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TEAC USB Interface

Updated 4/30/13


The new Teac UD-501 DSD capable DAC has received good reviews everywhere. Was curious about its USB interface. Here is a photo taken from a French site, qobuz.com [link]


There is a TMS320 chip and an unidentified chip. It is possible the unidentified chip is the USB receiver or the TMS320 is doing receiver function and the unidentified chip is a microprocessor to control the TMS320 chip.

The TMS320 is a DSP chip [link]. It is a “C67” series, an up to 1GFLOP 32-bit floating point DSP (the XMOS are rated at 500-1500 MIPS, likely equivalent performance). This family of DSP products was introduced in 1983 and new models have been introduced along the way.

The “C67” series is a current product and an EVAL kit, in particular for the C6748 chip,  is available from TI [link], [link]. According to the documentation:

TMS320C6748, a low-power dual-core applications processor based on a fixed-point C64x+™ instruction set and the floating-point C67x+™ instruction set. It provides significantly lower power than other members of the TMS320C6000™ platform of DSPs and provides both floating-point precision and fixed-point performance in the same device. With a wide variety of standard interfaces for connectivity and storage, the C6748 development kit enables developers to easily bring audio, video and other signals onto the board.

… Included in the C6748 development kit is all the hardware and software needed for two demonstrations, a fingerprint-recognition demo and a face-detection demo.

Here is the block diagram for the eval kit:


Looks like a very capable and general purpose processor for not just audio but a lot of other things not even related to audio. You can take a look at the WIKI for all the available libraries for the DSP [link]. The DSP can even implement audio decoding and filtering.

In addition, the USB-2 interface is provided by the FT232 chip (and thus the unidentified chip is  likely not the USB interface chip; however, there are no FT232 chips in 48-pin package).

Further, the DAC has an upsampling feature and is provided by the Cirrus CS8422 chip on the main taking the I2S output from the USB board.

Thus the USB board, I believe, it is just moving the bits  to the DACs. It looks kind of overkill; perhaps in some future Teac will add other capabilities such such as PCM to DSD conversion and different upsampling algorithm on the DSP chip. It is also likely that Teac is just reusing hardware from their TASCAM proline. A device such as the TASCAM US-366 is a “USB interface with DSP Mixer”

This design from TEAC gives credibility to what Musiland is doing in their upcoming “SuperDSP” chip. The good thing about the Musiland product is that the DSP is dedicated to audio, and the chip will have native support for USB 2 and USB 3 interfaces.


Appreciate Mr. Daussin, the reviewer of the TEAC DAC, providing additional information in the comments section. The unidentified chip is the TPS65070. Readers would recognize “TPS” being power chips. The TPS65070 is a single-chip with multiple voltage outputs. Here it provides the different voltages required by the DSP chip. It is a convenient, integrated solution to provide the power to the main chip instead of using separate regulators.

The TMS320 DSP chip has implemented USB 2.0 capability in s/w and there is no need for a FT USB receiver chip (In the block diagram the USB 2.0 receiving capability is provided by a separate chip because (I think) the DSP chip is already burdened with many different functions).

  1. Sam5050@comcast.net
    April 27, 2013 at 21:39

    Thanks for the heads up – nice unit! Here is the website with more information:

    “TEAC’s new UD-501 is the star of the 501 series. The UD-501 supports Direct Stream Digital (DSD) playback at either 2.8 MHz or 5.6MHz (DXD) rates. PCM audio is supported up to 384kHz/32-bit resolution. It connects to your computer over USB using ASIO 2.1 or DoP.

    The output section of the UD-501 features two BurrBrown 32-bit DACs per channel and JRC MUSES op amps, also with a dual monaural design.”

    Actually DXD has nothing to do with DSD but is a PCM standard 352.8kHz/24-bit. I think they mean DSD128 in reference to the 5.6MHz sampling rate. Well it looks to be able to handle both!

    Couple of questions:
    1) How are those JRC MUSES op amps? Say compared to the really nice LME 49720.
    2) it looks like the opamps could be rolled

    3) Nice having the IEC PC socket, any idea on the internal power supply configuration?
    Linear or Switched? Filtering or chokes??
    It looks linear with dual mono toroidal-core power transformers.

    Nice set of filter options: 4 selectable analog filters (playback USB, DSD)
    3 selectable digital filters (playback USB, PCM)

    At $850 a little expensive – I’m hoping the Musiland “SuperDSP” are cheaper – maybe half as much

  2. April 28, 2013 at 02:11

    “Les alimentations de ces circuits analogiques, filtrées par deux groupes de deux condensateurs de 4700 μF/35V, sont stabilisées par des régulateurs + ou – 12V de types 7812 et 7912”

    Two groups of two capacitors 4700 μF/35V and linear regulators LM7812 and LM7912

    => linear supply with toroidal transformer, one per analog channel (double mono)

    • BlgGear
      April 28, 2013 at 06:42

      Hello Mr editor, thanks for stopping by. Can you tell what is the chip next to the DSP chip in the USB board? Also I listed your site in the “free hires” list, but on the paid section. If there is a free hires sample download, let me know and I’ll move the site to the “free” list.

  3. Sam5050@comcast.net
    April 28, 2013 at 03:45

    >”The power of these analog circuits, filtered by two groups of two capacitors 4700 μF/35V are stabilized by regulators + or – 12V 7812 types and 7912″

    Two groups of two capacitors and μF/35V 4700 LM7812 and LM7912 linear regulators

    => Linear supply with toroidal turn, one per analog channel (dual mono)<

    Highly regulated linear PS – Quite impressive! (Très réglementé PS Très impressionnant!)


  4. April 29, 2013 at 09:12

    The chip (marked U4) above the TM320C6748 (wich contains 2 USB interfaces, http://www.ti.com/lit/ds/sprs590d/sprs590d.pdf) is a TPS65070 (http://www.ti.com/lit/ds/symlink/tps65070.pdf), this is not readable on the photo but I’ve noted the reference of this chip.

    This TPS65070 is perhaps used for the “Auto Power Save” function ?

    Best regards.

    • BlgGear
      April 29, 2013 at 16:06

      Thank you!. The TPS chip provides all the different supplies to the DSP chip.

  5. July 20, 2013 at 22:33

    Great weblog right here! Also your website lots
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  6. storrgie
    August 30, 2013 at 13:38

    I’ve been trying to use this device under Linux. Please see here if you’ve found this link searching for issues related to Linux and MPD playback: https://gist.github.com/storrgie/6389526

  7. September 14, 2016 at 16:57

    what is alkaline water

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