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PCM1704-K or NOT K

Claudio Mottini
Prodigy 10 points

Hi everyone, I hope someone can help me.

I had a Simaudio Andromeda CD player which uses 2 PCM1704-K DACs per channel.

One of these failed (one of the two 1704-k dedicated to Left channel) and had to be replaced.

The technician I turned to, installed a PCM1704 but without the K and the player works, I must say that I don't notice any differences, but I would like to know if it is a K version or not and the technician can't tell me unfortunately.

The two DACs work together on the left channel: is it possible that a K and a NON-K version can work together?

any comments, experiences or help are appreciated

Thank you

 

  • 0
    TI__Guru 51170 points

    Hi Claudio,

    I found a link to the datasheet in this thread: https://e2e.ti.com/support/audio-group/audio/f/audio-forum/866412/pcm1704-j

    The datasheet, doesn't make it very obvious, but this device (now discontinued) was graded, meaning you could buy different performance variants. K was the highest performing, while no marking was lowest. At 0dB output, your new device will have a slightly worse THD+N by about 4dB (-46 vs -50dB). You can do the math on the other specs to get an exact idea of the performance difference, but the parts function identically, which is why it works as a repair. Unless you've got an ear for these things, you probably won't notice any difference by listening.

    Best regards,
    Jeff McPherson

  • 0 in reply to Jeff McPherson
    Prodigy 10 points

    Hi Jeff, thank you very much for your help; 

    from what you say and from what I have read online, if I understand correctly, TI produced PCM1704U with identical electrical characteristics; he then carried out a quality test on the DACs produced and, depending on the results such as the THD, marked only those with the best results with K

    In another forum (unfortunately I can't find the link anymore) someone said that at a certain point the quality letter printing machine of TI broke and therefore, for the English market, TI marked PCM1704-J with one dot and PCM1704-K with two dots. Then at the end of the production cycle with no letter because no more tests were performed.

    Returning to my question, it is obvious that I don't hear any difference in the sound and so that's fine.

    I was also wondering what the numbers written under 57M037M and 82M069M mean?

     

    and then the 1 million dollar question: if I wanted to change all four DACs with original K safe versions, where to get them? It's a mess online, most of them are in China and I don't know where to go. I read that they were initially produced in Japan, then in Korea and finally in Taiwan.

    I found availability on utmel.com, a company between Canada and Hong Kong, but can I trust it? Any suggestions? Thank you

    Claudio

     

  • +1 in reply to Claudio Mottini
    TI__Guru 51170 points

    Hi Claudio

    57M037M and 82M069M are codes that help identify information about the chip manufacturing. For example, the first two numbers are the year and month that chip was manufactured (57 -> July, 2007). They're only useful to help TI keep track of devices in the manufacturing flow when customers report problems.

    Unfortunately because we don't produce the PCM1704 anymore, nothing is going to be a 100% guarantee. I can't really recommend anything here since it will be third party vendors. In my opinion you shouldn't bother risking hundreds of dollars on a DAC if you can't hear the difference.

    Best regards,
    Jeff McPherson

  • 0 in reply to Jeff McPherson
    Prodigy 10 points

    Thank you Jeff, very very kind. have a good day.

    Claudio