USB or normal DAC

Over a collection of commentary about DAC connections from a PC, many sources say that a USB1 interface may be to slow and more, the computer USB chips have to manage all other applications (mouses keyboards ...) that would reduce the transfer rate.

Well I'm not a computer expert, but they all say that a SPDIF connection would be better than the USB option .

So why pay extra money on a USB DAC wen the only difference between a USB and a normal one (CD player DAC) is the USB connector? See Benchmark DAC1 for example.

Maby there is something more within the USB DACs, but I do not see it.

thank you

jac

Hi Jac - Most of the USB v. SPDIF v. X are very misleading. No interface is always better than another. It all comes down to implementation.

The bandwidth of USB 1.1 is not a limitation up to the current 24/96 resolution some USB manufacturers are supporting.

Most industry sources I talk to agree that SPDIF is inherently more flawed than the other interfaces. But I think most agree that the flaws can be managed by very good engineering. I think all will agree that the flaws cannot be eliminated on any interface, just managed.

Chris,

Have you ever heard the Hagerman DH10? It seems like a competitor to Wavelength brick.

In the very hi end you recommend Weiss Minerva but today, given existing funds I feel like purchasing the Dac 1 Pre because I can plug it in directly in my amp. It is probably not the ultimate in refinement but it will be better than my nuforce icon.

Like everyone here I am amazed and obviously thankful for your personal support. I am now hooked on CA. I used to spend a lot of time on head fi but CA is really perfect for me.

Guys,

I was telling this story to a well respected audio engineer yesterday. I think it was CES 1984 and I was talking to the Philips engineer who designed SPDIF. He was basically asked to come up with a system that could test a closed box CD player before shipping. The third RCA was the answer to the problem. They could put a test cd in the box hook up the R&L analog and the SPDIF to a test rig which would verify the unit.

SPDIF was never really meant to be used for what it is.

Here are a few facts...

1) A computer reads the disk using ATAPI commands and reads the data in parallel just like a hard disk. Most transports use ATAPI just to tell the drive to change tracks, start stop etc... They use the SPDIF off the drive which is ttl and output that.

2) USB 12MBps can support up too 24/192 (9.216Mbps). This is called full speed mode and is supported under USB 1.1 and 2.0 specification.

3) SPDIF has a clock intertwined over the data in NRZ format. Since there is a clock on the data then there is inherent jitter in the interface. USB on the other hand only has data and therefore the jitter is only injected in the receiver which can be managed really well especially using Asynchronous mode USB.

4) A transport or CD player cannot go back and re-read errors when it has a problem with the disk. A computer re-reads the data and stores and error free copy on the hard drive. That copy is free of jitter and errors and can then be copied, stored and backup forever.

5) Sure you can put all the ports you want on a dac.... but then you are making compromises. If you have either SPDIF or USB then at least you can tackle the demons of one or the other.

Chris is right in the aspect that not all dac's are created equal. You can have equally bad or good dacs with either technology.

Thanks

Gordon

Hi Bluedy - I have heard of the Hagerman products, but I've never really listened to them or looked over the specs very well. You will be very happy with the DAC1 Pre. If you don't need the analog inputs you may also want to consider the DAC1 USB which has an AES input in addition to the others. This would allow you to output 24/192 with a Lynx card and Mac Pro is you every want to. Just a thought.

Thanks for the kind words about the site Bluedy!