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TAS6422EQ1EVM :Audio transmission speed limited to 48khz (in 16 and 24 bits)

Part Number: TAS6422EQ1EVM
Other Parts Discussed in Thread: TAS6422Q1EVM,

Hello, the audio transmission rate is limited to 48khz (in 16 and 24 bits) on the TAS6422EQ1VM (XMOS) and on the TAS6422Q1EVM (TAS1020)

In optical input the limit is also 48kHz. If I send audio at 88.2 or higher, the card fails and no sound comes out. If I go back to 48kHz, even without erasing the fault, the sound works again.

I can't find "If sampling frequency is greater than 48 kHz, select 96 kHz from the “Input FS” pull down." as explained in the instructions (in PPCC app).

Thank you in advance.

  • You also need to change the SCLK, MCLK and the SDIN clocks also.  With the correct clocks it should autodetect and just "work".  Let me know if this does not work for you.

  • I assume you are talking about the frequencies of the TAS6422 (and not those of the TAS1020BPFBR or the DIR9001IPWQ1 which in my opinion are automatic). The problem is that I can't find how to change the frequency for the TAS6422. These are inputs for the TAS6422 so I don't see where to change anything finally.
  • It should autodetect the frequency and work as long as SCLK, MCLK are in the correct ratios and within our device sped.

    Gregg Scott

  • I know, I don't understand. 44.1k OK at 16 or 24 bits /// 48k OK at 16 or 24 bits /// 88.2k or 96k or more does not work regardless of word length. Whether SPDIF or USB. And yet, when I use my external XMOS box (for TOSLINK) on another amplifier like the Lyngdorf TDAI1120, everything works fine up to 192kbps.

    I don't want to unsolder the resistors to send I2S directly to the TAS6422 because the operation would be irreversible. And besides, with an XMOS on the TAS6422EQ1EVM, everything should work at least at 96k, there is an error or manipulation to be done somewhere, but I can't find it.

  • The XMOS on the EVM is setup for 48kHz only.  The USB input is 44.1kHz only.  To use 96kHz, you can pull the jumpers on J5, J6, J7, and J8 that connect pins 1 and 2  on the header.  Then connect to pins 2 and 3 the proper clocks for 96kHz operation.  Pin 3 is ground and Pin 2 is signal.   You do not need to remove any resistors on the the TAS6522E-Q1 EVM.  You can see this on the schematic on page 2 (SPDIF).

  • Thank you, I had not seen that on the TAS6422EQ1 there were different jumpers to the TAS6422Q1. It will be easier if I want to enter I2S directly.

    On the other hand, if I want to use the SPDIF in 96kHz or the XMOS, I have to manage differently. I don't want to complicate myself too much. I see that the DIR9001IPWQ1 is clocked by a quartz at 12288 MHz instead of 24576 MHz. Is this one of the reasons for its limitation? Because the I2S bus should follow up to 96khz according to the DIR9001IPWQ1 technical sheet (with a quartz at 24.576 MHz in all cases).

    Concerning the XMOS, is the problem due to U3 which is not stable enough in frequency? Or is it a limit that I could increase thanks to the I2C bus? Maybe change the values ​​of the CDCE913PWR dividers by the I2C bus ? Thank you in advance !

  • I really do not have an idea why this was chosen.  This is a design block we have been using for quite sometime and it "just works" with the firmware we have for the XMOS.   In the automotive world 48k is typically used. 

  • To see the potential of the baby, it's insufficient in 48k, fortunately there is the I2S in direct connection (I haven't tried it yet, but it should be really great). I intend to use the TAS6422 to power my Gautier speakers, and maybe design and sell an amplifier based on it.

    I feel it will do better than the lyngdorf which is already very good. The rendering of the speakers is up to what you give them, in other words, powered by an FDA at 2.1MHZ on 96kHz FLAC, it should be very good! Too bad the TAS6422 seems limited to 96kHz input because that will be its weak point in my opinion.

  • If you have any more questions on the use of this device, please let me know. 

    Gregg Scott