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I was wondering if anyone knows of an inexpensive DAC that pays special attention to isolating well, that also provides it's own 5V reference voltage for the usb, and that reclocks. I don't want to get into the debate whether noise matters or not....just looking for a few different models that do this well. I already heard that the D90 does not have galvanic isolation...and i don't know about the other 2 features I want (provide their own 5v ref and reclocks).

 

I know the Schiits unison advertises it does this (galvanic isolation, reclock/regenerate, and provide their own 5v reference)

 

Miska said that the Schiit bi-frost doesn't measure well suggesting the 192k samping rate is not good enough.

 

In another thread Barrows said there are many dacs that do these things well, but didn't offer any suggestions....I am just wondering if there are any that do these things well under $1k?

 

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4 hours ago, beerandmusic said:

I was wondering if anyone knows of an inexpensive DAC that pays special attention to isolating well, that also provides it's own 5V reference voltage for the usb, and that reclocks. I don't want to get into the debate whether noise matters or not....just looking for a few different models that do this well. I already heard that the D90 does not have galvanic isolation...and i don't know about the other 2 features I want (provide their own 5v ref and reclocks).

I know the Schiits unison advertises it does this (galvanic isolation, reclock/regenerate, and provide their own 5v reference)

 

Sorry, but you mis-understand both clocking and digital isolation.

 

All DACs "reclock";

You are confusing DAC audio-rate clocking (22.5792MHz/24.576MHz and multiples thereof) with the data clocks for interface chips (e.g. 24.00MHz or 25.00MHz).

[And by the way, despite anyone's marketing--including my own--"regenerate" is technically a meaningless thing. 9_9 USB (and Ethernet) data has to pass through both a PHY and a MAC (medium access control) protocol processor (these days the former is generally integrated into the latter). You could call the passing through any MAC a "regeneration" of the signal. (The term "regenerate"--related to USB--dates back to UpTone Audio coining it for our original USB REGEN back in 2014; Call it our "Kleenex" moment. x-D) We use USB hub chips--those are a form of MAC too--to "regenerate."  With any act of passing data--through a processor of any kind--some things are left behind and some things are passed through. Such is beyond the scope of my interest in this reply...

 

In regards the above, the Schiit Unison USB input board--which you mention in multiple posts--is no different. They simply chose a more open architecture microprocessor (a Microchip PIC32) to tweak their own USB handling code--as opposed to staying with the Cmedia previously used or choosing the XMOS environment. I applaud them, but the rest of what they are doing on the Unison board about the same as their prior Gen5 USB, with a Wurth Ethernet transformer module and a standard digital isolator on the I2S lines.

 

No DACs (except for Auralic Vega G2 and Phasure NOS1a which both use the no-longer-available Silanna ICE08USB high-speed USB isolator--as also used in our ISO REGEN) have digital isolators BEFORE their USB input stage; Any DAC or DDC that you see advertising "galvanic isolation" of their USB (or Ethernet) input are doing so with digital isolators on the I2S lines--AFTER the USB input stage.  [That is because USB is a bi-directional protocol on a single pair of data wires and ALL digital isolator chips pass data in only one direction (yes, many isolators have more than one bit channel in the same package and one can choose the combination of directions; but that does not make them bi-directional). The USB protocol reverses data flow on a single wire pair.]

 

You also mention wanting a DAC that "provides its own 5V reference." I am sure you mean one that does not rely on USB 5VBUS power for its input stage. But unless a DAC designer goes to the trouble and expense of building in an entirely separate power supply just for the USB>I2S input board (and I mean if not a separate power transformer, at least a dedicated transformer secondary, separate set of AC>DC rectifying diodes, and voltage regulators--all to keep a separate 0-volt/-VE "ground" reference), your requirement will be at odds with having digital isolator chips on the I2S lines after said USB input stage.

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THanks for sharing...it will take awhile for me do digest even a fraction of this.

 

I guess where I am "trying to go", is that I am stuck...

 

I want usb for functionality purposes, but I always "think" that any solution other than usb (enet,toslink,thumbdrive, even hdmi) sound better.  Objectivists are trying to convince me that usb noise is not a problem and that all competent dacs will pretty much sound the same, and that my thinking is likely just a problem with "level-matching". 

 

Leaving that aside for a moment, i know that the only inputs to a dac are the digital music, the 5v reference voltage, and noise.

 

Some engineers will suggest the digital music always arrives at the dac perfectly or maybe lose 1 bit every so many hours, and that even if you lose a bit, it will be a dropout or glitch, something easily recognizable, not like something just "sounds better".

 

Anyway, that makes me conclude that "noise" on the usb is the problem with why other methods sound better.

That leads me to think that I want something that isolates this "noise".

 

I don't really care how the dac isolates the noise, i just want a solution that markets that it isolates the noise.  When I saw that schiit now markets that they reclock and isolate, I don't recall seeing that in their marketing before, and i have had a gen5 usb before, so perhaps i just overlooked that marketing...anyway, so i guess what you are saying here is that they haven't done anything new since gen5 regarding usb isolation.

 

hmmmm....where am I going with this.

 

I guess I just want usb to sound as good as toslink, but i want usb for DSD.

 

Maybe it is just as the other site suggests that it is just a matter of properly "level-matching" and that it is just in my head or bias....but it seems so much obviously better.....just frustrating when everyone thinks you are crazy...maybe i am crazy (grin).

 

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oh and regard to reclocking, i just noticed that schiit used that term, and I thought it had to do with "regenerating" the perfect bits, thinking that it may be necessary for timing purposes. (in my mind i just picture the bits coming into a circuit and then the dac uses it's own clock to pass the bits on to its circuitry at a control point that it is managing).... I don't really understand why reclocking may or may not be necessary.  I believe your device "regenerates" the signal because it is trying to compensate for usb noise that may affect the digital music?...and my thinking IF it is necessary, then that should be a function of the dac...and when I saw that schiit advertising re-clocking, that i thought it was doing something similar to your solution.

 

Nothing personal, I really don't want to buy gadgets between the pc and the dac, I am willing to wait patiently for a dac that won't need such technology...as you know i have already waited over 5 years (smile).

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1 hour ago, Superdad said:

 

Wurth Ethernet transformer module and a standard digital isolator on the I2S lines.

 

In your quote above, did you mean the gen5 already had Wurth Ethernet transformer module and a standard digital isolator on the I2S lines, or that is a new feature of the unison?

 

Not that it matters, because i don't want to fork out for a yggi, and miska suggests the bifrost sampling rate is not high enough, so I am not going to look at schiits anymore...at least not any of their current offerings.

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1 hour ago, Superdad said:

You also mention wanting a DAC that "provides its own 5V reference." I am sure you mean one that does not rely on USB 5VBUS power for its input stage. But unless a DAC designer goes to the trouble and expense of building in an entirely separate power supply just for the USB>I2S input board (and I mean if not a separate power transformer, at least a dedicated transformer secondary, separate set of AC>DC rectifying diodes, and voltage regulators--all to keep a separate 0-volt/-VE "ground" reference), your requirement will be at odds with having digital isolator chips on the I2S lines after said USB input stage.

 

Regarding 5v reference, i probably misunderstood schiits marketing:::

Self-power by the DAC for the critical low-noise re-clocking and latching sections.

 

I thought that meant that they are providing their own voltage (assuming some type of regulators), to do the reclocking so they didn't need to rely on the 5v from the usb in case it had problems.  I guess i just have a wild imagination (grin)...again, thinking the purpose is to isolate the usb noise.

 

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6 hours ago, beerandmusic said:

Nothing personal, I really don't want to buy gadgets between the pc and the dac, I am willing to wait patiently for a dac that won't need such technology...as you know i have already waited over 5 years (smile).

 

AFAIK, all who used gadgets with Schiit Yggdrasil before Unison do not use them with Unison anymore because they seem to reduce SQ.

 

Matt

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1 minute ago, matthias said:

 

AFAIK, all who used gadgets with Schiit Yggdrasil before Unison do not use them with Unison anymore because they seem to reduce SQ.

 

Matt

 

I stopped using USB Regen with multibit Gungnir, it was before Unison was introduced.

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There are a few usb cable with either no 5v wire inside (its simply not connected) or a sort of Y wire where one of the "Y"s provides the 5v that the dac needs for handshakes or whatever. The former is for dacs that do not need to see 5v the latter is for dacs that need to see it and you can simply hook up a good clean battery to provide the 5v (not phone chargers).

Did that make sense? 

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