Re: Sound quality question

"Chris27" <chris@[EMAIL PROTECTED]
> wrote in message

> Get an external USB DAC and it will offer much better
> sound quality than an internal card.

Some of the quietest audio interfaces around (e.g. LynxTWO) are PCI cards.
I 
know of no external converter that outperforms the best PCI cards. Can you

name one?

> The power supplies
> inside PCs are so noisy compared to an external USB DAC,

But, PC power supplies are inside a steel box and all the connections
going 
in and out are heavily bypassed.

Furthermore, the unique noise frequencies due to a PC power supply are all

ultrasonic.

Switchmode power supplies provide better isolation of power line 
disturbances than linear power supplies. A wide range of high quality
audio 
gear now uses switchmode power supplies.

It has long been known that the limitation to the noise of mixed-signal 
circuitry like a DAC is dependent on chip and circuit board design. 
Mixed-mode circuit design used to be a black art, but now most of the 
techniques are published.

Historically, USB DACs have been lower cost devices, with lower quality 
DACs. Often, the DAC, ADC, and USB interface are all in one chip.  Noise 
transmission within the chip is the final frontier.

Also, most USB gear is powered by the USB cable which is connected to one
of 
those much-maligned PC power supplies. Partciularly in the case of
laptops, 
we sometimes find that noise and grounding problems from the laptop can 
affect the operation of external audio interfaces.

There's no reason why a USB DAC couldn't be as quiet as a PCI DAC. I
suspect 
that for example, the Emu 0404 preforms about as well as a Lynx, is far
less 
expensive, and includes some pretty fair analog interfaces.

But the best possible USB data interface can't be as fast and realiable as
a 
well-designed and programmed PCI or PCI-E data interface that is inside a 
computer. Stereo is easy, multichannel can be far more stressful.

Bottom line - choose audio gear based on how it works, not the details of 
how it is made.