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Jitterbug Measured Properly

146.198.73.149
Posted on August 29, 2015 at 00:37:19
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 HiFi News tested the Jitterbug and published measurements of the eye pattern. With a 'standard' 2m usb cable in their rig, rise time was reduced from 22 to 15 nS, with jitter being reduced on the Dragonfly from 220 to 165 pS. Before and after, the square shapes showed the effects of band limiting due to filtration.

The jitter spectra also showed the differences before and after.

This is the first published test where measurements can be correlated to improved SQ using such devices.

The measure no difference, hear no difference, approach and conclusion are the results of deficient measurement and analysis techniques.




 

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RE: Jitterbug Measured Properly, posted on August 29, 2015 at 05:16:04
SBGK
Audiophile

Posts: 444
Joined: March 22, 2012
 common courtesy to post a link to the magazine and say which issue you're talking about.


http://mqnplayer.blogspot.co.uk/

 

RE: Jitterbug Measured Properly, posted on August 29, 2015 at 05:26:34
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 If you don't know about HiFi News then ????????

 

RE: Jitterbug Measured Properly, posted on August 29, 2015 at 09:04:57
Garg0yle
Audiophile

Posts: 859
Joined: December 1, 2014
 Who was not measuring properly, do you have a link?

Can to fill us in on the detail? I'm not interested in buying a subscription.

"If you don't know about HiFi News then????"
lol I've never heard of it myself.
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RE: Jitterbug Measured Properly, posted on August 29, 2015 at 10:56:47
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 I have summarised their findings. They are not a web freebie and there is no link to the details unless you subscribe.

The description of then issue is just that.

Google is your friend and those who are really interested in the details can always buy the issue.

 

Fred what do you expect?, posted on August 29, 2015 at 12:52:02
Gordon Rankin
Manufacturer

Posts: 2928
Joined: June 9, 2000
 Fred,

It's not like I am over here spending all my time doing nothing.

We did allot of research on the damn thing. We made boards that could be reconfigured into about 10 different devices, then we tweaked and tweaked some more.

Then we gave the resident sound guy Joe Harley all of them and he picked this one out as the best sounding.

This is a product people can try and doesn't even cost as much as many of the cables in your system.

Thanks for posting,
Gordon
J. Gordon Rankin

 

RE: Fred what do you expect?, posted on August 29, 2015 at 14:54:07
Sprezza Tura
Audiophile

Posts: 4585
Location: New York City
Joined: August 24, 2012
 Mr. Rankin:

Somebody on another board claims you did not have a hand in designing the Jitterbug, which I do NOT believe. (I think you did design it and just purchased one.)

I can provide a link. Can you comment?

 

DON'T COMMENT, Gordy..., posted on August 29, 2015 at 17:58:31
Ivan303
Audiophile

Posts: 48887
Location: Cadiere d'azur FRANCE - Santa Fe, NM
Joined: February 26, 2001
 This board is a sink-hole you can never get out of alive!

See you in Denver. :-)


First they came for the dumb-asses
And I did not speak out
Because I was not a dumb-ass

 

RE: Fred what do you expect?, posted on August 29, 2015 at 20:38:16
Bob_C
Audiophile

Posts: 2667
Location: NY
Joined: July 31, 2000
 Let's see a link. Gordon is one of the best and most honest guys in field. Love to see what moron said that...

 

RE: Fred what do you expect?, posted on August 29, 2015 at 20:44:08
Sprezza Tura
Audiophile

Posts: 4585
Location: New York City
Joined: August 24, 2012
 Post #109.

 

RE: Fred what do you expect?, posted on August 29, 2015 at 20:50:20
Bob_C
Audiophile

Posts: 2667
Location: NY
Joined: July 31, 2000
 Oh that moron.... figures. He also posts on CA... Dumber than driftwood...

 

RE: Fred what do you expect?, posted on August 29, 2015 at 20:52:08
Sprezza Tura
Audiophile

Posts: 4585
Location: New York City
Joined: August 24, 2012
 Oh really? Never heard of him..but a review of his posts shows he is an utter blowhard and a buffoon pretending to be an "expert". The thread came up in a search on the Jitterbug.

 

RE: Fred what do you expect?, posted on August 29, 2015 at 21:07:39
ssilberman@audioquest.com
Manufacturer

Posts: 3
Location: Colorado
Joined: July 6, 2012
 This will be my one and only post on the subject of who designed JitterBug.

Gordon Rankin is the head designer of AudioQuest's JitterBug (and DragonFly and the forthcoming Beetle asynchronous USB, asynchronous Bluetooth, optical Toslink DAC) Dual-Circuit USB Line Conditioner. In addition to Gordon we received a tremendous amount of invaluable input from our own Garth Powell. Along the way we relied on Bill Low and Joe Harley for their sonic opinions. The end result is a product we feel very thrilled to have created.

Steve Silberman
VP - Development
AudioQuest
Best regards,

Steve Silberman
AudioQuest

 

RE: Fred what do you expect?, posted on August 29, 2015 at 21:09:29
Garg0yle
Audiophile

Posts: 859
Joined: December 1, 2014
 I'm always amazed at the activity that site has, it seems to fly under the radar when googling things.

Perhaps the forum software is more conducive to longer threads.

The threads here fall apart after page 2, they become to hard to follow between the way the quoting works and the posts that usually disappear in discussions that big.

Anybody else think that site is creepy?
I know there are wackos here, but I feel I probably wouldn't like anybody there. lol

Whats best?



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RE: Fred what do you expect?, posted on August 29, 2015 at 21:12:54
Sprezza Tura
Audiophile

Posts: 4585
Location: New York City
Joined: August 24, 2012
 Steve, thank you for posting and clarifying. I had no doubt Mr. Rankin was the designer so when I saw that post, after simply googling "Jittebug Reviews", I was quite taken aback at the posters arrogance.

Note a follow up post by his engineer "buddy" who claims to know Mr. Rankin and it seems was the source.

Thanks again.

 

RE: 'dallasjustice', posted on August 29, 2015 at 21:13:09
Ivan303
Audiophile

Posts: 48887
Location: Cadiere d'azur FRANCE - Santa Fe, NM
Joined: February 26, 2001

dallasjustice

Friends 3

Basic Information
About dallasjustice

Location:
Dallas, Texas

Occupation:
Freedom Fighter

OK, do you STILL think Gordon should comment?




First they came for the dumb-asses
And I did not speak out
Because I was not a dumb-ass

 

RE: Fred what do you expect?, posted on August 29, 2015 at 21:14:32
Sprezza Tura
Audiophile

Posts: 4585
Location: New York City
Joined: August 24, 2012
 Creepy indeed

 

RE: 'dallasjustice', posted on August 29, 2015 at 21:15:37
Sprezza Tura
Audiophile

Posts: 4585
Location: New York City
Joined: August 24, 2012
 If some one was spreading misinformation about me and tarnishing my reputation I sure would.

 

If you took the time to comment every time some fool posted nonsense on an internet chat board..., posted on August 29, 2015 at 21:25:32
Ivan303
Audiophile

Posts: 48887
Location: Cadiere d'azur FRANCE - Santa Fe, NM
Joined: February 26, 2001
 Oh, wait...

Sorry, never mind. :-(






First they came for the dumb-asses
And I did not speak out
Because I was not a dumb-ass

 

RE: If you took the time to comment every time some fool posted nonsense on an internet chat board..., posted on August 29, 2015 at 22:14:36
Garg0yle
Audiophile

Posts: 859
Joined: December 1, 2014
 ba-doom tisshhh
△This message will self destruct in 10 seconds△

 

RE: 'dallasjustice', posted on August 29, 2015 at 22:16:20
Garg0yle
Audiophile

Posts: 859
Joined: December 1, 2014
 The sad part is I think he has more friends then me.

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RE: Fred what do you expect?, posted on August 29, 2015 at 22:24:44
Bob_C
Audiophile

Posts: 2667
Location: NY
Joined: July 31, 2000
 I read some more of the thread, it is also amazing how much of wind bag the site founder is and dallass has head up amir butt... The HFNRR review was mentioned but dallass is waiting for amir's measurements. LOL

 

What does it sound like? , posted on August 29, 2015 at 23:47:54
three_sox
 Have you used it?

 

RE: What does it sound like? , posted on August 30, 2015 at 00:38:41
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 Just bought one of the last ones in UK, mail order - no stock till mid September in most places.

 

I bought, posted on August 30, 2015 at 00:44:46
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 two to try out. Very difficult to source as there is virtually no stock.

 

RE: What does it sound like? , posted on August 30, 2015 at 00:50:42
three_sox
 Good stuff, let us know how it performs.

No stock for a couple of weeks shows either they have been keenly sort after or there were not many to start with. I suspect the first option.

Good luck with yours.

 

RE: Fred what do you expect?, posted on August 30, 2015 at 00:57:05
Audio Bling
Audiophile

Posts: 307
Location: Australia
Joined: October 9, 2007
 Steve, I think you have a winner.. I was prompted to get one after reading the AudioStream review. I have a Wyrd & the J'Bug works very nicely with it; I am pleased. The investment is modest; it is passive & portable which means you can take it to the office etc. etc.. All adds up to a very marketable product that will suit audiophiles & non-audiophiles who are interested in improving sound quality.

 

RE: Fred what do you expect?, posted on August 30, 2015 at 02:19:22
Mercman
Audiophile

Posts: 6581
Location: So. CA
Joined: October 20, 2002
 I'm looking forward to trying 2. Gordon designs great stuff.

 

RE: Fred what do you expect?, posted on August 30, 2015 at 03:17:20
internethandle
Audiophile

Posts: 42
Location: CA
Joined: November 30, 2011
 Glad to hear it's also sounding good with your Wyrd - Audiostream review hinted at as much but there's more confirmation of synergy with the Uptone Regen than the Wyrd, that I can find. My combo is also sounding good/better.

I did run into the problem (similar to Lavorgna's original Jitterbug review where he had to use a USB extension cable - which seems less than optimal to me sonically or otherwise - to fit two Jitterbugs next to each other on a Macbook's USB ports) of another filter I have made by Alan Maher Designs, which is just a standard USB A connector and a thin ground cord, not fitting next to the Jitterbug on my DAC's motherboard USB bus, so I had to crack open the thing with a razor blade and small hammer and do a makeshift Faraday around it with some EMF/RFI absorbing material for the hell of it. I was surprised how much plastic the thing has, it really is sort of unnecessary and bulky, but removing it solved the crowding issue. Of course, I've voided any potential warranty or return, but the thing is $50.

Anyway, have another one on order from MusicDirect, and can confirm they're also giving out late September estimates for their next batch.

 

RE: 'friend', posted on August 30, 2015 at 06:31:03
Ivan303
Audiophile

Posts: 48887
Location: Cadiere d'azur FRANCE - Santa Fe, NM
Joined: February 26, 2001
 Not so sure I'm comfortable living in a world where 'friend' is a verb.


First they came for the dumb-asses
And I did not speak out
Because I was not a dumb-ass

 

RE: Jitterbug Measured Properly, posted on August 30, 2015 at 06:39:33
soundchekk
Audiophile

Posts: 2426
Joined: July 11, 2007
 "The measure no difference, hear no difference, approach and conclusion are the results of deficient measurement and analysis techniques."

OK. I guess we're talking about Archimago here. But I guess we knew that before.
However. I think Gordon himself kept that kind of attitude up for quite along time.

Since more and more USB filter devices clearly showed how flawed many of todays USB Audio interfaces really are, it was time for AQ/Gordon to jump on the train. Better late then never.

Really funny that especially the AQ Dragonfly has been taken as test device.
As I mentioned before. In my opinion it's the deficiency of the DACs USB interface which is made visible by those filter devices.
And I don't think that the Jitter reduction really tells the whole story.
Correlating it to a difference on sound is usually half the story at best.
IMO knowing how the USB noise creeps into e.g. the analog parts (PS,output stage asf.) of the DAC is perhaps as much as interesting as a picosecond jitter more or less.

Let's keep the fingers crossed that soon DACs will be developed that won't show any improvements by adding these rather trivial filters.




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blog latest >> The Audio Streaming Series - tuning kit pCP

 

How do you rank this amongst the 10 or so: noise reduction units?, posted on August 30, 2015 at 08:16:11
Sordidman
Audiophile

Posts: 13665
Location: San Francisco
Joined: May 14, 2001
 Likely not as important as replacing the PC's power supply.
Or, perhaps, replacing a motorized HD with a SSD
But likely better than replacing the PC/MAC enclosure?

Or, perhaps, the chip fan? If there is one.

Or, maybe a shielded EIDE cable from the HD to the mainboard?

Adding in EMI reducing ERS paper?

Or, since everyone is saying that the JitterBug is really effective along with the USB Regen: does it rank somewhere in between the Regen and a new PSU? More effective than a designer USB cable?

I wonder how effective it would be on the Squeezebox Touch, (If someone is not using the USB port on their Touch)?

Of course the answer is "try it and find out for yourself."

Just curious, since a good linear PSU by any standards is $1000: a tweaked off-the-shelf, dedicated PC or MAC will be costing quite a bit after consumer mods. Cracking the case of certain MAC Mini's is "out-of-scope" for more than half of most consumers. A good SSD drive is double, if not triple the cost of normal, with a lot less space. Costs add up fast, and that's just hardware.




"Asylums with doors open wide,
Where people had paid to see inside,
For entertainment they watch his body twist
Behind his eyes he says, 'I still exist.'"

 

RE: How do you rank this amongst the 10 or so: noise reduction units?, posted on August 30, 2015 at 08:55:49
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 The sad thing is: better computer specifications and type don't often mean better sound.

For starters, a Pipo X7 for $120, properly configured, can sound as good as (though different!) from an expensive box; as long as the demand for simultaneous surfing and processing of other things is curbed.

 

flawed many of todays USB Audio interfaces , posted on August 30, 2015 at 10:16:43
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 I said so when they came out but the vendors did their best to shape consumer attitude which accepted the 'easy' interface solution.

 

RE: flawed many of todays USB Audio interfaces , posted on August 30, 2015 at 12:12:50
Mercman
Audiophile

Posts: 6581
Location: So. CA
Joined: October 20, 2002
 Posted by fmak (A) on May 20, 2009 at 06:14:50
In Reply to: USB port to DAC seems to be really difficult to implement posted by DSG on May 19, 2009 at 14:36:47:

The PCs 5V supply is rubbish and PS jitter is well known.

This is why all these posts about how marvellous the usb interface is for audio is just, well (rubbish?).

 

well, posted on August 30, 2015 at 12:34:32
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 you were amongst the first to sing high praises for it, with the SUSB - sometimes universal serial bus which took some years to sort.

 

RE: flawed many of todays USB Audio interfaces , posted on August 30, 2015 at 16:32:34
Dynobot
 So what if your Dac does not use the +5v, are the short comings of USB gone?

I think people have accepted that USB is the best way to get digital from a computer source...seeing that some if not most have some sort of spdif out...

Then there is Blue Tooth...

 

I got mine from Music Direct, ditto Dragonfly. nt, posted on August 30, 2015 at 17:12:08
oldmkvi
Audiophile

Posts: 10583
Joined: April 12, 2002
 /

 

Here's the Exasound E12 Manual, with their implementation of USB., posted on August 30, 2015 at 17:20:24
oldmkvi
Audiophile

Posts: 10583
Joined: April 12, 2002
 They say it eliminates any potential problems.
I'll know more soon, hope!

 

I used JB with Korg Audiogate, and JB/DF Combo for Finale Playback., posted on August 30, 2015 at 17:26:38
oldmkvi
Audiophile

Posts: 10583
Joined: April 12, 2002
 The sound is richer, smoother, more 3 dimensional.
Totally worth it for me.
I only use them on my Focal Book Desktop Speakers, IMac Yosemite.
Music Direct has both.

 

{I think people have accepted that USB is the best way to get digital from a computer source} , posted on August 30, 2015 at 18:10:14
three_sox
 ...They have?

Toslink?

Ethernet?

Wireless?

Even HDMI?

Or analogue?


The choices are many.

I don't know if there is an unequivocally clear winner of which is best.

 

"Mytek recommends the use of Firewire, as it is a true streaming format.", posted on August 30, 2015 at 18:25:55
oldmkvi
Audiophile

Posts: 10583
Joined: April 12, 2002
 I use Firewire, but USB 2 doesn't work for DSD on Mytek/Mac,
So no real choice.

 

RE: Here's the Exasound E12 Manual, with their implementation of USB., posted on August 30, 2015 at 18:41:10
Sprezza Tura
Audiophile

Posts: 4585
Location: New York City
Joined: August 24, 2012
 2 grand, one input, and it ships with a laptop power supply? You must be joking.

 

RE: "Mytek recommends the use of Firewire, as it is a true streaming format.", posted on August 30, 2015 at 18:42:02
Sprezza Tura
Audiophile

Posts: 4585
Location: New York City
Joined: August 24, 2012
 Basing your whole system around a unicorn format like DSD is rather quaint.

 

Quaint it is, Jack. It is Jack, isn't it? I Knew you'd live up to your rep! Thanks. nt, posted on August 30, 2015 at 18:58:58
oldmkvi
Audiophile

Posts: 10583
Joined: April 12, 2002
 /

 

Now I only listen in DSD 64 or 128. Soon it will only be DSD 256., posted on August 30, 2015 at 19:02:04
oldmkvi
Audiophile

Posts: 10583
Joined: April 12, 2002
 The only PCM I listen to is the Satellite Box, Mytek covers that.
The reviews have been fantastic, esp David Robinson, who used to post here.
I glad you don't approve!

 

RE: Quaint it is, Jack. It is Jack, isn't it? I Knew you'd live up to your rep! Thanks. nt, posted on August 30, 2015 at 19:03:09
Sprezza Tura
Audiophile

Posts: 4585
Location: New York City
Joined: August 24, 2012
 Man your posts crack me up. Are you communicating in a secret language?
Everything your post requires a decoder. LOL. And most of your posts have nothing to do with the threads you post in. Rock on. Different drummer for sure.

 

RE: Now I only listen in DSD 64 or 128. Soon it will only be DSD 256., posted on August 30, 2015 at 19:10:24
Sprezza Tura
Audiophile

Posts: 4585
Location: New York City
Joined: August 24, 2012
 Only DSD..64/128 and soon 256? LOL. So you listen to numbers.

What an absolute joke.

 

RE: flawed many of todays USB Audio interfaces , posted on August 31, 2015 at 00:00:02
soundchekk
Audiophile

Posts: 2426
Joined: July 11, 2007
 You seem to understand "No Nothin'".

You walk on thin ice (I know you wouldn't know how to do it down in San Diego) by trying to become a technical expert. Better leave it.

You just repeat what Gordon and the other commercials are trying to make you and these others non-teccies believe to hide their own deficiencies.

The basic logic is: As long as bits ( the bit-value = 1/0 ) arrive at the DAC as being send, we as users should be fine. Why? """We've got asynchronous USB.""" -- Just kidding. That's -- ah - no - it used to be -- Gordons story.

Because the DAC - and only the DAC - should take care on making the best out of what's coming in. No matter how unstable and polluted voltages - VBUS or D+D- or ground are, if the frames and bits stay in tact it should be OK to the DAC.
All isolation, reclocking/refreshing, filtering, rebuffering should then be done properly inside the DAC. Why?

Because an external filter can make a positive difference, can be neutral, can make things worse. The behaviour will change with every DAC, every transport, every cable, every system, every user. The users are forced to gamble for good sound. That's where we're still at.
And... The industry enjoys it. Just buy 10-20 USB-filters for all your USB ports in the house and you'll be fine.

Enjoy.








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RE: Here's the Exasound E12 Manual, with their implementation of USB., posted on August 31, 2015 at 00:43:25
soundchekk
Audiophile

Posts: 2426
Joined: July 11, 2007
I havn't seen anything that suggests that the DAC betters it's competition
on the USB interface.

And.
To be honest. I consider a DAC that still comes with proprietary drivers, thus limiting its use-cases - an absolute NoGo.

Enjoy.

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RE: Here's the Exasound E12 Manual, with their implementation of USB., posted on August 31, 2015 at 01:59:14
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 One can hope, but I doubt it.

 

usb?, posted on August 31, 2015 at 02:07:09
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 They love it as it adds a baseline cost of e50 with the usb card. Plus, of course, isolation bits and power supply with perhaps another e50. This means a retail cost of 6x base cost.

In mid-end cases, it is better and more economic to use spdif with relock and wave shaping. In high end cases 384k spdif can be had. Most computer based hardware spdif is junk, with little understanding of proper implementation.

Even some designers think that cheap phono plugs are ok, or are forced to use them.

 

RE: flawed many of todays USB Audio interfaces , posted on August 31, 2015 at 03:24:40
Mercman
Audiophile

Posts: 6581
Location: So. CA
Joined: October 20, 2002
 I'm doing just fine here in San Diego. Thanks for asking.

We all get what you are saying since you repeat it endlessly.

How about a few more personal insults?

 

RE: flawed many of todays USB Audio interfaces , posted on August 31, 2015 at 03:55:29
soundchekk
Audiophile

Posts: 2426
Joined: July 11, 2007
 "We all get what you are saying since you repeat it endlessly."

I don't think so. "We all..." -- for sure excludes you. Though you're not alone.

"Repetition..."

As long as I have to read over and over all this misleading nonsense or marketing BS, I'll keep doing so. Sorry.


"Personal insults..."

Saying that you don't have a technical background you consider an insult...
"Technical background " does not mean being able to swap boxes, cables
or applications to finally "hear " a difference.


Enjoy


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blog latest >> The Audio Streaming Series - tuning kit pCP

 

RE: flawed many of todays USB Audio interfaces , posted on August 31, 2015 at 05:32:42
Mercman
Audiophile

Posts: 6581
Location: So. CA
Joined: October 20, 2002
 "You seem to understand "No Nothin'".

I didn't realize this is a common greeting in the Fatherland.

You seem to have a fixation on my work, This is good. Maybe you'll learn something.

Be Happy.

 

RE: Here's the Exasound E12 Manual, with their implementation of USB., posted on August 31, 2015 at 05:37:14
Mercman
Audiophile

Posts: 6581
Location: So. CA
Joined: October 20, 2002
 The ASIO driver for OSX is an accomplishment that you fail to understand. You're too busy pissing on the product and have no experience with it. Typical for your characteristic analysis.

 

RE: Here's the Exasound E12 Manual, with their implementation of USB., posted on August 31, 2015 at 05:42:51
soundchekk
Audiophile

Posts: 2426
Joined: July 11, 2007

Just, grow up. You still got some years left.

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RE: Here's the Exasound E12 Manual, with their implementation of USB., posted on August 31, 2015 at 05:47:39
Mercman
Audiophile

Posts: 6581
Location: So. CA
Joined: October 20, 2002
 You obviously lack the technical understanding to comment on drivers.

Let me help you.

The custom ASIO drivers for OSX and Windows allow this DAC to play native DSD playback as opposed to DoP. There is a big difference in sound quality between the two.

Not that I feel that DSD256 for OSX and Windows is all that necessary, but the capability is there.

 

RE: Jitterbug Measured Properly, posted on August 31, 2015 at 06:17:23
Mercman
Audiophile

Posts: 6581
Location: So. CA
Joined: October 20, 2002
 "Let's keep the fingers crossed that soon DACs will be developed that won't show any improvements by adding these rather trivial filters."

Given your impressive technical background, perhaps you should offer your services to DAC manufacturers for improvement in their designs. I'm sure your understanding of these issues will be invaluable.

 

RE: Jitterbug Measured Properly, posted on August 31, 2015 at 07:07:36
Ryelands
Audiophile

Posts: 1867
Location: Scotland
Joined: January 9, 2009
 I'm sure your understanding of these issues will be invaluable.

AND it would keep him quiet.

D

 

RE: usb?, posted on August 31, 2015 at 08:19:49
Tony Lauck
Audiophile

Posts: 13629
Location: Vermont
Joined: November 12, 2007
 "In high end cases 384k spdif can be had. Most computer based hardware spdif is junk, with little understanding of proper implementation."

There would still be a problem with the reclocker, if it requires adapting to the incoming clock rate, since this will require a variable master clock with attendant complexity and jitter. However, this could be easily fixed by adding a clock signal (could be in SPDIF format) from the DAC back to the transport and the transport could slave to this clock. Then the "reclocker" would just be a small shift register and there would be no need for a variable frequency master clock and phase lock loop circuitry.

There remains one additional problem: conveying the speed the DAC is to operate at which will change depending on file format. This can be done by having the transport select its local clock based on the file format and use this clock whenever the clock from the DAC is at the wrong rate, but when the DAC is at the correct rate switch to the external clock. The DAC does the corresponding thing, namely when it sees that the incoming clock isn't at the same speed as its master clock it switches the master clock to the appropriate speed. (There are some messy details that need to be worked out, viz. state diagrams with timed transitions and when the analog output is muted and unmuted.)

There are also issues of DSD unless one uses the DoP kluge.

Of course this requires compatible logic on both sides, i.e. proprietary to one manufacturer or some kind of a "standard". However, were this to be done it would be advantageous over using packet based mechanisms such as USB and Ethernet, since the basic mechanism used between a transport and a DAC would also useful for isolation mechanisms within a DAC. If you compare the number of logic gates needed for this scheme and compare it with the number needed to implement any USB, Ethernet, or other packet based scheme you will see that all of the packet based schemes are obscenely more complex. This means that they will all create obscene amounts of digital noise in the proximity of critical mixed-signal and analog circuitry and hence for high end sound quality there will have to be additional isolation after this obscenely complex circuitry, adding unnecessary cost.






Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

 

RE: usb?, posted on August 31, 2015 at 17:13:58
Dynobot
 Hey Tony how many Dac's operated in this optimal format that you suggest?

 

RE: Jitterbug Measured Properly, posted on September 1, 2015 at 11:49:59
jkeny
Manufacturer

Posts: 502
Joined: May 4, 2001
 The published graphs are typical of a low pass filter

Can anybody tell me how a LPF can speed up the rise/fall time of a signal or did Paul Miller flip the 220nS & 165nS figure & the Jitterbug ACTUALLY slowed down the edge rates?

 

RE: Jitterbug Measured Properly, posted on September 3, 2015 at 01:10:05
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 By changing the level of the up and down ramp where transition takes place

 

Winner?, posted on September 3, 2015 at 01:14:04
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 SDIF 2 and 3, with up to 3 cables L, R, and Clock.

Not invented here as it was a Sony format but adopted by dCS. The whole chain is still affected by cabling, even an impedance matched clock cable!

 

Thanks for your ... , posted on September 3, 2015 at 01:22:56
three_sox
 ... Opinion.


 

RE: Jitterbug Measured Properly, posted on September 3, 2015 at 03:08:50
jkeny
Manufacturer

Posts: 502
Joined: May 4, 2001

Have you looked at the effect of an LPF on rise/fall time - it can only lengthen them, not shorten them - hence my question.

See the overlaid graphs of the eye diagrams with/without Jitterbug

If you take the threshold for 10 & 90% as about +/- 1.5V you can see that the time the graph takes to reach these levels is lengthened with the jitterbug in place.

 

RE: Jitterbug Measured Properly, posted on September 3, 2015 at 15:13:23
jkeny
Manufacturer

Posts: 502
Joined: May 4, 2001
 Stereophile review & measurements here http://www.stereophile.com/content/audioquest-jitterbug-usb-noise-filter#dr35VQtKVSPuVgGs.97
"Conclusions
You can see from the "Measurements" sidebar that I could find no significant effect that the JitterBug had on the analog signals output by three of the DACs I had to hand. Yet with those DACs and others, I heard an improvement in sound quality that I can attribute only to the JitterBug. I hate when that happens!"

 

RE: Jitterbug Measured Properly, posted on September 5, 2015 at 01:12:23
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 I think that they have taken a different reference; trace the risetimes they gave and look at the edges to identify the difference.

As for the Stereophile measurements, they were done in the analog domain (as far as I can see from your link) and the conclusion was:

''no significant effect that the JitterBug had on the analog signals output''.

Whatever the measurements, I have been quite surprised by the large SQ difference, ageing with the Stereophile observation about the mid high.

 

RE: Jitterbug Measured Properly, posted on September 5, 2015 at 01:24:48
jkeny
Manufacturer

Posts: 502
Joined: May 4, 2001
 "I think that they have taken a different reference; trace the risetimes they gave and look at the edges to identify the difference."
That's what I did & it doesn't matter where you take the 10% 90% crossings, it always equates to a longer rise/fall time with the AQJB than without

Yes, Stereophile measure on the analogue output some slight jitter spuriae differences on the Dragonfly, just like HF&N do but no difference on any of 3 other DAC outputs

I'm not disagreeing that the is a SQ difference (although I haven't listened to an AQJB yet) but just that the measurements, so far are contradictory AND that the HF&N jitter measurements seem to be reversed - the edgerates are increased with the AQJB inline & not decreased?

 

RE: Jitterbug Measured Properly, posted on September 5, 2015 at 03:13:21
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 My reckoning is different. Superimpose their risetimes onto the horizontal axis from the starting point (bottom) and look at the top edge and you will see what I mean.

If you have an issue, why not email the editor?

The issue of the trigger point, which is what is important, has been an opaque subject for me.

 

RE: Jitterbug Measured Properly, posted on September 5, 2015 at 03:56:39
jkeny
Manufacturer

Posts: 502
Joined: May 4, 2001
 I already posted a pic of the with/without eyepattern plots overlaid on top of one another & I can't see any possible way that this can be made to return a lower rise/fall time for the plot with AQJB. I think theory also predicts a lengthening of risetime with a LPF

I wanted to check my reasoning here first but you are the only respondent.

 

RE: Jitterbug Measured Properly, posted on September 5, 2015 at 09:07:42
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 Sad that this forum (nor others) does not go into things like this, which forms the basis of digital audio reproduction performance.

 

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