The only noise that I am familiar with is the ultrasonic noise. It does not come into the audio band unless the ancillary equipment is affected by it. I would suspect that any mods directed at reducing that will end up with negative sonic effects such as phase shift or frequency response changes. The Bricasti topology is nothing like the Directstream. It is chip based not FPGA. A more typical DAC design excluding the fact that it is dual mono.
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âAudio bandâ means up to 20kHz or thereabouts, the generally accepted limit of human hearing.
âUltrasonicâ means vibrations at a frequency higher than a human ear can hear.
âNoise floorâ refers to noise in a system thatâs present regardless of what signal youâre attempting to send through it â like the hiss of analog tape.
1-bit digital sampling is only usable for audio signal transmission because we have mathematical methods (sigma-delta modulation) for creating a large signal-to-noise ratio in the audio band, meaning the ânoise floorâ is very low at frequencies below 20kHz. By running our digital clock at a vastly higher frequency (at least 2882.4kHz!) we can create a stream of 1-bit samples such that the lack of precision inherent in having just two values (positive and negative) creates random noise above 20kHz but replicates an audio signal with a high signal-to-noise ratio below 20kHz. The idea behind DSD is to shift the noise energy far above what humans can hear and then run a low-pass analog filter to let only the audio through⊠but in reality we donât get rid of all of that high frequency noise energy and some of it continues into your system.
So sixpackâs âultrasonic noiseâ is the energy in frequencies well above human hearing that are inherent to all DSD systems including the DirectStream DAC, but which have not been completely filtered out.
The âaudio band noise floorâ is noise in the human hearing range that our SDM mathematics was unable to move to higher frequencies, plus anything analog in origin like noise from power supplies or the Johnson-Nyquist noise generated by current flowing through a resistor.
Both of these types of noise has a fixed level at the output stage of the Mk1 transformers, but can be reduced with analog attenuators such as the built-in one or a subsequent resistor in a pre-amp. Your digital volume control positions the level of your music signal somewhere in between the maximum level the DAC can produce and the audio band noise floor below which your music gets lost.
Edit: In the Mk2 context you donât have the built-in attenuator so the noise floor (both audible and ultrasonic) is at a fixed level at the outputs.
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I have tried this in the past a number of times with the mk 2 DAC. It is easy to do when you are running balanced interconnects as I am. I simply remove the cables from the preamp and plug them into each other. This provides a direct connection between the DAC and the BHK 250. When I do so even with the DAC volume set to the lowest possible setting I get a barely audible sound with my ear pressed to the tweeters. With the preamp in the chain the tube rush with my ear in this position is much louder. This is done with the PST input selected on the DAC no music playing. This should be a worse case example. Just for comparison I put the preamp back in the chain set the maximum volume to 100 than again with no music playing cranked the preamp level to 100 I tried the DAC at 0 level and 100 level. With my ear directly in front of the tweeter the only sound I could detect was the tube rush.
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This will be interesting to know if anyone that hasnât encountered the audible noise issue is having MK2 drive the power amp directly.
Yes this has been posted by 1 maybe two that HAVE the noise. But certainly not many. I have chatted with one, he put a BHK Pre in the mix and is very happy with Massive. The other may have returned or upgraded to another DAC. I cannot recall.
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The little test I have done is exactly that the DAC driving the amp Directly.
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I concur, I did a few times and I had never heard any noise using MK2 driving M1200 directly.
But with BHK pre inserted it just sounded better.
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I was also one of the early beta testers for the MK2. I had zero noise issues from day one with or without preamp installed. Yes, the sound is much better with the preamp in, big difference. There seem to be a system synergy with this DAC just like my MK1 before it. It completely outperformed my modified MK1 the moment I put it in the system, not close at all. The sound was even more natural, and the soundstage opened up to a degree that was startling! But itâs performance increased to a degree I didnât think possible when I put in a few upgrades to it. First I put in the SR Galileo SX power cable and the sound really opened up to a level that made my jaws dropped. Then I put in the AM M1 fuse that fill in and sweetened the sound further. And the ChordMusic USB cable brought out more resolution and air that is simply stunning! And the Massive firmware upgrade brought even more clarity to the sound. Then came the new speakers and speaker cables and the sound of this MK2 has not stop improving yet! What you get out of this MK2 is what you put into it, and the rest of your system. I canât believe there will be further free firmware updates that can improve the sound even more.
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Very well said.
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Any firmware updates expected before the end of the year?
Yes, absolutely.
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Will you be Santa this year? 
Just curious - I have massive on USB flash and as soon as i switched DS mk2 to Massive I donât need do the again after power off/on? So if there few FPGA firmwares on USB flash I just need chose once and it work until another one chosen?
This Christmas party in our house will be Massive 
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You only need to pick the one you want to install. The others are ignored, so you can keep Massive on the USB if you want.
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Counting down! The end of year comes sooner in Australia 
Looking forward to Massive (non beta) when it comes.
Seasonâs greetings everyone! PS Audio forums are fun. Thank you for the passion and joy you bring to high end audio.
Cheers,
Phil
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Thanks, Phil. Tedâs got the first 99% of Massive done. Itâs that last 1% problem that taking the next 99% of the time.
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Thatâs it Paul, the glass is always half full!
Will the new Massive release only solve problems or add to sound quality also?
Both, for sure. The versions I have heard so far add another degree of musical bliss I am excited to share with you.
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