Cleaning up USB signal for DAC

[Solstice380]

I noticed Superdad (Alex/UpTone) liked your comment.

 

I find it interesting since when he was asked at Whatsbestforum if he would blind A/B his own product he said he would with out any hesitation.

 

When Amir said he would fly out on his own dime, all the sudden Alex ceased posting at WBF.

 

My comment had nothing to with audio, decrapifiers, or blind testing. Are you getting the hints being dropped your way? Seemingly, not.

[STC]

..... To quote the maker of one of the products I tested, when I told him of my results *“When gear is properly designed all of the "fixes" have very*little effect on SQ, thankfully most gear isn’t, so I’ll be in business for a long time”

 

Did he list the poorly designed gears?

[The Computer Audiophile]

Based on my experience if a piece of gear is properly designed you have no need for after market fixes. With my old Dac the fixes improved the SQ, but with my present Dac I tested 3 devices, 6 USB cables and 3 ethernet cables. 2 of the devices had a slight negative effect and all other had no effect at all. To quote the maker of one of the products I tested, when I told him of my results *“When gear is properly designed all of the "fixes" have very*little effect on SQ, thankfully most gear isn’t, so I’ll be in business for a long time”

 

My concern with statements that use the terms "properly designed" is that there may be down sides to what's considered "proper design." Proper design to my friends is a device that includes bluetooth, wifi, USB, turntable, speakers, all-in-one. There's no free lunch. Sure some companies use optical isolation between the USB receiver ship and the rest of the DAC, but there's a down side to these according to other manufacturers.

 

Again, some manufacturers don't even believe it's possible to "properly design" a USB input in the same chassis as a DAC. I think this conversation would be much better if people could offer reasons, examples, and experience. I only wish I had the technical knowledge to explain some of this stuff.

[Jud]

*“When gear is properly designed all of the "fixes" have very*little effect on SQ, thankfully most gear isn’t, so I’ll be in business for a long time”

 

This is true. Though sometimes DAC design can't be responsive to the reason for SQ problems, for example if non-DAC power supply noise propagates through the system and into the amp. Of course in these situations USB tweaks won't resolve the problem either.

[plissken]

I'm not defending Alex, but you have to realize that whole thing with Amir offering to fly out on his own dime is just a clap trap.

 

In what way? One member there asked him if he would. Alex answered with a resounding:

 

 

Amir offered to fly out. You can try and shine that turd all you want Chris.

[The Computer Audiophile]

In what way? One member there asked him if he would. Alex answered with a resounding:

 

[ATTACH=CONFIG]33626[/ATTACH]

 

Amir offered to fly out. You can try and shine that turd all you want Chris.

 

Not trying to shine any turd. It's just a blowhard move to rally your base by saying you'll fly out there on your own dime. It's a big chest-puff that makes you appear one way, but the reality is far different.

[Jud]

Sure some companies use optical isolation between the USB receiver chip and the rest of the DAC, but there's a down side to these according to other manufacturers.

 

The optical interface will do a great job of shielding the DAC from external influences, but the optical to electrical conversion can itself be a source of noise inside the DAC. IIRC, some designers prefer GMR isolators for this reason.

[The Computer Audiophile]

The optical interface will do a great job of shielding the DAC from external influences, but the optical to electrical conversion can itself be a source of noise inside the DAC. IIRC, some designers prefer GMR isolators for this reason.

 

Thanks Jud. It's things like this that people without direct experience or knowledge of this design, don't want to think about. In a text book, an optical isolator is the perfect solution. In reality there's no free lunch.

[plissken]

My comment had nothing to with audio, decrapifiers, or blind testing. Are you getting the hints being dropped your way? Seemingly, not.

 

I wasn't commenting on your post. I was commenting on the fact that someone self exiled from a forum after agreeing to a blind A/B any time of day and then like a puff of smoke disappeared into the wind.

 

I can't wait for all the people to come out and defend his response, subsequent behavior, and faith in what he is selling.

[Jud]

I noticed Superdad (Alex/UpTone) liked your comment.

 

I find it interesting since when he was asked at Whatsbestforum if he would blind A/B his own product he said he would with out any hesitation.

 

When Amir said he would fly out on his own dime, all the sudden Alex ceased posting at WBF.

 

Be very, very careful what you "like," plissken is watching!

 

 

Please do try to calm down and let other folks enjoy themselves. You've repeated what you think enough times that everyone who wants to has long since gotten the point. So far, everyone I've seen in the conversation has accepted the notion that we ought to be skeptical of USB tweak manufacturers' claims, which I think is what you were trying so desperately to get at you had to shoehorn it in by talking about who "liked" another comment! In other words, we've already calmly discussed what you're hollering about.

[plissken]

Not trying to shine any turd. It's just a blowhard move to rally your base by saying you'll fly out there on your own dime. It's a big chest-puff that makes you appear one way, but the reality is far different.

 

Again in what way? Alex said he would do it. A member said he would go out on his own dime and even agreed to the other conditions set forth by Alex. Not exactly a one sided exchange. How is it unfair to Alex?

 

I've been harangued for not testing all these different devices out. Same can be said however for proper bias controlled evaluation. Sauce that is tasty on goose is equally tasty on gander. People railed at me for not getting expensive Ethernet cables (without realizing I already had previously). So what do I do? I get something in for 25 days, live with it in system, get some output recorded and post it vs 315 foot of cabling. Only to have all the people that wanted me to put up or shut up not take their own advice since they weren't going to know the answers before hand. If you want to know my morphed view point and conversational style, well there you have it.

 

The subjective camp can't have it both ways. I'm not asking for a tilted field here. We are all about discovery and I've taken pains to do so and share the result/s.

[plissken]

Be very, very careful what you "like," plissken is watching!

 

 

In other words, we've already calmly discussed what you're hollering about.

 

You aren't being fair Jud.

 

The like/unlike/thanks are just as public as a posting. Not on me if some thought it was anonymous. Any ones guess if it stays that way after this. I personally don't have an issue with the like/thanks/polls being public.

 

I think the fact that he was actually going to be tested blind and that he skipped town says a lot about the faith he has either in his ears or his product. It's a valid critique.

 

Anyone that wants to can start reading the WBF thread in question starting here.

[The Computer Audiophile]

Again in what way? Alex said he would do it. A member said he would go out on his own dime and even agreed to the other conditions set forth by Alex. Not exactly a one sided exchange. How is it unfair to Alex?

 

I've been harangued for not testing all these different devices out. Same can be said however for proper bias controlled evaluation. Sauce that is tasty on goose is equally tasty on gander. People railed at me for not getting expensive Ethernet cables (without realizing I already had previously). So what do I do? I get something in for 25 days, live with it in system, get some output recorded and post it vs 315 foot of cabling. Only to have all the people that wanted me to put up or shut up not take their own advice since they weren't going to know the answers before hand. If you want to know my morphed view point and conversational style, well there you have it.

 

The subjective camp can't have it both ways. I'm not asking for a tilted field here. We are all about discovery and I've taken pains to do so and share the result/s.

I never said it's unfair to Alex and I'm not defending him. I just said it's a blowhard move by Amir.

 

I certainly hear your points. I think it's cool you've done some of this stuff.

[plissken]

I just said it's a blowhard move by Amir.

 

I certainly hear your points. I think it's cool you've done some of this stuff.

 

Thanks. But I have to ask: In what way was Alex's agreement to blind A/B any day any time with his music and when to switch and Amir offering to go out a blowhard move?

 

So if if someone said to me: I can hear differences in Ethernet cables and I offered to come out with Client / Server / Switch and 315 foot of cabling that it's a 'blowhard move'? (and yes I have recently offered btw).

 

I'm by no means opposed to a $50,$99, $170 device providing a step up in performance BTW. Just given the measurements and the sighted method of evaluations are at odds. Also I don't see any return policy on Uptones site so that makes me hesitant to give it a whirl. I also don't know anyone in the NW KY/Cinci/Indiana region with one.

[Jud]

You aren't being fair Jud.

 

The like/unlike/thanks are just as public as a posting. Not on me if some thought it was anonymous. Any ones guess if it stays that way after this. I personally don't have an issue with the like/thanks/polls being public.

 

I think the fact that he was actually going to be tested blind and that he skipped town says a lot about the faith he has either in his ears or his product. It's a valid critique.

 

Anyone that wants to can start reading the WBF thread in question starting here.

 

They may also want to look at this other WBF thread here: I'm Not Gonna Tell How Great My MicroRendu plus Sonore Signature Power Supply Sounds! - Page 8

[tja1]

I think this conversation would be much better if people could offer reasons, examples, and experience. I only wish I had the technical knowledge to explain some of this stuff.

 

+1

 

I would add that an explanation of the potential ramifications of the design decisions would be helpful. Help me understand the trade offs and I will buy your product almost every time.

[jabbr]

The optical interface will do a great job of shielding the DAC from external influences, but the optical to electrical conversion can itself be a source of noise inside the DAC. IIRC, some designers prefer GMR isolators for this reason.

 

There is no single "optical isolator" and so noise specs depend on the device being selected. There are optical transceivers that have very low noise.

 

The issue with optical isolation is that the isolators often don't have the needed bandwidth. The highest speed commonly available optical isolators have a bandwidth of 50 Mbs while GMR goes up to 150 Mbs and so you need to look at things like jitter/skew etc. to decide on performance. Of course there are optical transceivers which do 100 Gbe so this is probably more of a cost issue than a technical capability issue.

 

This technical article has good explanations: http://www.ti.com/lit/an/slla198/slla198.pdf and goes over pros and cons of the common isolation techniques.

[Jud]

There is no single "optical isolator" and so noise specs depend on the device being selected. There are optical transceivers that have very low noise.

 

The issue with optical isolation is that the isolators often don't have the needed bandwidth. The highest speed commonly available optical isolators have a bandwidth of 50 Mbs while GMR goes up to 150 Mbs and so you need to look at things like jitter/skew etc. to decide on performance. Of course there are optical transceivers which do 100 Gbe so this is probably more of a cost issue than a technical capability issue.

 

Thanks, good to get more info.

 

 

I didn't make it clear enough that when I said "the optical to electrical conversion can itself be a source of noise," I really did mean "can" (depending on the specific isolator) rather than "will."

[jabbr]

I didn't make it clear enough that when I said "the optical to electrical conversion can itself be a source of noise," I really did mean "can" (depending on the specific isolator) rather than "will."

 

Sure, but I think that when designers say they picked GMR for better "noise" purposes they are being somewhat disingenuous. The parts just don't work well at high speeds.

 

I've been thinking about DAC isolation a fair amount recently and, you know, think that with optical Ethernet in, the whole ground loop/leakage current etc etc issue vanishes, but still left with the need to clean up the internal digital signals before being sent to the DAC. Ultimately what matters is the SI of the internal I2S or DSD signals themselves, and this is where DAC manufacturers really need to focus. I'd go so far as to say that if DACs all had good internal isolation/signal integrity/reclocking etc, then the permathreads about external isolation techniques, which power supplies and voltages to power the external devices, and the technologies in the external devices themselves would be moot.

[miksu8]

Mike, Chord said the same thing about Hugo 1, the 5Vbus flashing, no impact. Sorry, but there is an impact from my own testing. Rob said the same thing about power supply for 2Qute, no impact from there original switching power supply, meanwhile most users found an impact, including Ted here on the forum.

What I am saying is that what the manufacturer says I take with a grain of salt. Actual user experience, most important your own, are far better measures.

Overall, I think the Hugo 2 will be a great DAC but here are my complaints on it's design.

1. The need for 5Vbus on the USB input for flashing is more than likely a source of SQ degradation. Why even have it if not needed for galvanic isolation? For saving on battery life? Not for desktop of course.

2. The implementation of LIPO batteries as the power supply and inability to bypass has it's downfalls. I find it to be second fiddle to a great PSU for SQ. Replacement of those batteries once they fail, around 3 years or less of continuous use, will be an expensive fix if Chord requires you to do so by them the manufacturer.

3. Why overpay for features you don't need? You want a desktop DAC that inputs via USB. Do you need to be paying for other digital inputs? Do you need battery power?

 

4. Why pay for a DAC that tries to do everything but only falls short in PSU implementation, USB implementation. Better to find a DAC that doesn't try to make the DAC user impenetrable, but instead user friendly to outside design implementation.

 

After buying an Ifi Nano DSD LE dac for backup. It's simplicity of design and ability to provide great sound has opened up my eyes on DAC's. It may not have the exact detail or stage size of a Hugo, but at 1/20th the cost it rivals in musicality the Chord Hugo. Has me on pause of purchasing a new Chord DAC of their current line up. I would love to get another Chord DAC but I want it on my terms of features and thus pricing. Doesn't exist yet. 2Qute is probably the closest.

 

Those are fair points. Haven't tested any DAC with better powers or cleaners yet so don't have experiences.

 

Chord has been open about the fact that galvanic isolation can benefit their DACs which don't have it so I do trust them. But not so much as my own ears . So to be sure I'm going to bring at least some Ifi devices home with Hugo2 for listening.

 

Btw I tested Gustard U12 (USB->optical) with Mojo and another DAC but bass became a bit soft for some reason so sold it. Also have listened Hugo and 2Qute but didn't like them - too bright and lean sound for my taste. Could have been because of my bad USB source...

[Jud]

Those are fair points. Haven't tested any DAC with better powers or cleaners yet so don't have experiences.

 

Chord has been open about the fact that galvanic isolation can benefit their DACs which don't have it so I do trust them. But not so much as my own ears . So to be sure I'm going to bring at least some Ifi devices home with Hugo2 for listening.

 

No matter what the outcome, hope you enjoy it!

[mmerrill99]

Nothing is black and white. We now have a starting list of DAC's where USB section isn't going to be improved upon.

Again you demonstrate that you don't know what you are talking about & neither does your "hero" Amir

The USB interface is just the channel through which leakage currents are finding their way into the USB audio device - you know - the stuff that Amir knows nothing about & doesn't know how to measure.

 

You need to read up about current leakage (& get Amir to read his AP manual) before making these silly statements that you scatter around this forum.

[One and a half]

Those are fair points. Haven't tested any DAC with better powers or cleaners yet so don't have experiences.

 

Chord has been open about the fact that galvanic isolation can benefit their DACs which don't have it so I do trust them. But not so much as my own ears . So to be sure I'm going to bring at least some Ifi devices home with Hugo2 for listening.

 

Btw I tested Gustard U12 (USB->optical) with Mojo and another DAC but bass became a bit soft for some reason so sold it. Also have listened Hugo and 2Qute but didn't like them - too bright and lean sound for my taste. Could have been because of my bad USB source...

 

My experiences with the MPD-3 DAC, which was 'immune' from the effects of USB leakage, showed that with the Intona, this immunity was broken. The DAC was a 'new' DAC after the inclusion, the grunge just vanished. I would mirror your experiences in that the DACs you listened to were in all likelihood, keepers, had they a cleaner signal fed to them. As for which USB fixer is a silver bullet is not certain. The leakage paths manifest themselves via the source signal cable, in this case USB, and also via the AC supply. If the AC supply actively suppresses or cancels the leakage currents, the signal path then becomes a better conduit for leakage currents to flow and downgrades the SQ accordingly.

This is really getting complex, wish it was a lot simpler, maybe vinyl is 'right' after all. But the crackles, warping, cleaning, storage of vinyl makes it unattractive (to me), better the mind is engaged to rid ourselves of leakage currents instead from digital transmissions.

[ElviaCaprice]

Would be great if you could describe the key differences in the sound of your IFI DAC, with and without USB tweaks. TIA!

Hi Rexp,

It's like night and day. No digital hash, greater detail/soundstage/separation, overall better EQ levels. Another key with the Ifi Nano DSD LE is the power supply, I find the battery playback secondary to a galvanically implemented 5Vbus power supply. See signature below.

[plissken]

Hi Rexp,

It's like night and day. No digital hash, greater detail/soundstage/separation, overall better EQ levels. Another key with the Ifi Nano DSD LE is the power supply, I find the battery playback secondary to a galvanically implemented 5Vbus power supply. See signature below.

 

Curiosity @ work. You have a $129 DAC and between the computer and the DAC you have approximately $1100 PCIe USB, power supplies, regeneration, and galvonic isolation.

 

Did you look at any ~ $1200 DAC's?