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Analog vs digital volume control - case study with Mytek Stereo192-DSD DAC

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There has been a lot of discussion about different types of volume controls. For comparison purposes of one case I chose to use Mytek Stereo192-DSD DAC which has three different volume control modes; analog, digital and bypass. Signal routing is implemented using relays. DAC chip is ESS Sabre ES9016S in stereo mode (4 DACs in parallel per channel). ESS Sabre has 32-bit volume control and internal DSP pipeline so it has 8 bits more resolution than allowed by 24-bit external input. It also has higher output level than typical for increased dynamic range. I believe analog volume control chip is TI PGA2311, although the markings on the chip have been removed.

DAC was connected to iMac using Apple's Thunderbolt-to-Firewire adapter which also limits input resolution to 24-bit. Measurements were performed from the balanced outputs using typical 3 meter long XLR microphone cable (matches the typical DAC-to-power-amp case). For software volume control case

For built-in volume control, three levels were tested; -10, -60 and -96 dBFS. With software control it was possible to also use -120 dBFS setting. Source file is 44.1 kHz 32-bit PCM.

TPDF output dither for 24-bit target was used for testing built-in volume control case.

Results for the analog volume control.

-10 dBFS volume setting:

-60 dBFS volume setting:

-96 dBFS volume setting:

Results for the digital volume control.

-10 dBFS volume setting:

-60 dBFS volume setting:

-96 dBFS volume setting:

Results for DSD128 input and external software digital volume.

-10 dBFS volume setting:

-60 dBFS volume setting:

-96 dBFS volume setting:

-120 dBFS volume setting:

Results for 192/24 PCM input and external software digital volume with TPDF dither.

-60 dBFS volume setting:

-120 dBFS volume setting:


  1. esldude's Avatar
    Thanks Miska for posting this info. Just wanted to let you know it is valued. Good work.
  2. Jud's Avatar

    I agree with Dennis. Nice to see measurements.

    So for this layperson with no technical expertise: The Mytek's digital volume control looks like it does a nice job. The -96 and -120 external software settings look like they do a good job also, but hard to see needing those levels of attenuation very often, especially -120.

    Is that a reasonable interpretation of what we see here?
  3. Miska's Avatar

    Yes, typical settings would be somewhere between -10 and -60 dB. Those higher attenuations were included to see if the results become "bad" when the level goes really low. I also plotted results for -130, -140 and -150 dBFS attenuation. -140 at DSD128 was still clearly peaking out of the noise floor, while -150 although visible was getting to the level of 50 Hz power supply harmonics and not so clear anymore.
  4. Miska's Avatar
    The digital volume control in Mytek is what is implemented on ESS Sabre DAC chip.

    It is also interesting that THD is lower at -10 dB level when using DSD128 and software volume than when using PCM 44.1k and the built-in digital volume. I also checked IMD, both PCM and DSD are identical in that respect at 0.00014%.