Thanks Ted…in case of tiny differences and generally no hum…what’s the aspect to listen for? Ok I could turn up volume with nothing playing and listen for hum.
Not speaking for Ted… but generally improvements in grounding schemes can result in a blacker background making subtle inner-detail more clearly audible as well as a better recreation of space. It’s the kind of change that might be hard to quantify at first but when listening to a familiar piece of music you’ll notice the difference and increase in resolution.
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Hi Ted Does lowering the output impedance help to alleviate the need for a PreAmp. In other words if this idea works would that mean the TSS is more likely to work as well without a PreAmp as with one?
magicknow
In the DS when not using the attenuator issues without using a preamp are not related to output impedance: they are level matching (can you get as loud as you need for comfortable listening while not hearing an annoying hiss), some amps don’t like very much ultrasonic noise, very capacitive cables can interact with the leakage inductance of the transformer to raise the level of the frequency response between, say, 22kHz and 24kHz.
When the attenuator is used in the DS the last interaction changes to lowering the level of the frequency response near 22kHz instead of raising it.
Still the TSS should help. The TSS has at least 3dB better S/N so any hiss will be at a lower level for a given overall loudness setting. The TSS will default to the “standard” output signal levels: 2VRMS unbalanced and 4VRMS balanced (and with some configuration options 4VRMS unbalanced) which are about 3dB louder than the DS. The TSS will have output level trimming options of -6dB, -12dB, -18dB, -24dB and -30dB instead of the DS’s option of -20dB, this should allow better level matching in more systems.
The difference in topology also has the benefit that the frequency response won’t be as sensitive to the effects of very high capacitance cables at different levels of output attenuation. I.e. the overall sound character and quality won’t change as much when using various levels of attenuation as they do for some DS users.
Still, empirically, lower output impedance seems to help audio quality and so even if the above descriptions don’t explain the relevant effects of lowering the output impedance in the TSS the newer TSS design should help.
This will also allow the TSS to directly drive more styles of headphones directly. I don’t recommend driving headphones directly with the DS or TSS, but still some do use headphones directly and the lower output impedance will certainly drive them better.
I’m sure I’m forgetting some other new benefits 
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I couldn’t put together a proper cable yet, but I turned volume up to the max on DS and preamp and tried to hear a difference in hum between no add. ground connection and a cable held with my hands to both contacts (preamp central ground and RCA shell)…but even at max volume I don’t even have a slight hum with both options, just very slight hissing.
So I have to try to hear sound differences, but possibly won’t.
These kind of ad hoc grounding fixes work wonders in some systems and do next to nothing (or worse) in others. A lot of the ground loop issues are reasonably well addressed by balanced interconnects in a systems that’s designed to use them properly (e.g. actually do common mode noise rejection.) In some other systems you absolutely need isolation transformers or optical isolation, etc. to avoid hum and colored hiss.
Doing solid star grounding can hep because most of the induced ground loop current can flow thru the new grounding wires and not your current interconnects (and the components) in your system, how much of a difference really depends on the systems in question.
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Thanks Ted, Ill check it for sound differences when I made a connectable cable. Maybe I don’t have hum due to the balanced connection from DS to preamp and true balanced designs.
As audio.bin mentioned perhaps a blacker background would be the main result if there’s already no hum in your system.
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What’s the latest on the release date?
It’s hard to say. I think the new boards will be the final ones, but there’s still software work and I don’t know the state of PS Audio’s pieces of the puzzle: among other things they are doing the display and it will be nice, so it will take some work.
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Do you dare to comment on sound quality? What can we expect? What will the new hardware be able to do with a good firmware?
I think I spoke a little about it in some post above on this thread or the other TSS threads (Cost no object edition of DS DAC or New high end PS DAC in the works)
My ears aren’t what they used to be, but it’s immediately apparent that the bass is tighter: more controlled and deeper. E.g. I heard double basses in places I only noticed single basses before. The articulation of the bass is more apparent (e.g. on Shaggy’s “Lucky Day”)
The playing is more effortless, there’s more ease, never any sign of “running out of gas.”
One of my favorite things is “a darker background”. That always makes many things better: more inner detail, more dynamics, more space around the instruments and better instrument placement, etc. With a blacker background by definition things are a little clearer which makes you want to turn things up a little higher than you used to. Like Windom a little extra loudness doesn’t cause any ear fatigue.
I very much enjoy listening to it and it drives me to play many things I haven’t heard for a while just to see what I hear now.
Still the first prototypes have a few problems that I’ve addressed in the new boards, some of which might further improve sound quality.
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Still looking at mid 2020
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That sounds really great Ted!
Did you also notice anything special at the top end, e.g. in cymbal sound? Something like better resolution and differentiation between more than one sounds in that range and maybe even a little more openness and decay?
The DS is already fantastic there, just those are potentials I could imagine from my experience with analog.
Ted, I’m curious if you can carry some of that over to the next DirectStream update or are we running out of gas on the current FPGA capabilities? I remember you saying some of the work on the new DAC would carry over to the DSD but I realize the processor in the new unit is obviously more powerful. Just like to know how much room for improvement we have left in the current FPGA in the DSD?
To be honest my ears can’t really appreciate small differences in cymbals anymore. I do however notice more decay on everything - I forgot to mention that above… My wife reports more extention in the highs. The darker background helps all frequencies including the highs. The better transformers will certainly help both the lows and the highs.
There’s still room in the DS’s FPGA memory for more work and I’m certainly going to see what new work from the TSS can be backported to the DS. At this point I’m not sure exactly what they will be. I still have some things I have started but not finished in the sigma delta modulator. If they work, they are applicable to both the DS and the TSS.
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That’s great to hear Ted. It’s amazing to me to think the sound of the DSD with Windom can be improved even more! The best purchase I’ve made in my system yet. Thank you for continuing to push the envelope of what is possible!
Great, sounds as if it will be hard for even the best turntables to compete especially in bass performance and the improvements of blacker background we know from the firmware upgrades.
Good to hear you feel there is still potential for SQ improvements with the DS’s FPGA Ted.
You may have covered this elsewhere but I’d highlight the possibility of (further) noise reduction in the upper treble region, given the improvements you made with noise reduction in Snowmass in the bass & low mid-range, followed by improvements you made with noise reduction in Windom in the upper mid-range & low treble. Windom is wonderful but I do wonder whether there is scope for more clarity & delicacy that might come from further noise reduction in the upper treble. Given the extensive Forum discussion of problems in this area experienced by a significant minority of Windom adopters (fierce treble, excessive sibilance etc) this could be a fruitful focus for experimentation.
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