On Wed, 30 Jun 2004 02:14:38 GMT, Jim wrote:

(Marcus) wrote in
:

Suppose the DACs are based on (DAC) ICs, what differentiates the
various DACs? I knid of believe there is not much left for the DAC
designers to play with. The ICs pretty much are all that matters.

Absolutely correct.

Absolutely wrong! The main differentiator in modern standalone DACs is
how they handle the incoming bitstream. See the Benchmark DAC-1 for a
prime example of how this should be done. Please note that this DAC is
about as close to perfection as we'll ever see, and it costs less than
$1,000. Compare and contrast with the rubbish being sold at many times
this price by so-called 'high end' companies like Mark Levinson and
Audio Note.

There are also DACs based on discrete devices. How do they compete
with ICs from big players like Analog Devices, etc.?

In a nutshell, they can't.

Um, not necessarily true. Indeed, one of the most highly linear DACs
on the pro market, the dCS RingDAC, uses a discrete hybrid solution.

To get even close to 16-bit resolution, a DAC
made from disretes requires *very carefully* hand selected components
($$$), and probably can't maintain that resolution over temperature.

No, this assumes a full multi-bit DAC, which is not the norm today.

A
hybrid using laser-trimmed components does better, but why bother because
an integrated DAC's "components" are inherently matched and maintain the
same relative ratios to one another over temperature. The fact that a
discrete design is spread out over a substantial area means capacitance
and that makes the design of switching circuits difficult, so don't count
on all the bits settling at the same time.

Alternatively, use a high-oversampling design with 5 bits or less, and
such problems largely go away. They are of course replaced by
precision timing concerns, but the performance of modern 'low bit'
designs (both discrete and integrated) is proving the point that 'less
is more' when it comes to DAC design!
--

Stewart Pinkerton | Music is Art - Audio is Engineering