HQPlayer - EC modulators

Hi @jussi_laako , have you seen this recent ESS chat?

ESS DAC Technology | Pints with Ayre - YouTube

This is probably the most I’ve seen ESS talk publicly about how they do things.

Some cool things:

  • Multiple 1-bit DACs

  • He reveals errors are pushed to 4 or 6 MHz - I assume this means their modulator runs at equivalent of DSD128 sample rate?

  • He mentions reducing correlated noise is important

  • His transients plot is really interesting - how does EC modulator step response / transient plot vs non-EC modulator plot look? I assume HQPlayer EC modulators have an improvement in transients ! Maybe the key improvement?

  • Charles Hansen was the first to ask ESS about by-passing ASRC

Not that one, but I’ve seen similar things before.

They use 64 while my DSC1 design uses 32. But otherwise similar.

I think that is what I’ve been also saying. Major problem of PCM.

Here’s some with my older non-EC modulator version and DSC1 DAC.

7 kHz square wave at DSD256:

You can also see it is nicely stable:

But Mytek Stereo192-DSD DAC did it already in 2011.

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