Input could be 16 Bit, 20 Bit, 24 Bit.

The CD-Pro2 is a 24 Bit device, so I had to convert the signal. It functions perfect! On the base of the SRC4192 Metronome I´ve built my own project.

I control the whole player with a Teensy 3.2. It is similar to an Arduino.

https://www.dropbox.com/s/vkdlbp9quwqtj1l/IMG_0188.jpg?dl=0

https://www.dropbox.com/s/qf1yk2r4hol7s4m/IMG_0181.jpg?dl=0

https://www.dropbox.com/s/0888kdx4c1lbxcl/IMG_0180 Kopie.jpg?dl=0
Click to expand...

mc002,
nicely done. A "soekris R2R inside" CD-Pro2 CD player
:yes:
 
#5,716
mc002 said:
The SRC4192 produces 32 Bit I2S. Input could be 16 Bit, 20 Bit, 24 Bit.

The CD-Pro2 is a 24 Bit device, so I had to convert the signal. It functions perfect! On the base of the SRC4192 Metronome I´ve built my own project.

I control the whole player with a Teensy 3.2. It is similar to an Arduino.

https://www.dropbox.com/s/vkdlbp9quwqtj1l/IMG_0188.jpg?dl=0

https://www.dropbox.com/s/qf1yk2r4hol7s4m/IMG_0181.jpg?dl=0

https://www.dropbox.com/s/0888kdx4c1lbxcl/IMG_0180 Kopie.jpg?dl=0
Click to expand...

Very nice. What boards are you using to process signals from cd-pro and to control it?
 
#5,717
Nige2000,
I have mod ver1 with batteries on 4vref. It is good.
Now I am starting to mod ver3 with lifepo4 batteries too.
Attached a photo the scheme in my mind, I am thinking it can give more direct and better power supply to 4vref. Can I have your opinion? Thanks
 

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#5,719
rickmcinnis said:
Well, I am not Nigel, but that is how I have my DAC. Batteries are mounted underneath the board with short silver wires going to a switch (one for each channel) and then to the circuit.

I took some pictures here: Soekris DAC

These are pre SDTrans photos.
Click to expand...

Hi Rick my SDtrans friend,
the wiring in my mind is to make GND on each 4vref (total 12 pairs of wires), instead of making GND on buffer GND, I am think if I wire each vref GND directly, it may make better power supply to 4vref.
On the other hand, I am also thinking to wire TPS7a4700 revulator with two lifepo4 batteries in series providing more stable power supply to 4vref. But worrying it will lose the advantage of very low impedance of battery⋯⋯
 
#5,720
My CD-Pro2 project with the dam1021 and SRC4192

formatcd3 said:
Very nice. What boards are you using to process signals from cd-pro and to control it?
Click to expand...

First I use three boards:

1. The board from Kiven Chen (see this thread). With this board you can piggyback the dam1021.Additionally there is a connector for the USB-Amanero. I use this connector for my little receiver board which is build around the SRC4192.

2. Receiver board: This board converts with a high precision clock and the SRC4192 the 24 Bit 44,1 KHz I2S signal from my CD-Pro-2 to 32 Bit 48 KHz I2S. You need this conversion for the dam1021, which only can operate 32 Bit I2S.
I´ve built this board similar to the TPA Metronome, but with fixed configuration.

3. Control board: This board is the base of my Teensy 3.2. I control with the Teensy the following functions:

a) CD-PRO 2: power supply
b) CD-PRO 2: DSA-interface
c) Infrared RC
d) SD-Card to change filter files
e) Via RX/TX control the dam1021
f) OLED display
g) 4 keys to control the CD-Player directly without RC

The code is written in Arduino C.

This board is also made by myself.

The case is from Modushop Italy

My project is not only a CD-Player, but also a DAC for external sources. One for SPDIF and one for Toslink. I've also implemented a routine to change the filter files with the ir-remote. The filters, you can use, are on a SD-card on the back of the player.

The CD-Pro 2 in this configuration sounds perfect. The combination with the dam1021 and I2S CD-Pro 2 is far superior to a connection with SPDIF!

I hear mainly classical music and I love this cd-player. The sound is really astonishing! I own a really great CD-Transporter CEC-5N. This very professional player has no chance against my home built cd player.
 
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