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Got Jitter?

69.54.140.197
Posted on April 2, 2017 at 01:08:06
jaydacus
 I just got the Mamboberry LS+ and it is an absolutely incredible board.It is so much clearer than the IQaudio DAC Pro and the HiFi Berry . I've been reading about the use of The Allo Kali Reclocker board with this DAC for even better sound. The Mamboberry already has its own oscillator crystal, the Xpresso Clock. Am I really going to hear a difference if a re-reclock the i2s signal? I have done some research on the effects of jitter and from what I have found I'm going to say I have always had a jitter problem up until now.

Jitter is easier to explain in technical terms than to actually describe in terms of sound. This is what I have found and some of my own observations...

High jitter

-I noticed when I started burning CD-Rs, back when that was a thing, that the copy sounded identical to the original, but was often unpleasant to listen to depending on the media, burner, or speed I used. The copy just sounded "blurry" especially during a long listening session.

-I had an Onkyo CD player that always sounded amazing during the last 25% of the CD. The first 75% sounded good in short bursts, but seemed harsh with an invisible layer of static during long listening sessions.

-Most USB DACs no matter how well built probably have huge amounts of jitter. At least synchronous dacs for sure. I had all the way up to $1500 DAC and they all sounded like crap compared to what I am hearing now. I noticed that the level of crappiness varied widely depending on what computer is was using and even which USB port I used on the computer.

-Jitter is not very noticeable in the lower frequencies. This could explain why music like rap and R&B often sound good on the crummiest systems while other genres that focus more on mids and highs sound awful.

Low jitter-

-It feel like I can "see" into the music more. Like tiny details that were masked by digital noise are now visible. Little sounds I didn't even know were there are now jumping out at me.

-I'm hearing music that is very smooth and seems to flow effortlessly from my speakers.

-Listening fatigue is nonexistent. The hours seem to melt away as I listen to album after album.

-Anyone that favors analog has clearly never heard low jitter digital. Its all of the warmth, openness, and pleasure of analog, but with fine micro details that even the most expensive analog sources would kill. Things like very light cymbal strikes and every subtle nuance of the vocalist's voice.









 

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RE: Got Jitter?, posted on April 2, 2017 at 14:26:54
morricab
Distributor or Rep

Posts: 9178
Location: switzerland
Joined: April 1, 2005
 been using a jitter box (Monarchy Audio DIP) for more than 10 years now. Low jitter is important and I have found the improvement something that can't be lived without.

 

Yup!..., posted on April 2, 2017 at 14:47:50
kootenay
Audiophile

Posts: 8445
Location: Calgary, Alberta
Joined: October 16, 2007

Lucky me I was able to find a used one of this unit at my local high-end dealer. It still serves its purpose excellently well after all these years.

 

RE: Got Jitter?, posted on April 2, 2017 at 20:25:48
hahax@verizon.net
Audiophile

Posts: 4308
Location: New Jersey
Joined: March 22, 2006
 try 2 DIPs in series. It's even better. I'm told a 3rd is an improvement too but you have to listen carefully.

 

RE: Got Jitter?, posted on April 3, 2017 at 22:15:49
Todd Krieger
Audiophile

Posts: 37333
Location: SW United States
Joined: November 2, 2000
 "I had an Onkyo CD player ..... but seemed harsh with an invisible layer of static during long listening sessions."

Did this CD player have 24/96 or 24/192 upsampling? This is the very phenomenon I noticed with asynchronous upsampling......

 

RE: Got Jitter?, posted on April 3, 2017 at 22:22:11
Todd Krieger
Audiophile

Posts: 37333
Location: SW United States
Joined: November 2, 2000
 I personally think preserving the "jitter signature" of the original A/D conversion sounds better than reducing the jitter to the lowest levels possible......

 

RE: Got Jitter?, posted on April 3, 2017 at 23:49:10
EL Cheapo
Audiophile

Posts: 707
Location: San Diego, CA
Joined: October 31, 2002
 Very cool - i use raspberry pi with Moode os and i love it. It would be great to simplify my second system. I hate having a bunch of boxes, power supplies, and cables. What are you using for a power supply?

 

RE: Got Jitter?, posted on April 4, 2017 at 05:18:14
jaydacus
 It was a little expensive compared to other parts of the PI setup, but its built like a tank and provides really clean power.

 

RE: Got Jitter?, posted on April 6, 2017 at 02:06:19
morricab
Distributor or Rep

Posts: 9178
Location: switzerland
Joined: April 1, 2005
 I had two but one broke. There was an improvement but not as much as going from zero to one.

 

RE: Got Jitter?, posted on April 6, 2017 at 02:06:46
morricab
Distributor or Rep

Posts: 9178
Location: switzerland
Joined: April 1, 2005
 How would you ever know this?

 

RE: Got Jitter?, posted on April 7, 2017 at 03:13:51
Todd Krieger
Audiophile

Posts: 37333
Location: SW United States
Joined: November 2, 2000
 "How would you ever know this?"

I don't know.... But I think (believe).... Stated this in the comment.

I believe so because my experiences with digital re-clocking have not exactly been positive..... I've often tried it, and come to the realization that it made the sound worse.

The belief was reinforced by whenever I tried copying CDs..... The CD copies usually sounded worse with the "jitter reduction" turned on relative to being turned off. (The best sounding copies were done the "on the fly" method, where the data is transferred directly from CD to CD-R, without an intermediate step copying temporarily to hard drive.)

The belief is more experience than hard fact. There could be other phenomena going on that could account for this. (So I could be wrong.) But I have come to the conclusion that for me, the best re-clocker is no re-clocker.

 

RE: Got Jitter?, posted on April 7, 2017 at 06:11:16
knewton
Audiophile

Posts: 563
Location: Mid-Atlantic/Northeast
Joined: May 18, 2010
 The benefit of extreme jitter reduction seems like many other subjects in audio - highly disputed. I've reached no conclusion regarding continued jitter reduction aside from the general notion that if something is undesired in high quantities, then continually reducing it cannot be a bad thing. However, just as with harmonic distortion reduction, how low is low enough to be imperceptible? Is zero harmonic distortion really required? Are femtosecond levels of jitter really required? Some of the most highly regarded DACs actually utilize little no audio band jitter reduction. Audio Note and Ypsilon come quickly to mind.

Part of the difficulty with DACs is that they contain so many interrelated functional mechanisms that it can be very difficult to assign a given subjective listening artifact correctly to a single objective mechanism. One sign that may be trying to do that is when we percieve further reduction in some already vanishly low error parameter as perceptible.
_
Ken Newton

 

RE: Got Jitter?, posted on April 8, 2017 at 11:11:55
hahax@verizon.net
Audiophile

Posts: 4308
Location: New Jersey
Joined: March 22, 2006
 agreed

 

RE: Got Jitter?, posted on April 9, 2017 at 06:16:31
Old SteveA
Audiophile

Posts: 648
Joined: March 27, 2011
 I personally don't care to listen to entire Music Genres of recorded music if I know that generally high levels of Jitter are "Par for the Course"in how the music is recorded.

Acceptable recorded Jitter doesn't exist in my vocabulary. I guess everyone has to decide for themselves what they consider to have been avoidable & wasn't "addressed" at the recording stage.

 

RE: Got Jitter?, posted on April 12, 2017 at 04:53:55
morricab
Distributor or Rep

Posts: 9178
Location: switzerland
Joined: April 1, 2005
 Well, I have had only positive experience with it but then I have only used the Monarchy Audio DIPs to do the job.

 

Did you measure jitter of the Onkyo CD player?, posted on May 6, 2017 at 18:36:20
dave789
Audiophile

Posts: 559
Joined: September 21, 2001
 Jitter was not the single important factor to my ears.

Some very low jitter (according to Stereohpine and/or other magazines, and also not high by my own measurement) ("upsampling" DAC with SRC converter) DACs sounded more fatiguing than other similarly priced DADs with a little more jitter.

By the way, did you measure the jitter of the Onkyo CD player?

 

RE: Got Jitter?, posted on May 28, 2017 at 18:13:25
flood2
Audiophile

Posts: 2558
Joined: January 11, 2011
 Hi
Interesting post!
I have some possible explanations to some of your observations plus have added my own experience..

"-I noticed when I started burning CD-Rs.....The copy just sounded "blurry" especially during a long listening session.

It depends on the write speed used relative to the capability of the media and the writer. Basically you are hearing the effect of read-induced jitter due to imprecise pit "edge" creation. The CD-R organic dye layer has to be perfectly uniform relative to the test area where the laser power is calibrated. The faster the write speed rating, the thinner the layer, but also the higher the "optimum" speed for a write with minimum jitter. "Lowest" speed is not necessarily appropriate for all media. The slew rate of the laser is also a factor (i.e the time taken for the critical temperature of the dye to be reached before the laser has shifted physical position.
With care, CD-Rs can often sound "better" than the original! Rather than doing a direct "on the fly" copy from one disc to another, a better way is to rip the image to memory first then write the image as this will eliminate read-induced jitter and you can then do re-reads and more extensive error-correction.

"-I had an Onkyo CD player that always sounded amazing during the last 25% of the CD. The first 75% sounded good in short bursts, but seemed harsh with an invisible layer of static during long listening sessions."

Again, probably read-induced jitter. The "last portion" of the disc is on the outer edge and the angular speed of the disc has decreased. In theory you might actually get worse performance due to edge wobble and therefore stressing the position and focus servos more. So if you are getting better performance in this region, it suggests that something is not ideal in the transport itself.

"-Most USB DACs no matter how well built probably have huge amounts of jitter. At least synchronous dacs for sure."

A bit of a generalisation! It depends on the DAC design. A synchronous design just requires more effort in the buffering and re-clocking stage. Asynchronous designs rely on the interface IC more, but the data still requires re-clocking for best performance. The problem is that many DACs incorporating Upsampling tend to take the easy way out and simply rely on the Upsampling process to de-correlate the input jitter rather than ensuring that the input data to the upsampling IC has already been buffered and re-clocked.

"-Jitter is not very noticeable in the lower frequencies"

I would agree that the effect of jitter is masked depending on the music and as such, much pop music which is bass heavy tends to not be so discriminating of the playback equipment...
In fact, I find that a very low jitter DAC system has much better bass definition and depth. As in "noticeably deeper" and you can still discern the note/pitch clearly.

I find the soundstage becomes more palpable and the timbre of the instruments/voices becomes more realistic. Due to the effect on the soundstage depth and width, I don't find it necessarily "more detailed", just that everything is in its place with the correct scale and realism. This is noticeable even with Redbook which in my system takes on many of the qualities of High Resolution to the point where I don't bother worrying about the source resolution anymore and I can just enjoy the music.

In equipment reviews I've read where the component being reviewed had very high levels of jitter (of the order of nanoseconds), the comments usually referred to a very "warm" sound with a general lack of definition.


I use a Grimm CC1 reference master clock (primarily for my recordings) but also for reclocking the data to my DAC.
I don't know if a better Master Clock exists these days, but certainly when it was released, it was without peer in terms of jitter level of the output data and made many of the reclockers of the time (such as Monarchy DIPs) to be "merely toys". Not knocking those products - I'm talking about relative performance! I would say that "today" the reclockers available probably get very close to the Grimm CC1 at a fraction of the cost. A very close performer is the Apogee Big Ben which uses DDS to generate clock signals and can convert between different interfaces eg AES to optical etc with fully reclocked data.


Regards Anthony

"Beauty is Truth, Truth Beauty.." Keats

 

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