Wishes Upcoming PSA DirectStream MKII

I’d sign up for the MkII Brain Fart Edition with a “Ted-with-a-little-cloud popping out of his head” logo on it🤠

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You were just checking to see if we were dozing.

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Old farts (I’m one too) are allowed a brain fart or two every day!

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Just had one…and another…and another…

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I’m a fan of I2S between transport and DAC. That isn’t easy to do as so few streamers support this interface. Plus the various non-standardness and, yeah, difficult. I suspect this will be one the finer streamer / DAC combos if only for this reason.

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just to clarify, he said “Brain farts”

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The good thing for me is that I can still tell the difference.

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Just saw this. Yes, me on the list too!

My DirectStream DAC casing, input and outputs date back from 2010… All these components were part of the original PWD DAC…

I hope they will survive time until the DS MKII arrives…

You got it.

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I do use the remote control for volume adjustments since I do not have a PSA preamp for that purposes (but rather, Spectral with no remote). I would miss that functionality, although if the stepwise attenuation is controllable via the remote that would be just as good from a practicality standpoint.

Just noticed this bit as a reply was given to this old post. By “upstream” do you mean the voltage is being dropped prior to the audio transformer? Prior to the digital switches? I’m very curious to hear how this works out in practice – my guess is it removes the variable of interconnect capacitance from the equation of what impact the attenuation has on the sound quality.

Perhaps I’m misunderstanding you or something else has gone astray in communication but:

The volume control (via the remote) will be identical with the Mk II compared to the Mk I.

The new feature related to volume on the Mk II is that instead of having an optional 20dB attenuator (2 choices, 0dB or 20dB attenuation) the Mk II will have 6 settings (0dB, 6dB, 12dB, 18dB, 24dB and 30dB.) This should allow easier matching of levels between the DS and a given preamp or amp, but still the remote will give the 100 possible levels.

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Yes, we’re controlling the levels in analog before the digital switches (if that’s not a contradiction in terms.)

By having the level controlled before the digital switches we should have a constant impedance on the output no matter which attenuation is selected. Tho it’s not implemented the same, this is similar to digital amps that control the volume by controlling the voltage on the output power rails.

I wished I’d thought of it earlier, it’s a non-standard use of the relevant parts. But since I have accurate to the transistor level Spice models from the final reclocker on, I feel confident that it’s a proper solution (and it sounds good here too.)

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Hi @Ted: maybe it is interesting to the forum members to know what you are working on now on the MKII…

Have you finished the parallel working together of the 2 FPGA’s yet and is the revisited sigma delta coding finalized? Any other major chunks of work (besides testing)?

Thanks in advance.

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Right now I’m working on the TSS. The Mk II code is much better than the DS and is has all of the function I’m planning. There are always improvements to be made but until I have some feedback, I’d rather not just change things for the sake of changing things. The biggest thing I was worried about in the SDM is taken care of and if there’s any balancing in the SDM to be done it should be pretty simple.

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What I think would be great for @tedsmith to add is a NOS mode. This would allow people like me to use HQPlayer without the DAC doing its own upsampling/filtering/noise shaping.

Part of that is theoretically possible, part isn’t. If the input is quad rate DSD then no upsampling is done. If the input is double rate or single rate, tho there is technically upsampling, no extra filtering is done. The implicit filter in the SDM is sufficient for all three rates. The SDM can’t be done without noise shaping, but that shaping is far outside the audio band at quad rate DSD so there’s no phase or amplitude distortion.

On the other hand, skipping the volume control and the SDM isn’t really an option. The SDM is tailored around the specific hardware after it which isn’t calibrated the same as SACD’s 50% modulation DSD. On the DS the modulation ratio was more like 88% and the DS Mk II is under 50%. Sending 50% modulated DSD to the hardware would cause distortion from overload.

The Mk II will be much more transparent in the SDM, so I think you’ll be happier with it in any case.

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Was going to trade my Stellar Strata in for the Directstream Dac. Surprised to see it is unavailable.Did not know a new Dac was in the works. When will it be out and how much will it cost?

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We don’t know and we don’t know.

There’s plenty of speculation in this thread up above.

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