I am looking for an sound card that features dual DA converters in parallel.
Does anyone know of one?
tia
r


--
Nothing beats the bandwidth of a station wagon filled with DLT tapes.

"R" wrote in message

I am looking for an sound card that features dual DA converters in
parallel.
Does anyone know of one?
tia
r

Turtle Beach.

"Schizoid Man" wrote in news:cpo6ji$7jj$1
@geraldo.cc.utexas.edu:


"R" wrote in message

I am looking for an sound card that features dual DA converters in
parallel.
Does anyone know of one?
tia
r

Turtle Beach.




It is not apparant that any of the models have two d-a converters running
in parallel.

r


--
Nothing beats the bandwidth of a station wagon filled with DLT tapes.

"R" wrote in message
. 1
I am looking for an sound card that features dual DA converters in
parallel. Does anyone know of one?

Please explain more precisely what you mean.

On Wed, 15 Dec 2004 01:51:43 GMT, R wrote:

I am looking for an sound card that features dual DA converters in parallel.
Does anyone know of one?

You mean you want more than one stereo output? Sure. All the makers
of quality cards offer multichannel ones. M-Audio, Echo etc. etc.

"George M. Middius" wrote in message
...


Robot said:

I am looking for an sound card that features dual DA converters in
parallel.

Do you need the second DAC to feed your positronic chip?

Maybe he is capturing imaginary music that will result
in complex numbers for the samples.

"R" wrote ...
I am looking for an sound card that features dual DA
converters in parallel. Does anyone know of one?

You wanna try that again?

Are you trying to solve some problem?
I've never seen a computer sound card that *didn't* have
at least two channels (i.e. "stereo")

Why do you think there is something "magic" about
"in parallel"?

"Arny Krueger" wrote in news:QN2dnU2d2-ywhV3cRVn-
:

"R" wrote in message
. 1
I am looking for an sound card that features dual DA converters in
parallel. Does anyone know of one?

Please explain more precisely what you mean.



Arny,

What I mean by parallel is that the data stream for one channel feeds 2 dacs
at once and the resultant output of the dacs are tied together. Many of the
high end CD players and D-A units use that circuit topology as it lowers the
distortion levels.

Adding a second D-A to a sound card in the field would be very difficult at
best.

r

"Richard Crowley" wrote in news:10s0v9njpd1hha7
@corp.supernews.com:

"R" wrote ...
I am looking for an sound card that features dual DA
converters in parallel. Does anyone know of one?

You wanna try that again?

Are you trying to solve some problem?
I've never seen a computer sound card that *didn't* have
at least two channels (i.e. "stereo")

Why do you think there is something "magic" about
"in parallel"?



Not solving a problem per se, but I am trying to sort out which sound card I
might be happy with. Many of the common sound cards sound a bit harsh or
have some sort of "digital grunge" or both. The magic is that two DACs in
parallel lowers distortion. Proper chip decoupling lowers "digital grunge".

r

On Wed, 15 Dec 2004 22:45:20 GMT, "Rich.Andrews"
wrote:

"Arny Krueger" wrote in news:QN2dnU2d2-ywhV3cRVn-
:

"R" wrote in message
. 1
I am looking for an sound card that features dual DA converters in
parallel. Does anyone know of one?

Please explain more precisely what you mean.


Arny,

What I mean by parallel is that the data stream for one channel feeds 2 dacs
at once and the resultant output of the dacs are tied together. Many of the
high end CD players and D-A units use that circuit topology as it lowers the
distortion levels.

You don't mean parallel, you mean a differential pair. Given that
distortion levels with conventional DACs can be 0.001% or less, do you
think this is important?

Adding a second D-A to a sound card in the field would be very difficult at
best.

Try a Lynx sound card, you will find no 'digital grunge' there. The
LynxOne is perhaps the best stereo sound card available, while the
LynxTwo-A will give you what you asked for - four channels with
balanced outputs.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Stewart Pinkerton wrote in
:

On Wed, 15 Dec 2004 22:45:20 GMT, "Rich.Andrews"
wrote:

"Arny Krueger" wrote in news:QN2dnU2d2-ywhV3cRVn-
:

"R" wrote in message
. 1
I am looking for an sound card that features dual DA converters in
parallel. Does anyone know of one?

Please explain more precisely what you mean.


Arny,

What I mean by parallel is that the data stream for one channel feeds 2
dacs
at once and the resultant output of the dacs are tied together. Many of
the
high end CD players and D-A units use that circuit topology as it lowers
the
distortion levels.

You don't mean parallel, you mean a differential pair. Given that
distortion levels with conventional DACs can be 0.001% or less, do you
think this is important?



I don't think i mean a differential pair. Wuld not a differential pair be
2 dacs fed with the same source but one dac has it's invert pin asserted?

r


--
Nothing beats the bandwidth of a station wagon filled with DLT tapes.

"Rich.Andrews" wrote in message


What I mean by parallel is that the data stream for one channel feeds
2 dacs at once and the resultant output of the dacs are tied
together. Many of the high end CD players and D-A units use that
circuit topology as it lowers the distortion levels.

Seems like a total waste, given the rediculously-low distortion levels
already obtained by more conventional means.

What a concept - use a better converter!

Adding a second D-A to a sound card in the field would be very difficult
at best.

Agreed.

"Rich.Andrews" wrote in message


Not solving a problem per se, but I am trying to sort out which sound
card I might be happy with. Many of the common sound cards sound a
bit harsh or have some sort of "digital grunge" or both. The magic
is that two DACs in parallel lowers distortion. Proper chip
decoupling lowers "digital grunge".

Digital grunge is a marketing term with no real-world significance, in the
21st century world of top-quality converters.

Since I can run audio through a computer 20 times in a row without any
audible change as shown in the files from

http://www.pcabx.com/product/cardd_deluxe/index.htm

we have adequate proof that digital grunge is no longer a real-world
problem.

"R" wrote in message

Stewart Pinkerton wrote in
:

On Wed, 15 Dec 2004 22:45:20 GMT, "Rich.Andrews"
wrote:

What I mean by parallel is that the data stream for one channel
feeds 2 dacs at once and the resultant output of the dacs are tied
together. Many of the high end CD players and D-A units use that
circuit topology as it lowers the distortion levels.

Thinking back for a while, I remember the days when doubling up DAC chips
was sorta popular.

There was even a tweak that stacked two DAC chips on top of each other. This
kinda worked because many DAC chhips of the era had high impedance outputs,
so that their outputs were summed at the input to the following stage.

The net effect was that the output voltage was doubled (6 dB), while any
internally generated uncorrelated noise increased by only 3 dB.

However, the effects of running the sucessive stages at twice the signal
voltage were, err *unspecified*.

I never saw any technical tests that quantified the actual results. Of
course we had the usual "sounds better" garbage from the peanut gallery.

You don't mean parallel, you mean a differential pair. Given that
distortion levels with conventional DACs can be 0.001% or less, do
you think this is important?

Of course, the whole approach is rediculous and futile and turned out to
pretty much be yet another passing fancy of tweakdumb.

I don't think i mean a differential pair. Wuld not a differential
pair be 2 dacs fed with the same source but one dac has it's invert
pin asserted?

This would be the better idea (in a land of futile non-thinking) because it
would eliminate such vanishing amounts of even order distortion as there
might be in the analog side of a quality DAC. Internally uncorrelated noise
would also be reduced, such as it might be.

Right now the better DAC chips are among the most precise of all audio
circuits. In production quantities I understand they run about $30. The real
challenge is finding op amps that will accurately deliver their performance
to the output terminals. Furthermore, if you look at the performance of
commodity DAC chips running about $1 or less, they are often as good or
better than the media being played.

"Arny Krueger" wrote in
:

"R" wrote in message

Stewart Pinkerton wrote in
:

On Wed, 15 Dec 2004 22:45:20 GMT, "Rich.Andrews"
wrote:

What I mean by parallel is that the data stream for one channel
feeds 2 dacs at once and the resultant output of the dacs are tied
together. Many of the high end CD players and D-A units use that
circuit topology as it lowers the distortion levels.

Thinking back for a while, I remember the days when doubling up DAC
chips was sorta popular.


It is still done today by at least one manufacturer.

r


--
Nothing beats the bandwidth of a station wagon filled with DLT tapes.

In practice we take the one output and split it.

--

Jerry G.
======


"R" wrote in message
. 1...
I am looking for an sound card that features dual DA converters in parallel.
Does anyone know of one?
tia
r


--
Nothing beats the bandwidth of a station wagon filled with DLT tapes.

"R" wrote in message
. 1
"Arny Krueger" wrote in
:

"R" wrote in message

Stewart Pinkerton wrote in
:

On Wed, 15 Dec 2004 22:45:20 GMT, "Rich.Andrews"
wrote:

What I mean by parallel is that the data stream for one channel
feeds 2 dacs at once and the resultant output of the dacs are tied
together. Many of the high end CD players and D-A units use that
circuit topology as it lowers the distortion levels.

Thinking back for a while, I remember the days when doubling up DAC
chips was sorta popular.


It is still done today by at least one manufacturer.

Down from how many at the peak of this particular weirdness?

On Thu, 16 Dec 2004 07:20:41 GMT, R wrote:

Stewart Pinkerton wrote in
:

On Wed, 15 Dec 2004 22:45:20 GMT, "Rich.Andrews"
wrote:

"Arny Krueger" wrote in news:QN2dnU2d2-ywhV3cRVn-
:

"R" wrote in message
. 1
I am looking for an sound card that features dual DA converters in
parallel. Does anyone know of one?

Please explain more precisely what you mean.


Arny,

What I mean by parallel is that the data stream for one channel feeds 2 dacs
at once and the resultant output of the dacs are tied together. Many of the
high end CD players and D-A units use that circuit topology as it lowers the
distortion levels.

You don't mean parallel, you mean a differential pair. Given that
distortion levels with conventional DACs can be 0.001% or less, do you
think this is important?

I don't think i mean a differential pair. Wuld not a differential pair be
2 dacs fed with the same source but one dac has it's invert pin asserted?

Essentially yes, and this is a classic method of averaging errors
between the two DACs.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

"Stewart Pinkerton" wrote in message

On Thu, 16 Dec 2004 07:20:41 GMT, R wrote:

Stewart Pinkerton wrote in
:

On Wed, 15 Dec 2004 22:45:20 GMT, "Rich.Andrews"
wrote:

"Arny Krueger" wrote in
news:QN2dnU2d2-ywhV3cRVn- :

"R" wrote in message
. 1
I am looking for an sound card that features dual DA converters
in parallel. Does anyone know of one?

Please explain more precisely what you mean.


Arny,

What I mean by parallel is that the data stream for one channel
feeds 2 dacs at once and the resultant output of the dacs are
tied together. Many of the high end CD players and D-A units use
that circuit topology as it lowers the distortion levels.

You don't mean parallel, you mean a differential pair. Given that
distortion levels with conventional DACs can be 0.001% or less, do
you think this is important?

I don't think i mean a differential pair. Wuld not a differential
pair be 2 dacs fed with the same source but one dac has it's invert
pin asserted?

Invert pins are kinda like historical artifacts on modern audio DACs.

This goes back to no later than the acension of sigma-delta DACs which
nearly totally dominate the present market for SOTA audio DACs.

Essentially yes, and this is a classic method of averaging errors
between the two DACs.

The real problem with this proposed solution is that modern DACs are highly
deterministic and tend to lack symetrical errors.

In fact, more benefit might come from operating the op amp buffers in a
balanced configuration. Many better audio DACs have + and - outputs.

In rec.audio.tech R wrote:
Stewart Pinkerton wrote in
:

On Wed, 15 Dec 2004 22:45:20 GMT, "Rich.Andrews"
wrote:

"Arny Krueger" wrote in news:QN2dnU2d2-ywhV3cRVn-
:

"R" wrote in message
. 1
I am looking for an sound card that features dual DA converters in
parallel. Does anyone know of one?

Please explain more precisely what you mean.


Arny,

What I mean by parallel is that the data stream for one channel feeds 2
dacs
at once and the resultant output of the dacs are tied together. Many of
the
high end CD players and D-A units use that circuit topology as it lowers
the
distortion levels.

You don't mean parallel, you mean a differential pair. Given that
distortion levels with conventional DACs can be 0.001% or less, do you
think this is important?

I don't think i mean a differential pair. Wuld not a differential pair be
2 dacs fed with the same source but one dac has it's invert pin asserted?

Can someone tell me what the difference is here?

Summing the output of two DACs should give "s1 + s2".
A differential pair, as I understand it, would be "s1 - (-s2)"

I don't see a difference. Am I missing something?

"Colin B." wrote in message

In rec.audio.tech R wrote:
Stewart Pinkerton wrote in
:

On Wed, 15 Dec 2004 22:45:20 GMT, "Rich.Andrews"
wrote:

"Arny Krueger" wrote in
news:QN2dnU2d2-ywhV3cRVn- :

"R" wrote in message
. 1
I am looking for an sound card that features dual DA converters
in parallel. Does anyone know of one?

Please explain more precisely what you mean.


Arny,

What I mean by parallel is that the data stream for one channel
feeds 2 dacs at once and the resultant output of the dacs are tied
together. Many of the high end CD players and D-A units use that
circuit topology as it lowers the distortion levels.

You don't mean parallel, you mean a differential pair. Given that
distortion levels with conventional DACs can be 0.001% or less, do
you think this is important?

I don't think i mean a differential pair. Wuld not a differential
pair be 2 dacs fed with the same source but one dac has it's invert
pin asserted?

Can someone tell me what the difference is here?

Summing the output of two DACs should give "s1 + s2".
A differential pair, as I understand it, would be "s1 - (-s2)"

I don't see a difference. Am I missing something?

Your algebra is correct for a simpler case, but it ignores the inversion of
the digital input, and the effect of that inversion on distortion.

On Wed, 15 Dec 2004 23:06:54 GMT, "Rich.Andrews"
wrote:

Not solving a problem per se, but I am trying to sort out which sound card I
might be happy with. Many of the common sound cards sound a bit harsh or
have some sort of "digital grunge" or both. The magic is that two DACs in
parallel lowers distortion. Proper chip decoupling lowers "digital grunge".

There are good and bad-sounding cards out there. But I wouldn't
worry too much about this particular bit of snake-oil. You've picked
it up from an audiophile review or advert? Come on over to the pro
audio world. You can still spend a lot of money if you insist, but
you'll get more for it than in the audiophile arena :-)

"Arny Krueger" wrote in news:jNSdnfAzYIQMIVzcRVn-
:

"R" wrote in message
. 1
"Arny Krueger" wrote in
:

"R" wrote in message

Stewart Pinkerton wrote in
:

On Wed, 15 Dec 2004 22:45:20 GMT, "Rich.Andrews"
wrote:

What I mean by parallel is that the data stream for one channel
feeds 2 dacs at once and the resultant output of the dacs are tied
together. Many of the high end CD players and D-A units use that
circuit topology as it lowers the distortion levels.

Thinking back for a while, I remember the days when doubling up DAC
chips was sorta popular.


It is still done today by at least one manufacturer.

Down from how many at the peak of this particular weirdness?




I don't believe the count is relevant. The point is that putting two dacs
in parallel lowers distortion and I feel that if I am going to spend some
money, I might as well spend a bit more and get the best.

r

"Colin B." wrote in
:

In rec.audio.tech R wrote:
Stewart Pinkerton wrote in
:

On Wed, 15 Dec 2004 22:45:20 GMT, "Rich.Andrews"
wrote:

"Arny Krueger" wrote in news:QN2dnU2d2-ywhV3cRVn-
:

"R" wrote in message
. 1
I am looking for an sound card that features dual DA converters in
parallel. Does anyone know of one?

Please explain more precisely what you mean.


Arny,

What I mean by parallel is that the data stream for one channel feeds
2
dacs
at once and the resultant output of the dacs are tied together. Many
of
the
high end CD players and D-A units use that circuit topology as it
lowers
the
distortion levels.

You don't mean parallel, you mean a differential pair. Given that
distortion levels with conventional DACs can be 0.001% or less, do you
think this is important?

I don't think i mean a differential pair. Wuld not a differential pair
be 2 dacs fed with the same source but one dac has it's invert pin
asserted?

Can someone tell me what the difference is here?

Summing the output of two DACs should give "s1 + s2".
A differential pair, as I understand it, would be "s1 - (-s2)"

I don't see a difference. Am I missing something?


As I see it, in a balanced audio setup the positive dac output would be
the plus side and the inverted dac output would be the negative side. The
common mode noise would be diminished in such a configuration.

In the configuration I am referring to, it would e a simple single ended
unbalanced output but with 2 dacs sharing inputs and outputs.


r

Laurence Payne wrote in
:

On Wed, 15 Dec 2004 23:06:54 GMT, "Rich.Andrews"
wrote:

Not solving a problem per se, but I am trying to sort out which sound
card I might be happy with. Many of the common sound cards sound a bit
harsh or have some sort of "digital grunge" or both. The magic is that
two DACs in parallel lowers distortion. Proper chip decoupling lowers
"digital grunge".

There are good and bad-sounding cards out there. But I wouldn't
worry too much about this particular bit of snake-oil. You've picked
it up from an audiophile review or advert? Come on over to the pro
audio world. You can still spend a lot of money if you insist, but
you'll get more for it than in the audiophile arena :-)


I have actually picked it up from reviewing schematics of CD players and
stand alone DACs that I own or have considered owning.

r

"Rich.Andrews" wrote in message



I don't believe the count is relevant. The point is that putting two
dacs in parallel lowers distortion and I feel that if I am going to
spend some money, I might as well spend a bit more and get the best.

In audio interfaces, AFAIK "The Best" is the LynxTWO.

"Stewart Pinkerton" wrote in message
...
On Thu, 16 Dec 2004 07:20:41 GMT, R wrote:

Stewart Pinkerton wrote in
:

On Wed, 15 Dec 2004 22:45:20 GMT, "Rich.Andrews"

wrote:

"Arny Krueger" wrote in
news:QN2dnU2d2-ywhV3cRVn-
:

"R" wrote in message
. 1
I am looking for an sound card that features dual DA
converters in
parallel. Does anyone know of one?

Please explain more precisely what you mean.


Arny,

What I mean by parallel is that the data stream for one channel
feeds 2 dacs
at once and the resultant output of the dacs are tied together.
Many of the
high end CD players and D-A units use that circuit topology as it
lowers the
distortion levels.

You don't mean parallel, you mean a differential pair. Given that
distortion levels with conventional DACs can be 0.001% or less,
do you
think this is important?

I don't think i mean a differential pair. Wuld not a differential
pair be
2 dacs fed with the same source but one dac has it's invert pin
asserted?

Essentially yes, and this is a classic method of averaging errors
between the two DACs.

If the 2 DACs come from the entire universe of DACs then this will
probably work. But if they come from the same production run or, God
forbid, from the same wafer, the chances are excellent that both DACs
will have errors in exactly the same place--in the same direction.
You could get no benefit from averaging.

Norm Strong

"Arny Krueger" wrote in news:qZ-dnTNPju7CgF_cRVn-
:

"Rich.Andrews" wrote in message



I don't believe the count is relevant. The point is that putting two
dacs in parallel lowers distortion and I feel that if I am going to
spend some money, I might as well spend a bit more and get the best.

In audio interfaces, AFAIK "The Best" is the LynxTWO.




An input impedance of 24 ohms balanced and 12 ohms unbalanced? Isn't that
a bit low?

r


--
Nothing beats the bandwidth of a station wagon filled with DLT tapes.

R wrote:

"Arny Krueger" wrote in news:qZ-dnTNPju7CgF_cRVn-
:

"Rich.Andrews" wrote in message



I don't believe the count is relevant. The point is that putting two
dacs in parallel lowers distortion and I feel that if I am going to
spend some money, I might as well spend a bit more and get the best.

In audio interfaces, AFAIK "The Best" is the LynxTWO.




An input impedance of 24 ohms balanced and 12 ohms unbalanced? Isn't that
a bit low?


Apparently you can't read a spec sheet.

Input Impedance Balanced mode: 24 kW , Unbalanced mode: 12 kW ( the ohms
symbol appears as W in plain text btw ).

http://www.lynxstudio.com/lynxtwospecs.html

IIRC - most modern converters work differentially internally anyway. The
inputs and outputs on the converters I'm currently using are differential and
most others I've looked at are too. Those that are 'single ended' usually have
an internal inverting stage that converts them to internally differential.

You're worrying about non-issues.


Graham

On Thu, 16 Dec 2004 23:12:20 GMT, "Rich.Andrews"
wrote:

There are good and bad-sounding cards out there. But I wouldn't
worry too much about this particular bit of snake-oil. You've picked
it up from an audiophile review or advert? Come on over to the pro
audio world. You can still spend a lot of money if you insist, but
you'll get more for it than in the audiophile arena :-)


I have actually picked it up from reviewing schematics of CD players and
stand alone DACs that I own or have considered owning.

Yeah. But is it a marketing ploy, or is it actually solving a real
problem?

"Arny Krueger" wrote in message
...
"R" wrote in message

Stewart Pinkerton wrote in
:

On Wed, 15 Dec 2004 22:45:20 GMT, "Rich.Andrews"
wrote:

What I mean by parallel is that the data stream for one channel
feeds 2 dacs at once and the resultant output of the dacs are tied
together. Many of the high end CD players and D-A units use that
circuit topology as it lowers the distortion levels.

Thinking back for a while, I remember the days when doubling up DAC chips
was sorta popular.

There was even a tweak that stacked two DAC chips on top of each other.
This kinda worked because many DAC chhips of the era had high impedance
outputs, so that their outputs were summed at the input to the following
stage.

The net effect was that the output voltage was doubled (6 dB), while any
internally generated uncorrelated noise increased by only 3 dB.

Care to explain this voltage doubling claim of yours Arny? I smell more
snake oil than hi-rez in PC/ABX.

ScottW

ScottW wrote:

"Arny Krueger" wrote in message
...
"R" wrote in message

Stewart Pinkerton wrote in
:

On Wed, 15 Dec 2004 22:45:20 GMT, "Rich.Andrews"
wrote:

What I mean by parallel is that the data stream for one channel
feeds 2 dacs at once and the resultant output of the dacs are tied
together. Many of the high end CD players and D-A units use that
circuit topology as it lowers the distortion levels.

Thinking back for a while, I remember the days when doubling up DAC chips
was sorta popular.

There was even a tweak that stacked two DAC chips on top of each other.
This kinda worked because many DAC chhips of the era had high impedance
outputs, so that their outputs were summed at the input to the following
stage.

The net effect was that the output voltage was doubled (6 dB), while any
internally generated uncorrelated noise increased by only 3 dB.

Care to explain this voltage doubling claim of yours Arny? I smell more
snake oil than hi-rez in PC/ABX.

Just stepping in here.....

Those old converter chips were current output. 2 chips = twice the current =
double the voltage for the same output stage following it.

The noise only rises by 3dB since noise isn't a coherent signal ( it's random
). Each converter produces its own random noise so there is an overall
improvement in S/N of 3dB. You need to understand how signals sum to properly
follow this bit.

Standard output voltage can be obtained by halving the feedback resistor value
in the op-amp following the DAC. This helps reduce noise a tiny bit too since
lower value resistors have less thermal noise.

Graham

Arny Krueger wrote:

"Stewart Pinkerton" wrote in message

On Thu, 16 Dec 2004 07:20:41 GMT, R wrote:

Stewart Pinkerton wrote in
:

On Wed, 15 Dec 2004 22:45:20 GMT, "Rich.Andrews"
wrote:

"Arny Krueger" wrote in
news:QN2dnU2d2-ywhV3cRVn- :

"R" wrote in message
. 1
I am looking for an sound card that features dual DA converters
in parallel. Does anyone know of one?

Please explain more precisely what you mean.


Arny,

What I mean by parallel is that the data stream for one channel
feeds 2 dacs at once and the resultant output of the dacs are
tied together. Many of the high end CD players and D-A units use
that circuit topology as it lowers the distortion levels.

You don't mean parallel, you mean a differential pair. Given that
distortion levels with conventional DACs can be 0.001% or less, do
you think this is important?

I don't think i mean a differential pair. Wuld not a differential
pair be 2 dacs fed with the same source but one dac has it's invert
pin asserted?

Invert pins are kinda like historical artifacts on modern audio DACs.

This goes back to no later than the acension of sigma-delta DACs which
nearly totally dominate the present market for SOTA audio DACs.

Essentially yes, and this is a classic method of averaging errors
between the two DACs.

The real problem with this proposed solution is that modern DACs are highly
deterministic and tend to lack symetrical errors.

In fact, more benefit might come from operating the op amp buffers in a
balanced configuration. Many better audio DACs have + and - outputs.

This is the topology I use. I can't recall seeing a recent serious DAC data
sheet that doesn't recommend this method.

Graham

normanstrong wrote:

"Stewart Pinkerton" wrote in message
...
On Thu, 16 Dec 2004 07:20:41 GMT, R wrote:

Stewart Pinkerton wrote in
:

On Wed, 15 Dec 2004 22:45:20 GMT, "Rich.Andrews"

wrote:

"Arny Krueger" wrote in
news:QN2dnU2d2-ywhV3cRVn-
:

"R" wrote in message
. 1
I am looking for an sound card that features dual DA
converters in
parallel. Does anyone know of one?

Please explain more precisely what you mean.


Arny,

What I mean by parallel is that the data stream for one channel
feeds 2 dacs
at once and the resultant output of the dacs are tied together.
Many of the
high end CD players and D-A units use that circuit topology as it
lowers the
distortion levels.

You don't mean parallel, you mean a differential pair. Given that
distortion levels with conventional DACs can be 0.001% or less,
do you
think this is important?

I don't think i mean a differential pair. Wuld not a differential
pair be
2 dacs fed with the same source but one dac has it's invert pin
asserted?

Essentially yes, and this is a classic method of averaging errors
between the two DACs.

If the 2 DACs come from the entire universe of DACs then this will
probably work. But if they come from the same production run or, God
forbid, from the same wafer, the chances are excellent that both DACs
will have errors in exactly the same place--in the same direction.
You could get no benefit from averaging.

Not so. The differences are likely to be 'process related'. No 2 chips
from the same wafer are identical. The method is ( was ) valid.

Graham

Pooh Bear wrote in
:

R wrote:

"Arny Krueger" wrote in news:qZ-dnTNPju7CgF_cRVn-
:

"Rich.Andrews" wrote in message



I don't believe the count is relevant. The point is that putting
two dacs in parallel lowers distortion and I feel that if I am going
to spend some money, I might as well spend a bit more and get the
best.

In audio interfaces, AFAIK "The Best" is the LynxTWO.




An input impedance of 24 ohms balanced and 12 ohms unbalanced? Isn't
that a bit low?


Apparently you can't read a spec sheet.

Input Impedance Balanced mode: 24 kW , Unbalanced mode: 12 kW ( the
ohms symbol appears as W in plain text btw ).

http://www.lynxstudio.com/lynxtwospecs.html

IIRC - most modern converters work differentially internally anyway. The
inputs and outputs on the converters I'm currently using are
differential and most others I've looked at are too. Those that are
'single ended' usually have an internal inverting stage that converts
them to internally differential.

You're worrying about non-issues.


Graham



http://lynxstudio.com/reviews/LynxTWOBrochureLoRes.pdf

Clearly says "Unbalanced Mode: 12 greek omega"

That means 12 ohms, not 12k ohms.

What were you saying about reading a spec sheet?

r

"Colin B." wrote:

In rec.audio.tech R wrote:
Stewart Pinkerton wrote in
:

On Wed, 15 Dec 2004 22:45:20 GMT, "Rich.Andrews"
wrote:

"Arny Krueger" wrote in news:QN2dnU2d2-ywhV3cRVn-
:

"R" wrote in message
. 1
I am looking for an sound card that features dual DA converters in
parallel. Does anyone know of one?

Please explain more precisely what you mean.


Arny,

What I mean by parallel is that the data stream for one channel feeds 2
dacs
at once and the resultant output of the dacs are tied together. Many of
the
high end CD players and D-A units use that circuit topology as it lowers
the
distortion levels.

You don't mean parallel, you mean a differential pair. Given that
distortion levels with conventional DACs can be 0.001% or less, do you
think this is important?

I don't think i mean a differential pair. Wuld not a differential pair be
2 dacs fed with the same source but one dac has it's invert pin asserted?

Can someone tell me what the difference is here?

Summing the output of two DACs should give "s1 + s2".
A differential pair, as I understand it, would be "s1 - (-s2)"

I don't see a difference. Am I missing something?

Yup ! ;-)

The principle assumed a conversion error that had a common factor for a given
digital code input. Typically R-2R ladder types.

The output = ( sig1 + error ) - ( -sig2 + error )

= sig 1 + sig2 ( and no error ) = 2 x sig1

Modern converters aren't like this.

Graham

"Rich.Andrews" wrote:

"Richard Crowley" wrote in news:10s0v9njpd1hha7
@corp.supernews.com:

"R" wrote ...
I am looking for an sound card that features dual DA
converters in parallel. Does anyone know of one?

You wanna try that again?

Are you trying to solve some problem?
I've never seen a computer sound card that *didn't* have
at least two channels (i.e. "stereo")

Why do you think there is something "magic" about
"in parallel"?



Not solving a problem per se, but I am trying to sort out which sound card I
might be happy with. Many of the common sound cards sound a bit harsh or
have some sort of "digital grunge" or both. The magic is that two DACs in
parallel lowers distortion.

Not any more. In fact modern DACs have voltage outputs so you can't parallel
them like 12+ yr old current output DACs.


Proper chip decoupling lowers "digital grunge".

Actually - proper grounding design is the answer to that problem. I design
pro-audio DSP stuff so I know.


Graham

Laurence Payne wrote:

On Wed, 15 Dec 2004 23:06:54 GMT, "Rich.Andrews"
wrote:

Not solving a problem per se, but I am trying to sort out which sound card I
might be happy with. Many of the common sound cards sound a bit harsh or
have some sort of "digital grunge" or both. The magic is that two DACs in
parallel lowers distortion. Proper chip decoupling lowers "digital grunge".

There are good and bad-sounding cards out there. But I wouldn't
worry too much about this particular bit of snake-oil. You've picked
it up from an audiophile review or advert?

I think you can probably catch brain illness/malaise from audiophile reviews too
!


Come on over to the pro
audio world. You can still spend a lot of money if you insist, but
you'll get more for it than in the audiophile arena :-)

Pros don't mess about with snake oil we just get it right.

Don't forget that everything ever recorded was done on pro-audio gear, not some
audiophool ****.


Graham

Laurence Payne wrote in
:

On Thu, 16 Dec 2004 23:12:20 GMT, "Rich.Andrews"
wrote:

There are good and bad-sounding cards out there. But I wouldn't
worry too much about this particular bit of snake-oil. You've picked
it up from an audiophile review or advert? Come on over to the pro
audio world. You can still spend a lot of money if you insist, but
you'll get more for it than in the audiophile arena :-)


I have actually picked it up from reviewing schematics of CD players and
stand alone DACs that I own or have considered owning.

Yeah. But is it a marketing ploy, or is it actually solving a real
problem?


As far as I am concerned it does make a difference. Don't believe me?
Fine don't. I really don't care. Either the card I am looking for exists
or it doesn't. Unfortunately it appears it does not. So I am going to
have to start from scratch pouring over spec sheets.

The pro cards have more capabilities than what I would ever need but I fear
that they pro cards are geared toward 600 ohm balanced and I need high
impedance (~50k ohm) unbalanced as well as 600 ohms balanced.

r

"Rich.Andrews" wrote:

Pooh Bear wrote in
:

R wrote:

"Arny Krueger" wrote in news:qZ-dnTNPju7CgF_cRVn-
:

"Rich.Andrews" wrote in message



I don't believe the count is relevant. The point is that putting
two dacs in parallel lowers distortion and I feel that if I am going
to spend some money, I might as well spend a bit more and get the
best.

In audio interfaces, AFAIK "The Best" is the LynxTWO.




An input impedance of 24 ohms balanced and 12 ohms unbalanced? Isn't
that a bit low?


Apparently you can't read a spec sheet.

Input Impedance Balanced mode: 24 kW , Unbalanced mode: 12 kW ( the
ohms symbol appears as W in plain text btw ).

http://www.lynxstudio.com/lynxtwospecs.html

IIRC - most modern converters work differentially internally anyway. The
inputs and outputs on the converters I'm currently using are
differential and most others I've looked at are too. Those that are
'single ended' usually have an internal inverting stage that converts
them to internally differential.

You're worrying about non-issues.


Graham



http://lynxstudio.com/reviews/LynxTWOBrochureLoRes.pdf

Clearly says "Unbalanced Mode: 12 greek omega"

That means 12 ohms, not 12k ohms.

What were you saying about reading a spec sheet?

That's a 'printing error' obviously. Input impedances are clearly going to be
kilohms. They ought to get someone to proof read better.

Check my link.

Graham