24/96 USB DAC?

[the_eleven]

Have been reading here on the site, and really learning a lot.

 

One question I have is about the future of digital formats, given the interest in server based music systems. If I understand correctly there are not a lot of 24/96, recordings available at the moment. Is there some other high-sample rate format that could ultimately supplant 16/44.1?

 

That being said, is the ability to work with 24/96 over USB worth considering in the purchase of a DAC?

 

Which DAC's currently being sold can handle this format?

 

 

 

 

[The Computer Audiophile]

Hi the_eleven - You are correct that there aren't a lot of 24/96 recordings available yet. In the future you can expect releases on many different sample rates from 16/44.1 up to 24/192 and even beyond that. Right now it really depends on what music you like. Only the audiophile labels are offering higher resolution music. For example Reference Recordings is offering its HRx albums at 24/176.4. I've never heard anything better. You should also keep in mind that a higher sample rate does not always equate to better sound or sound that you'll like more.

 

If you're going to purchase a DAC I would make sure it supports at least 24/96 on one of the interfaces you will use. Benchmark and Wavelength Audio make some really nice 24/96 USB DACs. No current DACs can handle anything above 24/96 via USB. they often have other interfaces that support higher sample rates.

 

[sammie]

11,

I think all of Gordon's DAC's are now 24/96 capable....if not immediately available, they should be released very soon: http://wavelengthaudio.com/

 

Also, these guys are getting some good press, although I don't think they offer the higher sampling rates like Wavelength, Benchmark, etc. Still, they are very cool, tube based, and priced cheaply compared to many other DAC's: http://www.geocities.com/mhdtlab/

 

 

[Wavelength]

Chris,

 

Actually USB 1.1 protocol does not state a limit on the sampling rate. Actually 24/192 only requires 9.216Mbps which would work with most USB1.1/2 computers. Most of the USB 2.0 protocol additives were for other stuff that most High End companies would not require. That being said most of the host USB controllers that fall under the 2.0 realm are better suited for audio. Both OSX and Vista/XP support USB protocols to 210KHz. I think that limit is based on the USB 1.1 top limit of 12Mbps.

 

There are a few dacs that have 24/192 audio though none that I know of that would be considered high end.

 

The problem with the TAS1020B (used in mystuff, Benchmarks and others) is that it lacks the USB buffering to pull off the 24/192. That's not too say there are not litterally 100's of controllers that can handle this and I am looking at the benefits for dacs and other projects I am thinking of.

 

Thanks

Gordon

 

[Ashley James]

As discussed previously we stopped making USB DACs because there wasn't much demand and I can understand why. Most digital devices use optical digital connections and we think this is the most important one because it gives you a far greater choice of sources and allows you to use streaming devices if the computer is in another room. Do bear this in mind before you tie yourself to a particular way of doing things

 

Our DAC is a full 24/192 and we can offer, for an extra charge, a coaxial instead of optical in.

 

Just my thoughts.

 

Ash

 

[Wavelength]

Ashley,

 

In the beginning of all the external connection it did appear that USB would be better. Then some chip companies pushed companies to jump onto Firewire band wagon because they showed with simple drivers that they had that higher and more consistent data rates could be done simply.

 

But today actually it looks like Firewire is fadding fast. When companies like Apple start making computers without it, when they termed the name... then I think it's time to revist the USB idea.

 

USB now has a much better supported protocol for Audio. Especially because you can do things natively that is not supported by Firewire. My dacs all use Asynchronous USB command set and don't require additional PLL/VCXO, upsamplers or reclockers to reduce the jitter. Sure the TAS1020B only handles up too 24/96 but there are literally 100's of ARM processors that could do the same thing without issue up too 24/192 or higher.

 

Ashley, if you are looking into the crystal ball then I would start looking seriously at USB again.

 

Thanks

Gordon

 

[Ashley James]

Gordon, like you we'll do what the customer wants and for now that's definitely optical digital. I think everyone is revelling the luxury of discovering that the optical digital output from anything is bit perfect and allows a tremendous choice of source.

 

By comparison USB connections require the presence of a computer when many prefer to stream from a remote one or use Apple TV or even PS3! Optical always works for anyone too, whereas I suspect everyone has had issues plugging anything into a USB port. For us the disadvantages appreciably outweigh advantages.

 

Ashley

 

[darrenwm]

I'm sure USB and Firewire DACs are excellent if you're computer is permanently connected to the DAC, say in a home recording studio situation.

 

However, when I bought my AVI ADM9 I decided to go with the optical version as it's far more flexible.

 

We can hook up laptop, Airport Express, Apple TV, PS3, Xbox360, Sky box, Freeview box, CD player, DVD player, DAB radio, etc, etc

 

It's a far more universal way.

 

[Wavelength]

Ashley,

 

Actually I usually make the decision. If the customer wants Optical, then I talk him out of it. First off SPDIF never worked.

 

I remember in the 80's talking to the engineer at Philips who designed it. He was asked to create a way to test CD players closed box. The answer was a test cd with a IR transmitter and 3 rca connections, Right, Left and SPDIF.

 

Also of all three of the SPDIF connections, optical is the least capable of delivering good sound. I am still unsure who came up with AES/EBU, I never understood that... it's like saying and RCA can be 75 ohm connection. Common simple physics dictates that DOD determines the impedance and that is why BNC would be the only connection that I would use with SPDIF. But I left that ship five years ago. No more SPDIF for me it's just not the way too go.

 

So far no issues with USB because we are truely Native and don't require any drivers. Since Asynchronous means we control the PC and the clock is local the jitter can be reduced significantly over the Adaptive process used by many and Firewire.

 

I wrote drivers for PC's and MAC's for years and find it much easier to make it work with the OS instead of patching it.

 

Thanks

Gordon

 

[audiozorro]

A co-worker convinced me a couple of years ago to use PCs for work and Macs for fun. I have been trying to live by that advice ever since, which is a long way to getting around to say that I do not have a dedicated computer music server as a permanent part of my music system. My vinyl rig is always there, my DACs are always there, my CD/SACD/DVD players are always there, and my external music hard drive is there, but my MacBook Pro floats in and out of my music system depending on whatever source I care to listen to.

 

As such, I prefer flexible DACs that provide multiple/different digital input/output capabilities. Toslink and coaxial for my digital players and toslink, FW, and USB for my Mac. Ethernet and wireless are paths I have yet to explore. For me, it is because I have several DACs that a single path DAC, such as a Wavelength Cosecant or Apogee Duet, have remained on my wish list.

 

[Wavelength]

Guys,

 

Look the point is this... Anyone can make a swiss army knife of dacs. But with each additional port the engineer in question will be making more compromises to the electronics.

 

Ok let's look at it this way... Basically what Ashley is talking about is something like this.

inputs

SPDIF 1

SPDIF 2 ==== SPDIF reciever and selector---I2S----

SPDIF x/.................................................................I2S MUX---[Jitter Reduction]---I2S---DAC

USB=======USB Controller------I2S-----------------/

 

This is also similar to the way the Benchmark and the BelCanto is but put UPSAMPLER in the Jitter Reduction (JR) box. The input panel determines the selected I2S and SPDIF input.

 

All of these designers say that the JR device of choice makes it so that it does not matter what the jitter on the input is that it is removed before it hits the dac. My point is that testing has proved this theory wrong. If that was the case then all the Stereophile testing would conclude that the intrinsic jitter in the JR & DAC would constitute all the jitter in the system. BUT... as we have seen this is not corrent and actually the jitter for the interfaces are not the same and some better than others.

 

My philosophy is simple... make it the best it can be and only focus on that. If I made another SPDIF dac (which I won't) it would be BNC only. Therefore this is what I do....

 

 

 

Simple easy to implement (well the software took 9 months) and has excellent results. Really low jitter, intrinsic to the DAC and the oscillators only.

 

Thanks

Gordon