Wadia iTransport iPod Dock Gets Bit-Perfect Digital from iPods!

[lisnalee]

Originally Posted by HeadphoneAddict

I took half an hour composing this reply so it wouldn't look terribly insulting or as a challenge to you, but I can't seem to make it sound as diplomatic as I feel. Another career that I need to avoid... Sorry. I hope you understand, I really want to know why you would observe what you have. perhaps you meant to say "low-level" detail and not "low-end" detail?

I'm not trying to "bust your chops here" with my post, but I really find this confusing. If you are using digital out from Mac vs digital out from Wadia, with the same source files and the same external DAC, I don't understand how that is possible to get more low-end detail. Not unless your optical cable out of Mac is dropping data bits vs the $30 coax which is not, which can happen because my understanding is that digital-audio is one-way and does not use checksums to guarantee bit perfect like with hard drive data and such.

But, I always thought your digital cable would have to be exceptionally bad for dropped data bits to happen. I would expect dropped data-bits to similarly decrease the resolution in the high-end more than the low-end. I would guess that since low freq are longer sound waves, that there are more data points captured at 44.1Khz and losing one or two data points to a cable should have less effect in the low-end vs high-end. I am not an expert, so I welcome anyone's feedback about this phenomenon.

Hey HA

Basically i'm hearing more detail from tracks especially from instruments and vocals in the background. They are clearer and more prominent than when using optical from the mac.

For example at the start of summer of '69 ( waits to be flammed ) there is an underlying guitar chord that i can hardly make out via optical, its there just very far back and almost drowned out, whereas when i listen to it via coax from the wadia it's crystal clear and perfectly separated from everything else around it. Its this type of extra detail i was referring to as i low level, im sure there's is a more technical name for it.

I guess it could be due to a number of things such as the wadia being better than itunes at handling music, difference in cables, coax input better than optical who knows. But it's sufficient enough of an improvement for me not to want to go back to optical anytime soon.

[oxophone]

Originally Posted by davidhunternyc

Now if the Wadia had a fantastic DAC inside also, now we would be talking... oh, and an amplifier : )

This is the reply I received a while ago from Wadia:

"We are not currently working on a combined unit [170i+DAC, my addition], but we are working on a matching DAC to go with the 170iTransport. The matching DAC should be out first quarter 2009.

Thank You,
Brent Sitterley

Customer Support
Wadia Digital "

-----
YES, we want a DAC+Headphone Amp combo unit

[audioengr]

Originally Posted by lisnalee

Hey HA

Basically i'm hearing more detail from tracks especially from instruments and vocals in the background. They are clearer and more prominent than when using optical from the mac.

For example at the start of summer of '69 ( waits to be flammed ) there is an underlying guitar chord that i can hardly make out via optical, its there just very far back and almost drowned out, whereas when i listen to it via coax from the wadia it's crystal clear and perfectly separated from everything else around it. Its this type of extra detail i was referring to as i low level, im sure there's is a more technical name for it.

I guess it could be due to a number of things such as the wadia being better than itunes at handling music, difference in cables, coax input better than optical who knows. But it's sufficient enough of an improvement for me not to want to go back to optical anytime soon.

There is a simple explanation for this and it's not data errors, it's jitter. If you dont understand jitter, do some searches on the forums. I've posted hundreds of times on this. Jitter tends to muddy-up the detail, like looking through a dirty window.

The Wadia uses a TI PCM270X chip for S/PDIF output. This is the problem, besides the fact that an inexpensive oscillator was used to generate the data in the first place inside the iPod. Both of these add jitter.

The Mac laptop may actually have a bit lower jitter than the Wadia/iPod combo. They both have unacceptable jitter for critical listening IMO. Toslink is usually worse that S/PDIF coax due to the optical conversions alone.

Steve N.

[HeadphoneAddict]

Originally Posted by audioengr

There is a simple explanation for this and it's not data errors, it's jitter. If you dont understand jitter, do some searches on the forums. I've posted hundreds of times on this. Jitter tends to muddy-up the detail, like looking through a dirty window.

The Wadia uses a TI PCM270X chip for S/PDIF output. This is the problem, besides the fact that an inexpensive oscillator was used to generate the data in the first place inside the iPod. Both of these add jitter.

The Mac laptop may actually have a bit lower jitter than the Wadia/iPod combo. They both have unacceptable jitter for critical listening IMO. Toslink is usually worse that S/PDIF coax due to the optical conversions alone.

Steve N.

That doesn't really explain why lisnalee says the Wadia with coax sounds better than the Mac via optical. If anything your explanation says they both suck - which doesn't fit with my experience listening to my Macbook via optical, or lisnalee's experience with the Wadia.

[audioengr]

Originally Posted by HeadphoneAddict

That doesn't really explain why lisnalee says the Wadia with coax sounds better than the Mac via optical.

Sure it does. Toslink is generally inferior to coax, unless the coax driver/receiver implementation is poor, which happens too.

And they both suck IMO.

Steve N.

[Jelle Schrijver]

Originally Posted by audioengr

The Wadia uses a TI PCM270X chip for S/PDIF output.

I thought that chip familie has USB input only and put's out L and R analogue and I2S to feed an external DAC or DSP solution. And yes, that chip familie has a problem with clocks. There is only a 12 mhz oscillator for the USB signal and an advanced PLL to follow a clock inside the USB signal. Hence the high jitter levels.

[audioengr]

Originally Posted by Jelle Schrijver

I thought that chip familie has USB input only and put's out L and R analogue and I2S to feed an external DAC or DSP solution. And yes, that chip familie has a problem with clocks. There is only a 12 mhz oscillator for the USB signal and an advanced PLL to follow a clock inside the USB signal. Hence the high jitter levels.

All true, except for the comment on jitter levels. It is evidently in the signal chain in the Wadia. It has a Host interface to S/PDIF output capability.

It's the implemenation of the 270X chips that generates high jitter. The TAS1020, also designed by TI, but Burr-Brown division instead, is much better and capable of extremely low jitter levels. It also uses a 12MHz clock etc. See this review comparing several converters using 270X to converter using TAS1020:
ramblings computer based audio

Steve N.
Empirical Audio

[HeadphoneAddict]

Originally Posted by audioengr

Sure it does. Toslink is generally inferior to coax, unless the coax driver/receiver implementation is poor, which happens too.

And they both suck IMO.

Steve N.

And the alternative is?

[audioengr]

Originally Posted by HeadphoneAddict

And the alternative is?

The alternative to Toslink - there are several, including AES, S/PDIF Coax and I2S, with I2S being superior.

If you must use a Toslink source like a Mac, AirPort Express or Apple TV, then there is no alternative except to reclock and then convert to one of the better interfaces before the DAC. The goal is to lower jitter and keep it low all the way to the D/A chip. Same with a S/PDIF coax source like the Wadia, Sonos or Squeezebox. Just reclock it and output with a superior interface. The reclocker is the key.

If you dont believe me, just read this article:
ramblings computer based audio

The reviewer purchased the reclocker. It's his digital source reference now.

There are some companies that are leading the way in this arena and have I2S sources, reclockers and I2S input DAC's, namely Empirical Audio and soon PS Audio (announced).

BTW, looking at your systems, all I see is the bigger brand names. IMO, you dont get the best bang for the buck buying the equipment that has the most advertising dollars spent on it. Seeking out the smaller companies that are doing exceptional pieces can pay off in spades. It pays to keep your ear to the wall.

Steve N. Ex-Coloradan, now Oregonian.

[HeadphoneAddict]

Originally Posted by audioengr

The alternative to Toslink - there are several, including AES, S/PDIF Coax and I2S, with I2S being superior.

If you must use a Toslink source like a Mac, AirPort Express or Apple TV, then there is no alternative except to reclock and then convert to one of the better interfaces before the DAC. The goal is to lower jitter and keep it low all the way to the D/A chip. Same with a S/PDIF coax source like the Wadia, Sonos or Squeezebox. Just reclock it and output with a superior interface. The reclocker is the key.

If you dont believe me, just read this article:
ramblings computer based audio

The reviewer purchased the reclocker. It's his digital source reference now.

There are some companies that are leading the way in this arena and have I2S sources, reclockers and I2S input DAC's, namely Empirical Audio and soon PS Audio (announced).

BTW, looking at your systems, all I see is the bigger brand names. IMO, you dont get the best bang for the buck buying the equipment that has the most advertising dollars spent on it. Seeking out the smaller companies that are doing exceptional pieces can pay off in spades. It pays to keep your ear to the wall.

Steve N. Ex-Coloradan, now Oregonian.

I wouldn't say "all I see is bigger brand names" - aside from headphones, much of electronic stuff is from companies that I never heard of in the first 45 years of my life. I believe my Apogee mini-DAC re-clocks the signal, and I thought that most up-sampling DACs do something like that. I could be wrong.

As for asking about the alternatives, so I see you do support Coax S/PDIF as long as it is implemented properly. Originally it sounded like you thought it should be tossed out. I use Coax whenever possible - my DVD and CD rig uses Coax, and I invested in a good digital coax cable and DAC to minimize jitter.

If I understand, I2S has a separate channel for the clock signal, right? If it is superior, I wonder why so few sources offer that? I know Stello makes a DAC that accepts I2S and nobody can seem to provide a recommendation for source that puts out I2S. Same with AES - my Apogee can accept AES but I don't know any sources that offer that as an output.

As for optical, I have not had any problems with detail and resolution or distortion that could be blamed on the optical interface increasing jitter, which are admittedly mostly my portable sources (Macbook, Sony portable CD, iRiver).

[audioengr]

Originally Posted by HeadphoneAddict

I wouldn't say "all I see is bigger brand names" - aside from headphones, much of electronic stuff is from companies that I never heard of in the first 45 years of my life. I believe my Apogee mini-DAC re-clocks the signal, and I thought that most up-sampling DACs do something like that. I could be wrong.

Correct, and this is one way to reduce jitter. Medium effectiveness. No upsampling DAC that I have modded is insensitive to incoming jitter, regardless of what the manufacturers claim, and I have modded at least 15 different DAC's.

As for asking about the alternatives, so I see you do support Coax S/PDIF as long as it is implemented properly. Originally it sounded like you thought it should be tossed out. I use Coax whenever possible - my DVD and CD rig uses Coax, and I invested in a good digital coax cable and DAC to minimize jitter.

Absolutely. S/PDIF coax implemented well - that means fast edge-rates and good impedance matching can be outstanding. Still not quite as good as I2S, but can be very close, depending on the CODEC hardware used.

If I understand, I2S has a separate channel for the clock signal, right?

Correct, actually two clocks. The I2S signals are typically these four:

MCLK
SCLK
SDATA
L/RCLK (actually data bit)

If it is superior, I wonder why so few sources offer that? I know Stello makes a DAC that accepts I2S and nobody can seem to provide a recommendation for source that puts out I2S.

I2S is the native interface of the D/A chip. Most DAC's must end-up with I2S before the D/A chip. There have been a number of companies that have tried to establish it as a standard, however there are usually technical flaws in the implementation. Some of my mods remove these. I list Stello as one of the DAC's that can be driven with my Off-Ramp USB converter or my Pace-Car reclocker directly with I2S. Others are Northstar 192 and Extremo, Perpetual P-3A, Audio Logic and modified Benchmark DAC-1.

Same with AES - my Apogee can accept AES but I don't know any sources that offer that as an output.

There are several computer devices that output AES, including the UD-10, the Off-Ramp, the Pace-Car and HagUSB, as well as professional sound cards, such as the Hammerfall or Lynx.

As for optical, I have not had any problems with detail and resolution or distortion that could be blamed on the optical interface increasing jitter, which are admittedly mostly my portable sources (Macbook, Sony portable CD, iRiver).

You probably have a lot of jitter and just dont know it. Most audiophiles are shocked when it is eliminated to discover what they have been missing. It's almost impossible to get good depth of soundstage without first having very low jitter IME.

Steve N.

[emmodad]

Originally Posted by audioengr

There are some companies that are leading the way in this arena and have I2S sources, reclockers and I2S input DAC's, namely Empirical Audio and soon PS Audio (announced).

Steve, non-I2S query, and just for historical perspective: not asking as a yours-vs-X product question, and it's perhaps rather innocuous / moot as this one has been out of production for years... in your research and product development testing, have you ever analyzed performance of the old Genesis Digital Lens (for those who don't know, a "reclocker" / jitter reduction unit with a plethora of digital input and output options, incl AES/EBU XLR)? They put some good emphasis on output waveform integrity, consistent clean fast output edges, etc....

Of course the product is limited to 48 kHz, but I'll mention (purely anecdotally and subjectively, of course) that I certainly perceive improvements in playback from various sources when using my (still going-strong) GDL.

Thanks for your observations.

[audioengr]

Originally Posted by emmodad

Steve, non-I2S query, and just for historical perspective: not asking as a yours-vs-X product question, and it's perhaps rather innocuous / moot as this one has been out of production for years... in your research and product development testing, have you ever analyzed performance of the old Genesis Digital Lens (for those who don't know, a "reclocker" / jitter reduction unit with a plethora of digital input and output options, incl AES/EBU XLR)? They put some good emphasis on output waveform integrity, consistent clean fast output edges, etc....

I have not seen one in person, but I know how it works. The main disadvantage is that it will eventually overflow if the playlist is long enough or the computer streaming rate is a bit high (very common). It was designed for CD's, which have limited length. The timeframe of this design makes it a bit long in the tooth. There were not many low-jitter clocks available at that time, so that is the first negative. Secondly, the logic families available at that time were also not as good as the ones available today.

I think if you can get a good buy on one, it could be beneficial. I have modded the DIP and the Big Ben for customers and these are also old technology and needed lots of mods to make them good. I think the Lens would probably be better than these, but still in need of updating to get really low jitter.

Of course the product is limited to 48 kHz

This is a limitation of course, but if you are using it with an AirPort Express or Squeezebox, no need for 96.

Steve N.

[tunes]

Wadia iTransport and HD Tracks 24/96 Content

Is there a way to get the new HD Tracks 24/96 Content on to my ipod so that the Wadia iTtransport can resolve the information and export it bit perfect my Benchmark DAC 1 pre???

[HeadphoneAddict]

Good question - I converted some 24/96 FLAC to ALAC and they are about 2700 kbps and wont load on the ipod. So I had to make a copy as AIFF at 1411 kbps to get them onto the iPod, losing the benefits of 24/96. I used MAX for the Macintosh to convert, and it wouldn't change FLAC to ALAC at a smaller bit rate (pointless), but AIFF would automatically be 1411 to run on the ipod. So, the only way I can enjoy the 24/96 is off my Macbook and out via optical into my HR Micro DAC or Apogee Mini-DAC (unless I could burn it as DVD audio).