TAS1020B-based Asynchronous USB to I2S/SPDIF converter 24bit/96kHz

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hi,

I would like to present my new project "USB to I2S/SPDIF asynchronous mode conveter 24bit/96kHz based on TAS1020B"
I started this project about a year ago. It is now close to completion.
Most problems were with the proper implementation of the asynchronous algorithm,
in some cases TAS1020B documentation is incomplete and there are no examples.
PCB is prepared for all options except galvanic isolation
The project was developed on the Polish forum, dedicated to DIY audio.
The first test PCBs are ready and tested by users.
Convertes was tested on Windows and Linux, MAC OS will be tested this week.


The project was divided into several stages:
Stage 1: (READY)
- USB to I2S converter (fsample 44.1kHz,48kHz,88.2kHz,96kHz 24bit)
- Master Clock = 256Fs
- powered from USB or external power supply
- Master clock generated by TAS1020B from 6.000000MHz crystal
- 3 LEDs for indication an operating mode

Stage 2: (READY)
- USB to SPDIF converter (fsample 44.1kHz,48kHz,88.2kHz,96kHz 24bit)
- Wolfson WM8804 SPDIF transmitter
- Outputs: COAX, OPTO, AES/EBU (optional)
- Master Clock = 256Fs
- powered from USB or external power supply
- Master clock generated by TAS1020B from 6.000000MHz crystal
- 3 LEDs for indication an operating mode

Stage 3: (IN PROGRESS)
- USB to I2S/SPDIF converter
- two external master clocks 22.5792 Mhz (for 44.1Khz and 88.2kHz) and 24.576MHz (for 48Khz and 96 Khz)

Stage 4: (PLANNED)
- galvanic isolation for USB Bus (ADUM4160)

Bellow schematic and photos of first board (I2S and SPDIF versions).

Best regards
JarekC


PS.
Sorry for may bad english.
 

Attachments

  • 6107-I2S-SPDIF-bottom-DIY.jpg
    6107-I2S-SPDIF-bottom-DIY.jpg
    433.1 KB · Views: 3,776
  • 6107-I2S-SPDIF-top-DIY.jpg
    6107-I2S-SPDIF-top-DIY.jpg
    422.7 KB · Views: 3,550
  • 6105-2.pdf
    45.2 KB · Views: 1,061
Hi,

I had a chance to test this device, as I am also member of mentioned polish DIY forum.
What I might say is that a really smart, simple and wonderful sounding solution.

I had only opportunity to compare with synchronous devices (inlcuding PCM270x solutions). Actually there is nothing to compare - it is simply much better.

Sound is cleaner, there is a dark background but the biggest difference is in the sound stage presentation. Especially on high resolution files which do not need to be re-sampled in software domain. I was not testing it against another hi-res devices but I have ordered one, and maybe will do such comparison soon (TENOR, E-MU 0204).
 
Hi,

I designed an additional PCB layout with galvanic isolation (ADUM4160/3160).
The PCB is mounted instead of USB connector.
On the new PCB there is new USB mini connector.
TAS1020B controls the signal PIN of ADUM4160.
ADUM can be powered from 3.3V or from external power supply.

Bellow schematic.

Best regards
JarekC
 

Attachments

  • 6109.pdf
    28.1 KB · Views: 717
Hi,
The project was created for DIY (building DAC or extend the functionality of DAC).
At this moment PCB and kits are available on Polish DIY forum.
Published scheme allows independent modification of converter.
However, the source code is coryright and and will not be published.

Best regards
JarekC
 
Hi

USB to I2S module (STAGE1 specification, assembled & testet)
cost about 40$ + shipping

USB to SPDIF(COAX) module (STAGE2 specification, assembled & testet)
cost about 60$ + shipping

I never not send parcels outside the EU, so I don't know shipping cost.
I have to check this.

Version with externals oscillator is not available now because of problems with purchase of 22.5792MHZ oscillators in a small amount.
Mouser and Digikey stocks are empty.

If anyone knows a supplier for 22.5792MHz oscillators (SMD 7mmx5mm, 3.3V, 20-25ppm) in good price, I will be grateful for information

Best regards
JarekC
 
Hi

USB to I2S module (STAGE1 specification, assembled & testet)
cost about 40$ + shipping

USB to SPDIF(COAX) module (STAGE2 specification, assembled & testet)
cost about 60$ + shipping

I never not send parcels outside the EU, so I don't know shipping cost.
I have to check this.

Version with externals oscillator is not available now because of problems with purchase of 22.5792MHZ oscillators in a small amount.
Mouser and Digikey stocks are empty.

If anyone knows a supplier for 22.5792MHz oscillators (SMD 7mmx5mm, 3.3V, 20-25ppm) in good price, I will be grateful for information

Best regards
JarekC


JarekC

can you describe the performance for this convertor starting from stage 1 version to stage 4 version ? is it better towards the best performance......???
 
As I wrote, it is an interesting project. But why mini-USB? People might have invested on USB A-B cables...

Is it supporting USB Audio 2.0 like the XMOS Reference Design?

Thanks again
Roberto

Hi,

I designed an additional PCB layout with galvanic isolation (ADUM4160/3160).
The PCB is mounted instead of USB connector.
On the new PCB there is new USB mini connector.
TAS1020B controls the signal PIN of ADUM4160.
ADUM can be powered from 3.3V or from external power supply.

Bellow schematic.

Best regards
JarekC
 
In the standard version there is USB-B socket.
On the main PCB there no place for ADUM, so I add special doughter board.
After the addition this board there is no space for USB-B so I used USB-Mini socket.
I'm waiting for this doughter boards (planned delivery date March 2).

TAS1020B have USB Full Speed USB Interfece (12Mb/s) and supports only USB Audio Class 1.0

I plan to design new PCB with isolation and fitted in Harmond Alu case.

I also plan to design version with USB Audio Class 2.0 based on TI DSP C5xxx.

In XMOS I/O pins are reclocked with 400Mhz, this I do not like.

Best regards
JarekC
 
Thanks for the clarification, I stay tuned for the USB 2.0 version, I would like to order one with AES/EBU.

Cheers
Roberto


In the standard version there is USB-B socket.
On the main PCB there no place for ADUM, so I add special doughter board.
After the addition this board there is no space for USB-B so I used USB-Mini socket.
I'm waiting for this doughter boards (planned delivery date March 2).

TAS1020B have USB Full Speed USB Interfece (12Mb/s) and supports only USB Audio Class 1.0

I plan to design new PCB with isolation and fitted in Harmond Alu case.

I also plan to design version with USB Audio Class 2.0 based on TI DSP C5xxx.

In XMOS I/O pins are reclocked with 400Mhz, this I do not like.

Best regards
JarekC
 
In error...

Perhaps you should check this document first before saying such an error:
JarekC said:
In XMOS I/O pins are reclocked with 400Mhz, this I do not like.
Look at Figure 8 at page 24 (posted below) to see that I/O ports in XMOS processor are driven by external audio master clock (one of two available - depending on incoming sample rate). 400 Mhz is the running frequency for the processor's internal threads. Moreover, I2S signal's retiming should not be done using a multiple of 44.1 or 48 KHz freq.? .. like 22.5792 || 24.576 Mhz OR 45.1584 Mhz || 49.152 Mhz. How above frequencies would fit in 400 Mhz or you think that XMOS has implemented some sort of ASRC at outputs :)
 

Attachments

  • XMOS Audio Ports.jpg
    XMOS Audio Ports.jpg
    75.8 KB · Views: 1,452
Perhaps you should check this document first before saying such an error:

Look at Figure 8 at page 24 (posted below) to see that I/O ports in XMOS processor are driven by external audio master clock (one of two available - depending on incoming sample rate). 400 Mhz is the running frequency for the processor's internal threads. Moreover, I2S signal's retiming should not be done using a multiple of 44.1 or 48 KHz freq.? .. like 22.5792 || 24.576 Mhz OR 45.1584 Mhz || 49.152 Mhz. How above frequencies would fit in 400 Mhz or you think that XMOS has implemented some sort of ASRC at outputs :)

Hi.

You are not right.
Look at:
https://www.xmos.com/download/public/XS1-Ports-Specification(X1373A).pdf
In a description of the clock block in section 3.4 you find:
"Note that any external clock is itself clocked-in using the 400 MHz core clock."

Confirmation of this can be found here (XMOS technical forum)
XMOS Support Board • View topic - External clock

Respond of Larry XMOS employee:
"Yes, any external clock is resampled to 400MHz
If you tie I2S signals BCLK LRCLK and DATA to a low-jitter external
clock on the XMOS device, this will introduce a jitter in the order of
one to two 2.5ns (400MHz) cycles"
Another confirmation of this is that SPDIF out on XMOS reference board is reclocked with MCLK (U1 NS7SZ175 chip)

Best Regards
JarekC
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.